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  • 1.
    Axelsson, Peter
    et al.
    Univ Gothenburg, Sweden.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Bjorkman, Anders
    Univ Gothenburg, Sweden.
    Hand surgery training in Sweden - bridging the gap between specialities2022In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 47, no 6, p. 669-671Article in journal (Refereed)
    Abstract [en]

    n/a

  • 2.
    Bergkvist, Max
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Henricson, Joakim
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Emergency Medicine in Linköping.
    Bergstrand, Sara
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Nursing Sciences and Reproductive Health. Linköping University, Faculty of Medicine and Health Sciences.
    Strömberg, Tomas
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Droog Tesselaar, Erik
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Assessment of oxygenation with polarized light spectroscopy enables new means for detecting vascular events in the skin2020In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 130, article id 104000Article in journal (Refereed)
    Abstract [en]

    Introduction: Impaired oxygenation in the skin may occur in disease states and after reconstructive surgery. We used tissue viability imaging (TiVi) to measure changes in oxygenation and deoxygenation of haemoglobin in an in vitro model and in the dermal microcirculation of healthy individuals. Materials and methods: Oxygenation was measured in human whole blood with different levels of oxygenation. In healthy subjects, changes in red blood cell concentration (C-RBC,(TiVi)), oxygenation (Delta C-OH,(TiVi)) and deoxygenation (Delta C-DOH,(TiVi)) of haemoglobin were measured during and after arterial and venous occlusion using TiVi and were compared with measurements from the enhanced perfusion and oxygen saturation system (EPOS). Results: During arterial occlusion, C-RBC,(TiVi) remained unchanged while Delta C-OH,(TiVi) decreased to -44.2 (10.4) AU (p = 0.04), as compared to baseline. After release, C-RBC,C-TiVi increased to 39.2 (18.8) AU (p < 0.001), Delta C-OH,C-TiVi increased to 38.5. During venous occlusion, C-RBC,C-TiVi increased to 28.9 (11.2) AU (p < 0.001), Delta C-OH,C-TiVi decreased to -52.2 (46.1) AU (p < 0.001) compared to baseline after 5 min of venous occlusion. There was a significant correlation between the TiVi Oxygen Mapper and EPOS, for arterial (r = 0.92, p < 0.001) and venous occlusion (r = 0.87, p < 0.001), respectively. Conclusion: This study shows that TiVi can measure trends in oxygenation and deoxygenation of haemoglobin during arterial and venous stasis in healthy individuals.

  • 3.
    Bergkvist, Max
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Henricson, Joakim
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Iredahl, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Assessment of microcirculation of the skin using Tissue Viability Imaging: A promising technique for detecting venous stasis in the skin2015In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 101, p. 20-25Article in journal (Refereed)
    Abstract [en]

    Background: : Venous occlusion in the skin is difficult to detect by existing measurement techniques. Our aim was to find out whether Tissue Viability Imaging (TiVi) was better at detecting venous occlusion by comparing it with results of laser Doppler flowmetry (LDF) during graded arterial and venous stasis in human forearm skin. Methods: : Arterial and venous occlusions were simulated in 10 healthy volunteers by inflating a blood pressure cuff around the upper right arm. Changes in the concentration of red blood cells (RBC) were measured using TiVi, while skin perfusion and concentration of moving red blood cells (CMBC) were measured using static indices of LDF during exsanguination and subsequent arterial occlusion, postocclusive reactive hyperaemia, and graded increasing and decreasing venous stasis. Results: : During arterial occlusion there was a significant reduction in the mean concentration of RBC from baseline, as well as in perfusion and CMBC (p less than 0.008). Venous occlusion resulted in a significant 28% increase in the concentration of RBC (p = 0.002), but no significant change in perfusion (mean change -14%) while CMBC decreased significantly by 24% (p = 0.02). With stepwise increasing occlusion pressures there was a significant rise in the TiVi index and reduction in perfusion (p = 0.008), while the reverse was seen when venous flow was gradually restored. Conclusion: : The concentration of RBC measured with TiVi changes rapidly and consistently during both total and partial arterial and venous occlusions, while the changes in perfusion, measured by LDF, were less consistent This suggests that TiVi could be a more useful, non-invasive clinical monitoring tool for detecting venous stasis in the skin than LDF.

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  • 4.
    Bergkvist, Max
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Zötterman, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Henricson, Joakim
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Dermatology and Venerology.
    Iredahl, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Vascular Occlusion in a Porcine Flap Model: Effects on Blood Cell Concentration and Oxygenation.2017In: Plastic and Reconstructive Surgery - Global Open, E-ISSN 2169-7574, Vol. 5, no 11, article id e1531Article in journal (Refereed)
    Abstract [en]

    Background: Venous congestion in skin flaps is difficult to detect. This study evaluated the ability of tissue viability imaging (TiVi) to measure changes in the concentration of red blood cells (CRBC), oxygenation, and heterogeneity during vascular provocations in a porcine fasciocutaneous flap model.

    Methods: In 5 pigs, cranial gluteal artery perforator flaps were raised (8 flaps in 5 pigs). The arterial and venous blood flow was monitored with ultrasonic flow probes. CRBC, tissue oxygenation, and heterogeneity in the skin were monitored with TiVi during baseline, 50% and 100% venous occlusion, recovery, 100% arterial occlusion and final recovery, thereby simulating venous and arterial occlusion of a free fasciocutaneous flap. A laser Doppler probe was used as a reference for microvascular perfusion in the flap.

    Results: During partial and complete venous occlusion, increases in CRBC were seen in different regions of the flap. They were more pronounced in the distal part. During complete arterial occlusion, CRBC decreased in all but the most distal parts of the flap. There were also increases in tissue oxygenation and heterogeneity during venous occlusion.

    Conclusions: TiVi measures regional changes in CRBC in the skin of the flap during arterial and venous occlusion, as well as an increase in oxygenated hemoglobin during venous occlusion that may be the result of reduced metabolism and impaired delivery of oxygen to the tissue. TiVi may provide a promising method for measuring flap viability because it is hand-held, easy to-use, and provides spatial information on venous congestion.

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  • 5.
    Booij, Ronald
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Department of Radiology & Nuclear Medicine, Erasmus MC, The Netherlands.
    Sandstedt, Mårten
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Droog Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Photon-counting detector computed tomography (PCD-CT) – an emerging technology in hand and wrist imaging2023In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 48, no 5, p. 489-494Article in journal (Other academic)
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  • 6.
    Brown, Daniel J.
    et al.
    Univ Hosp NHS Fdn Trust, England; Univ Liverpool, England.
    Redfern, James A. I.
    Univ Hosp NHS Fdn Trust, England; Univ Liverpool, England.
    Silver, Natan
    Univ Hosp NHS Fdn Trust, England.
    Estfan, Rami
    Southend Univ Hosp Mid & South Essex NHS Trust, England.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Mcguire, Duncan
    Groote Schuur Hosp, South Africa.
    Solomons, Michael
    Groote Schuur Hosp, South Africa.
    Thorvaldson, K. Thomas
    Univ Newcastle, Australia.
    Learning curves in Motec total wrist arthroplasty: an international cohort study2023In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289Article in journal (Other academic)
    Abstract [en]

    We examined the learning curve of Motec total wrist arthroplasty (TWA) of six experienced surgeons in their first 30 cases. Three times more complications/revisions were encountered in the first half of the study compared with the second half. Motec TWA surgery should be concentrated in a smaller number of centres performing higher volumes.

  • 7.
    Detert, Hedvig
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Faculty of Medicine and Health Sciences.
    Karlernäs, Astrid
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Rubensson, Carin
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Nyman, Erika
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Microcirculatory response to cold stress test in the healthy hand2023In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 148, article id 104540Article in journal (Refereed)
    Abstract [en]

    Objective: Cold sensitivity of the fingers is common in several conditions. It has been linked to digital vasospasm, microvascular dysfunction, and neural mechanisms. This study aimed to investigate the normal digital micro-vascular response to a cold stress test in healthy individuals using Laser Speckle Contrast Imaging (LSCI).Methods: Twenty-six healthy individuals, mean age 31 (SD 9) years were included. Skin perfusion of digits II-V was measured using Laser Speckle Contrast Imaging before and after a standardized cold stress test. Changes in skin perfusion from baseline were analyzed between hands, digits, and sexes.Results: Skin perfusion was significantly (p < 0.0001) affected by cold provocation in both the cold exposed and the contralateral hands in all participants of the study. This effect was significantly different between the radial (digit II and III) and the ulnar (digit V) side of the hands (p < 0.001). There was a trend towards a larger decrease in perfusion in men (ns), and a faster recovery to baseline values in women (ns). A larger inter subject variability was seen in perfusion values in women.Conclusions: The normal microvascular response to cold provocation may involve both centrally and regionally mediated processes. When exposing one hand to a cold stress test, the contralateral hand responds with simul-taneous but smaller decreases in perfusion.

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  • 8.
    Droog Tesselaar, Erik
    et al.
    Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Flejmer, Anna M.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Oncology.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Dasu, Alexandru
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. The Skandion Clinic, Uppsala, Sweden.
    Changes in skin microcirculation during radiation therapy for breast cancer2017In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 56, no 8, p. 1072-1080Article in journal (Refereed)
    Abstract [en]

    Abstract:

    Background: The majority of breast cancer patients who receive radiation treatment are affected by acute radiation-induced skin changes. The assessment of these changes is usually done by subjective methods, which complicates the comparison between different treatments or patient groups. This study investigates the feasibility of new robust methods for monitoring skin microcirculation to objectively assess and quantify acute skin reactions during radiation treatment.

    Material and methods: Laser Doppler flowmetry, laser speckle contrast imaging, and polarized light spectroscopy imaging were used to measure radiation-induced changes in microvascular perfusion and red blood cell concentration (RBC) in the skin of 15 patients undergoing adjuvant radiation therapy for breast cancer. Measurements were made before treatment, once a week during treatment, and directly after the last fraction.

    Results: In the treated breast, perfusion and RBC concentration were increased after 1–5 fractions (2.66–13.3 Gy) compared to baseline. The largest effects were seen in the areola and the medial area. No changes in perfusion and RBC concentration were seen in the untreated breast. In contrast, Radiation Therapy Oncology Group (RTOG) scores were increased only after 2 weeks of treatment, which demonstrates the potential of the proposed methods for early assessment of skin changes. Also, there was a moderate to good correlation between the perfusion (r = 0.52) and RBC concentration (r = 0.59) and the RTOG score given a week later.

    Conclusion: We conclude that radiation-induced microvascular changes in the skin can be objectively measured using novel camera-based techniques before visual changes in the skin are apparent. Objective measurement of microvascular changes in the skin may be valuable in the comparison of skin reactions between different radiation treatments and possibly in predicting acute skin effects at an earlier stage.

  • 9.
    Elawa, Sherif
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Fredriksson, Ingemar
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. Perimed AB, Järfälla, Stockholm, Sweden.
    Steinvall, Ingrid
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Zötterman, Johan
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Droog Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Skin perfusion and oxygen saturation after mastectomy and radiation therapy in breast cancer patients2024In: Breast, ISSN 0960-9776, E-ISSN 1532-3080, Vol. 75, article id 103704Article in journal (Refereed)
    Abstract [en]

    The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate - MN). Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th-75th centile 0.59-1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th-75th centile 0.21-0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th-75th centile 89-94 % compared to 89 % 25th-75th centile 77-93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall. These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation.

  • 10.
    Elawa, Sherif
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Mirdell, Robin
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Skin blood flow response to topically applied methyl nicotinate: Possible mechanisms2020In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 26, no 3, p. 343-348Article in journal (Refereed)
    Abstract [en]

    Background Methyl nicotinate (MN) induces a local cutaneous erythema in the skin and may be valuable as a local provocation in the assessment of microcirculation and skin viability. The mechanisms through which MN mediates its vascular effect are not fully known. The aim of this study was to characterize the vasodilatory effects of topically applied MN and to study the involvement of nitric oxide (NO), local sensory nerves, and prostaglandin-mediated pathways. Methods MN was applied on the skin of healthy subjects in which NO-mediated (L-NMMA), nerve-mediated (lidocaine/prilocaine), and cyclooxygenase-mediated (NSAID) pathways were selectively inhibited. Microvascular responses in the skin were measured using laser speckle contrast imaging (LSCI). Results NSAID reduced the MN-induced perfusion increase with 82% (P &lt; .01), whereas lidocaine/prilocaine reduced it with 32% (P &lt; .01). L-NMMA did not affect the microvascular response to MN. Conclusion The prostaglandin pathway and local sensory nerves are involved in the vasodilatory actions of MN in the skin.

  • 11.
    Elawa, Sherif
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Mirdell, Robin
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Clinical Chemistry and Pharmacology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Chemistry.
    Stefanis, Aristotelis
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Droog Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Microcirculatory changes in the skin after postmastectomy radiotherapy in women with breast cancer2024In: Scientific Reports, E-ISSN 2045-2322, Vol. 14, no 1, article id 4149Article in journal (Refereed)
    Abstract [en]

    Postmastectomy radiotherapy (PMRT) increases the risk for complications after breast reconstruction. The pathophysiological mechanism underlying this increased risk is not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion in the skin directly after, and at 2 and 6 months after PMRT and to assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate-MN) after PMRT. Skin microvascular responses after PMRT were measured on two sites in the irradiated chest wall of 22 women before, immediately after, and at 2 and 6 months after unilateral PMRT with the contralateral breast as a control. A significant increase in basal skin perfusion was observed in the irradiated chest wall immediately after RT (p < 0.0001). At 2 and 6 months after RT, there was no longer a difference in basal skin perfusion compared to the contralateral breast and compared to baseline. Similarly, the blood flow response in the skin after application of MN was stronger immediately after RT compared to before RT (p < 0.0001), but there was no difference at later time points. These results indicate that the increased risk for complications after surgical procedures are not directly related to changes in skin perfusion and microvascular responsiveness observed after postmastectomy RT.

  • 12.
    Elawa, Sherif
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Mirdell, Robin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    The microvascular response in the skin to topical application of methyl nicotinate: Effect of concentration and variation between skin sites2019In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 124, p. 54-60Article in journal (Refereed)
    Abstract [en]

    Background

    Methyl nicotinate (MN) induces a local cutaneous erythema in the skin and may be used as a local provocation in the assessment of microcirculation and skin viability. The aims were to measure the effects of increasing doses of MN, to find the concentration that yields the most reproducible effect from day to day and between sites, and to study the variation between skin sites.

    Methods

    Microvascular responses to topically applied MN at different concentrations were measured in 12 subjects on separate days and on contralateral sides, using laserspeckle contrast imaging (LSCI). MN effects were measured in four different body sites.

    Results

    At 20 mmol/L, the response to MN was most reproducible day-to-day and site-to-site, and resulted in a plateau response between 5 and 20 min after application.

    The skin region of the lower back had a lower perfusion value compared to the epigastric region (p = 0.007). When responses were compared to nearby, unprovoked areas, a significantly larger increase in perfusion was seen in the forearm, compared to all other anatomical sites (p < 0.03).

    Conclusion

    A concentration of 20 mmol/L MN generated the most reproducible microvascular response in the skin. The response varies between different body sites.

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  • 13.
    Elmasry, Moustafa
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Plastic Surgery Unit, Surgery Department, Suez Canal University, Egypt.
    Mirdell, Robin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Medical and Health Sciences.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Steinvall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Laser speckle contrast imaging in children with scalds: Its influence on timing of intervention, duration of healing and care, and costs2019In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 45, no 4, p. 798-804Article in journal (Refereed)
    Abstract [sv]

    Background

    Scalds are the most common type of burn injury in children, and the initial evaluation of burn depth is a problem. Early identification of deep dermal areas that need excision and grafting would save unnecessary visits and stays in hospital. Laser speckle contrast imaging (LSCI) shows promise for the evaluation of this type of burn. The aim of this study was to find out whether perfusion measured with LSCI has an influence on the decision for operation, duration of healing and care period, and costs, in children with scalds.

    Methods

    We studied a group of children with scalds whose wounds were evaluated with LSCI on day 3–4 after injury during the period 2012–2015. Regression (adjustment for percentage total body surface area burned (TBSA%), age, and sex) was used to analyse the significance of associations between degree of perfusion and clinical outcome.

    Results

    We studied 33 children with a mean TBSA% of 6.0 (95% CI 4.4–7.7)%. Lower perfusion values were associated with operation (area under the receiver-operating characteristic curve 0.86, 95% CI 0.73–1.00). The perfusion cut-off with 100% specificity for not undergoing an operation was ≥191 PU units (66.7% sensitivity and 72.7% accurately classified). Multivariable analyses showed that perfusion was independently associated with duration of healing and care period.

    Conclusion

    Lower perfusion values, as measured with LSCI, are associated with longer healing time and longer care period. By earlier identification of burns that will be operated, perfusion measurements may further decrease the duration of care of burns in children with scalds.

  • 14.
    Engstrand, Fredrik
    et al.
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Gestblom, Rickard
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Validation of a smartphone application and wearable sensor for measurements of wrist motions2021In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 46, no 10, p. 1057-1063Article in journal (Refereed)
    Abstract [en]

    We developed a smartphone application to measure wrist motion using the mobile devices built-in motion sensors or connecting it via Bluetooth to a wearable sensor. Measurement of wrist motion with this method was assessed in 33 participants on two occasions and compared with those obtained with a standard goniometer. The test-retest reproducibility in healthy individuals ranged from good to excellent (intraclass correlation (ICC) 0.76-0.95) for all motions, both with and without the wearable sensor. These results improved to excellent (ICC 0.90-0.96) on the second test day, suggesting a learning effect. The day-to-day reproducibility was overall better with the wearable sensor (mean ICC 0.87) compared with the application without using sensor or goniometer (mean ICC 0.82 and 0.60, respectively). This study suggests that smartphone-based measurements of wrist range of motion are feasible and highly accurate, making it a powerful tool for outcome studies after wrist surgery.

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  • 15. Order onlineBuy this publication >>
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    On microvascular blood flow assessment with the new microdialysis urea clearance technique2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis was to develop and evaluate a new way of monitoring blood flow with microdialysis. A thin catheter consisting of a semipermeable membrane is implanted in the tissue being studied. The catheter is perfused by a solution that closely resembles interstitial fluid, and small water-soluble substances are allowed to diffuse passively through the pores of the membrane with the aim at reaching equilibrium with the surrounding tissue.  The minimally invasive character of microdialysis, and its ability to sample from the organ being studied, make microdialysis attractive in most research settings as well as for clinical surveillance. It has, however, become increasingly evident that microdialysis under conditions of non-equilibrium - for example, fluctuating regional blood flow, will alter the results gained. We have therefore aimed to explore the possibilities of developing a new marker of blood flow that will yield information about changes in blood flow that occur in the area of the microdialysis catheter itself.

    We hypothesised that the changes in the diffusion of exogenous urea could be used as markers of changes in tissue blood flow. The theoretical basis for this approach is that the mass transfer of urea will increase across the dialysis membrane secondary to increased blood flow. As removal of urea from the vicinity of the dialysis membrane increases with increased blood flow, the concentration gradient of urea between the perfusate and tissue will also increase. This in turn will result in a greater loss of urea from the perfusate. The changes noted in retrieval of urea from dialysate by the system are therefore thought to be inversely related to changes in blood flow. We tested our hypothesis in two species of animal (rat and pig) and in man, and in three organ systems (muscle, liver, and skin), and present four papers that indicate that the urea clearance technique provides reliable and reproducible results. The technique was evaluated against conventional metabolic markers (lactate and glucose), the ethanol clearance technique (microdialysis), laser Doppler perfusion imaging (LDPI), and polarisation light spectroscopy (TiVi).

    We present evidence that the urea clearance technique can be used to assess blood flow in the organs studied reliably and reproducibly with microdialysis. The microdialysis technique is minimally invasive and safe for the recipient, and catheters can easily be implanted during operation to monitor organs at risk. Urea is easily analysed as a standard assay among other “basic” metabolic markers (in a standard microdialysis kit) and has favourable characteristics with a standardised measurement system that is routinely used for monitoring metabolites in the clinic. The technique is also effective when used at lower perfusate flow rates (<1 μl/minute), which is advantageous as the recovery of metabolic markers increases at low perfusate flow rates.

    List of papers
    1. Continuous assessment of concentrations of cytokines in experimental injuries of the extremity
    Open this publication in new window or tab >>Continuous assessment of concentrations of cytokines in experimental injuries of the extremity
    Show others...
    2009 (English)In: International Journal of Clinical and Experimental Medicine, E-ISSN 1940-5901, Vol. 2, no 4, p. 354-362Article in journal (Refereed) Published
    Abstract [en]

    Background. Inflammation plays an important part in the healing process. Little is known about the extent local inflammatory trauma response interacts with the central circulation and inflammation produced by central organs. The aim of the present study was to examine whether high cut-off microdialysis catheters offer potential to in real time assess interstitial cytokines variations in conjunction to markers of metabolism distal to a blunt vascular contusion. Methods. In a standardised contusion trauma model, microdialysis catheters (high MW (100kDa)) were inserted in the gracilis muscle distal to the trauma for the local assessment of IL-6, IL-8, TNF-a, total protein and the metabolic mediators (glycerol, puruvate and lactate). The contra lateral uninjured leg served as control of the centrally mediated inflammation propagated to the extremities. Results. The trauma led to a significant and quantitatively large (8-10 fold) increase in inflammatory cytokines (IL6 and 8) as measured both in the injured and control legs. There was only a minor, and not significant increase in concentrations of cytokines in the injured leg compared to the control leg.. There were no signs of ischemia in either leg. Conclusion. The new finding in this study is that both central, and local, inflammatory responses as well as metabolic mediators may be assessed continuously in skeletal muscle tissue distal to a major injury in an animal model. The findings suggest that the large trauma elicits a generalised inflammatory response to trauma rather than propagating a local one distal to the trauma.

    Place, publisher, year, edition, pages
    e-Century Publishing Corporation, 2009
    Keywords
    Blunt trauma; Inflammation; Microcirculation; Microdialysis; Rat
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-57062 (URN)20057979 (PubMedID)
    Available from: 2010-06-11 Created: 2010-06-09 Last updated: 2024-01-10
    2. Urea clearance: a new method to register local changes in blood flow in rat skeletal muscle based on microdialysis
    Open this publication in new window or tab >>Urea clearance: a new method to register local changes in blood flow in rat skeletal muscle based on microdialysis
    Show others...
    2010 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 30, no 1, p. 57-63Article in journal (Refereed) Published
    Abstract [en]

    Pgreater thanIncreasing evidence suggests that local blood flow should be monitored during microdialysis (MD) as the recovery of analytes is affected by local blood flow. At present ethanol clearance is the standard technique for this purpose, but it is not functional at very low perfusion velocities. Here, we introduce a technique for MD whereby local tissue blood flow is recorded by the use of urea clearance (changes inflow/outflow concentration), in conjunction with measurements of tissue metabolism (glucose, lactate and puruvate). MD probes were inserted into the gracilis muscle of 15 rats and perfused with a medium containing urea (20 mmol l-1). Changes in muscle blood flow were made by addition of noradrenaline (5 mu g ml-1) to the perfusion medium at two perfusion velocities (0 center dot 6 and 0 center dot 4 mu l min-1). The clearance of urea from the perfusion medium was then calculated and examined in relation to the dose of noradrenaline and to the coexisting changes in extracellular metabolites. The results showed reproducible and dose-dependent changes in blood flow that were induced by noradrenaline. These were characterized by dose-dependent changes in the urea clearance as well as blood-flow-specific changes in the MD metabolic markers (reduction in glucose and increase in lactate). The sensitivity for blood flow changes as assessed by urea clearance (MD) was increased at 0 center dot 4 compared with the 0 center dot 6 mu l min-1 perfusion speed. The results indicate that inclusion of urea to the perfusion medium may be used to monitor changes in skeletal muscle blood flow at low perfusion velocities and in parallel assess metabolic variables with a high recovery (greater than 90%).

    Keywords
    extracellular fluid; glucose; lactate; metabolism; recovery
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-52899 (URN)10.1111/j.1475-097X.2009.00904.x (DOI)
    Available from: 2010-01-13 Created: 2010-01-12 Last updated: 2024-01-10
    3. Urea Clearance: A New Technique Based on Microdialysis to Assess Liver Blood Flow Studied in a Pig Model of Ischemia/Reperfusion
    Open this publication in new window or tab >>Urea Clearance: A New Technique Based on Microdialysis to Assess Liver Blood Flow Studied in a Pig Model of Ischemia/Reperfusion
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    2010 (English)In: EUROPEAN SURGICAL RESEARCH, ISSN 0014-312X, Vol. 45, no 2, p. 105-112Article in journal (Refereed) Published
    Abstract [en]

    Delayed detection of ischemia is one of the most feared postoperative complications. Early detection of impaired blood flow and close monitoring of the organ-specific metabolic status may therefore be critical for the surgical outcome. Urea clearance is a new technique for continuous monitoring of alterations in blood flow and metabolic markers with acceptable temporal characteristics. We compare this new microdialysis technique with the established microdialysis ethanol technique to assess hepatic blood flow. Six pigs were used in a liver ischemia/reperfusion injury model. Microdialysis catheters were placed in liver segment IV and all circulation was stopped for 80 min, followed by reperfusion for 220 min. Urea and ethanol clearance was calculated from the dialysate and correlated with metabolic changes. A laser Doppler probe was used as reference of restoration of blood flow. Both urea and ethanol clearance reproducibly depicted changes in liver blood flow in relation to metabolic changes and laser Doppler measurements. The two techniques highly correlated both overall and during the reperfusion phase (r = 0.8) and the changes were paralleled by altered perfusion as recorded by laser Doppler.

    Place, publisher, year, edition, pages
    S. Karger AG, 2010
    Keywords
    Liver perfusion, Lactate, Ethanol, Metabolism, Recovery
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-62299 (URN)10.1159/000319868 (DOI)000283851400006 ()
    Available from: 2010-11-26 Created: 2010-11-26 Last updated: 2024-01-10
    4. Assessment of blood flow changes in human skin by microdialysis urea clearance
    Open this publication in new window or tab >>Assessment of blood flow changes in human skin by microdialysis urea clearance
    2011 (English)In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 18, no 3, p. 198-204Article, review/survey (Refereed) Published
    Abstract [en]

    Objective: The aim of this study was to evaluate the urea clearance technique for the measurement of drug-induced blood flow changes in human skin, and compare it with two non-invasive techniques: polarization light spectroscopy and laser Doppler perfusion imaging.

    Methods: Fifteen microdialysis catheters were placed intracutaneously on the volar aspect of the forearms of healthy human subjects, and were perfused with nitroglycerine, noradrenaline, and again nitroglycerine, to induce local tissue hyperaemia, hypoperfusion, and hyperaemia, respectively.

    Results: Urea clearance, but not the other techniques, detected the changes in blood flow during all three periods of altered flow.  The last hyperaemic response was detected by all three methods.

    Conclusion: Urea clearance can be used as a relatively simple method to estimate blood flow changes during microdialysis of vasoactive substances, in particular when the tissue is preconditioned in order to enhance the contrast between baseline and the responses to the provocations. Our results support that, in the model described, urea clearance was superior to the optical methods as it detected both the increases and decrease in blood flow, and the returns to baseline between these periods.

    Place, publisher, year, edition, pages
    Wiley, 2011
    Keywords
    microcirculation; laser Doppler perfusion imaging; polarisation light spectroscopy; ischaemia; reperfusion; hypoperfusion; hyperaemia
    National Category
    Physiology
    Identifiers
    urn:nbn:se:liu:diva-63115 (URN)10.1111/j.1549-8719.2010.00077.x (DOI)000288759900004 ()
    Note
    The original title of article IV was "Assessment of blood flow changes in a new pharmacological model of microdosing in human skin by microdialysis urea clearance".Available from: 2010-12-11 Created: 2010-12-11 Last updated: 2024-01-10Bibliographically approved
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    On microvascular blood flow assessment with the new microdialysis urea clearance technique
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  • 16.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. VA Palo Alto Health Care System, Livermore, CA, USA.
    Farnebo, Lovisa
    Stanford University, CA, USA.
    Kim, Maxwell
    VA Palo Alto Health Care System, Livermore, CA, USA; Stanford University, CA, USA.
    Woon, Colin
    VA Palo Alto Health Care System, Livermore, CA, USA; Stanford University, CA, USA.
    Pham, Hung
    VA Palo Alto Health Care System, Livermore, CA, USA; Stanford University, CA, USA.
    Chang, James
    VA Palo Alto Health Care System, Livermore, CA, USA; Stanford University, CA, USA.
    Optimized Repopulation of Tendon Hydrogel: Synergistic Effects of Growth Factor Combinations and Adipose-Derived Stem Cells2017In: Hand (New York, N.Y.), ISSN 1558-9447, Vol. 12, no 1, p. 68-77Article in journal (Refereed)
    Abstract [en]

    Background: Tendon-derived extracellular matrix (ECM) hydrogel has been shown to augment tendon healing in vivo. We hypothesized that reseeding of the gel with adipose-derived stem cells (ASCs) could further assist repopulation of the gel and that combinations of growth factors (GFs) would improve the survival of these cells after reseeding. Methods: A tendon-specific ECM solution was supplemented with varying concentrations of basic fibroblast growth factor (bFGF), insulin-like growth factor-1 (IGF-1), and platelet-derived growth factor-BB (PDGF-BB). Gels were then seeded with ASCs transfected with a green fluorescent protein/luciferin construct. Cell proliferation was determined using the MTT assay and histology, and GF and ASC augmented gels were injected into the back of Sprague Dawley rats. Bioluminescence of seeded gels was continuously followed after reseeding, and cell counts were performed after the gels were explanted at 14 days. Results: Synergistic effects of the GFs were seen, and an optimal combination was determined to be 10 ng/mL bFGF, 100 ng/mL IGF-1, and 100 ng/mL PDGF-BB (2.8-fold increase; P amp;lt; .05). In vivo bioluminescence showed an improved initial survival of cells in gels supplemented with the optimal concentration of GF compared with the control group (10.6-fold increase at 8 days; P amp;lt; .05). Cell counts of explants showed a dramatic endogenous repopulation of gels supplemented by GF + ASCs compared with both gels with GF but no ASCs (7.6-fold increase) and gels with ASCs but no GF (1.6-fold increase). Conclusion: Synergistic effects of GFs can be used to improve cellular proliferation of ASCs seeded to a tendon ECM gel. Reseeding with ASCs stimulates endogenous repopulation of the gel in vivo and may be used to further augment tendon healing.

  • 17.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Gerber Ekblom, A.
    Karolinska Institute, Sweden.
    Hand surgery in Sweden2017In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 42, no 5, p. 537-539Article in journal (Other academic)
    Abstract [en]

    n/a

  • 18.
    Farnebo, Simon
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Harhaus, Leila
    BG Trauma Ctr Ludwigshafen, Germany; Heidelberg Univ, Germany.
    The research question: the What, Why and How in hand surgery2024In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289Article in journal (Other academic)
    Abstract [en]

    Identifying a good research question is one of the most important steps when laying the foundation of a research project. A good research question can aim to answer a hotly debated clinical issue, challenge a pre-existing dogma or make a contribution to specific aspects of a broader field of study. The difficulty in defining the question lies with pinpointing an important research topic or an area that is characterized by a lack of knowledge (the What), grasping the significance of how a precisely defined study can potentially impact on clinical practices (the Why) and determining the optimal study design tailored to answer the specific question (the How). These three domains constitute pivotal concepts in the process of shaping the research question.

  • 19.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Karlander, Lars-Erik
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Steinwall, Ingrid
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Sjögren, Florence
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Continuous assessment of concentrations of cytokines in experimental injuries of the extremity2009In: International Journal of Clinical and Experimental Medicine, E-ISSN 1940-5901, Vol. 2, no 4, p. 354-362Article in journal (Refereed)
    Abstract [en]

    Background. Inflammation plays an important part in the healing process. Little is known about the extent local inflammatory trauma response interacts with the central circulation and inflammation produced by central organs. The aim of the present study was to examine whether high cut-off microdialysis catheters offer potential to in real time assess interstitial cytokines variations in conjunction to markers of metabolism distal to a blunt vascular contusion. Methods. In a standardised contusion trauma model, microdialysis catheters (high MW (100kDa)) were inserted in the gracilis muscle distal to the trauma for the local assessment of IL-6, IL-8, TNF-a, total protein and the metabolic mediators (glycerol, puruvate and lactate). The contra lateral uninjured leg served as control of the centrally mediated inflammation propagated to the extremities. Results. The trauma led to a significant and quantitatively large (8-10 fold) increase in inflammatory cytokines (IL6 and 8) as measured both in the injured and control legs. There was only a minor, and not significant increase in concentrations of cytokines in the injured leg compared to the control leg.. There were no signs of ischemia in either leg. Conclusion. The new finding in this study is that both central, and local, inflammatory responses as well as metabolic mediators may be assessed continuously in skeletal muscle tissue distal to a major injury in an animal model. The findings suggest that the large trauma elicits a generalised inflammatory response to trauma rather than propagating a local one distal to the trauma.

  • 20.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Samuelsson, A.
    Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre, Department of Intensive Care UHL.
    Henriksson, J.
    Karolinska Inst, Dept Physiol and Pharmacol, Stockholm, Sweden.
    Karlander, Lars-Erik
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Urea clearance: a new method to register local changes in blood flow in rat skeletal muscle based on microdialysis2010In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 30, no 1, p. 57-63Article in journal (Refereed)
    Abstract [en]

    Pgreater thanIncreasing evidence suggests that local blood flow should be monitored during microdialysis (MD) as the recovery of analytes is affected by local blood flow. At present ethanol clearance is the standard technique for this purpose, but it is not functional at very low perfusion velocities. Here, we introduce a technique for MD whereby local tissue blood flow is recorded by the use of urea clearance (changes inflow/outflow concentration), in conjunction with measurements of tissue metabolism (glucose, lactate and puruvate). MD probes were inserted into the gracilis muscle of 15 rats and perfused with a medium containing urea (20 mmol l-1). Changes in muscle blood flow were made by addition of noradrenaline (5 mu g ml-1) to the perfusion medium at two perfusion velocities (0 center dot 6 and 0 center dot 4 mu l min-1). The clearance of urea from the perfusion medium was then calculated and examined in relation to the dose of noradrenaline and to the coexisting changes in extracellular metabolites. The results showed reproducible and dose-dependent changes in blood flow that were induced by noradrenaline. These were characterized by dose-dependent changes in the urea clearance as well as blood-flow-specific changes in the MD metabolic markers (reduction in glucose and increase in lactate). The sensitivity for blood flow changes as assessed by urea clearance (MD) was increased at 0 center dot 4 compared with the 0 center dot 6 mu l min-1 perfusion speed. The results indicate that inclusion of urea to the perfusion medium may be used to monitor changes in skeletal muscle blood flow at low perfusion velocities and in parallel assess metabolic variables with a high recovery (greater than 90%).

  • 21.
    Farnebo, Simon
    et al.
    Linköping University, Department of Biomedicine and Surgery, Division of surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Thorfinn, Johan
    Linköping University, Department of Biomedicine and Surgery, Division of surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Henricson, Joakim
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Hyperaemic changes in forearm skin perfusion and RBC concentration after increasing occlusion times2010In: MICROVASCULAR RESEARCH, ISSN 0026-2862, Vol. 80, no 3, p. 412-416Article in journal (Refereed)
    Abstract [en]

    Tissue occlusion and the hyperaemic response upon reperfusion can be used as a tool to assess microvascular function in various vascular diseases. Currently, laser Doppler flowmetry (LDF) is applied most often to measure hyperaemic responses. In this study, we have applied tissue viability imaging (TiVi) and LDF to measure the change in red blood cell concentration and perfusion in the skin after occlusions of the forearm with increasing duration. We have found that there is a strong correlation between the changes in perfusion and red blood cell (RBC) concentration during post-occlusive hyperaemia (perfusion: r = 0.80; RBC concentration: r = 0.94). This correlation increases with longer occlusion durations (1, 5 and 10 min). Furthermore, for both perfusion and RBC concentration, the maximum responses (perfusion: r(2) = 0.59; RBC concentration: r(2) = 0.78) and the recovery times (perfusion: r(2) = 0.62; RBC concentration: r(2) = 0.91) increase linearly with the duration of the occlusion. Maximum responses and recovery times were more reproducible for RBC concentration (as measured with TiVi) than for perfusion (as measured with LDF). These results show that perfusion and RBC concentration are related during post-occlusive hyperaemia and that TiVi can be used as a tool in the assessment of hyperaemic responses that has advantages in terms of reproducibility, sensitivity and ease of use.

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  • 22.
    Farnebo, Simon
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Wiig, Monica
    Uppsala Univ, Sweden; Uppsala Univ Hosp, Sweden.
    Holm, Bjorn
    Uppsala Univ, Sweden; Uppsala Univ Hosp, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Prevention, Rehabilitation and Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Differentially Expressed Proteins in Intra Synovial Compared to Extra Synovial Flexor Tendon Grafts in a Rabbit Tendon Transplantation Model2020In: Biomedicines, E-ISSN 2227-9059, Vol. 8, no 10, article id 408Article in journal (Refereed)
    Abstract [en]

    Uncomplicated healing of grafts for tendon reconstruction remains an unsolved problem in hand surgery. Results are limited by adhesion formation and decreased strength properties, especially within the tight fibro-osseous sheath of the digits. This is especially problematic when an extra synovial tendon graft is used to replace an intra synovial flexor tendon. Compositional differences are likely to play an important role in these processes. The aim of this study was, therefore, to compare protein expression in pair-matched intra synovial tendon grafts with extra synovial tendon grafts, using a rabbit tendon injury model. We hypothesized that there would be significant differences in proteins critical for response to tensile loading and adhesion formation between the two groups. Using mass spectrometry and multivariate statistical data analysis, we found tissue-specific differences in 22 proteins, where 7 explained 93% (R2) of the variation, with a prediction of 81% (Q2). Among the highest discriminating proteins were Galectin, Histone H2A, and Periostin, which were found in a substantially larger amount in the extra synovial tendons compared to the intra synovial tendons. These findings may contribute to improved understanding of the differences in outcome seen after tendon reconstruction using tendon grafts with intra synovial and extra synovial grafts.

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  • 23.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL.
    Winbladh, Anders
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Zettersten, Erik
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Sandström, Per
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Surgery in Östergötland.
    Gullstrand, P
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Samuelsson, Anders
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Intensive Care UHL.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Urea Clearance: A New Technique Based on Microdialysis to Assess Liver Blood Flow Studied in a Pig Model of Ischemia/Reperfusion2010In: EUROPEAN SURGICAL RESEARCH, ISSN 0014-312X, Vol. 45, no 2, p. 105-112Article in journal (Refereed)
    Abstract [en]

    Delayed detection of ischemia is one of the most feared postoperative complications. Early detection of impaired blood flow and close monitoring of the organ-specific metabolic status may therefore be critical for the surgical outcome. Urea clearance is a new technique for continuous monitoring of alterations in blood flow and metabolic markers with acceptable temporal characteristics. We compare this new microdialysis technique with the established microdialysis ethanol technique to assess hepatic blood flow. Six pigs were used in a liver ischemia/reperfusion injury model. Microdialysis catheters were placed in liver segment IV and all circulation was stopped for 80 min, followed by reperfusion for 220 min. Urea and ethanol clearance was calculated from the dialysate and correlated with metabolic changes. A laser Doppler probe was used as reference of restoration of blood flow. Both urea and ethanol clearance reproducibly depicted changes in liver blood flow in relation to metabolic changes and laser Doppler measurements. The two techniques highly correlated both overall and during the reperfusion phase (r = 0.8) and the changes were paralleled by altered perfusion as recorded by laser Doppler.

  • 24.
    Farnebo, Simon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Plastic Surgery, Hand Surgery and Burns. Linköping University, Faculty of Health Sciences.
    Zettersten, Erik
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Samuelsson, Anders
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Intensive Care UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Burn Center. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Plastic Surgery, Hand surgery UHL. Östergötlands Läns Landsting, Sinnescentrum, Department of Anaesthesiology and Surgery UHL.
    Assessment of blood flow changes in human skin by microdialysis urea clearance2011In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 18, no 3, p. 198-204Article, review/survey (Refereed)
    Abstract [en]

    Objective: The aim of this study was to evaluate the urea clearance technique for the measurement of drug-induced blood flow changes in human skin, and compare it with two non-invasive techniques: polarization light spectroscopy and laser Doppler perfusion imaging.

    Methods: Fifteen microdialysis catheters were placed intracutaneously on the volar aspect of the forearms of healthy human subjects, and were perfused with nitroglycerine, noradrenaline, and again nitroglycerine, to induce local tissue hyperaemia, hypoperfusion, and hyperaemia, respectively.

    Results: Urea clearance, but not the other techniques, detected the changes in blood flow during all three periods of altered flow.  The last hyperaemic response was detected by all three methods.

    Conclusion: Urea clearance can be used as a relatively simple method to estimate blood flow changes during microdialysis of vasoactive substances, in particular when the tissue is preconditioned in order to enhance the contrast between baseline and the responses to the provocations. Our results support that, in the model described, urea clearance was superior to the optical methods as it detected both the increases and decrease in blood flow, and the returns to baseline between these periods.

  • 25.
    Fredäng Kämmerling, Nina
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Booij, Ronald
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Erasmus MC, Netherlands.
    Fornander, Lotta
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Norrköping.
    Persson, Anders
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    A comparative study of image quality and diagnostic confidence in diagnosis and follow-up of scaphoid fractures using photon-counting detector CT and energy-integrating detector CT2024In: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 173, article id 111383Article in journal (Refereed)
    Abstract [en]

    Purpose: Scaphoid fractures in patients and assessment of healing using PCD-CT have, as far as we know, not yet been studied. Therefore, the aim was to compare photon counting detector CT (PCD-CT) with energy integrating detector CT (EID-CT) in terms of fracture visibility and evaluation of fracture healing. Method: Eight patients with scaphoid fracture were examined with EID-CT and PCD-CT within the first week posttrauma, and with additional scans at 4, 6 and 8 weeks. Our clinical protocol for wrist examination with EID-CT was used (CTDIvol 3.1 +/- 0.1 mGy, UHR kernel Ur77). For PCD-CT matched radiation dose, reconstruction kernel Br89. Quantitative analyses of noise, CNR, trabecular and cortical sharpness, and bone volume fraction were conducted. Five radiologists evaluated the images for fracture visibility, fracture gap consolidation and image quality, and rated their confidence in the diagnosis. Results: The trabecular and cortical sharpness were superior in images obtained with PCD-CT compared with EIDCT. A successive reduction in trabecular bone volume fraction during the immobilized periods was found with both systems. Despite higher noise and lower CNR with PCD-CT, radiologists rated the image quality of PCD-CT as superior. The visibility of the fracture line within 1 -week post -trauma was rated higher with PCD-CT as was diagnostic confidence, but the subsequent assessments of fracture gap consolidation during healing process and the confidence in diagnosis were found equivalent between both systems. Conclusion: PCD-CT offers superior visibility of bone microstructure compared with EID-CT. The evaluation of fracture healing and confidence in diagnosis were rated equally with both systems, but the radiologists found primary fracture visibility and overall image quality superior with PCD-CT.

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  • 26.
    Frueh, Florian S.
    et al.
    Univ Hosp Zurich, Switzerland.
    Megerle, Kai
    Tech Univ Munich, Germany.
    Luria, Shai
    Hadassah Hebrew Univ Med Ctr, Israel.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Research activity among European hand surgery residents2019In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 44, no 7, p. 764-765Article in journal (Other academic)
    Abstract [en]

    n/a

  • 27.
    Frueh, Florian S.
    et al.
    Univ Hosp Zurich, Switzerland.
    Wong, Jason K.
    Univ Manchester, England; Univ Manchester, England; Manchester Univ Fdn Trust, England.
    Megerle, Kai
    Tech Univ Munich, Germany.
    Luria, Shai
    Hadassah Hebrew Univ, Israel.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Striving for scientific excellence in hand surgery2020In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 45, no 8, p. 890-891Article in journal (Refereed)
    Abstract [en]

    n/a

  • 28.
    Herren, Daniel B.
    et al.
    Schulthess Klin, Switzerland; Schulthess Klin, Switzerland.
    Boeckstyns, Michel
    Capio Private Hosp, Denmark.
    Chung, Kevin C.
    Michigan Med, MI USA.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Hagert, Elisabet
    Aspetar Orthoped & Sports Med Hosp, Qatar; Karolinska Inst, Sweden.
    Tang, Jin Bo
    Nantong Univ, Peoples R China.
    Verstreken, Frederik
    AZ Mon Hosp, Belgium.
    Marks, Miriam
    Schulthess Klin, Switzerland.
    Diagnostic and treatment recommendations for recurrent or persistent symptoms after trapeziectomy: a Delphi study2024In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289Article in journal (Refereed)
    Abstract [en]

    The aim of this Delphi study was to provide a diagnostic and treatment algorithm for patients with persistent or recurrent symptoms after trapeziometacarpal joint resection arthroplasty. Three Delphi rounds were conducted in which surveys were sent to 182 experienced hand surgeons worldwide. Responses were received from 140 participants. A consensus threshold was set at 67% agreement. Diagnostic tools and treatment approaches for six common revision scenarios achieved consensus. Radiographs are appropriate as primary (97%) and CT scans as secondary (76%) diagnostic tools. For scaphometacarpal impingement, 67% of respondents agreed that revision interposition is appropriate, with 93% recommending autologous tendon for the interposition. Additional suspension was considered appropriate by 68% of the participants. The diagnostic and treatment algorithm can help the surgeon to identify the reason for persistent symptoms after trapeziometacarpal joint resection arthroplasty and to choose an appropriate treatment strategy.Level of evidence: V

  • 29.
    Högstedt, Alexandra
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Surgery in Linköping.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine.
    Ghafouri, Bijar
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Prevention, Rehabilitation and Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Investigation of proteins important for microcirculation using in vivo microdialysis after glucose provocation: a proteomic study2021In: Scientific Reports, E-ISSN 2045-2322, Vol. 11, no 1, article id 19093Article in journal (Refereed)
    Abstract [en]

    Insulin has metabolic and vascular effects in the human body. What mechanisms that orchestrate the effects in the microcirculation, and how the responds differ in different tissues, is however not fully understood. It is therefore of interest to search for markers in microdialysate that may be related to the microcirculation. This study aims to identify proteins related to microvascular changes in different tissue compartments after glucose provocation using in vivo microdialysis. Microdialysis was conducted in three different tissue compartments (intracutaneous, subcutaneous and intravenous) from healthy subjects. Microdialysate was collected during three time periods; recovery after catheter insertion, baseline and glucose provocation, and analyzed using proteomics. Altogether, 126 proteins were detected. Multivariate data analysis showed that the differences in protein expression levels during the three time periods, including comparison before and after glucose provocation, were most pronounced in the intracutaneous and subcutaneous compartments. Four proteins with vascular effects were identified (angiotensinogen, kininogen-1, alpha-2-HS-glycoprotein and hemoglobin subunit beta), all upregulated after glucose provocation compared to baseline in all three compartments. Glucose provocation is known to cause insulin-induced vasodilation through the nitric oxide pathway, and this study indicates that this is facilitated through the interactions of the RAS (angiotensinogen) and kallikrein-kinin (kininogen-1) systems.

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  • 30.
    Högstedt, Alexandra
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Prevention, Rehabilitation and Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sampling insulin in different tissue compartments using microdialysis: methodological aspects2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 1, article id 21948Article in journal (Refereed)
    Abstract [en]

    Sampling the concentration of insulin in human skin using microdialysis is challenging because of low intracutaneous concentrations and low recovery, presumably due to adsorption of insulin to the microdialysis system. In this study, we aimed to (1) measure how the concentration of insulin varies in three different tissue compartments (intracutaneous, subcutaneous and intravenous) and (2) to study how much insulin is adsorbed to the microdialysis catheter membranes and tubing during a typical microdialysis experiment, both in vivo and in vitro. We hypothesized that (1) the concentration of insulin decreases from the intravenous compartment to the intracutaneous and subcutaneous tissue, and that (2) adsorption of insulin to the microdialysis membrane and tubing impairs the recovery of insulin from the tissue. In this experimental study, microdialysis catheters were inserted intracutaneously, subcutaneously and intravenously in 11 healthy subjects. Systemic endogenous hyperinsulinemia was induced by intake of an oral glucose load. Insulin concentration was measured in the dialysate and in the extracted samples from the catheter membrane and tubings. In vitro microdialysis was performed to investigate the temporal resolution of the adsorption. After an oral glucose load insulin concentration increased intravenously, but not in the intracutaneous or subcutaneous compartments, while glucose, lactate and pyruvate concentrations increased in all compartments. The adsorption of insulin to the microdialysis membrane in vivo was highest in the intravenous compartment (p=0.01), compared to the intracutaneous and subcutaneous compartments. In vitro, the adsorption to the microdialysis membrane was highest one hour after sampling, then the concentration gradually decreased after three and five hours of sampling. The concentration of insulin in peripheral tissues is low, probably due to decreasing tissue vascularity. Adsorption of insulin to the microdialysis membrane is modest but time-dependent. This finding highlights the importance of a stabilization time for the microdialysis system before sampling tissue analytes.

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  • 31.
    Högstedt, Alexandra
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences.
    Iredahl, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Primary Care Center, Primary Health Care Center Åby.
    Droog Tesselaar, Erik
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Effect of N-G-monomethyl l-arginine on microvascular blood flow and glucose metabolism after an oral glucose load2020In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 27, no 3, article id e12597Article in journal (Refereed)
    Abstract [en]

    Objective The aim of this study was to investigate whether the effects on local blood flow and metabolic changes observed in the skin after an endogenous systemic increase in insulin are mediated by the endothelial nitric oxide pathway, by administering the nitric oxide synthase inhibitor N-G-monomethyl l-arginine using microdialysis. Methods Microdialysis catheters, perfused with N-G-monomethyl l-arginine and with a control solution, were inserted intracutaneously in 12 human subjects, who received an oral glucose load to induce a systemic hyperinsulinemia. During microdialysis, the local blood flow was measured by urea clearance and by laser speckle contrast imaging, and glucose metabolites were measured. Results After oral glucose intake, microvascular blood flow and glucose metabolism were both significantly suppressed in the N-G-monomethyl l-arginine catheter compared to the control catheter (urea clearance: P amp;lt; .006, glucose dialysate concentration: P amp;lt; .035). No significant effect of N-G-monomethyl l-arginine on microvascular blood flow was observed with laser speckle contrast imaging (P = .81). Conclusion Local delivery of N-G-monomethyl l-arginine to the skin by microdialysis reduces microvascular blood flow and glucose delivery in the skin after oral glucose intake, presumably by decreasing local insulin-mediated vasodilation.

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  • 32.
    Iredahl, Fredrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Högstedt, Alexandra
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Henricson, Joakim
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Dermatology and Venerology. Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Skin glucose metabolism and microvascular blood flow during local insulin delivery and after an oral glucose load2016In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 23, no 7, p. 597-605Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Insulin causes capillary recruitment in muscle and adipose tissue, but the metabolic and microvascular effects of insulin in the skin have not been studied in detail. The aim of this study was to measure glucose metabolism and microvascular blood flow in the skin during local insulin delivery and after an oral glucose load.

    METHODS: Microdialysis catheters were inserted intracutanously in human subjects. In eight subjects two microdialysis catheters were inserted, one perfused with insulin and one with control solution. First the local effects of insulin was studied, followed by a systemic provocation by an oral glucose load. Additionally, as control experiment, six subjects did not recieve local delivery of insulin or the oral glucose load. During microdialysis the local blood flow was measured by urea clearance and by laser speckle contrast imaging (LSCI).

    RESULTS: Within 15 minutes of local insulin delivery, microvascular blood flow in the skin increased (urea clearance: P=.047, LSCI: P=.002) paralleled by increases in pyruvate (P=.01) and lactate (P=.04), indicating an increase in glucose uptake. An oral glucose load increased urea clearance from the catheters, indicating an increase in skin perfusion, although no perfusion changes were detected with LSCI. The concentration of glucose, pyruvate and lactate increased in the skin after the oral glucose load.

    CONCLUSION: Insulin has metabolic and vasodilatory effects in the skin both when given locally and after systemic delivery through an oral glucose load.

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  • 33.
    Iredahl, Fredrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Löfberg, Andreas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Faculty of Medicine and Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Non-Invasive Measurement of Skin Microvascular Response during Pharmacological and Physiological Provocations2015In: PLOS ONE, E-ISSN 1932-6203, Vol. 10, no 8, p. 1-15, article id e0133760Article in journal (Refereed)
    Abstract [en]

    Introduction Microvascular changes in the skin due to pharmacological and physiological provocations can be used as a marker for vascular function. While laser Doppler flowmetry (LDF) has been used extensively for measurement of skin microvascular responses, Laser Speckle Contrast Imaging (LSCI) and Tissue Viability Imaging (TiVi) are novel imaging techniques. TiVi measures red blood cell concentration, while LDF and LSCI measure perfusion. Therefore, the aim of this study was to compare responses to provocations in the skin using these different techniques. Method Changes in skin microcirculation were measured in healthy subjects during (1) iontophoresis of sodium nitroprusside (SNP) and noradrenaline (NA), (2) local heating and (3) post-occlusive reactive hyperemia (PORH) using LDF, LSCI and TiVi. Results Iontophoresis of SNP increased perfusion (LSCI: baseline 40.9 +/- 6.2 PU; 10-min 100 +/- 25 PU; pless than0.001) and RBC concentration (TiVi: baseline 119 +/- 18; 10-min 150 +/- 41 AU; p = 0.011). No change in perfusion (LSCI) was observed after iontophoresis of NA (baseline 38.0 +/- 4.4 PU; 10-min 38.9 +/- 5.0 PU; p = 0.64), while RBC concentration decreased (TiVi: baseline 59.6 +/- 11.8 AU; 10-min 54.4 +/- 13.3 AU; p = 0.021). Local heating increased perfusion (LDF: baseline 8.8 +/- 3.6 PU; max 112 +/- 55 PU; pless than0.001, LSCI: baseline 50.8 +/- 8.0 PU; max 151 +/- 22 PU; pless than0.001) and RBC concentration (TiVi: baseline 49.2 +/- 32.9 AU; max 99.3 +/- 28.3 AU; pless than0.001). After 5 minutes of forearm occlusion with prior exsanguination, a decrease was seen in perfusion (LDF: p = 0.027; LSCI: pless than0.001) and in RBC concentration (p = 0.045). Only LSCI showed a significant decrease in perfusion after 5 minutes of occlusion without prior exsanguination (pless than0.001). Coefficients of variation were lower for LSCI and TiVi compared to LDF for most responses. Conclusion LSCI is more sensitive than TiVi for measuring microvascular changes during SNP-induced vasodilatation and forearm occlusion. TiVi is more sensitive to noradrenaline-induced vasoconstriction. LSCI and TiVi show lower inter-subject variability than LDF. These findings are important to consider when choosing measurement techniques for studying skin microvascular responses.

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  • 34.
    Iredahl, Fredrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sadda, Veeranjaneyulu
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Ward, Liam
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Hackethal, Johannes
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. University of Appl Science, Austria.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Modeling Perfusion Dynamics in the Skin During Iontophoresis of Vasoactive Drugs Using Single-Pulse and Multiple-Pulse Protocols2015In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 22, no 6, p. 446-453Article in journal (Refereed)
    Abstract [en]

    Objective: After iontophoresis of vasoactive drugs into the skin, a decrease in perfusion is commonly observed. We delivered vasoactive drugs by iontophoresis using different delivery protocols to study how these affect this decrease in perfusion as measured using LDF. Methods: We measured skin perfusion during iontophoresis of (ACh), MCh, andNAusing a single pulse or separate pulses at different skin sites, and during repeated delivery of ACh at the same site. Results: Perfusion half-life was 6.1 (5.6-6.6) minutes for ACh and 41 (29-69) minutes for MCh (p less than 0.001). The maximum response with multiple pulses of ACh iontophoresis was lower than with a single pulse, 30 (22-37) PU vs. 43 (36-50) PU, p less than 0.001. Vasoconstriction to NA was more rapid with a single pulse than with multiple pulses. The perfusion half-life of ACh decreased with repeated delivery of ACh at the same site-first 16 (14-18), second 5.9 (5.1-6-9) and third 3.2 (2.9-3.5) minutes, p less than 0.001. Conclusions: The drug delivery protocol affects microvascular responses to iontophoresis, possibly as a result of differences in the dynamics of local drug concentrations. Perfusion half-life may be used as a measure to quantify the rate of perfusion recovery after iontophoresis of vasoactive drugs.

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  • 35.
    Iredahl, Fredrik
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences.
    Sarker, Saikat
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    The Microvascular Response to Transdermal Iontophoresis of Insulin is Mediated by Nitric Oxide2013In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 20, no 8, p. 717-723Article in journal (Refereed)
    Abstract [en]

    ObjectiveInsulin has direct effects on blood flow in various tissues, most likely due to endothelial NO production. We investigated whether insulin delivered to the skin by iontophoresis increases microvascular perfusion and whether this effect is partly or completely mediated by the release of NO. MethodsIn healthy subjects, regular insulin and monomeric insulin were delivered to the skin by cathodal iontophoresis. The skin was pretreated either with L-NAME or control solution (PBS) using anodal iontophoresis. Microvascular responses were measured using laser Doppler flowmetry. ResultsA dose-dependent increase in perfusion was observed during iontophoresis of regular and monomeric insulin. The maximum perfusion was significantly elevated compared with control after PBS (regular insulin 53.6 (12.7-95.6) PU vs. 4.2 (3.4-4.8) PU, p = 0.002; monomeric insulin 32.6 (8.9-92.6) PU vs. 5.9 (3.4-56.0) PU, p = 0.03). The microvascular response to insulin was abolished after L-NAME (regular insulin: 25.6 (11.6-54.4) PU vs. control: 4.7 (2.9-11.5) PU, p = 0.15; monomeric insulin 10.9 (5.4-56.8) PU vs. control: 4.7 (2.9-11.5) PU, p = 0.22). ConclusionsThe main finding is that iontophoresis of insulin induces a dose-dependent vasodilation in the skin, which could be suppressed after pretreatment with a NO synthase inhibitor. This suggests that vasodilation in the skin after iontophoresis of insulin is mediated by the NO pathway.

  • 36.
    Kifle, Yonatan Habteslassie
    et al.
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Wikner, Jacob
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, Faculty of Science & Engineering.
    Zötterman, Johan
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Ryden, L.
    Gothenburg Univ, Sweden.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    NFC Powered Implantable Temperature Sensor2019In: 2019 41ST ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), IEEE , 2019, p. 4359-4362Conference paper (Refereed)
    Abstract [en]

    Inductively powered 99% accurate implantable temperature sensor is designed, characterized and the findings are presented in this paper. The implantable sensors deliver a continuous temperature reading to external storage or readout devices via Near Field Communication interface. A 2.76 mu H rectangular inductive coil printed on a thin biocompatible plastic substrate is designed to establish the coupling link through NFC interface with external readout devices. A commercially available wide range temperature sensor chip is mounted along with the developed inductive coil on the same plastic substrate. For 50 samples, the received signal strength indicator, temperature accuracy and statistical distribution of measurement levels is investigated. Comparison of predetermined temperature in a controlled temperature and humidity chamber versus the temperature reading from the developed sensors proves a 99% accuracy.

  • 37.
    Kämmerling, Nina
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Sandstedt, Mårten
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Persson, Anders
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Tesselaar, Erik
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Assessment of image quality in photon-counting detector computed tomography of the wrist - An ex vivo study2022In: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 154, article id 110442Article in journal (Refereed)
    Abstract [en]

    Purpose: The aim of this study was to evaluate the effect of reconstruction parameters on image quality in wrist imaging using photon-counting detector CT (PCD-CT) and to compare the results with images from an energyintegrating detector CT (EID-CT). Methods: Twelve cadaveric wrist specimens were examined using a prototype PCD-CT and a clinical EID-CT using similar radiation dose. Reconstruction parameters were matched between scanners. Also, sharper reconstruction kernels, a larger matrix size, and smaller slice thicknesses were evaluated for PCD-CT. Image noise, contrast-tonoise ratio (CNR) and image sharpness in trabecular structures were quantitatively measured. Image quality with respect to the visibility of cortical and trabecular bone structures was assessed by six radiologists using visual grading methods.Results: Images obtained with PCD-CT had lower noise (42.6 +/- 3.9 HU vs 75.1 +/- 6.3 HU), higher CNR (38.9 +/- 4.5 vs 19.0 +/- 2.4) and higher trabecular sharpness (63.5 +/- 6.0 vs 53.7 +/- 8.5) than those obtained with EID-CT using similar scan and reconstruction parameters (p &lt; 0.001). The image sharpness in trabecular structures was further improved by using sharper kernels, despite higher noise levels. Radiologists had a strong preference for PCD-CT images both in terms of spatial resolution and suitability for bone imaging. Visual grading analysis showed an improved visibility of cortical bone, trabeculae and nutritive canals (p &lt; 0.005).Conclusion: PCD-CT offers improved image quality regarding bone structures in the wrist relative to EID-CT systems, particularly when sharper reconstruction kernels, smaller slice thickness and a larger image matrix size are used.

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  • 38.
    Lienemann, Samuel
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Donahue, Mary
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zötterman, Johan
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    A Soft and Stretchable Multielectrode Cuff for Selective Peripheral Nerve Stimulation2023In: Advanced Materials Technologies, E-ISSN 2365-709X, Vol. 8, no 6, article id 2201322Article in journal (Refereed)
    Abstract [en]

    Bioelectronic medicine can treat diseases and disorders in humans by electrically interfacing with peripheral nerves. Multielectrode cuffs can be used for selective stimulation of portions of the nerve, which is advantageous for treatment specificity. The biocompatibility and conformability of cuffs can be improved by reducing the mechanical mismatch between nerve tissue and cuffs, but selective stimulation of nerves has yet to be achieved with soft and stretchable cuff electrodes. Here, this paper reports the development of a soft and stretchable multielectrode cuff (sMEC) for selective nerve stimulation. The device is made of 50 mu m thick silicone with embedded gold nanowire conductors, which renders it functional at 50% strain, and provides superior conformability for wrapping nerves. By using different stimulation protocols, high functional selectivity is achieved with the sMECs eight stimulation electrodes in a porcine sciatic nerve model. Finite element modeling is used to predict the potential distribution within the nerve, which correlate well with the achieved stimulation results. Recent studies are showing that mechanical softness is of outermost importance for reducing foreign body response. It is therefore believed that the soft high-performance sMEC technology is ideal for future selective peripheral nerve interfaces for bioelectronic medicine.

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  • 39.
    Lienemann, Samuel
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zötterman, Johan
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tybrandt, Klas
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Stretchable gold nanowire-based cuff electrodes for low-voltage peripheral nerve stimulation2021In: Journal of Neural Engineering, ISSN 1741-2560, E-ISSN 1741-2552, Vol. 18, no 4, article id 045007Article in journal (Refereed)
    Abstract [en]

    Objective. Electrical stimulation of the peripheral nervous system (PNS) can treat various diseases and disorders, including the healing process after nerve injury. A major challenge when designing electrodes for PNS stimulation is the mechanical mismatch between the nerve and the device, which can lead to non-conformal contact, tissue damage and inefficient stimulation due to current leakage. Soft and stretchable cuff electrodes promise to tackle these challenges but often have limited performance and rely on unconventional materials. The aim of this study is to develop a high performance soft and stretchable cuff electrode based on inert materials for low-voltage nerve stimulation. Approach. We developed 50 mu m thick stretchable cuff electrodes based on silicone rubber, gold nanowire conductors and platinum coated nanowire electrodes. The electrode performance was characterized under strain cycling to assess the durability of the electrodes. The stimulation capability of the cuff electrodes was evaluated in an in vivo sciatic nerve rat model by measuring the electromyography response to various stimulation pulses. Main results. The stretchable cuff electrodes showed excellent stability for 50% strain cycling and one million stimulation pulses. Saturated homogeneous stimulation of the sciatic nerve was achieved at only 200 mV due to the excellent conformability of the electrodes, the low conductor resistance (0.3 Ohm sq(-1)), and the low electrode impedance. Significance. The developed stretchable cuff electrode combines favourable mechanical properties and good electrode performance with inert and stable materials, making it ideal for low power supply applications within bioelectronic medicine.

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  • 40.
    Lysak, Andrii
    et al.
    Natl Acad Med Sci Ukraine, Ukraine.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Geuna, Stefano
    Univ Torino, Italy.
    Dahlin, Lars
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Lund Univ, Sweden; Skane Univ Hosp, Sweden.
    Muscle preservation in proximal nerve injuries: a current update2024In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 49, no 6, p. 773-782Article, review/survey (Refereed)
    Abstract [en]

    Optimal recovery of muscle function after proximal nerve injuries remains a complex and challenging problem. After a nerve injury, alterations in the affected muscles lead to atrophy, and later degeneration and replacement by fat-fibrous tissues. At present, several different strategies for the preservation of skeletal muscle have been reported, including various sets of physical exercises, muscle massage, physical methods (e.g. electrical stimulation, magnetic field and laser stimulation, low-intensity pulsed ultrasound), medicines (e.g. nutrients, natural and chemical agents, anti-inflammatory and antioxidants, hormones, enzymes and enzyme inhibitors), regenerative medicine (e.g. growth factors, stem cells and microbiota) and surgical procedures (e.g. supercharge end-to-side neurotization). The present review will focus on methods that aimed to minimize the damage to muscles after denervation based on our present knowledge.

  • 41.
    Miller, Robert
    et al.
    Chelsea & Westminster Hosp, England; London Med Imaging & AI Ctr Value Based Healthcare, England; Chelsea & Westminster Hosp, England.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Horwitz, Maxim D.
    Chelsea & Westminster Hosp, England.
    Insights and trends review: artificial intelligence in hand surgery2023In: Journal of Hand Surgery, European Volume, ISSN 1753-1934, E-ISSN 2043-6289, Vol. 48, no 5, p. 396-403Article, review/survey (Refereed)
    Abstract [en]

    Artificial intelligence (AI) in hand surgery is an emerging and evolving field that will likely play a large role in the future care of our patients. However, there remain several challenges to makes this technology meaningful, acceptable and usable at scale. In this review article, we discuss basic concepts in AI, including challenges and key considerations, provide an update on how AI is being used in hand and wrist surgery and propose potential future applications. The aims are to equip clinicians and researchers with the basic knowledge needed to understand and explore the incorporation of AI in hand surgery within their own practice and recommends further reading to develop knowledge in this emerging field.

  • 42.
    Mirdell, Robin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences.
    Accuracy of laser speckle contrast imaging in the assessment of pediatric scald wounds2018In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 44, no 1, p. 90-98Article in journal (Refereed)
    Abstract [en]

    Background: Changes in microvascular perfusion in scalds in children during the first four days, measured with laser speckle contrast imaging (LSCI), are related to the time to healing and need for surgical intervention. The aim of this study was to determine the accuracy (sensitivity and specificity) of LSCI on different days after injury in the prediction of healing outcome and if the accuracy can be improved by combining an early and a late measurement. Also, the accuracy of LSCI was compared with that of clinical assessment. Methods: Perfusion was measured between 0-24h and between 72-96h using LSCI in 45 children with scalds. On the same occasions, burn surgeons assessed the burns as healing amp;lt; 14days or healing amp;gt; 14days/surgery. Receiver operating characteristic (ROC) curves were constructed for the early and late measurement and for the double measurement (DM) using two different methods. Results: Sensitivity and specificity were 92.3% (95% CI: 64.0-99.8%) and 78.3% (95% CI: 69.985.3%) between 0-24h, 100% (95% CI: 84.6-100%) and 90.4% (95% CI: 83.8-94.9%) between 72-96h, and was 100% (95% CI: 59.0-100%) and 100% (95% CI: 95.1-100%) when combining the two measurements into a modified perfusion trend. Clinical assessment had an accuracy of 67%, Cohens k=0.23. Conclusion: The perfusion in scalds between 72-96h after injury, as measured using LSCI, is highly predictive of healing outcome in scalds when measured. The predictive value can be further improved by incorporating an early perfusion measurement within 24h after injury. (C) 2017 Elsevier Ltd and ISBI. All rights reserved.

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  • 43.
    Mirdell, Robin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping (ANOPIVA).
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Medical and Health Sciences.
    Interobserver reliability of laser speckle contrast imaging in the assessment of burns2019In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 45, no 6, p. 1325-1335Article in journal (Refereed)
    Abstract [en]

    Objectives: Laser speckle contrast imaging (LSCI) is an emerging technique for the assessment of burns in humans and interobserver differences have not been studied. The aim of this study was to compare assessments of perfusion images by different professional groups regarding (i) perfusion values and (ii) burn depth assessment. Methods: Twelve observers without LSCI experience were included. The observers were evenly recruited from three professional groups: plastic surgeons with experience in assessing burns, nurses with experience in treating burns, and junior doctors with limited experience of burns. Ten cases were included. Each case consisted of one digital photo of the burn with a pre-marked region of interest (ROI) and two unmarked perfusion images of the same area. The first and the second perfusion image was from 24h and 72-96h after injury, respectively. The perfusion values from both perfusion images were used to generate a LSCI recommendation based on the perfusion trend (the derivative between the two perfusion values). As a last step, each observer was asked to estimate the burn depth using their clinical experience and all available information. Intraclass correlation (ICC) was calculated between the different professional groups and among all observers. Results: Perfusion values and perfusion trends between all observers had an ICC of 0.96 (95% CI 0.91-0.99). Burn depth assessment by all observers yielded an ICC of 0.53 (95% CI: 0.31-0.80) and an accuracy of 0.53 (weighted kappa). LSCI recommendations generated by all observers had an ICC of 0.95 (95% CI: 0.90-0.99). Conclusion: Observers can reliably identify the same ROI, which results in observer-independent perfusion measurements, irrespective of burn experience. Extensive burn experience did not further improve burn depth assessment. The LSCI recommendation was more accurate in all professional groups. Introducing LSCI measurements would be likely improve early assessment of burns. (C) 2019 Elsevier Ltd and ISBI. All rights reserved.

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  • 44.
    Mirdell, Robin
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Sjöberg, Folke
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, ANOPIVA US.
    Tesselaar, Erik
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Using blood flow pulsatility to improve the accuracy of laser speckle contrast imaging in the assessment of burns2020In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 46, no 6, p. 1398-1406Article in journal (Refereed)
    Abstract [en]

    Objectives: Measurement of perfusion is an establishedmethod to evaluate the depth of burns. However, high accuracy is only achievable &gt;48 h after injury. The aim of the study was to investigate if measurement of blood flow pulsatility, combined with perfusion measurement, can improve early assessment of burn depth using laser speckle contrast imaging (LSCI). Methods: Perfusion and pulsatility were measured with LSCI in 187 regions of interest in 32 patients, between 0 and 5 days after injury. The reproducibility of pulsatility was tested for recording durations between 1 and 12 s. The most reproducible duration was chosen, and receiver operator characteristics were created to find suitable pulsatility cut-offs to predict surgical need. Results: A measurement duration of 8 s resulted in a good reproducibility of the pulsatility (% CV: 15.9%). Longer measurement durations resulted in a small improvement of the accuracy of the assessment. A pulsatility of &lt;1.45 (Perfusion Units)(2) on day 0-2 after injury predicted surgical need with a sensitivity of 100% (95% CI: 83.2-100%), specificity of 100% (95% CI: 95.2-100%), a positive predictive value of 100%, and a negative predictive value of 100%. Pulsatility was not significantly different when comparing measurements done day 0-2 today 3-5. Perfusion was however significantly higher day 3-5 compared today 0-2 for wound shealing with in 3 weeks. Conclusion: Measurement of pulsatility improves the accuracy of the assessment of burns with LSCI and makes it possible to predict the need for surgery during day 0-2 after injury with a high accuracy. (C) 2020 Elsevier Ltd and ISBI. All rights reserved.

  • 45.
    Mirdell, Robin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Iredahl, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Faculty of Medicine and Health Sciences.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Microvascular blood flow in scalds in children and its relation to duration of wound healing: A study using laser speckle contrast imaging2016In: Burns, ISSN 0305-4179, E-ISSN 1879-1409, Vol. 42, no 3, p. 648-654Article in journal (Refereed)
    Abstract [en]

    Background: Microvascular perfusion changes in scalds in children during the first weeks after injury is related to the outcome of healing, and measurements of perfusion, based on laser Doppler imaging, have been used successfully to predict the need for excision and grafting. However, the day-to-day changes in perfusion during the first weeks after injury have not to our knowledge been studied in detail. The aim of this study, based on a conservative treatment model where excision and grafting decisions were delayed to day 14 after injury, was to measure changes in perfusion in scalds using laser speckle contrast imaging (LSCI) during the first three weeks after injury. Methods: We measured perfusion with LSCI in 34 patients at regular intervals between 6 h after injury until complete reepithelialization or surgery. Duration of healing was defined as the time to complete reepithelialization. Results: Less perfusion, between 6 and 96 h after injury, was associated with longer duration of healing with the strongest association occurring between 72 and 96 h. Burns that healed within 14 days had relatively high initial perfusion, followed by a peak and subsequent slow decrease. Both the maximum perfusion and the time-to-peak were dependent on the severity of the burn. Burns that needed excision and grafting had less initial perfusion and a gradual reduction over time. Conclusion: The perfusion in scalds in children shows characteristic patterns during the first weeks after injury depending on the duration of wound healing, the greatest difference between wounds of different severity being on the 4th day. Perfusion should therefore preferably be measured on the fourth day if it is to be used in the assessment of burn depth. (c) 2015 Elsevier Ltd and ISBI. All rights reserved.

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  • 46.
    Mirdell, Robin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Lemstra-Idsardi, Aukje Nienke
    University of Twente, Enschede, Netherlands.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences.
    Data on microcirculatory perfusion dips in the resting nail bed2018In: Data in Brief, E-ISSN 2352-3409, Vol. 21, p. 1232-1235Article in journal (Refereed)
    Abstract [en]

    This article contains the raw data from the article entitled: "The presence of synchronized perfusion dips in the microcirculation of the resting nail bed" Mirdell et al. (in press). A laser speckle contrast imager (LSCI) was used to make a total of 21 recordings of the perfusion in the resting nail bed of 10 healthy test subjects. The first 10 recordings were acquired after 5?min of acclimatization. An additional 10 recordings were acquired in the same test subjects, after 20?min of acclimatization. In the last recording, a digital nerve block was applied to the left dig III. The data show the presence of highly irregular perfusion variations, a phenomenon we like to call perfusion dips. The data also show how the perfusion dips can be abolished through a digital nerve block. An algorithm for the quantification of the perfusion dips is included in the data.

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  • 47.
    Mirdell, Robin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Lemstra-Idsardi, Aukje Nienke
    Univ Twente, Netherlands.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Tesselaar, Erik
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Medical radiation physics. Linköping University, Department of Medical and Health Sciences.
    The presence of synchronized perfusion dips in the microcirculation of the resting nail bed2019In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 121, p. 71-81Article in journal (Refereed)
    Abstract [en]

    Objectives: Laser speckle contrast imaging (LSCI) has seen limited use in the study of perfusion dynamics such as vasomotion. The aim of this study was to investigate the effects of a prolonged seated position on perfusion dynamics in the nail bed using LSCI. Methods: Perfusion was recorded in digits II to IV bilaterally for 20 min during two separate sessions in ten healthy volunteers. The acclimatization period was 5 min for the 1st session and 20 min for the 2nd. Perfusion variability and the presence of recurring perfusion dips were analyzed. A digital nerve block was done to verify suspected nervous origin of phenomenon. Results: Synchronized phases of vasoconstriction were observed in all subjects with perfusion dips in all digits bilaterally and simultaneously. Application of a digital nerve block abolished perfusion dips. The frequency of this phenomenon increased by 25.0% (95% CI: 1.6 to 49.2%) in the left-hand digits after a prolonged seated position. Perfusion variability increased by 11.6% (95% CI: 2.6 to 20.3%) in the digits of the left hand. Perfusion changes in right-hand digits did not significantly increase. During the 1st session, temperature increased by 2.7 degrees C (1.1 to 4.2) while it decreased by 1.3 degrees C (0.2 to 2.4) during the 2nd session. Conclusion: The observed perfusion dips are of a centrally mediated nervous origin but are also affected by local factors. They are affected by seating duration and differ between left and right hands, likely because of local micro perfusion dips. This phenomenon seems related to digital thermoregulation.

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  • 48.
    Moloney, Maria
    et al.
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Adolfsson, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    20-Year outcome of TFCC repairs2018In: Journal of Plastic Surgery and Hand Surgery, ISSN 2000-656X, E-ISSN 2000-6764, Vol. 52, no 3, p. 193-197Article in journal (Refereed)
    Abstract [en]

    The aims of this study were to investigate the functional result and rate of osteoarthritis 15-25 years after a TFCC-repair. Forty-seven patients completed the questionnaire Patient Rated Wrist Evaluation (PRWE), and 43 had new X-rays. Fifty-seven percent had a simultaneous arthroscopy. Sixteen patients had later additional surgery to the wrist, of these eight had a reoperation of the TFCC-injury due to recurrent instability. Radiographs showed that 17.5% had developed radiocarpal osteoarthritis and 34% osteoarthritis in the distal radioulnar joint. The median PRWE result was 22.5. Patients with radiocarpal osteoarthritis and patients who had additional surgery had significantly worse scores. Patients who had undergone arthroscopy significantly less often had developed radiocarpal osteoarthritis. The result is acceptable but not impressive and efforts should be made to diagnose these injuries early and also diagnose associated injuries, advisably by arthroscopy.

  • 49.
    Moloney, Maria
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Adolfsson, Lars
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Distal ulna fractures in adults - subcapitular, transverse fractures did not benefit from surgical treatment2023In: Archives of Orthopaedic and Trauma Surgery, ISSN 0936-8051, E-ISSN 1434-3916, Vol. 143, no 1, p. 381-387Article in journal (Refereed)
    Abstract [en]

    Introduction Fractures of the distal ulna, excluding the styloid, are rare. The cause of injury is often a fall on an outstretched hand with an extended wrist, and in most cases there is a concomitant distal radius fracture. The aims of this retrospective study were to investigate the results of the current treatment of distal ulna fractures in adults, with or without a concomitant distal radius fracture, and if a recently presented fracture classification could predict outcome. Materials and methods Patients, 18 years or older, treated for a fracture of the distal third of ulna in our county, were included. Fractures of the styloid tip were excluded. The radiographs of the fractures were independently classified by two specialists in radiology according to the 2018 AO/OTA classification. Follow-up was performed 5-7 years after the injury, through the questionnaire Patient-Rated Wrist Evaluation (PRWE) and new radiographs of both wrists. Results Ninety-six patients with 97 fractures were included and filled out the PRWE. 65 patients also had new radiographs taken. 79 patients were women and the mean age at the time of injury was 63 years (SD 14.5). The most common fracture class was the extra-articular transverse fracture, 2U3A2.3 (42%). We found that 40% of the fractures had been treated by internal fixation and only 2 fractures had not healed, one conservatively treated and one operated. The median PRWE was 15 (IQR 33.5). The PRWE score was significantly worse in the operated ulna fractures (p = 0.01) and this was also true for extra-articular transverse fractures 2U3A2.3 (p = 0.001). Initial displacement was more common in operated transverse fractures, but it could not be proven that this was the reason for the inferior result. Conclusions Distal ulna fractures almost always unite and the result is comparable to that of isolated distal radius fractures when measured by PRWE. Based on the opinions of the radiologists and how often a consensus discussion was needed for classification, we found the updated AO classification system difficult to use, if dependent only on standard radiographic views. In the present study, transverse extra-articular ulna fractures did not benefit from internal fixation regardless if associated with a distal radius fracture or isolated.

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  • 50.
    Moloney, Maria
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Farnebo, Simon
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology.
    Adolfsson, Lars
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Incidence of distal ulna fractures in a Swedish county: 74/100,000 person-years, most of them treated non-operatively2020In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 91, no 1, p. 104-108Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Fractures of the distal ulna can occur in isolation or in conjunction with a distal radius fracture. They may result in incongruence and instability of the distal radioulnar joint. We investigated the incidence of distal ulna fractures, whether any fracture types were more common, and the methods of treatment used. Patients and methods - Data were collected from patients 18 years or older, treated for a fracture of the distal ulna in ostergotland, Sweden, during 2010-2012. Patients were identified in the patient registry. The fractures were classified according to the AO comprehensive classification of fractures. Results - The incidence of distal ulna fractures was 74/100,000 person-years. The most common fracture type was that of the ulnar styloid Q1 (79%), followed by the ulnar neck Q2 (11%). Rarest was ulna head fracture, type Q4 (1%). Incidental findings were a mean age of 63 years (SD 18), a concomitant distal radius fracture in 92% of the patients and that 79% were caused by falling from standing height. Internal fixation was performed in 30% of the Q2-Q6 fractures. This indicates that most were considered stable without internal fixation or stable after fixation of a concomitant radius fracture. Interpretation - Our results show that fractures of the distal ulna are not very common, and some fracture types are even rare. There seem to be no consensus on treatment.

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