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  • 1.
    Antonsson, Johan
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Eriksson, Ola
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Blomstedt, Patric
    Department of Neurosurgery, University Hospital, Umeå, Sweden.
    Bergenheim, Tommy
    Department of Neurosurgery, University Hospital, Umeå, Sweden.
    Hariz, Marwan
    Department of Neurosurgery, University Hospital, Umeå, Sweden.
    Richter, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diffuse reflectance spectroscopy measurements for tissue type discrimination during deep brain stimulation2008In: Journal of neural engineering, ISSN 1741-2560, Vol. 5, no 2, p. 185-190Article in journal (Refereed)
    Abstract [en]

    Diffuse reflectance spectroscopy as a method for improving intracerebral guidance during functional neurosurgery has been investigated. An optical probe was developed for measurements during stereotactic and functional neurosurgery in man. The aim of the study was to investigate the spectral differences between white and grey matter and between white matter and functional targets. Diffuse reflectance spectroscopy measurements in ten patients were recorded at incremental steps towards and in three different functional targets (STN, GPi and Zi). The recorded spectra along the trajectory were sorted into white or grey matter, based on preoperative MRI images or the recorded spectral shape and intensity. The difference between tissue types was calculated as a quotient. Significant intensity differences between white and grey matter were found to be at least 14% (p < 0.05) and 20% (p < 0.0001) for MRI and spectral-sorted data respectively. The reflectance difference between white matter and the functional targets of GPi was higher than for STN and Zi. The results indicate that diffuse reflectance spectroscopy has a potential to be developed to a suitable complement to other intracerebral guidance methods.

  • 2.
    Bak, Julia
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine.
    Gunnarsson, Thorsteinn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Stereotactic brain biopsies guided by intraoperative cytological diagnosis2001In: Modern Pathology, ISSN 0893-3952, E-ISSN 1530-0285, Vol. 14, no 1, p. 1214-Conference paper (Other academic)
  • 3.
    Boström, Sverre
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Bobinski, L
    Zsigmond, Peter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Theodorsson, Annette
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Improved brain protection at decompressive craniectomy - a new method using Palacoso (R) R-40 (methylmethacrylate)2005In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940, Vol. 147, no 3, p. 279-281Article in journal (Refereed)
    Abstract [en]

    A new method is described for protecting the brain after decompressive craniectomy in which a temporary methylmethacrylate flap is formed, somewhat larger than the original bone flap, thus gaining "extra" volume for the oedematous brain in which to expand. The present procedure was developed as a pan of ordinary clinical practice particularly in response to demands from the NICU staff and our colleagues at other clinics who were responsible for the care of the patient in the post NICU period. They made us keenly aware that these patients frequently lack optimal co-ordination and balance and therefore run an increased risk of trauma to the unprotected brain when failing. This prompted us to develop a method for brain protection after decompressive craniectomy aiding in the care and rehabilitation until the final installation of the patient's own bone flap can be performed.

  • 4.
    Boström, Sverre
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Milos, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Bobinski, Lukas
    Department of Neurosurgery, Umeå University Hospital, Umeå.
    A new microsurgical instrument - a suction tube combined with a microdissector2011In: BRITISH JOURNAL OF NEUROSURGERY, ISSN 0268-8697, Vol. 25, no 3, p. 320-321Article in journal (Refereed)
    Abstract [en]

    A microsurgical suction tube with an attached ball probe has been developed. It functions as a microdissector when the ball probe is in its extended position, creating a larger working field than an ordinary sucker. When the ball probe is in the repose position, it does not interfere with the suction capacity, and the suction tube serves as a regular sucker. By adding the properties of the microdissector to the suction tube, dissection of exquisitely fine and subtle structures, including arachnoidal membranes, is facilitated. The ball probe is easily dismantled from the suction tube and the whole instrument conveniently cleaned.

  • 5.
    Diczfalusy, Elin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Didzar, Nil
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Biochemical monitoring and simulation of the electric field during deep brain stimulation (oral)2010Conference paper (Other academic)
  • 6.
    Diczfalusy, Elin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Dizdar (Dizdar Segrell), Nil
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Simulations and visualizations for interpretation of brain microdialysis data during deep brain stimulation2012In: IEEE Engineering in Medicine and Biology Society (EMBC), 2012, IEEE , 2012, p. 6438-6441Conference paper (Refereed)
    Abstract [en]

    Microdialysis of the basal ganglia was used in parallel to deep brain stimulation (DBS) for patients with Parkinson’s disease. The aim of this study was to patientspecifically simulate and visualize the maximum tissue volume of influence (TVImax) for each microdialysis catheter and the electric field generated around each DBS electrode. The finite element method (FEM) was used for the simulations. The method allowed mapping of the anatomical origin of the microdialysis data and the electric stimulation for each patient. It  was seen that the sampling and stimulation targets differed among the patients, and the results will therefore be used in the future interpretation of the biochemical data.

  • 7.
    Diczfalusy, Elin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Dizdar (Dizdar Segrell), Nil
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    A model for simulation and patient-specific visualization of the tissue volume of influence during brain microdialysis2011In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 49, no 12, p. 1459-1469Article in journal (Refereed)
    Abstract [en]

    Microdialysis can be used in parallel to deep brain stimulation (DBS) to relate biochemical changes to the clinical outcome. The aim of the study was to use the finite element method to predict the tissue volume of influence (TVI(max)) and its cross-sectional radius (r (TVImax)) when using brain microdialysis, and visualize the TVI(max) in relation to patient anatomy. An equation based on Fick's law was used to simulate the TVI(max). Factorial design and regression analysis were used to investigate the impact of the diffusion coefficient, tortuosity and loss rate on the r (TVImax). A calf brain tissue experiment was performed to further evaluate these parameters. The model was implemented with pre-(MRI) and post-(CT) operative patient images for simulation of the TVI(max) for four patients undergoing microdialysis in parallel to DBS. Using physiologically relevant parameter values, the r (TVImax) for analytes with a diffusion coefficient D = 7.5 × 10(-6) cm(2)/s was estimated to 0.85 ± 0.25 mm. The simulations showed agreement with experimental data. Due to an implanted gold thread, the catheter positions were visible in the post-operative images. The TVI(max) was visualized for each catheter. The biochemical changes could thereby be related to their anatomical origin, facilitating interpretation of results.

  • 8.
    Diczfalusy, Elin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Didzar, Nil
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    A finite element model for biochemical monitoring in the brain during deep brain stimulation (poster)2010Conference paper (Refereed)
  • 9.
    Diczfalusy, Elin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Dizdar, Nil
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    A Finite Model for Biochemical Monitoring in the Brain during Deep Brain Stimulation (oral)2010Conference paper (Refereed)
  • 10.
    Dizdar (Dizdar Segrell), Nil
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Nezirevic, Dzeneta
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Letter: Untitled2013In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 212, no 2, p. 363-363Article in journal (Refereed)
    Abstract [en]

    n/a

  • 11.
    Eneling, J
    et al.
    Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Boström, Sverre
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Rossitti, Sandro
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Editorial Material: Subarachnoid Hemorrhage-associated Arachnoiditis and Syringomyelia2012In: CLINICAL NEURORADIOLOGY, ISSN 1869-1439, Vol. 22, no 2, p. 169-173Article in journal (Other academic)
    Abstract [en]

    n/a

  • 12.
    Forsberg, Daniel
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Lundström, Claes
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Andersson, Mats
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Vavruch, Ludvig
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Tropp, Hans
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Knutsson, Hans
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Health Sciences.
    Fully automatic measurements of axial vertebral rotation for assessment of spinal deformity in idiopathic scoliosis2013In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 58, no 6, p. 1775-1787Article in journal (Refereed)
    Abstract [en]

    Reliable measurements of spinal deformities in idiopathic scoliosis are vital, since they are used for assessing the degree of scoliosis, deciding upon treatment and monitoring the progression of the disease. However, commonly used two dimensional methods (e.g. the Cobb angle) do not fully capture the three dimensional deformity at hand in scoliosis, of which axial vertebral rotation (AVR) is considered to be of great importance. There are manual methods for measuring the AVR, but they are often time-consuming and related with a high intra- and inter-observer variability. In this paper, we present a fully automatic method for estimating the AVR in images from computed tomography. The proposed method is evaluated on four scoliotic patients with 17 vertebrae each and compared with manual measurements performed by three observers using the standard method by Aaro-Dahlborn. The comparison shows that the difference in measured AVR between automatic and manual measurements are on the same level as the inter-observer difference. This is further supported by a high intraclass correlation coefficient (0.971-0.979), obtained when comparing the automatic measurements with the manual measurements of each observer. Hence, the provided results and the computational performance, only requiring approximately 10 to 15 s for processing an entire volume, demonstrate the potential clinical value of the proposed method.

  • 13.
    Gunnarsson, Thorsteinn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Olafsson, E.
    Ólafsson, E..
    Sighvatsson, V.
    Sighvatsson, V..
    Hannesson, B.
    Hannesson, B..
    Surgical treatment of patients with low-grade astrocytomas and medically intractable seizures2002In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 105, no 4, p. 289-292Article in journal (Refereed)
    Abstract [en]

    Objective - Low-grade astrocytomas can present with seizures that respond poorly to antiseizure medications, with a consequent reduction in the quality of life, because of both seizures and the medication's side-effects. We report our experience with operative treatment of such patients. Subjects and methods - Five patients (two children and three adults) with supratentorial low-grade astrocytomas associated with severe seizures were operated on. We followed the effects of the operation on post-operative neurological deficit, seizure frequency and the quality of life. Results - No serious neurological complications followed the operations. The patients were followed for a median period of 12 months (6-46). Post-operatively, three of the patients became seizure-free, one experiences only auras, and one had a great reduction in seizure frequency and severity. All patients reported great improvement in their quality of life. Conclusion - Resections of low-grade astrocytomas in patients with medically intractable seizures are safe procedures that effectively control seizures in the majority of patients, resulting in significant improvement in the patients' quality of life.

  • 14.
    Haj-Hosseini, Neda
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Richter, Johan
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Olivecrona, Magnus
    Department of Neurosurgery, Umeå University.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Fluorescence guided spectroscopy versus fluorescence microscopy for brain tumor resection2013Conference paper (Other academic)
  • 15.
    Hemm, Simone
    et al.
    Institute for Medical and Analytical Technologies (IMA), FHNW, Switzerland.
    Richter, Johan C.O.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Optical measurements for guidance during deep brain stimulation implantation2011Conference paper (Refereed)
  • 16.
    Hemm, Simone
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Richter, Johan
    Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL. Linköping University, Department of Biomedical Engineering.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Laser doppler for guidance during DBS-typical optical trajectories toward Vim and STN2012Conference paper (Other academic)
  • 17.
    Herngren, Bengt
    et al.
    Lund University, Sweden.
    Stenmarker, Margaretha
    Ryhov County Hospital, Sweden.
    Vavruch, Ludek
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Hagglund, Gunnar
    Lund University, Sweden.
    Slipped capital femoral epiphysis: a population-based study2017In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 18, article id 304Article in journal (Refereed)
    Abstract [en]

    Background: Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in children 9-15 years old. This is a population-based study in Sweden presenting the epidemiology for SCFE. Methods: In a prospective cohort study, we analysed pre- and postoperative radiographs, medical records for all children treated for SCFE in Sweden 2007-2013, demographic data, severity of slip and surgical procedures performed. Results: We identified 379 Swedish children with primary SCFE 2007-2013; 162 girls, median age 11.7 (7.2-15.4) years, and 217 boys, median age 13 (3.8-17.7) years. The average annual incidence was 4.4/10000 for girls and 5.7/10000 for boys 9-15 years old. Obesity or overweight was found in 56% of the girls and in 76% of the boys. As an initial symptom, 66% of the children had hip/groin pain and 12% knee pain. At first presentation, 7% of the children had bilateral SCFE. Prophylactic fixation was performed in 43%. Of the remaining children, 21% later developed a contralateral slip. Fixation with implants permitting further growth was used in amp;gt;90% of the children. Femoral neck osteotomy was performed for 11 hips. Conclusions: The annual average incidence 2007-2013 in Sweden showed a mild increase for girls. The male-to-female ratio was lower than previous regional data from Sweden. Overweight or obesity is one major characteristic for boys with SCFE but to a less extent for girls. Knee pain as initial symptom cause a delay in diagnosis. Most hospitals in Sweden treat amp;lt;2 children annually.

  • 18.
    Hillman, Jan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Fridriksson, Steen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Nilsson, O
    Saveland, H
    Jakobsson, KE
    Prevention of early rebleeding: response2003Other (Other academic)
    Abstract [en]

    No abstract available.

  • 19.
    Hillman, Jan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Fridriksson, Steen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Yu, ZQ
    Linkoping Univ Hosp, S-58185 Linkoping, Sweden Univ Lund Hosp, S-22185 Lund, Sweden Sahlgrens Univ Hosp, S-41345 Gothenburg, Sweden.
    Nilsson, O
    Saveland, H
    Linkoping Univ Hosp, S-58185 Linkoping, Sweden Univ Lund Hosp, S-22185 Lund, Sweden Sahlgrens Univ Hosp, S-41345 Gothenburg, Sweden.
    Jakobsson, KE
    Linkoping Univ Hosp, S-58185 Linkoping, Sweden Univ Lund Hosp, S-22185 Lund, Sweden Sahlgrens Univ Hosp, S-41345 Gothenburg, Sweden.
    Protection from rebleeding: response2002Other (Other academic)
    Abstract [en]

    No abstract available.

  • 20.
    Holmberg, Lars
    et al.
    Kings Coll London, Div Canc Studies, London SE1 9RT, England.
    Garmo, Hans
    Regional Oncologic Center, University Hospital, Uppsala.
    Granstrand, Bengt
    Norrland University Hospital, Umeå.
    Ringberg, Anita
    Malmö University Hospital.
    Arnesson, Lars-Gunnar
    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.
    Sandelin, Kerstin
    Karolinska Hospital, Stockholm.
    Karlsson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Anderson, Harald
    University Hospital, Lund.
    Emdin, Stefan
    Norrland University Hospital, Umeå.
    Absolute risk reductions for local recurrence after postoperative radiotherapy after sector resection for ductal carcinoma in situ of the breast2008In: Journal of Clinical Oncology, ISSN 0732-183X, E-ISSN 1527-7755, Vol. 26, no 8, p. 1247-1252Article in journal (Refereed)
    Abstract [en]

    Purpose Evaluate the effects of radiotherapy after sector resection for ductal carcinoma in situ of the breast (DCIS) in patient groups as defined by age, size of the lesion, focality, completeness of excision and mode of detection. Patients and Methods A total of 1,067 women in Sweden were randomly assigned to either postoperative radiotherapy (RT) or control from 1987 to 1999, and 1,046 were followed for a mean of 8 years. The main outcome was new ipsilateral breast cancer events and distant metastasis-free survival analyzed according to intention to treat. Results There were 64 ipsilateral events in the RT arm and 141 in the control group corresponding to a risk reduction of 16.0 percentage points at 10 years (95% CI, 10.3% to 21.6%) and a relative risk of 0.40 (95% CI, 0.30 to 0.54). There was no statistically significant difference in distant metastasis free survival. There was an effect modification by age, yielding a low effect of RT in women younger than 50, but substantial protection in women older than 60 years. The age effect was not confounded by focality, lesion size, completeness of excision, or detection mode. There was no group as defined by our stratification variables that had a low risk without radiotherapy. Conclusion Our results indicate that younger women have a low protective effect of conventional RT after sector resection. Older women benefit substantially. We caution that the age effect was seen in a subgroup analysis. Further search with conventional clinical variables for a low risk group that does not need RT does not seem fruitful.

  • 21.
    Ingberg, Edvin
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ström, Jakob O
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Methods for long-term 17β-estradiol administration to mice2012In: General and Comparative Endocrinology, ISSN 0016-6480, E-ISSN 1095-6840, Vol. 175, no 1, p. 188-193Article in journal (Refereed)
    Abstract [en]

    Rodent models constitute a cornerstone in the elucidation of the effects and biological mechanisms of 17β-estradiol. However, a thorough assessment of the methods for long-term administration of 17β-estradiol to mice is lacking. The fact that 17β-estradiol has been demonstrated to exert different effects depending on dose emphasizes the need for validated administration regimens. Therefore, 169 female C57BL/6 mice were ovariectomized and administered 17β-estradiol using one of the two commonly used subcutaneous methods; slow-release pellets (0.18 mg, 60-day release pellets; 0.72 mg, 90-day release pellets) and silastic capsules (with/without convalescence period, silastic laboratory tubing, inner/outer diameter: 1.575/3.175 mm, filled with a 14 mm column of 36 μg 17β-estradiol/mL sesame oil), or a novel peroral method (56 μg 17β-estradiol/day/kg body weight in the hazelnut cream Nutella). Forty animals were used as ovariectomized and intact controls. Serum samples were obtained weekly for five weeks and 17β-estradiol concentrations were measured using radioimmunoassay. The peroral method resulted in steady concentrations within – except on one occasion – the physiological range and the silastic capsules produced predominantly physiological concentrations, although exceeding the range by maximum a factor three during the first three weeks. The 0.18 mg pellet yielded initial concentrations an order of magnitude higher than the physiological range, which then decreased drastically, and the 0.72 mg pellet produced between 18 and 40 times higher concentrations than the physiological range during the entire experiment. The peroral method and silastic capsules described in this article constitute reliable modes of administration of 17β-estradiol, superior to the widely used commercial pellets.

  • 22.
    Javid, D.
    et al.
    Department of Orthopedic Surgery, Huddinge University Hospital, 141 86 Stockholm, Sweden.
    Hedlund, R.
    Department of Orthopedic Surgery, Huddinge University Hospital, 141 86 Stockholm, Sweden.
    Vavruch, Ludek
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery .
    Leszniewski, W.
    Is the efficacy of the Cloward procedure overestimated? Technique of evaluation affects the outcome2001In: European spine journal, ISSN 0940-6719, E-ISSN 1432-0932, Vol. 10, no 3, p. 222-227Article in journal (Refereed)
    Abstract [en]

    The purpose of the present study was to investigate the influence of the evaluation technique on the outcome of the Cloward procedure in cervical radiculopathy. The retrospective study included 94 consecutive patients operated on with anterior decompression and fusion with heterologous bone (Surgibone, Unilab). There were 56 men and 38 women, with a mean age of 48 years (range 27-78 years). Sixty-six patients had a single-level fusion, 26 a two-level fusion and one patient had a three-level fusion. The follow-up rate was 91/94 (97%) and evaluation was performed by an independent observer. Pain was quantified by visual analogue scale (VAS, range 0-100), functional disability by the new functional index Cervical Spine Functional Score (CSFS, range 0-100) and by the Neck Pain Disability Index (NPDI, range 0-100). The overall clinical outcome was assessed as excellent, good, fair or poor by both the patient and by the independent observer using Odom's criteria. At a mean follow-up of 26 months (range 12-56 months) the mean pain index was 39 (range 0-98), the mean CSFS 39 (range 0-85) and the mean NPDI 32 (range 0-76). The classification of the observer was 37% excellent, 40% good, 17% fair and 6% poor, and that of the patient was 53% excellent, 23% good, 20% fair and 4% poor. In the group classified as good by the observer, all scores were above 40, suggesting considerable remaining symptoms, and only 50% had returned to work. The results suggest that previous reports on the Cloward procedure using categorizations into excellent, good, fair or poor have overestimated the efficacy of the procedure. Only an excellent, but not a good, result as classified by the patient or an independent observer reflects a successful outcome. Neither of the variables studied seems independently sufficient for a balanced reflection of the outcome. The results suggest pain (VAS) as the primary outcome measurement, which, combined with the overall evaluation by the independent observer and work status, gives a multidimensional expression of the outcome.

  • 23.
    Mazya, Michael
    et al.
    Vrinnevisjukhuset Norrköping.
    Rossitti, Sandro
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Andersson, Mats
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurology . Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    New endovascular treatment of intracranial arterial stenosis in clinical practice. Good result in a patient with high risk of cerebral ischemia2008In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 105, no 37, p. 2486-2487Article in journal (Refereed)
    Abstract [en]

       

  • 24.
    Mellergard, Pekka
    et al.
    Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Sjögren, Florence
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Dermatology and Venerology in Östergötland.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Release of VEGF and FGF in the extracellular space following severe subarachnoidal haemorrhage or traumatic head injury in humans2010In: British Journal of Neurosurgery, ISSN 0268-8697, E-ISSN 1360-046X, Vol. 24, no 3, p. 261-267Article in journal (Refereed)
    Abstract [en]

    Microdialysate fluid from 145 severely injured NSICU-patients, 88 with subarachnoidal haemorrage (SAH), and 57 with traumatic brain injury (TBI), was collected by microdialysis during the first 7 days following impact, and levels of the neurotrophins fibroblast growth factor-2 (FGF2) and vascular endothelial growth factor (VEGF) were analysed. The study illustrates both similarities and differences in the reaction patterns of the 2 inflammatory proteins. The highest concentrations of both FGF2 and VEGF were measured on Day 2 (mean (+/- SE) values being 47.1 +/- 15.33 and 116.9 +/- 41.85 pg/ml, respectively, in the pooled patient material). The VEGF concentration was significantly higher in TBI-patients, while the FGF2 showed a tendency to be higher in SAH-patients. This is the first report presenting in some detail the human cerebral response of FGF2 and VEGF following SAH and TBI. Apart from increasing the understanding of the post-impact inflammatory response of the human brain, the study identifies potential threshold values for these chemokines that may serve as monitoring indicators in the NSICU.

  • 25.
    Mellergard, Pekka
    et al.
    Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Sjögren, Florence
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Dermatology and Venerology in Östergötland.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    The Cerebral Extracellular Release of Glycerol, Glutamate, and FGF2 Is Increased in Older Patients following Severe Traumatic Brain Injury2012In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 29, no 1, p. 112-118Article in journal (Refereed)
    Abstract [en]

    Old age is associated with a poor recovery from traumatic brain injury (TBI). In a retrospective study we investigated if the biochemical response following TBI is age dependent. Extracellular fluids were continuously sampled by microdialysis in 69 patients admitted to our NSICU following severe TBI. The concentrations of glycerol, glutamate, lactate, pyruvate, and eight different cytokines (IL-1 beta, IL-6, IL-10, IL-8, MIP-1 beta, RANTES, FGF2, and VEGF) were determined by fluorescence multiplex bead technology. Patients in the oldest age group (andgt;= 65 years) had significantly higher microdialysate concentrations of glycerol and glutamate compared to younger patients: the mean microdialysate concentration of glycerol increased from 55.9 mu mol/L (25-44 year) to 252 mu mol/L (andgt;= 65 years; p andlt; 0.0001); similarly glutamate increased from 15.8 mmol/L to 92.2 mmol/L (p andlt; 0.0001). The lactate-pyruvate ratio was also significantly higher in the patients andgt;= 65 years of age (63.9) compared with all the other age groups. The patterns of cytokine responses varied. For some cytokines (IL-1b, IL-10, and IL-8) there were no differences between age groups, while for others (MIP-1b, RANTES, VEGF, and IL-6) some differences were observed, but with no clear correlation with increasing age. For FGF2 the mean microdialysate concentration was 43 pg/mL in patients andgt;= 65 years old, significantly higher compared to all other age groups (p andlt; 0.0001). Increased concentrations of glycerol and glutamate would indicate more extensive damaging processes in the elderly. An increase in concentration of FGF2 could serve a protective function, but could also be related to a dysregulation of the timing in the cellular response in elderly patients.

  • 26.
    Mellergård, Pekka
    et al.
    Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Åneman, Oscar
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Sjögren, Florence
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Dermatology and Venerology in Östergötland.
    Säberg, Carina
    Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Differences in Cerebral Extracellular Response of Interleukin-1 beta, Interleukin-6, and Interleukin-10 After Subarachnoid Hemorrhage or Severe Head Trauma in Humans2011In: NEUROSURGERY, ISSN 0148-396X, Vol. 68, no 1, p. 12-19Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Microdialysis has become a routine method for biochemical surveillance of patients in neurosurgical intensive care units. OBJECTIVE: To analyze the intracerebral extracellular levels of 3 interleukins (ILs) during the 7 days after major subarachnoid hemorrhage or traumatic brain injury). METHODS: Microdialysate from 145 severely injured neurosurgical intensive care unit patients (88 with subarachnoid hemorrhage, 57 with traumatic brain injury) was collected every 6 hours for 7 days. The concentrations of IL-1 beta and IL-6 were determined by fluorescence multiplex bead technology, and IL-10 was determined by enzyme-linked immunosorbent assay. RESULTS: Presented are the response patterns of 3 ILs during the first week after 2 different types of major brain injury. These patterns are different for each IL and also differ with respect to the kind of pathological impact. For both IL-1 beta and IL-6, the initial peaks (mean values for all patients at day 2 being 26.9 +/- 4.5 and 4399 +/- 848 pg/mL, respectively) were followed by a gradual decline, with IL-6 values remaining 100-fold higher compared with IL-1 beta. Female patients showed a stronger and more sustained response. The response of IL-10 was different, with mean values less than 23 pg/mL and with no significant variation between any of the postimpact days. For all 3 ILs, the responses were stronger in subarachnoid hemorrhage patients. The study also indicates that under normal conditions, IL-1 beta, IL-6, and IL-10 are present only at very low concentrations or not at all in the extracellular space of the human brain. CONCLUSION: This is the first report presenting in some detail the human cerebral response of IL-1 beta, IL-6, and IL-10 after subarachnoid hemorrhage and traumatic brain injury. The 3 ILs have different reaction patterns, with the response of IL-1 beta and IL-6 being related to the type of cerebral damage sustained, whereas the IL-10 response was less varied.

  • 27.
    Mellergård, Pekke
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Åneman, Oscar
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion.
    Sjögren, Florence
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology .
    Pettersson, P.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Linköping University, Faculty of Health Sciences.
    Hillman, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Changes in Extracellular Concentrations of Some Cytokines, Chemokines, and Neurotrophic Factors After Insertion of Intracerebral Microdialysis Catheters in Neurosurgical Patients2008In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 62, no 1, p. 151-157Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: The extracellular levels of eight different inflammatory agents were analyzed during the initial 36 hours after insertion of microdialysis catheters in patients. METHODS: Cerebral extracellular fluid from 38 patients who were treated in a neurosurgical intensive care unit for severe brain injury was collected every 6 hours for 36 hours. The concentration of interleukin (IL)-1ß, IL-6, IL-8, macrophage inflammatory protein-1ß, regulated on activation, normal T-cell expressed and secreted (RANTES), fibroblast growth factor-2, and vascular endothelial growth factor was determined by a multiplex assay, and IL-10 was determined by enzyme-linked immunosorbent assay. RESULTS: This is the first report regarding the presence of IL-10, IL-8, macrophage inflammatory protein-1ß, regulated on activation, T-cell expressed and secreted, vascular endothelial growth factor, and fibroblast growth factor-2 in the tissue level proper of the living human brain. The study also provides new information regarding the response of IL-1ß and IL-6 after insertion of a microdialysis catheter. The study confirms that the intriguing patterns of interplay between different components of the inflammatory response studied in laboratory settings are present in the human brain. This was most clearly observed in the variations in response between the three different chemokines investigated, as well as in the rapid and transient response of fibroblast growth factor-2. CONCLUSION: The data presented illustrate the opportunity to monitor biochemical events of possible importance in the human brain and indicate the potential of such monitoring in neurosurgical intensive care. The study also underlines that any analysis of events in the brain involving mechanical invasiveness needs to take into account biochemical changes that are directly related to the manipulation of brain tissue.

  • 28.
    Nord, Maria
    et al.
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Årstrand, Kerstin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Dizdar (Dizdar Segrell), Nil
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    The Effect of Peripheral Enzyme Inhibitors on Levodopa Concentrations in Blood and CSF2010In: Movement Disorders, ISSN 0885-3185, E-ISSN 1531-8257, Vol. 25, no 3, p. 363-367Article in journal (Refereed)
    Abstract [en]

    Levodopa combined with a dopa-decarboxylase inhibitor, such as carbidopa. shifts the metabolism to the COMT pathway. Adding the peripheral acting COMT inhibitor entacapone provides improvement for patients with PD suffering from motor fluctuations. We studied the effects of the enzyme inhibitors entacapone and carbidopa on the levodopa concentrations in CSF and in blood. Five PD patients with wearing-off underwent lumbar drainage and intravenous microdialysis. Samples were taken 12 h daily for 3 days. Day I; intravenous levodopa was given, day 2; additional oral entacapone 200 mg tid, day 3; additional oral entacapone 200 mg bid and carbidopa 25 mg bid. Levodopa in CSF and in dialysates was analysed. The AUC for levodopa increased both in blood and CSF when additional entacapone was given alone and in combination with carbidopa. The C-max of levodopa in both CSF and blood increased significantly. Additional entacapone to levodopa therapy gives an increase of C-max in CSF and in blood. The increase is more evident when entacapone is combined with carbidopa.

  • 29.
    Paues, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Ström, Jakob
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Eriksson, Lars
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Tuberculous meningitis with positive cell-count in lumbar puncture CSF though negative cell-count from ventricular drainage CSF2011In: Journal of Infection, ISSN 0163-4453, E-ISSN 1532-2742, Vol. 62, no 5, p. 404-405Article in journal (Other academic)
  • 30.
    Rejmstad, Peter
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Åkesson, Gustav
    Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Intracerebral perfusion monitoring by laser Doppler flowmetry, Medicinteknikdagarna2012Conference paper (Other academic)
  • 31.
    Rossitti, Sandro
    et al.
    Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Radzinska, Renata
    Högland Hospital.
    Vigren, Patrick
    Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Letter: Postoperative Ophthalmic Artery Pseudoaneurysm Presenting as Monocular Blindness Successful Endovascular Treatment2009In: Klinische Neuroradiologie, ISSN 0939-7116, E-ISSN 1615-6706, Vol. 19, no 3, p. 230-234Article in journal (Other academic)
    Abstract [en]

    n/a

  • 32.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Boström, Sverre
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Bobinski, L.
    Umeå University, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Low-grade infection complicating silastic dural substitute 32 years post-operatively2011In: Brain Injury, ISSN 0269-9052, E-ISSN 1362-301X, Vol. 25, no 2, p. 250-254Article in journal (Refereed)
    Abstract [en]

    Background: A complication of a silastic dural substitute is described, which appeared after 32 years-by far the longest latency period reported in the literature. Methods: Case report and literature review. Results: In 1971, a 20-year old woman suffered from an acute subdural haematoma and a temporal cerebral contusion due to a motorbike accident. She underwent an operation with evacuation of these and the dura was mended with a silastic duraplasty. Thirty-two years later she deteriorated with increased memory problems and dysphasia. CT revealed an expanding haemorrhagic mass around the previous duraplasty, which demanded surgery with removal of the silastic dural implant and evacuation of the haemorrhagic mass. Although the haemorrhagic mass enveloped the silastic implant, a contribution of the acrylate flap cannot be ruled out. Bacteriological cultures revealed Acinetobacter spp. in the CSF. Adequate post-operative antibiotic treatment was administered. The patient slowly improved, but the complication represented a major setback in her long-term cognitive and communicative functions. Conclusions: This case widens the previously reported time-frame of late complications by 60%, from 20 to 32 years, and will hopefully serve to increase the awareness of late infections and haemorrhages induced by silastic dural implants, thereby improving diagnosis and treatment in future cases.

  • 33.
    Ström, Jakob
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Method parameters’ impact on mortality and variability in rat stroke experiments: a meta-analysis2013In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 14, no 41Article in journal (Refereed)
    Abstract [en]

    Background

    Even though more than 600 stroke treatments have been shown effective in preclinical studies, clinically proven treatment alternatives for cerebral infarction remain scarce. Amongst the reasons for the discrepancy may be methodological shortcomings, such as high mortality and outcome variability, in the preclinical studies. A common approach in animal stroke experiments is that A) focal cerebral ischemia is inflicted, B) some type of treatment is administered and C) the infarct sizes are assessed. However, within this paradigm, the researcher has to make numerous methodological decisions, including choosing rat strain and type of surgical procedure. Even though a few studies have attempted to address the questions experimentally, a lack of consensus regarding the optimal methodology remains.

    Methods

    We therefore meta-analyzed data from 502 control groups described in 346 articles to find out how rat strain, procedure for causing focal cerebral ischemia and the type of filament coating affected mortality and infarct size variability.

    Results

    The Wistar strain and intraluminal filament procedure using a silicone coated filament was found optimal in lowering infarct size variability. The direct and endothelin methods rendered lower mortality rate, whereas the embolus method increased it compared to the filament method.

    Conclusions

    The current article provides means for researchers to adjust their middle cerebral artery occlusion (MCAo) protocols to minimize infarct size variability and mortality.

  • 34.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Ingberg, Edvin
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Druvefors, Emma
    Ryhov County Hospital, County Council of Jönköping, Sweden.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    The female menstrual cycle does not influence testosterone concentrations in male partners2012In: Journal of Negative Results in Biomedicine, ISSN 1477-5751, E-ISSN 1477-5751, Vol. 11, no 1Article in journal (Refereed)
    Abstract [en]

    Background

    The time of ovulation has since long been believed to be concealed to male heterosexual partners. Recent studies have, however, called for revision of this notion. For example, male testosterone concentrations have been shown to increase in response to olfactory ovulation cues, which could be biologically relevant by increasing sexual drive and aggressiveness. However, this phenomenon has not previously been investigated in real-life human settings. We therefore thought it of interest to test the hypothesis that males' salivary testosterone concentrations are influenced by phases of their female partners' menstrual cycle; expecting a testosterone peak at ovulation.

    Methods

    Thirty young, healthy, heterosexual couples were recruited. During the course of 30-40 days, the women registered menses and ovulation, while the men registered sexual activity, physical exercise, alcohol intake and illness (confounders), and obtained daily saliva samples for testosterone measurements. All data, including the registered confounders, were subjected to multiple regression analysis.

    Results

    In contrast to the hypothesis, the ovulation did not affect the testosterone levels, and the resulting testosterone profile during the menstrual cycle was on the average flat. The specific main hypothesis, that male testosterone levels on the day of ovulation would be higher than day 4 of the cycle, was clearly contradicted by a type II error(β)-analysis (< 14.3% difference in normalized testosterone concentration; β = 0.05).

    Conclusions

    Even though an ovulation-related salivary testosterone peak was observed in individual cases, no significant effect was found on a group level.

  • 35.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Theodorsson, Elvar
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Hormesis and Female Sex Hormones2011In: Pharmaceuticals, ISSN 1424-8247, E-ISSN 1424-8247, Vol. 4, p. 726-740Article in journal (Refereed)
    Abstract [en]

    Hormone replacement after menopause has in recent years been the subject of intense scientific debate and public interest and has sparked intense research efforts into the biological effects of estrogens and progestagens. However, there are reasons to believe that the doses used and plasma concentrations produced in a large number of studies casts doubt on important aspects of their validity. The concept of hormesis states that a substance can have diametrically different effects depending on the concentration. Even though estrogens and progestagens have proven prone to this kind of dose-response relation in a multitude of studies, the phenomenon remains clearly underappreciated as exemplified by the fact that it is common practice to only use one hormone dose in animal experiments. If care is not taken to adjust the concentrations of estrogens and progestagens to relevant biological conditions, the significance of the results may be questionable. Our aim is to review examples of female sexual steroids demonstrating bidirectional dose-response relations and to discuss this in the perspective of hormesis. Some examples are highlighted in detail, including the effects on cerebral ischemia, inflammation, cardiovascular diseases and anxiety. Hopefully, better understanding of the hormesis phenomenon may result in improved future designs of studies of female sexual steroids.

  • 36.
    Ström, Jakob O
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    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.
    Holm, Lovisa
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Theodorsson, Annette
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Different methods for administering 17 beta-estradiol to ovariectomized rats result in opposite effects on ischemic brain damage2010In: BMC neuroscience (Online), ISSN 1471-2202, E-ISSN 1471-2202, Vol. 11, p. 39-Article in journal (Refereed)
    Abstract [en]

    Background: Numerous stroke studies have controversially shown estrogens to be either neuroprotective or neurodamaging. The discordant results observed in rat brain ischemia models may be a consequence of discrepancies in estrogen administration modes resulting in plasma concentration profiles far from those intended. To test this hypothesis we reproduced in detail and extended an earlier study from our lab using a different mode of 17 beta-estradiol administration; home-made silastic capsules instead of commercial slow-release 17 beta-estradiol pellets. Four groups of female rats (n = 12) were ovariectomized and administered 17 beta-estradiol or placebo via silastic capsules. All animals underwent MCAo fourteen days after ovariectomy and were sacrificed three days later.

    Results: In contrast to our earlier results using the commercial pellets, the group receiving 17 beta-estradiol during the entire experiment had significantly smaller lesions than the group receiving placebo (mean +/- SEM: 3.85 +/- 0.70% versus 7.15 +/- 0.27% of total slice area, respectively; p = 0.015). No significant neuroprotection was found when the 17 beta-estradiol was administered only during the two weeks before or the three days immediately after MCAo.

    Conclusions: The results indicate that different estrogen treatment regimens result in diametrically different effects on cerebral ischemia. Thus the effects of estrogens on ischemic damage seem to be concentration-related, with a biphasic, or even more complex, dose-response relation. These findings have implications for the design of animal experiments and also have a bearing on the estrogen doses used for peri-menopausal hormone replacement therapy.

  • 37.
    Vigren, Patrick
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery.
    Tisell, Anders
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Low Thalamic NAA-Concentration Corresponds to Strong Neural Activation in Working Memory in Kleine-Levin Syndrome2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 2Article in journal (Refereed)
    Abstract [en]

    Background

    Kleine Levin Syndrome (KLS) is a rare disorder of periodic hypersomnia and behavioural disturbances in young individuals. It has previously been shown to be associated with disturbances of working memory (WM), which, in turn, was associated with higher activation of the thalamus with increasing WM load, demonstrated with functional magnetic resonance imaging (fMRI). In this study we aimed to further elucidate how these findings are related to the metabolism of the thalamus.

    Methods

    fMRI and magnetic resonance spectroscopy were applied while performing a WM task. Standard metabolites were examined: n-acetylaspartate (NAA), myo-inositol, choline, creatine and glutamate-glutamine. Fourteen KLS-patients and 15 healthy controls participated in the study. The patients with active disease were examined in asymptomatic periods.

    Results

    There was a statistically significant negative correlation between thalamic fMRI-activation and thalamic NAA, i.e., high fMRI-activation corresponded to low NAA-levels. This correlation was not seen in healthy controls. Thalamic levels of NAA in patients and controls showed no significant differences between the groups. None of the other metabolites showed any co-variation with fMRI-activiation.

    Conclusion

    This study shows negative correlation between NAA-levels and fMRI-activity in the left thalamus of KLS-patients while performing a WM task. This correlation could not be found in healthy control subjects, primarily interpreted as an effect of increased effort in the patient group upon performing the task. It might indicate a disturbance in the neuronal networks responsible for WM in KLS patients, resulting in higher effort at lower WM load, compared with healthy subjects. The general relationship between NAA and BOLD-signal is also discussed in the article.

  • 38.
    Wårdell, Karin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Blomstedt, P.
    Department of Neurosurgery, University Hospital, Umeå, Sweden.
    Richter, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Antonsson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Eriksson, Ola
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zsigmond, Peter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Bergenheim, A.T.
    Department of Neurosurgery, University Hospital, Umeå, Sweden.
    Hariz, M.I.
    Department of Neurosurgery, University Hospital, Umeå, Sweden, Institute of Neurology, University College London, London, United Kingdom.
    Intracerebral microvascular measurements during deep brain stimulation implantation using laser doppler perfusion monitoring2007In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 85, no 6, p. 279-286Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate if laser Doppler perfusion monitoring (LDPM) can be used in order to differentiate between gray and white matter and to what extent microvascular perfusion can be recorded in the deep brain structures during stereotactic neurosurgery. An optical probe constructed to fit in the Leksell® Stereotactic System was used for measurements along the trajectory and in the targets (globus pallidus internus, subthalamic nucleus, zona incerta, thalamus) during the implantation of deep brain stimulation leads (n = 22). The total backscattered light intensity (TLI) reflecting the grayness of the tissue, and the microvascular perfusion were captured at 128 sites. Heartbeat-synchronized pulsations were found at all perfusion recordings. In 6 sites the perfusion was more than 6 times higher than the closest neighbor indicating a possible small vessel structure. TLI was significantly higher (p < 0.005) and the perfusion significantly lower (p < 0.005) in positions identified as white matter in the respective MRI batch. The measurements imply that LDPM has the potential to be used as an intracerebral guidance tool.

  • 39.
    Wårdell, Karin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Hariz, Marwan
    Institute of Neurology University College London, UK.
    Dizdar Segrell, Nil
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurology. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Hillman, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Andersson-Engels, Stefan
    Department of Physics Lund University, Sweden.
    Neuro-engineering for navigation, Intervention and Implementation in Neurosurgery2008In: Medicinteknikdagarna 2008,2008, 2008, p. 122-122Conference paper (Other academic)
  • 40.
    Wårdell, Karin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Richter, Johan C.O.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Hemm, Simone
    Institute for Medical and Analytical Technologies, University of Applied Sciences, Northwestern Switzerland.
    Optical measurements for guidance during deep brain stimulation implantation2011Conference paper (Refereed)
  • 41.
    Wårdell, Karin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Richter, Johan
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Hemm, Simone
    Fachhochschule Nordwestschweiz.
    Intraoperative laser doppler measurements for navigation during deep brain stimulation implantation2012Conference paper (Other academic)
  • 42.
    Wårdell, Karin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Rejmstad, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Åneman, Oscar
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Hillman, Jan
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Combined laser Doppler and reflectance spectroscopy measurements during brain surgery2013Conference paper (Other academic)
  • 43.
    Wårdell, Karin
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Richter, Johan
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Hemm, Simone
    University of Applied Sciences Northwestern Switzerland .
    Optical Measurements for Guidance during Deep Brain Stimulation Implantation2012Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinson’s disease and related movement disorders. The success of DBS is highly dependent on electrode location, electrical parameter settings and the surgical procedure. In this paper an overview of the current status of optical measurements for intracerebral guidance performed during DBS implantation is presented. Laser Doppler perfusion monitoring and/or reflection spectroscopy measurements have been done in relation to more than 70 DBS lead implantations to wards targets in the deep brain structures. The techniques have also been compared with impedance monitoring, and simulation of the measurement depth has been done with Monte Carlo technique. These studies show that grey-white matter boundaries can be determined with a resolution higher than for both impedance measurements and magnetic resonance imaging.

  • 44.
    Wårdell, Karin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Richter, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Hemm, Simone
    University of Applied Sciences Northwestern Switzerland, Institute for Medical and Analytical Technologies, Muttenz, Switzerland..
    Relationship Between Laser Doppler Signals and Anatomy During Deep Brain Stimulation Electrode Implantation Toward the Ventral Intermediate Nucleus and Subthalamic Nucleus2013In: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 72, no 2, p. 127-140Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Deep brain stimulation (DBS) requires precise and safe navigation to the chosen target. Optical measurements allow monitoring of gray-white tissue boundaries (total light intensity [TLI]) and microvascular blood flow during stereotactic procedures.

    OBJECTIVE: To establish the link between TLI/blood flow and anatomy along trajectories toward the ventral intermediate nucleus (Vim) and subthalamic nucleus (STN).

    METHODS: Stereotactic laser Doppler measurements were obtained with millimeter precision from the cortex toward the Vim (n = 13) and STN (n = 9). Optical trajectories of TLI and blood flow were created and compared with anatomy by superimposing the Schaltenbrandt-Wahren atlas on the patients' pre- and postoperative images. Measurements were divided into anatomic subgroups and compared statistically.

    RESULTS: Typical TLI trajectories with well-defined anatomic regions could be identified for the Vim and STN. TLI was significantly lower (P < .001) and microvascular blood flow significantly higher (P = .01) in the Vim targets. Of 1285 sites, 38 showed blood flow peaks, 27 of them along the Vim trajectories. High blood flow was more common close to the sulci and in the vicinity of the caudate/putamen. Along 1 Vim trajectory, a slight bleeding was suspected during insertion of the probe and confirmed with postoperative computed tomography.

    CONCLUSION: Laser Doppler is useful for intraoperative guidance during DBS implantation because simultaneous measurement of tissue grayness and microvascular blood flow can be done along the trajectory with millimeter precision. Typical but different TLI trajectories were found for the Vim and STN.

  • 45.
    Zsigmond, Peter
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Biochemical and pharmacokinetic studies in vivo in Parkinson’s disease2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Parkinson’s disease (PD) is a neurodegenerative disease affecting approximately 25000 people in Sweden. The main cause of the disease is the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) projecting to the striatum. The motor symptoms of PD, due to decreased levels of dopamine, includes bradykinesia, rigidity and tremor.

    During the 1960ies oral L-dopa treatment was introduced increasing quality of life for PD patients. In recent decades, enzyme inhibitors have been introduced, increasing bioavailability of L-dopa in plasma. After 5-10 years of L-dopa treatment, 50% of PD patients develop disabling dyskinesias. This can be due to rapid changes in L-dopa conentrations with non physiological stimulation of the dopamine receptor.

    For over 20 years deep brain stimulation (DBS) has grown to be a good neurosurgical procedure for improving quality of life in advanced PD with disabling dyskinesias. With stereotactic technique, electrodes are implanted in the brain and connected to a pacemaker sending electrical impulses. The most common target in PD is the subthalamic nucleus (STN). The knowledge about DBS mechanism(s) and its interaction with L-dopa is unsatisfactory.

    The aims of this thesis were; to study the effect of the enzyme inhibitor entacapone on the L-dopa concentration over the blood brain barrier (BBB); to study possible interactions between L-dopa and DBS; to study alterations in neurotransmitters during DBS; to visualize microdialysis catheters in anatomical targets and to estimate sampling area of the catheters.

    In all four papers the microdialysis technique was used. It is a well-established technique for continuous sampling of small water-soluble molecules within the extracellular fluid space in vivo, allowing studies of pharmaceutical drugs and neurotransmitters.

    We showed that entacapone increases the bioavailability of L-dopa in blood with a subsequent increase of L-dopa peak levels in the cerebrospinal fluid. This in turn may cause a larger burden on the dopaminergic neurons causing an increased degeneration rate and worsening of the dyskinesias; we showed that 18% of L-dopa crosses the BBB and that there is a possible interaction between L-dopa and DBS, L-dopa concentrations increase during concomitant STN DBS, which can clarify why its possible to decrease L-dopa medication after DBS surgery. The research has also shown that STN DBS has an effect on various neurotransmitter systems, mainly L-dopa, dopamine and GABA. We showed that STN DBS may have an effect on the SNc, resulting in putaminal dopamine release.

    We have shown that with stereotactic technique, it is safe to do microdialysis sampling in specific areas in the human brain. Simulations with the finite element method combined with patient specific preoperative MRI and postoperative CT images gave us exact knowledge about the positions of the catheters and that the studied structures were the intended. The research has given an assumption of the maximum tissue volume that can be sampled around the microdialysis catheters.

    List of papers
    1. The Effect of Peripheral Enzyme Inhibitors on Levodopa Concentrations in Blood and CSF
    Open this publication in new window or tab >>The Effect of Peripheral Enzyme Inhibitors on Levodopa Concentrations in Blood and CSF
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    2010 (English)In: Movement Disorders, ISSN 0885-3185, E-ISSN 1531-8257, Vol. 25, no 3, p. 363-367Article in journal (Refereed) Published
    Abstract [en]

    Levodopa combined with a dopa-decarboxylase inhibitor, such as carbidopa. shifts the metabolism to the COMT pathway. Adding the peripheral acting COMT inhibitor entacapone provides improvement for patients with PD suffering from motor fluctuations. We studied the effects of the enzyme inhibitors entacapone and carbidopa on the levodopa concentrations in CSF and in blood. Five PD patients with wearing-off underwent lumbar drainage and intravenous microdialysis. Samples were taken 12 h daily for 3 days. Day I; intravenous levodopa was given, day 2; additional oral entacapone 200 mg tid, day 3; additional oral entacapone 200 mg bid and carbidopa 25 mg bid. Levodopa in CSF and in dialysates was analysed. The AUC for levodopa increased both in blood and CSF when additional entacapone was given alone and in combination with carbidopa. The C-max of levodopa in both CSF and blood increased significantly. Additional entacapone to levodopa therapy gives an increase of C-max in CSF and in blood. The increase is more evident when entacapone is combined with carbidopa.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2010
    Keywords
    Parkinsons Disease, levodopa, continuous infusion, COMT
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-54855 (URN)10.1002/mds.22613 (DOI)000276136900016 ()
    Available from: 2010-04-16 Created: 2010-04-16 Last updated: 2018-01-12
    2. Stereptactic microdialysis of the basal ganglia in Parkinson's disease
    Open this publication in new window or tab >>Stereptactic microdialysis of the basal ganglia in Parkinson's disease
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    2012 (English)In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 207, no 1, p. 17-22Article in journal (Refereed) Published
    Abstract [en]

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an efficacious treatment in patients with advanced Parkinson's disease, yet the mechanisms of STN DBS are poorly understood. The aims of this study were to develop a useful method for studying neurotransmitter alterations during DBS and for the pharmacokinetics of L-dopa in brain tissue. Ten patients with Parkinson's disease participated, whereof two had no previous L-dopa medication. The electrodes and catheters were placed using MRI-guided stereotaxic targeting. Two microdialysis probes were placed, one in the right internal globus pallidus, and one in a brachial vein. The quadripolar deep brain electrodes were placed in the right STN. Microdialysates from brain tissue and blood were collected in 15-min fractions at baseline and during DBS. After stimulation new baseline fractions were taken and finally three fractions during continuous intravenous infusion of L-dopa. Clinical evaluation showed that both DBS and L-dopa infusion gave good relief of rigidity and tremor in all ten patients. During DBS the L-dopa levels in the brain increased in some of the patients but did not persist during the whole stimulation period. The concentration in brain increased substantially during intravenous L-dopa infusion. A number of catecholamines and their metabolites were analysed with high pressure liquid chromatography (HPLC). With our study we could show that this model is suitable for the monitoring of neurotransmitters and for pharmacokinetic studies in human brain, although we found that the sampling time was too short to follow the possible alterations in brain activity caused by DBS.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Parkinson's disease; Microdialysis; L-dopa; Pharmacokinetics; Stereotaxy; Neurotransmitter
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-89705 (URN)10.1016/j.jneumeth.2012.02.021 (DOI)
    Available from: 2013-03-04 Created: 2013-03-04 Last updated: 2018-01-12
    3. A model for simulation and patient-specific visualization of the tissue volume of influence during brain microdialysis
    Open this publication in new window or tab >>A model for simulation and patient-specific visualization of the tissue volume of influence during brain microdialysis
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    2011 (English)In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 49, no 12, p. 1459-1469Article in journal (Refereed) Published
    Abstract [en]

    Microdialysis can be used in parallel to deep brain stimulation (DBS) to relate biochemical changes to the clinical outcome. The aim of the study was to use the finite element method to predict the tissue volume of influence (TVI(max)) and its cross-sectional radius (r (TVImax)) when using brain microdialysis, and visualize the TVI(max) in relation to patient anatomy. An equation based on Fick's law was used to simulate the TVI(max). Factorial design and regression analysis were used to investigate the impact of the diffusion coefficient, tortuosity and loss rate on the r (TVImax). A calf brain tissue experiment was performed to further evaluate these parameters. The model was implemented with pre-(MRI) and post-(CT) operative patient images for simulation of the TVI(max) for four patients undergoing microdialysis in parallel to DBS. Using physiologically relevant parameter values, the r (TVImax) for analytes with a diffusion coefficient D = 7.5 × 10(-6) cm(2)/s was estimated to 0.85 ± 0.25 mm. The simulations showed agreement with experimental data. Due to an implanted gold thread, the catheter positions were visible in the post-operative images. The TVI(max) was visualized for each catheter. The biochemical changes could thereby be related to their anatomical origin, facilitating interpretation of results.

    Place, publisher, year, edition, pages
    Springer Publishing Company, 2011
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-72911 (URN)10.1007/s11517-011-0841-0 (DOI)000297550600012 ()22081236 (PubMedID)
    Available from: 2011-12-09 Created: 2011-12-09 Last updated: 2018-01-12Bibliographically approved
    4. Neurotransmitter levels in basal ganglia during L-dopa and Deep Brain Stimulation treatment in Parkinson’s Disease
    Open this publication in new window or tab >>Neurotransmitter levels in basal ganglia during L-dopa and Deep Brain Stimulation treatment in Parkinson’s Disease
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    2013 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Background: Bilateral deep brain stimulation of the nucleus subthalamicus (STN DBS) is a wellestablishedtreatment in patients with advanced Parkinson’s disease (PD). The mechanism bywhich STN DBS improves the PD symptoms remains unclear. In a previous perioperativestudy we have shown that there might be alterations of neurotransmitter levels in the Globuspallidum interna (GPi) during STN DBS. In this study we wanted to examine if STN DBSand L-dopa infusion interact and affect the levels of neurotransmitters.

    Methods: Five patients with advanced PD took part in the study. During STN surgery microdialysis catheters were inserted bilaterally in the GPi and unilaterally in the right putamen. A study protocol was set up and was followed for three days including STN DBS left side, right side and bilateral. L-dopa infusion with and without concomitant bilateral STN DBS was also performed.

    Results: The putaminal dopamine levels increase during STN DBS. In addition an increase of GABA concentrations in the GPi during STN DBS and during L-dopa infusion was found.

    Conclusions: These findings can provide evidence that the STN has a direct action on the substantia nigra pars compacta (SNc) and that STN DBS may indirectly release putaminal dopamine. There is also evidence that STN DBS interferes with L-dopa therapy resulting in higher levels of Ldopa in the brain explaining why its possible to decrease L-dopa medication after DBS surgery.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-91293 (URN)
    Available from: 2013-04-19 Created: 2013-04-19 Last updated: 2017-06-19Bibliographically approved
  • 46.
    Zsigmond, Peter
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Bobinski, L.
    Boström, Sverre
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery . Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Beh?et's disease, associated with subarachnoid heamorrhage due to intracranial aneurysm2005In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940, Vol. 147, no 5, p. 569-571Article in journal (Refereed)
    Abstract [en]

    Beh?et's disease is an unusual medical condition in central Europe and North America, however more common in Turkey and Japan. It was originally described in Turkey, characterized by recurrent oral ulcers, genital ulcers and also uveitis. A variety of vascular lesions such as venous occlusions, arterial aneurysms and varices account for the high rate of morbidity and mortality with this disease. Arterial aneurysms most commonly occur in the abdominal aorta, femoral arteries and in the pulmonary arteries. To our knowledge there have been seventeen documented reports of patient's with Beh?et's disease combined with aneurysms of cerebral arteries. We describe a patient with Beh?et's disease and subarachnoid haemorrhage due to a ruptured cerebral aneurysm. © Springer-Verlag 2005.

  • 47.
    Zsigmond, Peter
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Nezirevic Dernroth, Dzeneta
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Augustinsson, Lars-Erik
    Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Dizdar (Dizdar Segrell), Nil
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Stereptactic microdialysis of the basal ganglia in Parkinson's disease2012In: Journal of Neuroscience Methods, ISSN 0165-0270, E-ISSN 1872-678X, Vol. 207, no 1, p. 17-22Article in journal (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an efficacious treatment in patients with advanced Parkinson's disease, yet the mechanisms of STN DBS are poorly understood. The aims of this study were to develop a useful method for studying neurotransmitter alterations during DBS and for the pharmacokinetics of L-dopa in brain tissue. Ten patients with Parkinson's disease participated, whereof two had no previous L-dopa medication. The electrodes and catheters were placed using MRI-guided stereotaxic targeting. Two microdialysis probes were placed, one in the right internal globus pallidus, and one in a brachial vein. The quadripolar deep brain electrodes were placed in the right STN. Microdialysates from brain tissue and blood were collected in 15-min fractions at baseline and during DBS. After stimulation new baseline fractions were taken and finally three fractions during continuous intravenous infusion of L-dopa. Clinical evaluation showed that both DBS and L-dopa infusion gave good relief of rigidity and tremor in all ten patients. During DBS the L-dopa levels in the brain increased in some of the patients but did not persist during the whole stimulation period. The concentration in brain increased substantially during intravenous L-dopa infusion. A number of catecholamines and their metabolites were analysed with high pressure liquid chromatography (HPLC). With our study we could show that this model is suitable for the monitoring of neurotransmitters and for pharmacokinetic studies in human brain, although we found that the sampling time was too short to follow the possible alterations in brain activity caused by DBS.

  • 48.
    Zsigmond, Peter
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Neurosurgery.
    Nord, M.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Dizdar (Segrell), Nil
    Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Neurotransmitter levels in basal ganglia during L-dopa and Deep Brain Stimulation treatment in Parkinson’s Disease2013Manuscript (preprint) (Other academic)
    Abstract [en]

    Background: Bilateral deep brain stimulation of the nucleus subthalamicus (STN DBS) is a wellestablishedtreatment in patients with advanced Parkinson’s disease (PD). The mechanism bywhich STN DBS improves the PD symptoms remains unclear. In a previous perioperativestudy we have shown that there might be alterations of neurotransmitter levels in the Globuspallidum interna (GPi) during STN DBS. In this study we wanted to examine if STN DBSand L-dopa infusion interact and affect the levels of neurotransmitters.

    Methods: Five patients with advanced PD took part in the study. During STN surgery microdialysis catheters were inserted bilaterally in the GPi and unilaterally in the right putamen. A study protocol was set up and was followed for three days including STN DBS left side, right side and bilateral. L-dopa infusion with and without concomitant bilateral STN DBS was also performed.

    Results: The putaminal dopamine levels increase during STN DBS. In addition an increase of GABA concentrations in the GPi during STN DBS and during L-dopa infusion was found.

    Conclusions: These findings can provide evidence that the STN has a direct action on the substantia nigra pars compacta (SNc) and that STN DBS may indirectly release putaminal dopamine. There is also evidence that STN DBS interferes with L-dopa therapy resulting in higher levels of Ldopa in the brain explaining why its possible to decrease L-dopa medication after DBS surgery.

  • 49.
    Zsigmond, Peter
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Neurosurgery UHL.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Kullman, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Neurosurgery. Linköping University, Faculty of Health Sciences.
    Dizdar, Nil
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Biochemical Monitoring and Simulation of the Electric Field during Deep Brain Stimulation2009Conference paper (Refereed)
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