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Sörensen, Jan
Publications (10 of 16) Show all publications
Biurrun Manresa, J. A., Sörensen, J., Andersen, O. K., Arendt-Nielsen, L. & Gerdle, B. (2015). Dynamic Changes in Nociception and Pain Perception After Spinal Cord Stimulation in Chronic Neuropathic Pain Patients. The Clinical Journal of Pain, 31(12), 1046-1053
Open this publication in new window or tab >>Dynamic Changes in Nociception and Pain Perception After Spinal Cord Stimulation in Chronic Neuropathic Pain Patients
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2015 (English)In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 31, no 12, p. 1046-1053Article in journal (Refereed) Published
Abstract [en]

Objectives: Patients with an implanted spinal cord stimulation (SCS) system for pain management present an opportunity to study dynamic changes in the pain system in a situation where patients are not stimulated (ie, experiencing severe pain) compared with a situation in which patients have just been stimulated (ie, pain free or greatly reduced pain). The aims of this study were (1) to determine if there are differences in nociceptive withdrawal reflex thresholds (NWR-T) and electrical pain thresholds (EP-T) before and after SCS; and (2) to establish if these differences are related to psychological factors associated with chronic pain. Methods: Seventeen volunteers with chronic neuropathic pain participated in the experiment. Electrical stimuli were applied to assess the NWR-T and the EP-T. In addition, psychological factors (ie, pain characteristics, depression, anxiety, and disability indexes) were also recorded. The NWR-T and EP-T were assessed with the SCS system off (at least 8 h before the experiment), and then reassessed 1 hour after the SCS system was turned on. Results: Ongoing pain intensity ratings decreased (P=0.018), whereas the NWR-T increased (P=0.028) after the SCS was turned on, whereas no significant difference was found for EP-T (P=0.324). Psychological factors were significant predictors for EP-T but not for NWR-T. Discussion: The results of this study suggest that pain relief after SCS is partially mediated by a decrease in the excitability of dorsal horn neurons in the spinal cord.

Place, publisher, year, edition, pages
LIPPINCOTT WILLIAMS and WILKINS, 2015
Keywords
spinal cord stimulation; nociceptive withdrawal reflex; electrical pain threshold; psychological assessment
National Category
Basic Medicine
Identifiers
urn:nbn:se:liu:diva-123128 (URN)10.1097/AJP.0000000000000209 (DOI)000364766000004 ()25789414 (PubMedID)
Note

Funding Agencies|Swedish Research Council, Stockholm, Sweden [K2011-69X-21874-01-6]; Swedish Council for Working Life and Social Research, Stockholm, Sweden [2010-0913]

Available from: 2015-12-07 Created: 2015-12-04 Last updated: 2018-01-10
Bäckryd, E., Sörensen, J. & Gerdle, B. (2015). Ziconotide Trialing by Intrathecal Bolus Injections: An Open-Label Non-Randomized Clinical Trial in Postoperative/Posttraumatic Neuropathic Pain Patients Refractory to Conventional Treatment. Neuromodulation (Malden, Mass.), 18(5), 404-413
Open this publication in new window or tab >>Ziconotide Trialing by Intrathecal Bolus Injections: An Open-Label Non-Randomized Clinical Trial in Postoperative/Posttraumatic Neuropathic Pain Patients Refractory to Conventional Treatment
2015 (English)In: Neuromodulation (Malden, Mass.), ISSN 1094-7159, E-ISSN 1525-1403, Vol. 18, no 5, p. 404-413Article in journal (Refereed) Published
Abstract [en]

Objectives: The aim of this open-label, non-randomized, clinical trial was to evaluate the feasibility of trialing ziconotide by intrathecal bolus injections. Material and Methods: Twenty-three patients, who had peripheral neuropathic pain refractory to pharmacological treatment and were under consideration for Spinal Cord Stimulation, received up to three ziconotide bolus injections according to a comprehensive algorithm. After a first injection of 2.5g, the patients progressed in the algorithm depending on the presence or absence of pain reduction and significant adverse events. A patient was considered a "responder" if experiencing pain reduction and no significant adverse event on two consecutive occasions at the same dosage. Results: We found a low proportion of responders (13%). However 30% of patients experienced greater than= 30% pain reduction on a least one injection, yielding a number needed to treat of similar to 3 for clinically significant pain relief. Pain intensity changed significantly over time (0-6h) (p = 0.047) after a mean ziconotide dose of 2.75 mu g. Adverse events were as expected, and no serious adverse event occurred. We did not find any statistical association between response to Spinal Cord Stimulation and response to ziconotide. Conclusions: Ziconotide bolus injection trialing seems feasible, but the proportion of responders in the present study was low. Adverse events were as expected, and no serious adverse event occurred. The predictive power of ziconotide bolus trialing remains unclear, and the pharmacological profile of ziconotide (slow tissue penetration due to high hydrophilicity) calls the rationale for bolus trialing into question.

Place, publisher, year, edition, pages
Wiley, 2015
Keywords
Bolus; intrathecal; spinal; trialing; ziconotide
National Category
Clinical Medicine Basic Medicine
Identifiers
urn:nbn:se:liu:diva-120352 (URN)10.1111/ner.12293 (DOI)000357388400010 ()25879804 (PubMedID)
Note

Funding Agencies|County Council of Ostergotland; Swedish Research Council

Available from: 2015-07-31 Created: 2015-07-31 Last updated: 2018-01-11
Persson, M., Sörensen, J. & Gerdle, B. (2012). Whiplash Associated Disorders (WAD): Responses to pharmacological challenges and psychometric tests. Scandinavian Journal of Pain, 3(3), 151-163
Open this publication in new window or tab >>Whiplash Associated Disorders (WAD): Responses to pharmacological challenges and psychometric tests
2012 (English)In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 3, no 3, p. 151-163Article in journal (Refereed) Published
Abstract [en]

Objectives

The present study challenges chronic WhiplashAssociatedDisorders (WAD)-subjects to a pharmacological intravenous (i.v.) test with morphine, ketamine, and active placebo (midazolam). The aim was to describe the short-term responses to drugs and the assumed heterogeneity in the patterns of responses. We related the different responder groups to the results from psychometrictests.

Methods

The study includes 95 patients, all with chronic WAD and referred to our departments. They answered a questionnaire including the following psychometric instruments relevant for chronic pain: Beck Depression Inventory, Coping Strategies Questionnaire, Multidimensional Pain Inventory, Life Satisfaction Checklist, SF36 and EuroQol. The subjects also went through sessions with separate infusions of morphine (0.3 mg/kg), ketamine (0.3 mg/kg) and midazolam (0.05 mg/kg). Infusion time was 30 min followed by a 2-h post-infusion assessment. Assessments were made using a Visual Analogue Scale (VAS) for pain intensity and unpleasantness and by statements of per cent pain relieved. A categorical pain rating scale was also used. A positive response was defined as ≥50% decrease of the VAS-level on two consecutive assessment points during the test sessions, anything less was a non response. The placebo responders were defined as those with a positive response to the active placebo infusion.

Results

The tests were completed by 94 subjects and 26% of these were placebo responders. Among the placebo non responders, 47% responded to morphine, 41% to ketamine, 25% to both drugs and 37% to neither morphine nor ketamine (pain intensity assessments). Similar proportions were found in the assessments of pain unpleasantness and per cent pain relieved. Approximately one in four subjects (27%, pain intensity assessment) did not respond to any of the drugs tested. This relatively high proportion of non responders seemed to be worst cases in some aspects of the psychometrictests. Generally, this non responder group had a trend to score worse for most items in the psychometrictests with some reaching significance in a univariate analysis. This result was confirmed in a multivariate context, although the results indicated only small differences between the groups. All three substances showed significant pain relief compared to baseline on all assessment points. On most variables, morphine and ketamine were significantly more effective compared to the active placebo.

Conclusions

There are different subgroups among subjects with chronic WAD with variations in responses to i.v. morphine, ketamine, and midazolam (active placebo). Subjects with chronic WAD who did not respond to any of the drugs tested scored badly in some aspects of the psychometric instruments.

Implications

The present study confirms one aspect of the heterogeneity in the population with chronic WAD. The study does not elucidate precise pain mechanisms but taken together with other studies exploring other aspects, it stresses the importance of individualizing the assessment and treatment of subjects with chronic WAD. A common clinical experience is that depression, anxiety and maladaptive coping strategies often are obstacles for successful medical treatment of chronic pain. The present study supports this experience and emphasizes the need for assessment of psychometric variables when planning the treatment of chronic WAD.

Place, publisher, year, edition, pages
Elsevier, 2012
Keywords
Whiplash associated disorders; Neck; Ketamine; Morphine; Placebo; Psychometric test
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-79965 (URN)10.1016/j.sjpain.2012.01.003 (DOI)
Available from: 2012-08-16 Created: 2012-08-16 Last updated: 2017-12-07
Lemming, D., Graven-Nielsen, T., Sörensen, J., Arendt-Nielsen, L. & Gerdle, B. (2012). Widespread pain hypersensitivity and facilitated temporal summation of deep tissue pain in whiplash associated disorder: an explorative study of women. Journal of Rehabilitation Medicine, 44(8), 648-657
Open this publication in new window or tab >>Widespread pain hypersensitivity and facilitated temporal summation of deep tissue pain in whiplash associated disorder: an explorative study of women
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2012 (English)In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 44, no 8, p. 648-657Article in journal (Refereed) Published
Abstract [en]

Objective: Widespread deep tissue pain hyperalgesia was evaluated in women with chronic whiplash associated disorder (n=25) and controls (n=10) using computerized cuff pressure algometry and hypertonic saline infusion. Methods: A pneumatic double-chamber cuff was placed around: (i) the arm and (ii) the leg. Cuff inflation rate was constant and the pain intensity was registered continuously on a visual analogue scale (VAS); thresholds of detection and tolerance were extracted. For assessment of spatial summation the protocol was repeated with a single-chamber cuff inflated around the leg. Temporal summation of pain was assessed from the leg with constant cuff pressure stimulation at 2 different pressure intensities for 10 min. Hypertonic saline was infused in the tibialis anterior muscle. Results: Cuff pressure pain thresholds were lower in subjects with whiplash associated disorder compared with controls (pless than0.05). Tonic pressure stimulation evoked higher maximal VAS and larger areas under the VAS curve in subjects with whiplash associated disorder compared with controls (pless than0.05). The pain threshold and tolerance were higher during single cuff than double cuff stimulation. The area under the VAS curve after intramuscular saline infusion was larger in whiplash associated disorder (pless than0.05). Conclusion: The results indicated widespread hyperalgesia in chronic whiplash associated disorder and facilitated temporal summation outside the primary pain area, suggesting involvement of central sensitization.

Place, publisher, year, edition, pages
Foundation for Rehabilitation Information, 2012
Keywords
assessment; cuff algometry; neck; pain; WAD
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-79674 (URN)10.2340/16501977-1006 (DOI)000306296400007 ()
Available from: 2012-08-14 Created: 2012-08-13 Last updated: 2017-12-07
Bäckryd, E., Sörensen, J. & Gerdle, B. (2010). Nerve block as analgesia forneoplastic brachial plexopathy. European Journal of Palliative Care, 17(5), 218-220
Open this publication in new window or tab >>Nerve block as analgesia forneoplastic brachial plexopathy
2010 (English)In: European Journal of Palliative Care, ISSN 1352-2779, E-ISSN 1479-0793, Vol. 17, no 5, p. 218-220Article in journal (Other academic) Published
Abstract [en]

Brachial plexus nerve blocks are performed to treat patients with chronic pain referable to the brachial plexus. The needle insertion and trajectory are based on palpation of surface landmarks. Occasionally, the surface landmarks are difficult to identify owing to body habitus or anatomic alterations secondary to surgery or radiation therapy. The intent of this manuscript is to describe a technique for brachial plexus block guided with computed tomography and to report our initial results for regional pain management.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-66477 (URN)
Available from: 2011-03-16 Created: 2011-03-16 Last updated: 2017-12-11Bibliographically approved
Lemming, D., Graven-Nielsen, T., Sörensen, J., Arendt-Nielsen, L. & Gerdle, B. (2008). Facilitated temporal summation and generalized hyperalgesia in whiplash associated disorder.
Open this publication in new window or tab >>Facilitated temporal summation and generalized hyperalgesia in whiplash associated disorder
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2008 (English)Article in journal (Refereed) Submitted
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-12922 (URN)
Available from: 2008-01-30 Created: 2008-01-30
Lemming, D., Sörensen, J., Graven-Nielsen, T., Lauber, R., Arendt-Nielsen, L. & Gerdle, B. (2007). Managing chronic whiplash associated pain with a combination of low-dose opioid (remifentanil) and NMDA-antagonist (ketamine). European Journal of Pain, 11(7), 719-732
Open this publication in new window or tab >>Managing chronic whiplash associated pain with a combination of low-dose opioid (remifentanil) and NMDA-antagonist (ketamine)
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2007 (English)In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 11, no 7, p. 719-732Article in journal (Refereed) Published
Abstract [en]

The aim was to investigate the efficacy of a combination of low-dose remifentanil (REMI) and ketamine (KET) compared to the single drugs and placebo (P) on whiplash associated pain (WAD) in a double-blind, randomized, placebo-controlled, cross-over study.

Twenty patients with chronic (>1 year) WAD were included. Four different drug combinations were tested in four sessions: placebo/placebo (P/P), placebo/remifentanil (P/REMI), ketamine/placebo (KET/P) and ketamine/remifentanil (KET/REMI). Target concentrations were 1 and 2 ng/ml (stepwise) for remifentanil and 100 ng/ml for ketamine.

Habitual pain intensity was assessed on a visual analogue scale (VAS). Experimental pain was assessed with electrical stimulation (single and repeated) of tibialis anterior (TA) muscle, pressure pain algometry applied over infraspinatus (IS) and TA muscles and VAS scores after intramuscular hypertonic saline infusion in TA.

KET/REMI significantly reduced habitual pain. KET/REMI infused at low REMI target concentration (1 ng/ml) significantly elevated electrical intramuscular pain thresholds (single and repeated). Pain thresholds to electrical stimulation were similarly increased by both P/REMI and KET/REMI at 2 ng/ml target concentration. Pressure pain thresholds were increased by both KET/REMI and P/REMI. VAS-scores after intramuscular saline were also similarly decreased by both REMI combinations. Seven out of 20 subjects were non-responders (<50% pain relief). No correlation was found between effects on spontaneous pain and experimental pain.

KET/REMI showed an analgesic effect on habitual pain. Experimental pain was attenuated by both combinations containing the opioid, however, KET seemed to enhance the effect of REMI on electrical pain thresholds when a low REMI target concentration was used.

Keywords
WAD, Neck pain, Remifentanil, Ketamine, Experimental pain, Pain assessment
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-12920 (URN)10.1016/j.ejpain.2006.11.002 (DOI)
Available from: 2008-01-30 Created: 2008-01-30 Last updated: 2017-12-13
Gerdle, B. & Sörensen, J. (2006). Radiofrekvensbehandling. In: Statens beredning för medicinsk utvärdering (Ed.), Metoder för behandling av långvarig smärta: En systematisk litteraturöversikt (pp. 339-343). Stockholm: Statens beredning för medicinsk utvärdering (SBU)
Open this publication in new window or tab >>Radiofrekvensbehandling
2006 (English)In: Metoder för behandling av långvarig smärta: En systematisk litteraturöversikt / [ed] Statens beredning för medicinsk utvärdering, Stockholm: Statens beredning för medicinsk utvärdering (SBU) , 2006, p. 339-343Chapter in book (Other academic)
Abstract [sv]

I denna rapport sammanfattas det vetenskapliga underlaget för behandling av långvariga smärttillstånd. Smärta vid cancer innefattas inte. Smärtlindrande effekter, liksom biverkningar och andra negativa konsekvenser av behandling berörs samt hälsoekonomiska aspekter.

Place, publisher, year, edition, pages
Stockholm: Statens beredning för medicinsk utvärdering (SBU), 2006
Series
SBU-rapport, ISSN 1400-1403 ; 177:1
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-36812 (URN)32674 (Local ID)91-85413-08-9 (ISBN)32674 (Archive number)32674 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2013-09-19Bibliographically approved
Kalso, E., Allan, L., Dobrogowski, J., Johnson, M., Krcevski-Skvarc, N., Macfarlane, G. J., . . . Sörensen, J. (2005). Do strong opioids have a role in the early management of back pain? Recommendations from a European expert panel. Current Medical Research and Opinion, 21(11), 1819-1828
Open this publication in new window or tab >>Do strong opioids have a role in the early management of back pain? Recommendations from a European expert panel
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2005 (English)In: Current Medical Research and Opinion, ISSN 0300-7995, E-ISSN 1473-4877, Vol. 21, no 11, p. 1819-1828Article in journal, Editorial material (Other academic) Published
Abstract [en]

Background: Since chronic low back pain (CLBP) is a complex biopsychosocial problem the ideal treatment is multimodal and multidisciplinary. However, in many countries, primary-care physicians care for many people with CLBP and have a pivotal role in selecting patients for more intensive treatments when these are available. Guidelines on the general use of strong opioids in chronic non-cancer pain have been published but, until now, no specific guidelines were available on their use in chronic low back pain. Given the prevalence of CLBP, and the complex nature of this multifactorial condition, it was felt that specific, evidence-based recommendations, with a focus on primary-care treatment, would be helpful. Methods: An expert panel drawn from across Europe including pain specialists, anaesthetists, neurologists, rheumatologists, a general practitioner, an epidemiologist and the chairman of a pain charity was therefore convened. The aim of the group was to develop evidence-based recommendations that could be used as a framework for more specific guidelines to reflect local differences in the availability of specialist pain services and in the legal status and availability of strong opioids. Statements were based on published evidence (identified by a literature search) wherever possible, and supported by clinical experience when suitable evidence was lacking. Recommendations: Strong opioids have a role in the treatment of low back pain when other treatments have failed. They should be prescribed as part of a multimodal, and ideally interdisciplinary, treatment plan. The aim of treatment should be to relieve pain and facilitate rehabilitation.

Place, publisher, year, edition, pages
Taylor & Francis, 2005
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-37113 (URN)10.1185/030079905X65303 (DOI)000233360100015 ()16307703 (PubMedID)2-s2.0-27944461708 (Scopus ID)33732 (Local ID)33732 (Archive number)33732 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13Bibliographically approved
Rosendal, L., Kristiansen, J., Gerdle, B., Sögaard, K., Peolsson, M., Kjaer, M., . . . Larsson, B. (2005). Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia. Pain, 119( 1-3), 201-209
Open this publication in new window or tab >>Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia
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2005 (English)In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 119, no 1-3, p. 201-209Article in journal (Refereed) Published
Abstract [en]

The mechanisms behind the development of work-related trapezius pain are suggested to involve both peripheral and central components, but the specific contribution of alterations in muscle nociceptive and other substances is not clear. Female patients with chronic trapezius myalgia (N=19, TM) and female controls (N=20, CON) were studied at rest, during 20 min repetitive low-force exercise and recovery, and had their interstitial concentrations of potassium (K+), lactate dehydrogenase (LDH), interleukin-6 (IL-6) and collagen turnover determined in the trapezius muscle by the microdialysis technique. K+ levels were at all time points higher in TM than in CON (P<0.0001). Baseline levels of LDH and IL-6 were similar in both groups. In response to exercise pain intensity, rated perceived exertion, and the concentrations of K+, LDH and IL-6 increased significantly in both groups. [K+] immediately decreased to baseline levels in CON but remained elevated during the first 20 min of recovery in TM (P<0.01) whereafter it returned to baseline level. In all subjects taken together mean [K+] correlated negatively with pressure pain threshold of trapezius (P<0.001), positively with mean pain intensity VAS (P<0.001) and mean perceived exertion (P<0.001). Rises in muscle LDH and IL-6 as well as the anabolic ratio for collagen type I was not significantly different between groups. In conclusion, patients with chronic pain in the trapezius muscle had increased levels of interstitial potassium. This finding could be causally related to myalgia or secondary to pain due to deconditioned muscle or altered muscle activity pattern. © 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-31094 (URN)10.1016/j.pain.2005.09.026 (DOI)16824 (Local ID)16824 (Archive number)16824 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
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