Scandinavian Journal of Pain最新文献

Objectives: The endocannabinoid system is a neuromodulatory system linked to pain, distress, and physical activity. The endocannabinoids (eCBs) arachidonoylethanolamide (AEA) and 2-arachidonoylglycerol are known to activate the cannabinoid receptors. The eCB system has been reported to be acutely affected by physical activity. Altered connectivity related to pain intensity in patients with fibromyalgia (FM) has been reported. However, how the peripheral eCBs, including eCB-like N-acylethanolamines (NAEs) concentrations, associate with pain-related regions of the brain and physical activity in FM, is not known. This study aimed to investigate eCBs and eCB-like NAEs in plasma and the association with functional connectivity in brain regions relevant for pain and with physical fitness.

Methods: The plasma concentrations of eCBs and eCB-like NAEs were measured in 31 women with FM and 29 healthy controls (HC). Functional magnetic resonance imaging, measurement of physical fitness and questionnaire regarding pain and depression/anxiety were included.

Results: Significantly higher concentrations of AEA were found in FM compared to HC. The AEA level correlated positively with pain intensity and was inversely associated with physical fitness, which in turn were inversely correlated with pain intensity and psychological distress in FM. Periaqueductal gray (PAG)-thalamus connectivity was not associated with circulating eCB and eCB-like NAEs. Stronger PAG-thalamus connectivity was related to a higher level of physical activity.

Conclusions: These results confirm that impaired physical fitness is an important aspect of FM, which can be reflected in the increased eCB levels and in PAG-thalamus connectivity. Further studies are necessary to establish a causal relationship between physical fitness, eCBs, eCB-like NAEs, and brain connectivity.

Objectives: Pain is a prevalent non-motor symptom in patients with Parkinson's Disease (PD) and associated with significant quality-of-life impairments. Yet, qualitative literature examining how patients with PD experience their pain and pain treatment is scarce. The aim of this study is to understand and report firsthand experiences with pain in PD.

Methods: Individual interviews (N = 15 patients with PD) following a semi-structured interview guide organized in 7 main topics and 18 subtopics covering both medical and psychological aspects of pain in PD. Data were analyzed by a reflexive thematic analysis.

Results: Three major themes emerged: (1) Pain is related to PD: A majority of interviewees were confident pain is caused by motor symptoms and related to sleep disturbances. (2) Healthcare professionals neglect pain in PD: frequently, interviewees expressed satisfaction with general PD treatment, yet urged healthcare professionals to show interest in their pain. Many were uncertain as to who was responsible for pain treatment and wished for increased coordination among healthcare professionals. (3) Treatment of pain is insufficient: self-medication was prevalent. Most interviewees told they hide their pain. Interviewees broadly reported low and/or temporary effect of alternative pain treatment, yet perceived training as efficient. Multiple interviewees called for research on physical or psychological rather than pharmacological pain treatment.

Conclusion: Patients with PD yearn for dialogue on pain with healthcare professionals. Frequently, patients take medication unsupervised, suggesting a need for integrating assessment of self-medication in standard treatment regimes. Patients urge healthcare professionals to discuss pain with them and acknowledge that motor symptoms may cause pain.

Background: Persistent severe intensity pain after groin hernia repair (PSPG; 200-400/10,000 repairs) is a significant surgical complication impacting the activity of daily living (ADL) and psychosocial functioning. This PhD synopsis presents an outline and a summary of three clinical studies examining outcomes and pathophysiology behind the post-surgical pain state.

Objective: The studies assessed (I) treatment outcomes, i.e., re-surgery with meshectomy and selective neurectomy vs pharmacotherapy, (II) temporal trajectories of pain intensity following the primary repair, and (III) somatosensory profiles before and after re-surgery.

Methods: On a national basis, patients experiencing PSPG (>3 months) with an activity-related or maximal pain intensity >7 (NRS; 0-10) referred to our unit were examined. Validated questionnaires classifying NRS, ADL functions, and psychometrics, and standardized quantitative sensory testing assessing somatosensory phenotypes were used. Study I was a prospective, questionnaire-based cohort analysis comparing outcomes from a 5-year perspective. Study II retrospectively examined patient-reported pain intensity trajectories. Study III followed somatosensory outcomes before and after re-surgery.

Results: In Study I (responder ratio: 172/204 [84%]), patients were allocated to re-surgery (n = 54) or to pharmacotherapy (n = 118). Compared to baseline, both cohorts showed significant improvements in pain intensity and ADL functions (P < 0.0001), with a slight superiority in ADL functions for the re-surgical cohort (P = 0.02). The number needed to operate for one patient to achieve a positive outcome (≥25% change in NRS/ADL) ranged between 1.5 and 1.9, and for experiencing a negative outcome, between 14 and 28. Study II (n = 95) identified two main prototypes of post-surgical pain intensity trajectories, where 51% experienced undiminished pain after the primary repair, while 29% experienced normal post-surgical recovery followed by late development of PSPG. Study III (n = 60) indicated that re-surgery was associated with a loss in the cutaneous somatosensory function and deep mechanical nociceptive function (decrease in evoked pain sensitivity).

Summary: The thesis corroborates that both re-surgical intervention and pharmacotherapy may ameliorate high-intensity pain and increase ADL functions in PSPG. Since the study design cannot account for non-specific therapeutic effects, a high-quality RCT is still needed. The pathophysiologic results indicate that the implanted mesh acts as a "pain generator", and future research should be targeted at dampening the immuno-inflammatory response to the implanted mesh.

Objectives: To understand how different individuals respond to placebo effects, it is relevant to disentangle the influence of someone's personality and genetic variations. The aim of this exploratory study was to investigate the role of different personality characteristics and different single-nucleotide polymorphisms (SNPs) on the responsiveness to placebo analgesia.

Methods: Secondary data analyses were conducted on an experimental behavioural study in healthy controls primarily aimed at the influence of three learning mechanisms (i.e., verbal suggestions, classical conditioning, or observational learning) or combinations thereof, on placebo analgesia in heat pain. Moderation by five different personality characteristics (optimism, neuroticism, worrying, empathy, and somatosensory amplification) was studied. Also, the predictive role of three different SNPs on the OPRM-1 gene, the COMT gene, and the FAAH gene on placebo analgesia was assessed. The personality characteristics were studied with validated questionnaires. The genetic variants were obtained by sequencing DNA from saliva cells.

Results: The moderation analysis from 206 participants concerning the personality characteristics did not show significant effects. Of the 108 (52%) genotyped participants, the results showed no significant relationship between any of the SNPs and placebo analgesia.

Conclusions: Results did not support a role of a person's personality characteristics or genetic variations in predicting their responsiveness to placebo analgesia through learning mechanisms. The clinical relevance of predicting someone's responsiveness to placebo effects, therefore, requires careful reconsideration.

Objectives: Canadian Armed Forces (CAF) Veterans report living with chronic pain at nearly double the rate of comparable Canadians. They have unique pain management needs, highlighting the need for further research. Aquatic exercise is one treatment option that may offer meaningful benefits. This study aimed to explore the lived experiences of CAF Veterans incorporating aquatic exercise as part of their pain management routines, offering insight into its potential role in managing chronic pain among military Veterans.

Methods: Informed by interpretive phenomenological analysis, ten CAF Veterans with chronic pain and experience with aquatic exercise were interviewed.

Results: Three superordinate themes were constructed: Respite from the pain; reconstructing an identity as a physically capable individual; and reclaiming a sense of self and seeing a new path forward. Exercise has the potential to improve pain, function, and quality of life for individuals living with pain. Among CAF Veterans, aquatic exercise can further support personal growth, development, and recovery after release from the military.

Conclusions: The findings provide insight for rehabilitation providers of the positive experiences and additional impacts of participating in aquatic exercise for CAF Veterans with chronic pain. Rehabilitation providers may consider incorporating aquatic exercise into physical activity-based rehabilitation programs for CAF Veterans living with musculoskeletal pain. The current investigation was approved by and followed the recommendations of the Health Sciences and Affiliated Teaching Hospitals Research Ethics Board at Queen's University (REH-797-21).

Objectives: Patients with non-specific neck, back, and/or chronic pain increasingly seek information about their condition on websites of healthcare practitioners. This information can influence their treatment expectation and should align with contemporary biopsychosocial (BPS) understanding of pain. It is unclear whether Dutch websites in the fields of rehabilitation and anaesthesiology align with the BPS model. The aim of this study is to assess the BPS content about non-specific neck, back, and chronic pain in Dutch rehabilitation and anaesthesiology websites.

Methods: All Dutch rehabilitation and anaesthesiology webpages were potentially eligible for inclusion. All webpages focusing on the topics of neck, back, and chronic pain were included. BPS content analyses were performed according to a standardised rating method with criteria for biomedical, limited-, and reasonably BPS. Analyses were performed separately for specialisms, and for the three topics. Additionally, frequency of nocebo words usage on the websites is explored.

Results: A total of 71 webpages were included, of which 42 (59.2%) were rehabilitation, 28 (39.4%) were anaesthesiology webpages, and 1 webpage described both. Across all webpages, 7 (9.7%) were rated as biomedical, 54 (75.0%) limited BPS, and 11 (15.3%) reasonably BPS. Differences between specialisms were not significantly different (p = 0.055). Differences between BPS ratings and the topics were significant (p = 0.005). Nocebos were present on 22.2% (n = 16) of the webpages.

Conclusion: Majority of the anaesthesiology and rehabilitation webpages (84.7%) did not achieve a "reasonable biopsychosocial" rate. Improvements are particularly needed in describing pain as a universal and/or normal phenomenon experienced by most individuals, as well as in explaining how an individual's environment influences their thoughts, emotions, and behaviours regarding pain perception.

With the aim of improving care for patients with musculoskeletal disorders of different durations, this thesis, defended in December 2024, evaluates team-based rehabilitation in primary care. The objectives of the interventions were to improve physical function and mental well-being, promote health, and prevent ill health. The theoretical underpinnings are anchored in a biopsychosocial understanding of pain, person-centredness, and salutogenesis, i.e. a holistic approach. Both qualitative and quantitative methods were used in this thesis, comprising four studies: an interview study exploring patients' experiences, a randomised controlled study evaluating effects on sickness absence and health-reported outcomes, a focus group study exploring the healthcare professionals' experiences, and a process evaluation of the implementation of a team-based rehabilitation model. The results support a person-centred approach, identifying and addressing biopsychosocial factors in musculoskeletal care, being beneficial both for patients' rehabilitation and the healthcare professionals' work satisfaction. A person-centred approach with a biopsychosocial understanding of pain is a desired way of working in primary care; however, contextual challenges were identified in the studies, as the organisation also expects high availability and has a volume-based reimbursement system. These factors were perceived as conflicting and stressful by the healthcare professionals.

Objectives: Disturbed sleep and chronic pain are public health concerns. Sleep disturbances seem to influence inflammation and may contribute to the increased pain sensitivity after sleep restriction (SR), such as after night work. The primary objective of this study was to determine the effects of SR on pain sensitivity and on relevant markers of inflammation. A secondary objective was to determine if SR affected pain sensitivity and inflammatory responses differently in men and women.

Methods: A paired crossover design with block randomization was applied. Subjects were instructed to follow their habitual sleep (HS) rhythm for two nights (HS condition) and to delay their bedtime to shorten their sleep with 50% for two nights (SR condition). Thirty-nine healthy volunteers between 19 and 44 years old participated (21 women). Experimental pain sensitivity was tested with heat-, electrical-, and pressure pain thresholds (PPTs); electrical temporal summation threshold; pinprick pain; suprathreshold heat pain tolerance; and rating of suprathreshold heat and cold pain. The following markers of inflammation were measured in plasma from a blood sample taken between 10:00 and 12:00: C-reactive protein, fractalkine, tumor necrosis factor, interleukin -8, and monocyte chemoattractant protein-1.

Results: Most subjects did not comply with the SR instructions. Total sleep time during SR was on average 2.6 h shorter than during HS. Therefore, the SR condition was re-defined to be "at least 40% reduction in the time in bed (TIB) the last night." The HS condition was re-defined to "at least 85% of normally reported TIB." SR produced higher suprathreshold heat pain sensitivity and cold pressor pain, compared to HS, but no significant change in electrical pain threshold, electrical temporal summation threshold, PPT, or any of the measured immune parameters. Sex-stratified analyses indicated that the effect on heat pain only occurred in women and that the effect on cold pressor pain was significant only in men.

Conclusions: The present findings indicate that heat and cold pressor pain were rated higher following SR, whereas pain thresholds remained unchanged. We did not find an effect of SR on biomarkers of inflammation. The findings should be cautiously interpreted given the poor adherence to the SR condition.

Objectives: This study aimed to evaluate the validity and reliability of the two subscales of a Swedish version of the Brief Pain Coping Inventory-2 (BPCI-2:SWE) in a population of patients seeking primary care physiotherapy for musculoskeletal pain (MSKP). The BPCI-2 is a patient-reported outcome measure (PROM) originally developed to measure traditional pain management strategies (TPMS) and psychological flexibility (PF) in populations with chronic pain.

Methods: This study followed guidance from the "COnsensus based Standards for the selection of health Measurement INstruments-group" and the stages described by Beaton. The BPCI-2 was translated and cross-culturally adapted from English to Swedish. The BPCI-2:SWE's content validity was evaluated using the face-validity index and qualitative content analysis of semi-structured interviews in a cohort of 13 patients seeking primary care physiotherapy for MSKP. The BPCI-2:SWE's construct validity, floor and ceiling effects, reliability, and measurement error were evaluated using a test-retest design in a cohort of 124 patients seeking primary care physiotherapy for MSKP.

Results: The BPCI-2:SWE had excellent content validity, but patients' experiences indicated that the scoring method may benefit from amendment. The PF subscale demonstrated good construct validity on hypothesis testing. However, the TPMS subscale did not reach the a priori threshold for good construct validity, correlating positively with pain intensity and demonstrating low correlation with all other PROMs. Neither subscale demonstrated floor or ceiling effects. The PF subscale had moderate, and the TPMS subscale had good, test-retest reliability. Measurement error was relatively high for both subscales at the individual patient level but low at the group level.

Conclusions: The BPCI-2:SWE is comprehensible and relevant within a Swedish primary care context. The BPCI-2:SWE demonstrated adequate measurement properties for use as an outcome measure in research studies, but future research should further evaluate the BPCI-2:SWE's reliability, responsiveness, and prognostic utility.

Objectives: This survey aims to identify and describe the characteristics of registries for neuromodulation implantations used to treat chronic pain in Europe. Neuromodulation therapies such as spinal cord stimulation (SCS) are employed to treat chronic pain through implantable medical devices. These therapies are considered effective and are part of standard care in many countries. Registries can provide valuable real-world data to complement randomized controlled clinical trials.

Materials and methods: We conducted a web-based survey to gather information on registries monitoring neuromodulation implants for chronic pain treatment, and the survey was sent to 101 European centers.

Results: We received responses from 47 centers across 17 European countries. Of these, 27 centers reported using a registry for neuromodulation therapies to treat pain, which this study is based upon. National registries exist in Belgium, the Netherlands, the UK, as well as a national registry solution in France. Non-national registries were identified in Denmark, Finland, Norway, Spain, Sweden, Switzerland, and Turkey. We present an overview on data types collected from different registries. Categories of variables collected are quite consistent across registries and are mostly in line with recommendations for chronic pain. The primary objective of the registries is most commonly measuring clinical outcomes and complications, while guideline adherence is less commonly monitored. The most frequently reported challenge is the lack of personnel for planning, designing, and funding for running the registries.

Conclusions: We identified 27 centers utilizing neuromodulation registries for chronic pain treatment, with 23 providing detailed data. Although the survey's limitation is its findings are not generalizable to all registries, the findings offer key insights for the establishment and growth of registries in neuromodulation. Registries primarily aim to investigate the clinical and patient-reported outcomes, though variability in other clinical data collection remains a challenge for benchmarking and guideline adherence. Significant financial and organizational hurdles exist, which can be addressed through cooperative initiatives.