Long-term intrathecal infusion of low-dose morphine effectively relieves symptoms of severe restless legs syndrome/Willis-Ekbom disease without inducing opioid tolerance.

ABSTRACT: Restless legs syndrome/Willis-Ekbom disease (RLS/WED) causes a strong urge to move legs while resting. Restless legs syndrome/WED is an often-inherited disease occurring in 3% to 10% of adult populations, increasing with age. Severity varies from mild disturbance of sleep to painful restless legs and arms, loss of sleep, fatigue, and risk of suicide. Dopaminergic drugs relieve symptoms, but cause augmentation, ie, initially helpful but later increase the burden of symptoms. Oral gabapentinoids and opioids are often added, but opioid tolerance and adverse effects are common. With the high prevalence and incomplete help from oral drugs, significant unmet needs exist for effective therapy for severe RLS/WED. Ongoing spinal intrathecal infusion of low-dose morphine is effective, but not generally recognized, as only 12 cases have been published since 2002. We report 7 patients suffering from severe RLS/WED, who had no relief from oral dopaminergic, gabapentinoid, or opioid drugs; they all had excellent relief during ongoing spinal intrathecal infusion of morphine at only 1 to 5 µg/h, ongoing for 1 to 21 years without need of higher doses of morphine.. We suggest that morphine may be transported with the cerebrospinal fluid reaching and readjusting malfunctioning dopamine neuronal systems in the brain and spinal cord. The effects last only as long as the infusion continues. A patient with RLS/WED and persistent genital arousal disorder (PGAD) was relieved of both RLS/WED and PGAD symptoms. These case reports suggest that intrathecal infusion of low-dose morphine is an effective treatment of severe RLS.

H-coil repetitive transcranial magnetic stimulation does not improve executive function in patients with chronic peripheral neuropathic pain: a randomized sham-controlled crossover study.

Introduction: Deep rTMS is an increasingly popular noninvasive brain stimulation technique which has shown promise for treating cognitive impairments. However, few studies have investigated the cognitive effects it could exert in patients with chronic peripheral neuropathic pain. Therefore, we aimed to assess the effects of deep rTMS on executive functioning in patients with peripheral neuropathic pain, in a randomized, double-blind crossover trial. Methods: In total, 17 patients were randomly assigned to receive both active and sham deep H-coil rTMS targeting the primary motor cortex. Each treatment period consisted of five daily rTMS sessions. Selected tests of executive functioning from the CANTAB test battery (paired associates learning, stop signal task, spatial working memory and multitasking test) were performed at baseline, and at 1 week and 3 weeks follow-ups. Results: We did not find any significant interactions between time and treatment for the measures of executive functioning for the patient group, or for patients with reduced cognition compared to normative means. Conclusion: High-frequency deep H-coil rTMS targeting the hand area of the primary motor cortex and delivered over 5 consecutive days did not improve executive functioning in patients with chronic peripheral neuropathic pain. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT05488808.

Living well with chronic pain: a 12-month randomized controlled trial revealing impact from the digital pain self-management program EPIO.

Introduction: Chronic pain affects a wide range of physical and psychological aspects of life for those impacted. Psychosocial treatment approaches may be of support, but outreach is still limited. Objectives: To evaluate the efficacy of EPIO, an evidence-informed, user-centered digital self-management intervention for people with chronic pain, in a 12-month randomized controlled trial. Methods: People living with chronic pain (N = 266) were randomized to the EPIO intervention (n = 132) or a usual-care control group (n = 134). The intervention was delivered in a simple blended care model, and outcome measures collected at baseline, 6 months, and 12 months. Generalized linear models for repeated measures were fitted to compare groups over time. Results: Participants were primarily female (81%), median age 49 years (range 22-78), with heterogeneous pain conditions, and had lived with pain >5 years (77.6%). A mixed linear model with all timepoints included revealed no statistically significant group differences for the primary outcome of pain interference. Significant psychological benefits in favor of the intervention group were however detected for depression (P = 0.022), self-regulatory fatigue (P = 0.024), vitality (P = 0.016), and mental health (P = 0.047). Baseline to 12-month changes showed additional favorable effects for anxiety (between-group mean differences [MDs] = 0.79, P = 0.047), depression (MD = 1.08, P = 0.004), self-regulatory fatigue (MD = 2.42, P = 0.021), pain catastrophizing (MD = 2.62, P = 0.009), and health-related quality of life. Conclusions: The EPIO program aims to improve outreach of evidence-based pain self-management interventions. Findings demonstrate how using EPIO can lead to sustainable psychological change, enhancing mental health and health-related quality of life for people suffering from pain, providing a chance to live well with the pain.

How is age at menopause and reproductive lifespan associated with chronic pain outcomes in postmenopausal women?

ABSTRACT: Female sex is a prominent risk factor for chronic pain, although the underlying mechanisms are not fully understood. This cross-sectional study aimed to investigate the relationship between age at menopause, reproductive lifespan, and chronic pain in a sample of postmenopausal women aged 40 to 93 years. Data were collected from the Tromsø study conducted in Norway between 2015 and 2016 (Tromsø7). Chronic pain was assessed using a single question, which formed a sample size of 5741 participants. Chronic widespread pain was evaluated using the more comprehensive Graphical Index of Pain, resulting in a sample size of 5920 women. Premenopausal women and those who experienced menstrual cessation due to chemotherapy/radiation or hormonal intrauterine devices were excluded from the analysis. Adjusted relative risk ratios with 95% confidence intervals were calculated to determine associations. The results showed that early menopause was associated with a 1% increase in the prevalence of chronic pain for each year of earlier onset at menopause (0.992, CI 95% 0.985-0.998). This association was also observed in women who experienced natural menopause only. However, the association between menopause and chronic widespread pain did not reach statistical significance in the fully adjusted analysis (0.996, CI 95% 0.975-1.017). There were no significant associations found between reproductive lifespan and either outcome. In conclusion, the findings suggest that early menopause in postmenopausal women is linked to a higher prevalence of chronic pain. However, reproductive lifespan does not appear to have a significant impact on chronic pain or chronic widespread pain.

Spinal cord stimulation has a place in the treatment of chronic pain conditions. / Ryggmargsstimulering har en plass i behandling av langvarige smertetilstander.

Spinal cord stimulation is an important modality of treatment for some patients with chronic pain. Patient satisfaction following this treatment is comparable to outcomes from spine surgery in Norway.

Absorption and pharmacokinetics of bupivacaine after bilateral topical administration in tonsillar fossae for posttonsillectomy pain relief.

No previous studies have investigated the systemic absorption of bupivacaine when used topically for posttonsillectomy pain. The present study was undertaken to investigate the pharmacokinetics of bupivacaine after administration by a swab in the tonsillar fossae over 4 min after tonsillectomy. Eleven adult patients undergoing elective tonsillectomy were recruited. After removal of both tonsils, each of the two tonsillar fossae was covered with a swab moistened with 2 mL of bupivacaine 5 mg/mL, that is, a total of 20 mg bupivacaine. Blood samples were drawn after 0, 5, 10, 20, 30, 45, and 60 min. Bupivacaine was analyzed with an ultra-high-performance liquid chromatography-tandem mass spectrometry method. The highest single measured bupivacaine serum concentration was 23.2 ng/mL and took place 10 min after drug administration. Mean (±SD) Cmax was 11.4 ± 6.0 ng/mL and mean tmax was 11.3 ± 4.7 min. Mean t1/2 was 31.6 ± 9.3 min. As the toxic concentration threshold has been reported to be in the interval 1500-4500 ng/mL, the concentrations measured were well below 2% of the lowest cited toxic threshold. In conclusion, this study shows that applying 4 mL of bupivacaine 5 mg/mL by a swab in the tonsillar fossae posttonsillectomy yields very low plasma concentrations, suggesting its safe application without any risk of systemic toxic effects.

Associations between cognitive test scores and pain tolerance: The Tromsø study.

OBJECTIVES: Previous studies have suggested that experimental pain sensitivity is associated with cognitive function. The aim of this study is to assess this relationship in a large population-based sample. METHODS: We included 5,753 participants (aged 40-84 years) from the seventh wave of the population-based Tromsø Study who had been examined with cognitive tests and experimental pain assessments, and for whom information on covariates were available. Cox regression models were fitted using standardized scores on cognitive tests (12-word immediate recall test, digit symbol coding test, and Mini-Mental State Examination [MMS-E]) as the independent variable and cold pressor or cuff pressure pain tolerance as the dependent variables. Statistical adjustment was made for putative confounders, namely, age, sex, education, smoking, exercise, systolic blood pressure, body mass index, symptoms indicating anxiety or depression, analgesic use, and chronic pain. RESULTS: In multivariate analysis, cold pressor tolerance time was significantly associated with test scores on the 12-word immediate recall test (hazard ratio [HR] 0.93, 95% confidence interval [CI] 0.90-0.97, p < 0.001), the digit symbol coding test (HR 0.94, 95% CI 0.89-0.98, p = 0.004), and the MMS-E (HR 0.93, 95% CI 0.90-0.96 p < 0.001). Tolerance to cuff pressure algometry was significantly associated with 12-word immediate recall (HR 0.94-0.97, p < 0.001) and Digit Symbol Coding test scores (HR 0.93, 95% CI 0.89-0.96, p < 0.001) while there was no significant association with Mini Mental State Examination test score (HR 0.98, 95% CI 0.95-1.00, p = 0.082). CONCLUSION: Lower pain tolerance was associated with poorer performance on cognitive tests.

Periodontitis is associated with decreased experimental pressure pain tolerance: The Tromsø Study 2015-2016.

AIM: To assess the relationship between periodontitis and experimental pain tolerance. MATERIALS AND METHODS: Participants from the population-based seventh survey of the Tromsø Study with data on periodontitis were included (n = 3666, 40-84 years old, 51.6% women). Pain tolerance was assessed through (i) pressure pain tolerance (PPT) test with a computerized cuff pressure algometry on the leg, and (ii) cold-pressor tolerance (CPT) test where one hand was placed in circulating 3°C water. Cox proportional hazard regression was used to assess the association between periodontitis and pain tolerance adjusted for age, sex, education, smoking and obesity. RESULTS: In the fully adjusted model using the 2012 Centers for Disease Control/American Academy of Periodntology case definitions for surveillance of periodontitis, moderate (hazard ratio [HR] = 1.09; 95% confidence interval [CI]: 1.01, 1.18) and severe (HR = 1.25, 95% CI: 1.11, 1.42) periodontitis were associated with decreased PPT. Using the 2018 classification of periodontitis, having Stage II/III/IV periodontitis was significantly associated with decreased PPT (HR = 1.09; 95% CI: 1.01, 1.18) compared with having no or stage I periodontitis. There were no significant associations between periodontitis and CPT in fully adjusted models. CONCLUSIONS: Moderate and severe periodontitis was associated with experimental PPT.

Does pain tolerance mediate the effect of physical activity on chronic pain in the general population? The Tromsø Study.

ABSTRACT: Knowledge is needed regarding mechanisms acting between physical activity (PA) and chronic pain. We investigated whether cold pain tolerance mediates an effect of leisure-time physical activity on the risk of chronic pain 7 to 8 years later using consecutive surveys of the population-based Tromsø Study. We included participants with information on baseline leisure-time PA (LTPA) and the level of cold pressor-assessed cold pain tolerance, who reported chronic pain status at follow-up as any of the following: chronic pain for ≥3 months, widespread chronic pain, moderate-to-severe chronic pain, or widespread moderate-to-severe chronic pain. We included 6834 participants (52% women; mean age, 55 years) in counterfactual mediation analyses. Prevalence decreased with severity, for example, 60% for chronic pain vs 5% for widespread moderate-to-severe chronic pain. People with one level higher LTPA rating (light to moderate or moderate to vigorous) at baseline had lower relative risk (RR) of 4 chronic pain states 7 to 8 years later. Total RR effect of a 1-level LTPA increase was 0.95 (0.91-1.00), that is, -5% decreased risk. Total effect RR for widespread chronic pain was 0.84 (0.73-0.97). Indirect effect for moderate-to-severe chronic pain was statistically significant at RR 0.993 (0.988-0.999); total effect RR was 0.91 (0.83-0.98). Statistically significantly mediated RR for widespread moderate-to-severe chronic pain was 0.988 (0.977-0.999); total effect RR was 0.77 (0.64-0.94). This shows small mediation of the effect of LTPA through pain tolerance on 2 moderate-to-severe chronic pain types. This suggests pain tolerance to be one possible mechanism through which PA modifies the risk of moderate-to-severe chronic pain types with and without widespread pain.

Associations of long-term clinical recovery and improved quality of life across ICD-11 chronic pain categories in a real-world registry study.

BACKGROUND: There is little knowledge of what factors are needed for successful chronic pain management. We aim to identify psychosocial and treatment predictors of clinical recovery and improved quality of life (QOL) at 12-month follow-up across three chronic pain groups, based on the International Classification of Diseases-11: neuropathic pain, secondary non-neuropathic pain, and primary pain. Furthermore, we investigate baseline differences across diagnostic groups. METHODS: The sample included baseline and 12-month follow-up data from 1056 chronic pain patients from the Oslo University Hospital's Pain Registry. Logistic regression models investigated longitudinal associations between psychosocial and treatment characteristics, and the outcome measures clinical recovery and improved QOL. Characteristics were compared across the diagnostic groups. RESULTS: Increased odds of clinical recovery and improved QOL were seen in patients receiving invasive treatment (OR = 8.04, 95% CI = 3.50-19.40; OR = 5.47, 95% CI = 2.42-12.86), while decreased odds of clinical recovery were seen for secondary non-neuropathic pain patients with pain-related disability (0.05, 95% CI = 0.01-0.29). In comparing baseline characteristics, neuropathic pain patients had lower QOL, and more severe insomnia compared to the other groups. CONCLUSION: Invasive treatment modalities were strongly associated with clinical recovery and improved QOL. Although this could be due to patient selection, it does warrant further examination as an intervention alternative for chronic pain. Intervention efficacy, risk factors and predictors of clinical recovery across diagnostic groups should be further investigated through longitudinal RCTs. SIGNIFICANCE: This observational study indicates a potential advantage in sustained recovery for pre-selected individuals with chronic pain who undergo invasive treatments. The relationship between sustained recovery and psychosocial factors differs across neuropathic, secondary non-neuropathic, and primary pain patients. This suggests that employing ICD-11 for classifying patients into mechanistically distinct pain groups could inform the evaluation and management of chronic pain. Furthermore, factors previously identified as negative indicators for long-term outcomes in chronic pain cohorts were not clinically significant in this study.

The costs of chronic pain-Long-term estimates.

BACKGROUND: Chronic pain is a condition with severe impact on many aspects of life, including work, functional ability and quality of life, thereby reducing physical, mental and social well-being. Despite the high prevalence and burden of chronic pain, it has received disproportionally little attention in research and public policy and the societal costs of chronic pain remain largely unknown. This study aimed to describe the long-term healthcare and work absence costs of individuals with and without self-identified chronic pain. METHODS: The study population were participants in two Norwegian population health studies (HUNT3 and Tromsø6). Participants were defined as having chronic pain based on a self-reported answer to a question on chronic pain in the health studies in 2008. Individuals in the study population were linked to four national register databases on healthcare resource use and work absence. RESULTS: In our study, 36% (n = 63,782) self-reported to have chronic pain and the average years of age was 56.6. The accumulated difference in costs between those with and without chronic pain from 2010 to 2016 was €55,003 (CI: 54,414-55,592) per individual. Extrapolating this to the entire population suggests that chronic pain imposes a yearly burden of 4% of GDP. Eighty per cent of the costs were estimated to be productivity loss. CONCLUSION: Insights from this study can provide a greater understanding of the extent of healthcare use and productivity loss by those with chronic pain and serve as an important basis for improvements in rehabilitation and quality of care, and the education of the public on the burden of chronic pain. SIGNIFICANCE: This was the first study to estimate the economic burden associated with chronic pain in the general population using linked individual-level administrative data and self-reported survey answers. We provide calculations showing that annual costs of chronic pain may be as high as €12 billion or 4% of GDP. Findings from this study highlight the need for a greater understanding of the substantial healthcare use and productivity losses among individuals with chronic pain.