Pain Research & Management最新文献

Background: Paracetamol is one of the most commonly used analgesic and antipyretic drug, available as a single or a combined formulation. Caffeine is an adjuvant analgesic to several drugs such as paracetamol. The goal of combining paracetamol with caffeine is to achieve a higher analgesic efficacy of paracetamol while lowering its dose and thus reducing side effects. Objective: This narrative literature review aims to provide an overview of the cumulative analgesic effects of this combination and the mechanisms underlying the potentiation by caffeine of the antinociceptive effect of paracetamol. Methods: The search was conducted in PubMed, MEDLINE, ClinicalTrials.gov, and Cochrane Database. For the clinical efficacy and safety, only randomized controlled trials and meta-analysis assessing paracetamol 1000 mg in combination with caffeine 130 mg were considered. Results: As emphasized by the data presented in this review, there is a potentiation of paracetamol-induced analgesia by caffeine with synergistic interactions observed in preclinical and clinical studies. Caffeine enhances the antinociceptive effect of paracetamol and accelerates the absorption of associated paracetamol, which explains the significant faster analgesics' effect with the combination. In clinical trials in patients with mild to moderate acute pain, the combination demonstrates a higher pain relief compared with paracetamol alone with a significant improvement of pain relief in patients with primary headaches without added safety issues. Conclusions: This combination is effective and safe in the treatment of acute mild and moderate pain. Prescribing physicians might consider using paracetamol and caffeine combination among other options in treating these types of pain.

Objective: Mental imagery involves forming internal sensory representations, while osteoarthritis is a degenerative joint disease characterized by cartilage loss. This study explores how mental imagery can modulate pain perception and enhance visual processing in individuals with knee osteoarthritis. Methods: Forty-eight participants were randomly assigned to a mental imagery group or a treatment group. The treatment group received conventional physiotherapy interventions, including ultrasound, transcutaneous electrical nerve stimulation, hot pack application, and isometric knee exercises, while the mental imagery group mentally imagined the same treatments. Both groups underwent interventions for 10 days, with assessments before and after. Pain intensity was measured using the visual analog scale (VAS), and visual processing was assessed through the digital pareidolia test. Results: Both groups exhibited significant reductions in VAS scores, with the mental imagery group demonstrating a more substantial decrease. Notably, the mental imagery group had faster reaction times to face pareidolia images, indicating improved visual processing. In contrast, the treatment group's reaction times to face pareidolia images remained unchanged. Conclusion: These findings highlight that mental imagery could serve as an alternative approach to pain management and cognitive enhancement, potentially influencing top-down mechanisms in facial pattern recognition. This highlights the potential for mental imagery to be integrated into therapeutic strategies for pain-related conditions, promoting personalized, innovative treatments.

Exposing the skin to high levels of ultraviolet B (UVB) radiation induces an inflammatory response that upregulates local nociceptive processing; this, in turn, facilitates protective responses to limit further injury. In this study, the UVB model was used to explore additional effects of inflammation on supraspinal nociceptive processing. Thirty-one healthy participants attended two sessions approximately 24 h apart. In each session, pressure-pain thresholds and sensitivity to sharp stimulation and heat were assessed in both forearms, and pressure-pain thresholds and sensitivity to sharp stimulation were assessed on each side of the forehead. In a novel paradigm, supraspinal nociceptive processing was explored by assessing pain and blink reflexes to electrical stimulation of the forehead, paired with acoustic startle stimuli. At the end of the first session, UVB radiation at a dose sufficient to induce erythema at the most exposed site was administered to one forearm. Consistent with local sensitization, sensitivity to heat and sharp stimulation had increased at the maximally exposed site 24 h later. This local response was accompanied by changes in supraspinal nociceptive processing-pressure-pain thresholds were lower on the ipsilateral than contralateral side of the forehead, and acoustic startle stimuli augmented electrically evoked pain. Blink reflexes weakened from the first to the second session, but decreases were smaller on the UVB-treated than contralateral side. Together, these findings suggest that acoustic startle stimuli facilitated activity in sensitized supraspinal nociceptive pathways. Potentially, this supraspinal mechanism adds to the burden of chronic nociplastic pain during states of heightened arousal and stress.

Background: Pain status is a common concern among older adults and has been linked to functional limitations. This study aimed to examine the association between pain status and disabilities risk in basic activities of daily living (BADL) and instrumental activities of daily living (IADL) in older adults in China, using data from the 2020 China Health and Retirement Longitudinal Study (CHARLS). Methods: A cross-sectional analysis was conducted using data from 8102 participants aged 60 and older from the 2020 CHARLS. Univariate and multivariate binary logistic regression analyses were performed to assess the association between pain status and BADL/IADL disabilities. We further examined the contribution of each covariate and categorized participants by pain location and number of pain sites. Subgroup analyses were conducted to examine the consistency of findings across demographic and health-related factors. Results: Pain status was significantly associated with higher odds of both BADL and IADL disabilities (p < 0.05), even after adjusting for covariates. Self-rated health and depressive symptoms exerted the greatest influence on the OR values. Pain in any anatomical region, particularly when present at multiple sites, was associated with increased odds of disability. Head and neck pain was specifically associated with IADL disability, while pain in the upper limbs, torso, and lower limbs was associated with both BADL and IADL disabilities. Subgroup analyses confirmed the robustness of these associations. Conclusions: Pain status, especially multisite pain, is significantly associated with BADL and IADL disabilities in older Chinese adults. Although causality cannot be inferred due to the study's cross-sectional design, these findings underscore the importance of addressing pain alongside other health and psychological factors when developing strategies to support functional independence in aging populations.

Background: Chronic nonspecific low back pain (CNLBP) is often associated with impaired mobility, functional limitations, and psychological distress. While myofascial release (MFR) and capacitive-resistive therapy (TECAR) have individually shown potential benefits, evidence regarding their combined application is limited. Methods: This assessor-blinded, three-arm randomized controlled trial included 67 patients with CNLBP. Participants were assigned to MFR alone, resistive-mode TECAR (R-TECAR) alone, or MFR plus R-TECAR. Interventions were administered twice weekly for 4 weeks, with each session lasting 20 min. Primary outcomes included the Numeric Pain Rating Scale (NPRS) and the Roland-Morris Disability Questionnaire (RMDQ), assessed at the baseline, 4 weeks, and one-and-a-half-month follow-up. Secondary outcomes encompassed thoracolumbar fascia (TLF) thickness, pressure pain threshold (PPT), trunk mobility, quality of life, anxiety, and depression. Intention-to-treat analyses were performed. Results: All interventions yielded significant improvements in pain and disability over time, although the combined MFR + R-TECAR therapy did not achieve statistically significant additional benefits compared with single therapies. Notably, a significant interaction effect emerged for PPT in the right quadratus lumborum muscle (p=0.01), with the MFR + R-TECAR group demonstrating greater improvement than R-TECAR alone. Other secondary outcomes, including TLF thickness and psychometric measures, improved over time but showed no significant between-group differences. Conclusions: Combining MFR with R-TECAR for CNLBP did not produce superior outcomes compared with individual treatments though certain muscle-specific benefits were observed. Future research should focus on optimizing treatment parameters, extending intervention and follow-up periods, and exploring individualized approaches to maximize therapeutic efficacy. Trial Registration: Chinese Registry of Clinical Trials: ChiCTR2400087961.

Objective: The objective was to compare the effectiveness of a combined pain neuroscience education and resistance training program (PNE + RT) with that of a combined aerobic and flexibility exercise program (AE + FE). Design: A randomized pilot study was conducted in women with fibromyalgia. Methods: Thirty-one women with fibromyalgia were randomized into the experimental group (PNE + RT, n = 15) and the usual care group (AE + FE, n = 16). Both groups carried out the intervention 3 days a week for 12 weeks. Primary outcomes were pain intensity, disability, and symptoms related to central sensitization (CS). Among them, pain intensity was considered the main primary endpoint for statistical analysis and interpretation. Secondary outcomes were pressure pain threshold (PPT), maximum handgrip strength (MHS), and stiffness. Results: Statistically significant between-group differences were found in favor of PNE + RT group for short-term pain intensity (p < 0.05) and PPT trapezius (p < 0.05). PNE + RT also showed statistically significant within-group improvements in pain intensity (p < 0.01), CS-related symptoms (p < 0.01), PPT quadriceps (p < 0.01), and MHS of the left hand (p < 0.01). Disability improved significantly in both groups (p < 0.01). There were no significant changes in stiffness. Conclusion: The PNE + RT program is more effective than the AE + FE program in improving pain intensity in the short term and PPT in the trapezius muscle in the long term. PNE + RT is also effective in improving disability, pain intensity, CS-related symptoms (short and long term), and left MHS and PPT in the quadriceps muscle (long term), although it is not more effective than AE + FE. The AE + FE program is only effective in improving disability. These findings are preliminary, and larger studies are needed to confirm the results. Trial Registration: ClinicalTrials.gov identifier: NCT04855851.

Background: Postoperative pain in thoracic surgery often requires opioids, yet can be poorly managed with short-acting anesthetics. Liposomal bupivacaine (LB) offers prolonged analgesia, potentially improving pain control and reducing opioid use. This study evaluates LB's effectiveness and safety in thoracic postoperative pain management, aiming to provide an alternative to current practices. Methods: In this single-center, double-blind, prospective, randomized controlled trial, patients undergoing uniportal lobectomy, segmentectomy, or wedge resection from November 2023 to May 2024 were enrolled. Participants were randomly assigned in a 1:1 ratio to receive either 0.375% ropivacaine (control group, n = 57) or LB (LB group, n = 56) for intercostal nerve blocks (ICNBs). Postoperative visual analog scale (VAS) scores, opioid consumption, overall benefit of analgesia score (OBAS), chest tube duration, length of hospital stay, and adverse events (AEs) were recorded and analyzed. Results: Data from 57 patients in the control group and 56 patients in the LB group were included in the analysis, with no significant demographic differences between the groups. The LB group demonstrated lower VAS scores at rest and during activity (p > 0.05), reduced opioid consumption (p=0.021), and higher OBAS (p < 0.01) compared with the control group. No significant differences were observed in chest tube duration, length of hospital stay, or AEs between the groups. Conclusion: LB is safe and effective for ICNB, providing significant postoperative pain relief for patients undergoing uniportal thoracoscopic surgery. Trial Registration: Chinese Registry of Clinical Trials: chiCTR2300075463.

The American Migraine Foundation estimates that over 39 million Americans and over 1 billion people worldwide suffer from some form of migraine. Treatment of migraine generally falls into two categories: treatment of attacks once they have begun, and prophylactic prevention, including lifestyle changes. The use of phytocannabinoids to reduce both the frequency and severity of migraine is widely documented in scientific, grey, and popular literature. This review provides descriptions of both preclinical and clinical studies involving the treatment of migraines with phytocannabinoids as well as the involvement of endocannabinoids and endocannabinoid-like compounds in migraine pathology, including the receptors and associated mechanisms. Currently unanswered questions and areas for further exploration are discussed.

Background: Self-declared chronic pain has not been compared to existing definitions. Our objective was to evaluate the agreement between self-declared chronic pain and different chronic pain definitions, three months after an emergency department (ED) visit. Methods: In this planned substudy of a prospective multicenter cohort study, we included consecutive patients aged ≥ 18 years with an acute pain condition discharged from the ED with an opioid prescription. Three months after their ED visit, participants were asked about their pain intensity, pain frequency, pain disability, and self-declared chronic pain. Agreement between self-declared chronic pain and five other definitions were calculated with kappas. Results: A total of 1411 participants were included; mean age was 52 (±16) years, and 53% were female. Prevalence of self-declared chronic pain was 23.0% and varied from 16.9% to 45.3% for other definitions. Agreement of self-declared chronic pain was moderate (0.57-0.60) with most definitions but lower with the pain intensity ≥ 1 definition (0.47). The proportion of chronic pain participants using opioids ( ⁓20%) or other analgesics (⁓80%) was similar with all definitions except for the pain intensity ≥ 1 definition which was associated with a lower proportion of analgesic use (11%, 64%). Conclusion: In summary, self-declared chronic pain displayed moderate agreement with other chronic pain definitions and similar analgesic consumption but lower with the pain intensity ≥ 1 definition. Nonetheless, chronic pain prevalence varied greatly depending on how it was defined. Self-declared chronic pain might be a more patient-centered outcome and could be easily applied to standardize chronic pain definition. Trial Registration: ClinicalTrials.gov identifier: NCT03953534.

Chronic pain is a prevalent and debilitating condition that imposes substantial personal and societal burdens. Despite its significance, the neural mechanisms underlying individual susceptibility to chronic pain remain inadequately understood. In this study, we examined the prospective associations between 1325 brain structural imaging phenotypes and the future risk of developing chronic pain in a UK Biobank cohort of 5754-5756 participants. These phenotypes encompassed regional and tissue volume, cortical surface area and thickness. General linear models (GLMs) were employed to identify brain structural variations associated with the risk of developing chronic pain, and then Mendelian randomization (MR) was employed to explore potential causal relationships between brain structure and chronic pain development. GLMs identified three significant associations between imaging phenotypes and the future development of chronic pain. All three imaging phenotypes pertained to the cortical surface area of the frontal operculum, albeit derived from three different brain atlases. Specifically, reduced cortical surface area in the frontal operculum was significantly associated with an increased risk of developing chronic pain: BA atlas area 44 (T=-4.10, p=4.24 × 10^-5), Desikan atlas pars opercularis (T=-4.21, p=2.55 × 10^-5), and DKT atlas pars opercularis (T=-3.96, p=7.47 × 10^-5). Subsequent MR analysis further demonstrated a causally protective effect of larger cortical area in the prefrontal operculum against the risk of developing chronic pain (OR = 0.91, p=1.91 × 10^-2). These results indicate a critical role of the surface area of frontal operculum in individual chronic pain susceptibility and provide a potential risk predictor for chronic pain development.