Pain
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Migraine is commonly reported in patients with temporomandibular disorders (TMDs), but little is known about the mechanisms underlying the comorbid condition. Here, we prepared a mouse model to investigate this comorbidity, in which masseter muscle tendon ligation (MMTL) was performed to induce a myogenic TMD, and the pre-existing TMD enabled a subthreshold dose of nitroglycerin (NTG) to produce migraine-like pain in mice. ⋯ Moreover, chemogenetic activation of Pdyn -expressing neurons or microinjection of dynorphin A (1-17) peptide in the Sp5C enabled a subthreshold dose of NTG to induce migraine-like pain in female mice but not in male mice. Taken together, our results suggest that trigeminal dynorphin has a female-specific role in the modulation of comorbid TMDs and migraine.
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Opioid prescribing varies widely, and prescribed opioid dosages for an individual can fluctuate over time. Patterns in daily opioid dosage among patients prescribed long-term opioid therapy have not been previously examined. This study uses a novel application of time-series cluster analysis to characterize and visualize daily opioid dosage trajectories and associated demographic characteristics of patients newly initiated on long-term opioid therapy. ⋯ Time-series cluster analysis identified 2 clusters for each of the 3 baseline dosage categories <150 MME and 3 clusters for the baseline dosage category ≥150 MME. One cluster in each baseline dosage category comprised opioid dosage trajectories with decreases in dosage at the end of the follow-up period (80.7%, 98.7%, 98.7%, and 99.0%, respectively), discontinuation (58.5%, 80.0%, 79.3%, and 81.7%, respectively), and rapid tapering (50.8%, 85.8%, 87.5%, and 92.9%, respectively). These findings indicate multiple clusters of patients newly initiated on long-term opioid therapy who experience discontinuation and rapid tapering and highlight potential areas for clinician training to advance evidence-based guideline-concordant opioid prescribing, including strategies to minimize sudden dosage changes, discontinuation, or rapid tapering, and the importance of shared decision-making.
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Randomized Controlled Trial
Mechanisms of education and graded sensorimotor retraining in people with chronic low back pain: a mediation analysis.
An improved understanding of the biopsychosocial influences that contribute to and maintain pain has promoted the development of new efficacious treatments for chronic low back pain (CLBP). This study aimed to investigate the mechanisms of a new treatment-education and graded sensorimotor retraining-on pain and disability. We conducted a preplanned causal mediation analysis of a randomized clinical trial which allocated 276 participants with CLBP to 12 weekly clinical sessions of education and graded sensorimotor retraining (n = 138) or a sham and attention control (n = 138). ⋯ Five of 7 mechanisms (71%) mediated the intervention effect on disability; the largest mediated effects were for beliefs about back pain consequences (-1.66 [-2.62 to -0.87]), pain catastrophizing (-1.06 [-1.79 to -0.53]), and pain self-efficacy (-0.84 [-1.89 to -0.45]). When all 7 mechanisms were considered simultaneously, the joint mediation effect explained most of the intervention effect for both pain and disability. Optimizing interventions to target beliefs about the consequences of back pain, pain catastrophizing, and pain self-efficacy is likely to lead to improved outcomes for people with CLBP.
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Randomized Controlled Trial
STRategies to Improve Pain and Enjoy life (STRIPE): results of a pragmatic randomized trial of pain coping skills training and opioid medication taper guidance for patients on long-term opioid therapy.
Because long-term opioid therapy (LtOT) for chronic pain has uncertain benefits and dose-dependent harms, safe and effective strategies for opioid tapering are needed. Adapting a promising pilot study intervention, we conducted the STRategies to Improve Pain and Enjoy life (STRIPE) pragmatic clinical trial. Patients in integrated health system on moderate-to-high dose of LtOT for chronic noncancer pain were randomized individually to usual care plus intervention (n = 79) or usual care only (n = 74). ⋯ We did not observe significant differences between intervention and usual care for MME (adjusted mean difference: -2.3 MME; 95% confidence interval: -10.6, 5.9; P = 0.578), the Pain, Enjoyment of Life, General Activity scale (0.0 [95% confidence interval: -0.5, 0.5], P = 0.985), or most secondary outcomes. The intervention did not lower opioid dose or improve pain or functioning. Other strategies are needed to reduce opioid doses while improving pain and function for patients who have been on LtOT for years with high levels of medical, mental health, and substance use comorbidity.