Pain
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Randomized Controlled Trial Multicenter Study
Ambulatory continuous peripheral nerve blocks to treat post-amputation phantom limb pain a multicenter, randomized, quadruple-masked, placebo-controlled clinical trial.
Phantom limb pain is thought to be sustained by reentrant neural pathways, which provoke dysfunctional reorganization in the somatosensory cortex. We hypothesized that disrupting reentrant pathways with a 6-day-long continuous peripheral nerve block reduces phantom pain 4 weeks after treatment. We enrolled patients who had an upper- or lower-limb amputation and established phantom pain. ⋯ Patients given local anesthetic had improved global impression of change and less pain-induced physical and emotional dysfunction, but did not differ on depression scores. For subjects who received only the first infusion (no self-selected crossover), the median decrease in phantom limb pain at 6 months for treated subjects was 3.0 (0, 5.0) vs 1.5 (0, 5.0) for the placebo group; there seemed to be little residual benefit at 12 months. We conclude that a 6-day continuous peripheral nerve block reduces phantom limb pain as well as physical and emotional dysfunction for at least 1 month.
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Chronic pain is highly comorbid with affective disorders, including major depressive disorder. A core feature of major depressive disorder is a loss of interest in previously rewarding activities. Major depressive disorder is also associated with negative affective biases where cognitive processes are modulated by the affective state. ⋯ In the affective bias test, PSNI rats developed a positive affective bias when treated with gabapentin, an effect not seen in the controls suggesting an association with the antinociceptive effects of the drug inducing a relatively more positive affective state. Together, these data suggest that there are changes in reward-related cognition in this chronic pain model consistent with previous findings in rodent models of depression. The effects seen with gabapentin suggest that pain-associated negative affective state may be remediated by this atypical analgesic.
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Randomized Controlled Trial
Effect of a brief scenario-tailored educational program on parents' risk knowledge, perceptions and decisions to administer prescribed opioids: a randomized controlled trial.
This randomized, controlled trial evaluated whether a brief educational program (ie, Scenario-Tailored Opioid Messaging Program [STOMP]) would improve parental opioid risk knowledge, perceptions, and analgesic efficacy; ensure safe opioid use decisions; and impact prescription opioid use after surgery. Parent-child dyads (n = 604) who were prescribed an opioid for short-term use were randomized to routine instruction (Control) or routine plus STOMP administered preoperatively. Baseline and follow-up surveys assessed parents' awareness and perceived seriousness of adverse opioid effects, and their analgesic efficacy. ⋯ Instead, parents' analgesic efficacy and pain-relief preferences explained 7%, whereas child and surgical factors explained 22% of the variance in opioid doses. Scenario-tailored education enhanced parents' opioid risk knowledge, perceptions, and scenario-based decision-making. Although this may inform later situation-specific decision-making, our research did not demonstrate an impact on total opioid dosing, which was primarily driven by surgical and child-related factors.
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Complex regional pain syndrome (CRPS) is thought to be characterized by cognitive deficits affecting patients' ability to represent, perceive, and use their affected limb as well as its surrounding space. This has been tested, among others, by straight-ahead tasks testing oneself's egocentric representation, but such experiments lead to inconsistent results. Because spatial cognitive abilities encompass various processes, we completed such evaluations by varying the sensory inputs used to perform the task. ⋯ However, in this latter task, limb position could only be estimated by proprioception, as vision of the limb was prevented. Whereas in the 2 former tasks CRPS participants' performance was not different from that of controls, they made significantly more deviations errors during the visuospatial task, regardless of the limb used to point or the direction of pointing. Results suggest that CRPS patients are not specifically characterized by difficulties in representing their body but, more particularly, in integrating somatic information (ie, proprioception) during visually guided movements of the limb.
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Randomized Controlled Trial
Balloon compression versus radiofrequency for primary trigeminal neuralgia: a randomized, controlled trial.
Surgical procedures are necessary in up to 50% of trigeminal neuralgia patients. Although radiofrequency (RF) is more widely used, it is associated with high intraprocedural costs and long technical learning time. Other simpler procedures such as balloon compression (BC) require a lower training period and have significant lower costs. ⋯ Complications, interference of pain in daily life (CI 95% -0.1 to 2.3 and -0.4 to 2.3, for BC and RF), neuropathic pain symptoms (CI 95% 1.7 to 3.6 and 3.0 to 5.7, for BC and RF), mood (CI 95% 4.8 to 11.5 and 5.5 to 15.1, BC and RF, respectively), medication use, and quality of life (CI 95% 80.4 to 93.1 and 83.9 to 94.2, for BC and RF) were also not different. Radiofrequency presented more paresthetic symptoms than BC at 30 days after intervention. Based on these results, the study was halted due to futility because BC was not superior to RF.