Canzanello, Nicholas

Abstract The availability of knowledge about the effects of buprenorphine on pain perception in healthy adults could help investigators select experimental tests with evidence of responsiveness to buprenorphine in nondiseased states. The purpose of this meta-narrative systematic review is to summarize the effects of buprenorphine on pain perception in healthy adults. Comprehensive database searches were conducted from inception dates through July 16, 2024. Inclusion criteria included all study designs involving healthy adults receiving buprenorphine and tests of pain perception. Risk of bias was assessed using a tool developed for randomized controlled trials (RCTs). A meta-narrative approach was used due to high levels of clinical heterogeneity. A total of 10 RCTs were included, and healthy adults comprised the comparator groups in all trials. Three RCTs had a low risk of bias, 6 had some concerns, and 1 had a high risk of bias. Six RCTs used intravenous buprenorphine, 3 used transdermal, and 1 study used intravenous and sublingual buprenorphine. The effects of buprenorphine on pain perception are influenced by the route of administration, dose, and pain stimulus modality. Considerable differences exist in the effects of intravenous and transdermal buprenorphine, but only 1 study used sublingual buprenorphine, which limited comparison with the other drug formulations. Based on these findings, recommendations for clinical trials are proposed. These recommendations should be cautiously interpreted due to the clinical heterogeneity, but they provide a framework for advancing the use of experimental pain tests in trials of buprenorphine involving comparator groups of healthy adults.

Abstract Erythromelalgia is a rare neurovascular disorder characterized by erythema, warmth, and episodic burning pain, often felt in the face, hands, and feet. Symptoms are typically worse with heat, exercise, stress, and during the overnight hours. Management often requires a multidisciplinary approach, including pain trigger avoidance, cool water baths, and topical and oral neuropathic medications. The use of spinal cord stimulation has been described in multiple case reports with success reported out to 24 months. To our knowledge, the use of dorsal root ganglion (DRG) stimulation for erythromelalgia‐related pain has not been described. Herein, we present a case of erythromelalgia‐related pain at the bilateral plantar surfaces of the feet, which was treated successfully with bilateral sacral S1 nerve root DRG stimulation.

Introduction Spinal cord stimulation is frequently used for the treatment of intractable chronic pain conditions. Trialing of the spinal cord stimulator device is recommended to assess the patient’s response to neurostimulation before permanent implantation. The trial response is often assessed by Numeric Rating Scale changes and patient-reported percentage pain improvement. Using number rating scale changes between prespinal and postspinal cord stimulation trial, a calculated percentage pain improvement can be obtained. The aim of this study was to assess the difference between calculated and patient-reported percentage improvement in pain scale during spinal cord stimulation trials. Methods This study was a retrospective single center review of all spinal cord stimulation trials from January 1 2017 to July 1 2019. A total of 174 patients were included. The paired t-test was used to compare numeric pain scores obtained prestimulation versus poststimulation. The mean difference between methods (patient-reported minus calculated) was compared with zero using the 1-sample t-test. Lin’s concordance correlation coefficient was computed with a 95% CI, calculated using Fisher z-transformation; and a bootstrapping approach was used to compare the concordance correlation coefficient between groups. In all cases, two-tailed tests were used with p<0.05 considered statistically significant. Results Based on prestimulation and poststimulation numeric rating scale scores, the mean±SD calculated percentage improvement in pain scale was 54±28. The mean±SD patient-reported percentage improvement in pain scale was 59±25. The overall 95% limits of agreement for the two methods are −30% to +41%. The overall concordance correlation coefficient was 0.76 (95% CI 0.69 to 0.81). Conclusion Although the two methods are highly correlated, there is substantial lack of agreement between patient-reported and calculated percentage improvement in pain scale, suggesting that these measures should not be used interchangeably for spinal cord stimulator trial outcome assessment. This emphasizes the need for improved metrics to better measure patient response to neuromodulation therapies. Additionally, patient-reported percentage improvement in pain was found to be higher than calculated percentage improvement in pain, potentially highlighting the multidimensional experience of pain and the unpredictability of solely using Numeric Rating Scale scores to assess patient outcomes.