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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.

IntroductionSpinal 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.MethodsThis 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 pResultsBased 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).ConclusionAlthough 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.

The diagnosis of sacroiliac joint dysfunction is often difficult and requires a thoughtful and thorough workup to uncover. A proper diagnosis is required so that appropriate treatment can be provided for the chronic pain patients suffering from sacroiliac joint dysfunction. This chapter discusses the symptoms of sacroiliac joint dysfunction (including inciting factors, location, and inflammatory etiologies), the components of a physical examination (including detailed explanations of several physical examination maneuvers, as well as their reliability), the utility of diagnostic injections, the imaging techniques that are useful in this setting (radiography, ultrasound, computed tomography, magnetic resonance imaging), and laboratory evaluation that might be required in this setting (bloodwork).

Jonathan M Hagedorn, Nicholas Canzanello, Markus A Bendel, Thomas P Pittelkow, Tim J Lamer Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USACorrespondence: Jonathan M HagedornDepartment of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, 55905, USAFax +1 507-266-7732Email jonhagedornmd@yahoo.comObjective: Surgical site infection in patients who undergo spinal cord stimulator implant surgery represents a significant concern in terms of increased health care costs and patient morbidity. The use of antibacterial envelopes in spinal cord stimulator implant surgeries has not been previously described. The aim of this retrospective review was to evaluate the effectiveness of the antibacterial envelope in reducing surgical site infection in spinal cord stimulator implant surgeries when used adjunctively to standard infection prevention measures.Materials and Methods: The study included 52 patients, all of whom were implanted with a spinal cord stimulator between January 2015 and November 2020. To be included, patients were required to have had an antibacterial envelope utilized at the time of surgery. Patient records were retrospectively reviewed. All patients who received an antibacterial envelope at the time of implant surgery were included.Results: Data was collected and analyzed on 52 permanent SCS implantations, including primary implantation (n=26) and revision surgery (n=26). All patients were at least three months post-operative from the implant surgery (average follow-up time period was 518.4 days). There were no surgical site infections reported in the 52 patient cohort.Conclusion: Antibiotic impregnated envelopes appear to be a safe and effective modality to decrease surgical site infection risk in spinal cord stimulation implant surgeries.Keywords: spinal cord stimulation, surgical site infection, outcomes, infection prevention

Background At least 50% of individuals who suffer a brachial plexus avulsion (BPA) will develop chronic pain, frequently more debilitating than their functional limitations. Similar to other neuropathic pain states, BPA pain is often refractory to pharmacological agents. Despite spinal cord stimulation (SCS) first being used for BPA in 1974, there have been no published literature reviews examining the current evidence of SCS for the treatment of neuropathic pain following BPA. In addition to a clinical review of the literature for this indication, we also share our experience with high-frequency SCS (HF-SCS) for BPA-related pain. Methods MEDLINE and EMBASE databases were searched. All published articles including at least one BPA individual treated with SCS for pain treatment were included. Results The initial search identified 288 articles, of which 13 met inclusion criteria for a total of 41 patients. These patients were primarily male and underwent SCS with reported improved pain scores. Case reports HF-SCS leads were percutaneously placed in two male patients who suffered BPA from traumatic injuries. At follow-ups of 13 and eight months, respectively, both patients continued to report an improvement in their pain. Conclusions Despite published reports showing benefit for pain control in patients with BPA, the overall low quality, retrospective evidence included in this review highlights the need for a rigorous prospective study to further address this indication.