Incidence and Risk Factors for Spinal Cord Stimulator Lead Migration With or Without Loss of Efficacy: A Retrospective Review of 91 Consecutive Thoracic Lead Implants.

OBJECTIVE: Lead migration after spinal cord stimulator (SCS) implant is a commonly reported complication and the most common reason for revision surgery in cases of loss of efficacy. The primary aims of this study are to describe the incidence and degree of lead migration in the subacute postoperative period after SCS implant and to report potential risk factors for lead migration. MATERIALS AND METHODS: We performed a retrospective chart review of all patients at a single academic center who received an SCS implant from January 1, 2020, to December 31, 2020. Information on patient (age, sex, weight, and height) and operative factors (device manufacturer, epidural access level and method, and implantable pulse generator location) were extracted from medical records. Intraoperative imaging was compared to subacute follow-up imaging obtained less than 20 days postimplant to measure lead migration distance. Regression models were fitted to determine associations between lead migration distance and potential clinical risk factors. RESULTS: A total of 91 cases (182 leads) were included in the study. Within 20 days of implantation, 88.5% of leads had migrated (86.3% caudal and 2.2% cephalad). Mean migration distance for leads with caudal migration only was 12.34 ± 12.19 mm based on anteroposterior radiographs and 16.95 ± 15.68 mm on lateral radiographs. There was an association of greater caudal lead migration as patient body mass index increased (ß-coefficient 0.07 [95% confidence interval 0.01-0.13], p = 0.031). Within the entire cohort, one patient (1.1%) required lead revision for loss of efficacy. CONCLUSIONS: In the subacute postoperative period after SCS implant, the majority of SCS leads migrated caudally with an average of two lead contacts. Knowledge of this expected migration and risk factors can better inform implanting physicians intraoperatively when deciding final lead placement location. The finding of high likelihood of caudal lead migration in the subacute postoperative period brings the need for a well-designed prospective study to the forefront of our field. This will allow implanting providers to make well-informed decisions for intraoperative lead placement.

Spinal Cord Stimulation for Neuropathic Pain Treatment in Brachial Plexus Avulsions: A Literature Review and Report of Two Cases.

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.

Current Evidence Lacking to Guide Clinical Practice for Spinal Cord Stimulation in the Treatment of Neuropathic Pain in Spinal Cord Injury: A Review of the Literature and a Proposal for Future Study.

BACKGROUND/OBJECTIVE: Chronic pain is commonly reported in individuals with spinal cord injuries (SCIs), with recent prevalence reported as high as 80%. Uncontrolled pain is known to decrease quality of life, attenuate mood, and impact sleep. Spinal cord stimulation (SCS) for the treatment of refractory pain was first used in the SCI population in 1972. To date there have been no randomized controlled trials examining the effect of SCS on neuropathic pain post-SCI. A literature review in 2009 identified 27 studies, the majority prior to 2000, that included at least 1 patient with SCI. Given the significant advancements in the field of SCS, this review examines the updated evidence of SCS for the treatment of neuropathic pain in individuals with SCI and provides guidance on future investigations. METHODS: MEDLINE and EMBASE databases were searched. All published reports, case series, and clinical trials reviewing SCS for neuropathic pain that included at least 1 individual with SCI were included. RESULTS: The initial search identified 376 reports, of which 22 met inclusion criteria, for a total of 69 patients. All reports were of very low quality. A majority of the reported patients were male, underwent tonic stimulation, and reportedly experienced improvement in pain and spasticity, with decreased use of pain medication. CONCLUSIONS: The synthesized findings from primarily case studies support the safety of SCS in SCI with the suggestion of potential pain relief benefit; however, data from low-quality studies are insufficient for informing clinical practice. A well-designed, prospective clinical trial is proposed to further investigate this indication.