Effect of High-frequency (10-kHz) Spinal Cord Stimulation in Patients With Painful Diabetic Neuropathy: A Randomized Clinical Trial.

Importance: Many patients with diabetic peripheral neuropathy experience chronic pain and inadequate relief despite best available medical treatments. Objective: To determine whether 10-kHz spinal cord stimulation (SCS) improves outcomes for patients with refractory painful diabetic neuropathy (PDN). Design, Setting, and Participants: The prospective, multicenter, open-label SENZA-PDN randomized clinical trial compared conventional medical management (CMM) with 10-kHz SCS plus CMM. Participants with PDN for 1 year or more refractory to gabapentinoids and at least 1 other analgesic class, lower limb pain intensity of 5 cm or more on a 10-cm visual analogue scale (VAS), body mass index (calculated as weight in kilograms divided by height in meters squared) of 45 or less, hemoglobin A1c (HbA1c) of 10% or less, daily morphine equivalents of 120 mg or less, and medically appropriate for the procedure were recruited from clinic patient populations and digital advertising. Participants were enrolled from multiple sites across the US, including academic centers and community pain clinics, between August 2017 and August 2019 with 6-month follow-up and optional crossover at 6 months. Screening 430 patients resulted in 214 who were excluded or declined participation and 216 who were randomized. At 6-month follow-up, 187 patients were evaluated. Interventions: Implanted medical device delivering 10-kHz SCS. Main Outcomes and Measures: The prespecified primary end point was percentage of participants with 50% pain relief or more on VAS without worsening of baseline neurological deficits at 3 months. Secondary end points were tested hierarchically, as prespecified in the analysis plan. Measures included pain VAS, neurological examination, health-related quality of life (EuroQol Five-Dimension questionnaire), and HbA1c over 6 months. Results: Of 216 randomized patients, 136 (63.0%) were male, and the mean (SD) age was 60.8 (10.7) years. Additionally, the median (interquartile range) duration of diabetes and peripheral neuropathy were 10.9 (6.3-16.4) years and 5.6 (3.0-10.1) years, respectively. The primary end point assessed in the intention-to-treat population was met by 5 of 94 patients in the CMM group (5%) and 75 of 95 patients in the 10-kHz SCS plus CMM group (79%; difference, 73.6%; 95% CI, 64.2-83.0; P < .001). Infections requiring device explant occurred in 2 patients in the 10-kHz SCS plus CMM group (2%). For the CMM group, the mean pain VAS score was 7.0 cm (95% CI, 6.7-7.3) at baseline and 6.9 cm (95% CI, 6.5-7.3) at 6 months. For the 10-kHz SCS plus CMM group, the mean pain VAS score was 7.6 cm (95% CI, 7.3-7.9) at baseline and 1.7 cm (95% CI, 1.3-2.1) at 6 months. Investigators observed neurological examination improvements for 3 of 92 patients in the CMM group (3%) and 52 of 84 in the 10-kHz SCS plus CMM group (62%) at 6 months (difference, 58.6%; 95% CI, 47.6-69.6; P < .001). Conclusions and Relevance: Substantial pain relief and improved health-related quality of life sustained over 6 months demonstrates 10-kHz SCS can safely and effectively treat patients with refractory PDN. Trial Registration: ClincalTrials.gov Identifier: NCT03228420.

Novel spinal cord stimulation parameters in patients with predominant back pain.

OBJECTIVES: To examine the feasibility of novel high-frequency spinal cord stimulation therapy in a cohort of patients with chronic predominant back pain during a four day, percutaneous trial. DESIGN: Prospective, multicenter open label pilot trial. SETTING AND PATIENTS: Twenty-four patients with back pain greater than leg pain who were candidates for spinal cord stimulation were trialed at five U.S. centers. INTERVENTIONS: Patients completed a percutaneous trial with a commercially available spinal cord stimulator. The implanted leads were then connected to the novel external stimulation device and patients were trialed for an additional four days. OUTCOME MEASURES: Pain intensity ratings, subjective descriptions, and patients' preference. RESULTS: There was significant improvement from baseline in overall pain scores (8.68 to 2.03, [p < 0.001]) and back pain scores (8.12 to 1.88, [p < 0.001]) with the investigational stimulation. The investigational stimulation was preferred to the commercially available systems in 21 of 24 patients (88%). CONCLUSIONS: Patients with predominant back pain reported a substantial reduction in overall pain and back pain when trialed with high-frequency spinal cord stimulation therapy.

A randomized, placebo-controlled study to assess the efficacy of lateral branch neurotomy for chronic sacroiliac joint pain.

OBJECTIVE: The objective of this study was to compare the efficacy of lateral branch neurotomy using cooled radiofrequency to a sham intervention for sacroiliac joint pain. DESIGN: Fifty-one subjects were randomized on a 2:1 basis to lateral branch neurotomy and sham groups, respectively. Follow-ups were conducted at 1, 3, 6, and 9 months. Subjects and coordinators were blinded to randomization until 3 months. Sham subjects were allowed to crossover to lateral branch neurotomy after 3 months. SUBJECTS: Subjects 18-88 years of age had chronic (>6 months) axial back pain and positive response to dual lateral branch blocks. INTERVENTIONS: Lateral branch neurotomy involved the use of cooled radiofrequency electrodes to ablate the S1-S3 lateral branches and the L5 dorsal ramus. The sham procedure was identical to the active treatment, except that radiofrequency energy was not delivered. OUTCOME MEASURES: The principal outcome measures were pain (numerical rating scale, SF-36BP), physical function (SF-36PF), disability (Oswestry disability index), quality of life (assessment of quality of life), and treatment success. RESULTS: Statistically significant changes in pain, physical function, disability, and quality of life were found at 3-month follow-up, with all changes favoring the lateral branch neurotomy group. At 3-month follow-up, 47% of treated patients and 12% of sham subjects achieved treatment success. At 6 and 9 months, respectively, 38% and 59% of treated subjects achieved treatment success. CONCLUSIONS: The treatment group showed significant improvements in pain, disability, physical function, and quality of life as compared with the sham group. The duration and magnitude of relief was consistent with previous studies, with current results showing benefits extending beyond 9 months.

Painful medial branch neuroma treated with minimally invasive medial branch neurectomy.

STUDY DESIGN: Case report. OBJECTIVE: To report an unusual complication following lumbar facet radiofrequency denervation and describe a successful, minimally invasive treatment of a presumed medial branch neuroma. SUMMARY OF BACKGROUND DATA: Radiofrequency medial branch neurotomy is a common procedure for the treatment of mechanical back pain. Deafferentation injury and neuroma formation is well known and reported following chemical, surgical, and cryoablation neurolysis; however, it is thought to be rare with radiofrequency ablation. When this problem is encountered, treatment options appear to be limited. Further radiofrequency ablations may be ineffective and indeed may cause further injury. METHODS: A 17-year-old male who sustained a traumatic fracture of the right L3-4 facet joint presented with increasing back pain after multiple radiofrequency ablations of the medial branches of the L2 and L3 dorsal rami. The description of the back pain, initially nociceptive in nature, had become progressively neuropathic with clear focal areas of allodynia and hyperesthesia. Further medial branch radiofrequency denervation was found to be ineffective. RESULTS: Diagnostic block of the right medial branch of the L2 dorsal ramus provided the patient with total relief of pain. This was followed by a minimally invasive open surgical ablation of the L2 medial branch neuroma using three-dimensional, fluoroscopy-based image guidance. At 7 months of follow-up, the patient reported complete resolution of pain, discontinuation of all pain medications, and return to all previous physical activities. CONCLUSION: Deafferentation injury is a rare but recognized complication of chemical, surgical, and thermal neuroablation. This case report presents a rare instance of presumed neuroma formation following multiple radiofrequency ablations for the treatment of facet-generated mechanical back pain. Open and minimally invasive medial branch neurectomy resulted in complete resolution of pain and return to baseline function.