Peer-Review ReportA Review of Oscillating Field Stimulation to Treat Human Spinal Cord Injury

ObjectiveTo report the results of use of a human oscillating field stimulator (OFS) in a phase 1 trial of 14 human patients with complete motor and sensory spinal cord injury.MethodsEntry criteria were complete spinal cord injury between C5 and T10 in patients 18-65 years old with no transection on magnetic resonance imaging. All patients received the National Acute Spinal Cord Injury Study III methylprednisolone protocol. Cord compression or instability was treated before entry. All patient injuries remained complete (based on American Spinal Cord Injury scoring) with no somatosensory evoked potentials (SSEPs) below the injury after surgery or for 48 hours. All patients were implanted with the OFS within 18 days. Patients were checked every 2 weeks after implantation. The OFS was explanted at 15 weeks. Independent neurologic examinations (American Spinal Cord Injury score, visual analog scale for pain, and SSEPs) were done at 6 weeks, 6 months, and 1 year. Statistical analyses were done by Wilcoxon rank sum test and analysis of variance (ANOVA).ResultsThere were no complications at insertion, and one wound infection occurred after explant for a 3.5% infection rate. One patient was lost to follow-up after 6 months. All 14 patients had a mean visual analog scale score of 8 at implant and 2 at 6 months, and 13 remained a mean score of 2 at 1 year. Mean improvement in light touch score at 1 year was 25.9 points (ANOVA, P < 0.001; Wilcoxon, P = 0.02). Mean improvement in pinprick score at 1 year was 15.2 points (ANOVA, P < 0.001; Wilcoxon, P = 0.02). Mean improvement in motor score was 6.9 (ANOVA, P < 0.01; Wilcoxon, P = 0.02). Of eight patients with cervical cord injuries, six had improvement in arm SSEPs, and one recovered a tibial SSEP. Of six patients with thoracic injuries, one recovered an abnormal lower SSEP.ConclusionsTreatment of human spinal cord injury with an OFS is safe, reliable, and easy. Compared with National Acute Spinal Cord Injury Study III compliant paralyzed patients, our results suggest efficacy.