The use of implantable direct current stimulation in multilevel spinal fusion without instrumentation - A prospective clinical and radiographic evaluation with long-term follow-up

Study Design. A prospective study with long-term follow-up of 143 patients who patients who underwent spinal fusion with direct current stimulation and no instrumentation. Objectives. To assess the effects of direct current stimulation on fusion success, clinical outcome, and return to work in multilevel lumbar spinal fusion procedures. Summary of Background Data. Efforts to ensure higher fusion success rates in multilevel procedures have resulted in the use of surgical adjuncts, such as spinal instrumentation systems and electrical stimulation. Methods. Patients were assessed 3, 6, 12, 18, and 24 or more months after surgery (long-term follow-up). Fusion was determined by anteroposterior and lateral radiographs and lateral bending films and was considered successful if there was evidence of bony fusion and the absence of motion between the operated vertebrae. Surgical technique included either a posterior facet or posterolateral fusion. Results. There were no significant differences (P > 0.05) in fusion success between 12-month results and the long-term results. The median length of the long-term follow-up period was 5.0 years (range, 2-9 years). Nineteen patients were lost to follow-up; five were unwilling to return for assessment and one patient died. Fusion success among the remaining 118 patients was 91.5%. Two-level procedures (22) had a fusion rate of 91%. Eighty-five patients (72%) had no pain; 27 patients (23%) had mild pain occasionally, and six patients (5%) had some degree of moderate pain. One hundred patients (85%) returned to work; 12 (10%) retired; five (4%) were not working before the surgery, and one patient (1%) was unable to return to work. There were no worker's compensation patients, and there were no major surgical complications in this series. Conclusions. Multilevel fusion in the series with long-term follow-up evaluation of direct current stimulated patients without instrumentation showed clinical and radiographic success higher than in recent studies without instrumentation and comparable with recent studies using instrumentation.