Trends and Costs of External Electrical Bone Stimulators and Grafting Materials in Anterior Lumbar Interbody Fusion

Study Design Retrospective review. Purpose To identify the trends in stimulator use, pair those trends with various grafting materials, and determine the influence of stimulators on the risk of revision surgery. Overview of Literature A large number of studies has reported beneficial effects of electromagnetic energy in healing long bone fractures. However, there are few clinical studies regarding the use of electrical stimulators in spinal fusion. Methods We used insurance billing codes to identify patients with lumbar disc degeneration who underwent anterior lumbar interbody fusion (ALIF). Comparisons between patients who did and did not receive electrical stimulators following surgery were performed using logistic regression analysis, chi-square test, and odds ratio (OR) analysis. Results Approximately 19% of the patients (495/2,613) received external stimulators following ALIF surgery. There was a slight increase in stimulator use from 2008 to 2014 (multi-level R2=0.08, single-level R2=0.05). Patients who underwent multi-level procedures were more likely to receive stimulators than patients who underwent single-level procedures (p0.05), except those in the multilevel ALIF+PLF cohort, wherein the patients who underwent stimulation had higher rates of revision surgery. Conclusions Concurrent PLF or multi-level procedures increased patients’ likelihood of receiving stimulators, however, the presence of comorbidities did not. Patients who received BMA plus autograft or allograft were more likely to receive stimulation. Patients with and without bone stimulators had similar rates of revision surgery.