Effects of Electrical Stimulator Use with Boston Overlapping Bracing for Spondylolysis Healing in Athletes

Abstract

Repetitive load on the spine increases the risk of back pain and spondylolysis. “High-risk” sports include ballet, diving, figure skating, football, gymnastics, rowing, weight lifting, and wrestling. Rates of spondylolysis in sports have been reported from 17 to 43%. Electrical stimulation (e-stim) is typically used to heal recalcitrant cases of non-union. Retrospective studies suggest that e-stim may improve healing rates of spondylolysis. PURPOSE: To determine if patients with spondylolysis fractures have a higher rate of healing with the Boston Overlapping Brace (BOB) and e-stim versus those who use BOB alone. METHODS: In this prospective case control study, 56 athletes ages 12–22 (mean= 16) with extension-based back pain were enrolled after being diagnosed with spondylolysis by either positive SPECT bone scan and CT scan, or positive MRI and CT scan. Patients were randomly assigned to standard treatment or experimental treatment. The standard arm (BOB group) consisted of activity restriction, antilordotic bracing 23 hours/day, and physical therapy (PT). The experimental arm (e-stim group) involved standard therapy plus an external electrical bone stimulator, worn outside the brace over the spondylolysis site 3 hours/day. At 4 months, repeat CT exams were obtained. Patients in the standard group who were still experiencing back pain and had radiographic evidence of non-union of the fracture were then crossed-over to begin e-stim therapy (CO group). Patients were followed for one year with physical exams, compliance and pain surveys, and CT scans until bony/fibrous union was noted. RESULTS: 30 patients were randomized to e-stim, 26 patients to BOB, and 7 of the BOB patients became CO patients. Bony or fibrous union was noted on CT in 20/50 of the e-stim group, 13/32 in the BOB group, and 6/7 of the CO group. When radiographic results of e-stim and CO were combined and compared with BOB using chi square testing, there was no significant difference in the frequency of bony/fibrous union between the two groups (p ≤ 1.0). CONCLUSIONS: The preliminary data of this study suggest that adding e-stim to BOB and PT in the treatment of spondylolysis does not improve the rate of bony/ fibrous union compared to BOB and PT alone. However, more patients are being recruited to enhance future subgroup analysis.