Efficacy of implanted bone growth stimulation in instrumented lumbosacral spinal fusion

Ninety-four patients were assigned to groups either with or without implanted bone growth stimulation as an adjunct to instrumented animal fusion between May 1990 and December 1992. Consecutive groups with or without stimulation were compared prospectively; a small group was compared with random assignment of surgery with or without stimulation.

To test the efficacy of implanted bone growth stimulation in instrumented fusion, especially regarding high-rist patient groups including smokers, those with previous back surgery, and those with multiple fusion levels.

No reports have specifically addressed implanted bone growth stimulation with instrumented spinal fusion, although the effects of stimulation on long-bone and in situ spinal fusion have been reported.

Fusion surgery was performed by the same two surgeons for all patients, using autologous graft and instrumentation (pedicle screw and rod). Surgical indications and pre- and postoperative regimens were similar for all patients. Average follow-up period was 20.5 months.

Ninety-six percent of patients with stimulation had solid fusion versus 85% fusion in patients who did not have stimulation.

Implanted bone growth stimulation can improve fusion results in patients with instrumented lumbosacral fusion as has been demonstrated in in situ fusions. Patients in high-risk categories (smokers, those with multiple back surgeries, and multilevel fusions) also are demonstrated to have higher fusion rates with implanted bone growth stimulation than those without benefit of stimulation.