A PROSPECTIVE-STUDY OF 342 PATIENTS USING TRANSPEDICULAR FIXATION INSTRUMENTATION FOR LUMBOSACRAL SPINE ARTHRODESIS

The objective of this research was to determine the efficacy and safet y of an experimental instrumentation device designed for transpedicula r spinal fixation by evaluating fusion rates and clinical pain and fun ction scores; to determine complication rates associated with the devi ce; and to compare the obtained data with that previously published in the literature. Four hundred forty-two consecutive patients were enro lled in this 4-year, Food and Drug Administration-monitored investigat ional device exemption trial to undergo surgery for implantation of th e device. Eighteen surgeons at 11 nationwide medical centers performed the operations and subsequent evaluations. The study population was d erived from three diagnostic categories: degenerative disc disease, mu ltioperated back, and vertebral fracture. The data source consisted of radiographs, clinical examination, and structured forms and questionn aires. Patients were evaluated preoperatively, intraoperatively, and p ostoperatively at 3, 6, 12, and 24 months. By the 24-month postoperati ve interval, attrition had reduced the study population to 342 patient s, among whom bony fusion was obtained in 91.5%. Pain scores demonstra ted a statistically significant improvement in clinical outcome. Intra operative complications occurred in 21.9% of patients. Of the 442 stud y patients, 2.9% experienced device-related complications. Moreover, a total of 2,304 screws and bolts were implanted in this patient popula tion. Of these, 0.39% were reported to have fractured. Among the 342 s tudy patients observed during 24 months, the breakage rate of device c omponents (bolt or screw) was 2.63%. These data compare favorably to e xisting reports of spinal arthrodesis effected with other types of ins trumentation and without device implantation. In a 4-year trial, the e xperimental transpedicular fixation instrumentation produced successfu l spinal fusion in the majority of our study population, with acceptab le complication rates.