IS IT NECESSARY TO DECORTICATE SEGMENTALLY INSTRUMENTED SPINES TO ACHIEVE FUSION

Study Design. The effects of spinal instrumentation and decortication on spinal arthrodesis rates-when performed independently and when used together-were studied in an experimental animal model. Materials and Methods. Fifty-two immature New Zealand white rabbits underwent six di fferent spinal procedures. The animals were killed six weeks postopera tively and their spines were evaluated by gross examination, radiograp hy, manual stress testing, and histologic means. Results. The addition of rigid instrumentation to autologous iliac grafting significantly i mproved fusion rates in animals that were not decorticated. However, w hen decortication was done, a statistically significant improvement co uld not be documented. The addition of decortication to autologous ili ac grafting significantly improved fusion rates in noninstrumented spi nes, but in instrumented spines, a statistically significant improveme nt could not be demonstrated.