PSEUDOARTHROSIS RATE AFTER ALLOGRAFT POSTERIOR LUMBAR INTERBODY FUSION WITH PEDICLE SCREW AND PLATE FIXATION

Study Design. Twenty-five of 26 consecutive patients were studied after posterior lumbar interbody fusion using ethylene oxide-sterilized allograft bone for posterior lumbar interbody fusion and autologous bone for posterolateral fusion with posterior fixation using pedicle screws and variable screw placement plates. Objectives. Patients were studied at 1 year to determine rate of complications, pseudarthrosis, and re-operations. Methods. Clinical success was determined by combined five-point analog pain and function scales. Fusion success was determined by plain radiographs. Results. Complications occurred in four of 25 patients (16%). Re-operations were done in nine of 25 patients (36%) with seven re-operations (28%) to treat frank failures of the donor bone. Although some patients subsequently improved with repeat surgery, the result of the donor bone posterior lumbar interbody fusion was excellent in nine patients, good in four, fair in eight, and poor in four. Posterior lumbar interbody fusion success was achieved in 14 of 25 patients (56%). Clinical success was achieved in 15 of 25 patients (60%). Conclusions. Although the mechanical principles of posterior lumbar interbody fusion were affirmed, the adequacy of ethylene oxide-sterilized allograft bone in meeting the mechanical and biologic needs of posterior lumbar interbody fusion was questioned.