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

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