Anterior cervical discectomy with freeze-dried fibula allograft - Overviewof 317 cases and literature review

Study Design, A retrospective review of 317 patients to determine the effic acy of allogeneic fibula arthrodesis after anterior cervical discectomy. Objective. To examine the efficacy of allogeneic fibula as an alternative f usion substrate after anterior cervical discectomy, and to determine the ef fects of cigarette smoking on the healing of fibula allografts. Summary of Background Data, The use of autogeneic iliac crest is associated with graft harvest complications in up to 20% of patients. Most studies re porting on the use of allogeneic iliac crest cite a high collapse rate. Few studies exist that note the efficacy of allogeneic fibula in this procedur e and the effects of cigarette smoking on fusion rate. Methods. From 1988 to 1993, 317 patients underwent grafting by the Smith-Ro binson technique with allogeneic fibula after anterior cervical discectomy. Patients who described themselves as habitual cigarette smokers or who smo ked during the perioperative or postoperative period were categorized as sm okers. All patients were immobilized in a rigid cervical orthosis (Philadel phia collar) for at least 10 weeks postoperatively. Results. A minimum of 2 years follow-up was achieved in 289 patients. In al l, 162 men and 127 women had a total of 311 levels grafted, and the mean fo llow-up period was 33 months (range, 24 to 51 months). Of patients who rece ived allogeneic fibula at one level, 90% (242/269) achieved radiologic fusi on. The fusion rate was 92% (182/198) among nonsmokers compared with 85% (6 0/71) among smokers (not a statistically significant difference; P = 0.120) . After two-level procedures, 72% (13/18) of the patients showed fusion. Th e fusion rate was 50% (2/4) among smokers compared with 79% (11/14) among n onsmokers (P = 0.53). When one-level arthrodesis (90%) was compared with tw o-level arthrodesis (72%), the difference approached statistical significan ce (P = 0.054). Neither of the two patients, both nonsmokers, who received grafts at three levels achieved fusion. There were no infections, and no gr afts collapsed. Two grafts extruded (0.6%), but these were partial and did not require reoperation. Both patients fused and constituted the only patie nts with more than 10 degrees of angulation in the series. Graft subsidence occurred in 5% (17/311) of the grafts, mostly in the beginning of the seri es, and was not problematic. This phenomenon was thought to have been cause d by overaggressive removal of the cortical endplate. Conclusion. Allogeneic fibula is an effective substrate for use in achievin g fusion after anterior cervical discectomy. Maximal results are achieved w ith its use at one level in nonsmokers, Cigarette smoking decreased the fus ion rate with allogeneic fibula in the anterior cervical spine, but not by a statistically significant amount.