Comparison of Fusion Rate between Iliac Autograft versus Fibular Allograft in Instrumented Anterior Cervical Fusion

ABSTRACT

OBJECTIVE: The authors performed instrumented anterior cervical fusion with either iliac autograft or fibular allograft for various clinical entities. The purposes of the study are to compare the fusion rate and the time to fusion according to graft material, and to identify the factors affecting fusion. METHOD:57 patients underwent instrumented anterior cervical fusion during 3 years between Jan. 1995 and Dec. 1997, among them 31 patients with iliac autograft(autograft group), and 26 patients with freeze-dried fibular allograft (allograft group). The clinical entities were trauma(n=0), soft disc herniation(n=), spondylotic radiculopathy(n=1), spondylotic myelopathy(n=6), and ossified posterior longitudinal ligament(n=). The method of fusion was either interbody fusion confined to disc space or strut fusion after corpectomy. Outcomes were assessed for fusion status and time to fusion, and comparison between autograft group versus allograft group. RESULT: Between autograft and allograft group there were no differences in distribution of perioperative clinical variables such as patients' age and gender, clinical entity, method of fusion, and length of fusion as determined by the number of disc space fused. Mean follow-up period was 19 months(range 10-28 months) in autograft group and 16 months(range 8-22 months) in allograft group. The fusion rate was 90% in autograft group and 85% in allograft group(p=.691). The median time to fusion was 7 months in autograft group and 15 months in allograft group(p<0.001). The perioperative variables affecting fusion, defined as those being significantly associated with the time to fusion, were the graft material(p=.000) and the length of fusion(p=.007). The rate of graft-related complications including donor-site morbidity was 41% in autograft group and 8% in allograft group. CONCLUSION: It is concluded that the use of freeze-dried fibular allograft in instrumented anterior cervical fusion is, though the time to fusion is delayed more than two times, as an effective way as the use of iliac autograft to achieve fusion, and is a better way to ameliorate graft-related complications.