A COMPARATIVE-ANALYSIS OF FUSION RATES AND DONOR-SITE MORBIDITY FOR AUTOGENEIC RIB AND ILIAC CREST BONE-GRAFTS IN POSTERIOR CERVICAL FUSIONS

Object. Autogeneic bone graft is often incorporated into posterior cer vical stabilization constructs as a fusion substrate. Iliac crest is u sed frequently, although donor-site morbidity can be substantial. Rib is used rarely, despite its accessibility, expandability, unique curva ture, and high bone morphogenetic protein content. The authors present a comparative analysis of autogeneic rib and iliac crest bone grafts, with emphasis on fusion rate and donor-site morbidity. Methods. A rev iew was conducted of records and radiographs from 600 patients who und erwent cervical spinal fusion procedures in which autogeneic bone graf ts were used. Three hundred patients underwent rib harvest and posteri or cervical fusion. The remaining 300 patients underwent iliac crest h arvest (248 for an anterior cervical fusion and 52 for posterior fusio n). The analysis of fusion focused on the latter subgroup; donor-site morbidity was determined by evaluating the entire group. Fusion criter ia included bony trabeculae traversing the donor-recipient interface a nd long-term stability on flexion-extension radiographs. Graft morbidi ty was defined as any untoward event attributable to the graft harvest . Statistical comparisons were facilitated by using Fisher's exact tes t. Conclusions. Demographic data obtained in both groups were comparab le. Rib constructs were placed in the following regions: occipitocervi cal (196 patients), atlantoaxial (35 patients), and subaxial cervical spine (69 patients). Iliac crest grafts were placed in the occipitocer vical (28 patients), atlantoaxial (10 patients), and subaxial cervical (14 patients) regions. Fusion occurred in 296 (98.8%) of 300 rib graf t and 49 (94.2%) of 52 iliac crest graft constructs (p = 0.056). Graft morbidity was greater with iliac crest than with rib (p < 0.00001). D onor-site morbidity for the rib graft was 3.7% and included pneumonia (eight patients), persistent atelectasis (two patients), and super fic ial wound dehiscence (one patient). Pneumothorax, intercostal neuralgi a, and chronic chest wall pain were not encountered. Iliac crest morbi dity occurred in 25.3% of the patients and consisted of chronic donor- site pain (52 patients), wound dehiscence (eight patients), pneumonia (seven patients), meralgia paresthetica (four patients), hematoma requ iring evacuation (three patients), and iliac spine fracture (two patie nts). Even when chronic pain was not considered, morbidity encountered in obtaining iliac crest still exceeded that encountered with rib har vest (p = 0.035). The fusion rate and donor-site morbidity for rib aut ograft compare favorably with those for iliac crest when used in poste rior cervical constructs. To the authors' knowledge, this represents t he largest series to date in which the safety and efficacy of using au togeneic bone graft materials in spinal surgery are critically analyze d.