Identification of predisposing factors for osteonecrosis of the jaw after marginal mandibulectomy in the surgical management of oral squamous cell carcinoma.

BACKGROUND: The aim of this study is to evaluate osteonecrosis of the jaw (ONJ) with the extent of marginal mandibulectomy. METHODS: Between January 2006 and December 2012, 3087 patients undergoing ablative resection were consecutively enrolled. Among them, 345 cases undergoing marginal mandibulectomy were retrospectively reviewed. RESULTS: The occurrence of ONJ was 5.51% and associated with body mass index, overall stage, diabetes, concomitant mandibulotomy, and radiotherapy (P = 0.023, 0.033, 0.009, 0.016, and 0.006, respectively). As for bone parameters based on radiological measurements after marginal mandibulectomy, resected bone height, remaining bone height to original bone height ratio, and resected bone height to original bone height ratio were associated with ONJ. In multivariate logistic analyses, concomitant mandibulotomy, radiotherapy, diabetes, resected bone height of >14.5 mm, resected bone height to original bone height ratio of >49.5%, and remaining bone height to original bone height ratio of <53.5% indicated higher risks for ONJ (adjusted HR: 4.345, 4.152, 4.079, 3.402, 3.541, and 3.211; P = 0.018, 0.013, 0.009, 0.021, 0.018, and 0.043, respectively). CONCLUSIONS: This study demonstrated the predisposing factors and parameters associated with ONJ with marginal mandibulectomy; more caution is necessitated in performing marginal mandibulectomy in patients with multiple risks to prevent ONJ.