Immediate Reconstruction of Segmental Mandibular Defects With Nonvascular Bone Grafts: A 30-Year Perspective

Abstract

The use of nonvascular bone grafts for immediate mandibular reconstruction has remained a controversial topic. The purpose of the present study was to investigate the variables that might influence graft survival examining the outcomes from 30years of experience. We designed a retrospective cohort study to analyze the data from patients at a tertiary university medical center who had undergone segmental mandibular resection with immediate reconstruction with a nonvascularized free bone graft with or without adjuncts from 1989 to 2019. The predictor variables recorded included general demographic data, pathologic diagnosis, resection length, reconstruction modality, bone graft type, and inferior alveolar nerve procedures. The primary outcome variable was graft success, defined as bony union demonstrated on panoramic radiographs and mandibular stability demonstrated on clinical examination at 4months postoperatively. Descriptive, bivariate, and linear regression models were computed. The sample included 47 subjects with a mean age of 43±16years; 51.1% were men. Of the 47 patients, 25 had a tissue diagnosis of benign tumor, most of which were ameloblastoma (n=16) or ossifying fibroma (n=6), and 22 had a tissue diagnosis of osteomyelitis or medication-related osteonecrosis of the jaw (MRONJ). The average resection size for all the patients was 6.9±2.5cm and was 6.1±1.5cm for those with a benign tumor and 7.8±3.1cm for those with osteomyelitis or MRONJ. The mean defect size of grafts that failed was 10.7±3.5cm and 6.5±2.0cm for those that succeeded (P≤.001). A linear regression model revealed that graft length correlated significantly with graft outcome (β-coefficient, -0.548; 95% confidence interval, 0.905 to 1.542; P≤.001). The results of our study have shown that nonvascular bone grafts can be used to immediately reconstruct mandibular defects greater than 6cm from benign pathologic lesions; however, larger grafts are more likely to fail.