The aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split... Show moreThe aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split osteotomy (BSSO). The study including 78 consecutive patients (156 osteotomy sites). In preoperative cone-beam computed tomographic (CT) scans, the volumes of cancellous and cortical bone in the BSSO surgical field were estimated. Patients were divided into two groups based on the cancellous:cortical bone ratio. We studied postoperative cone-beam CT scans for lingual fracture lines and subcategorised them according to the lingual split scale (LSS). Generalised linear mixed models (GLMM) were estimated to evaluate the association between the cancellous:cortical bone ratio and the lingual fracture pattern. There was a significant association between the cancellous:cortical bone ratio of the mandibular angle and the lingual fracture pattern after BSSO. Mandibular angles with a relatively small amount of cancellous bone showed significantly more LSS3 fracture lines (OR = 1.990, 95%CI 1.043 to 3.796, p = 0.043). These mandibular angles also showed more unfavourable fractures (LSS4), although this was not significant (OR = 2.352, 95%CI 0.748 to 7.392, p = 0.143). The relative amount of cancellous bone in the mandibular angle is significantly associated with the lingual fracture line after BSSO. (C) 2020 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Show less
Bilateral sagittal split osteotomy (BSSO) is a widely used surgical technique that is used to treat mandibular deformity. This thesis investigated BSSO with splitter and separators. The... Show moreBilateral sagittal split osteotomy (BSSO) is a widely used surgical technique that is used to treat mandibular deformity. This thesis investigated BSSO with splitter and separators. The occurrences of common complications and their risk factors are assessed. BSSO was performed according to the Hunsuck modification with splitter and separator without the use of chisels. Retrospective analysis of more than 250 patients was performed. BSSO performed with the splitter-separator technique was found to be associated with a low mean incidence of permanent hypoaesthesia of 9.9% per patient. Age was a significant risk factor for hypoaesthesia with marked differences between age groups (<19 years: 4.8%; 19-30 years: 7.9%; >30 years 15.2%). The incidence of bad split was 4.0% per patient. The intra-operative presence of third molars significantly increased the risk of bad split. Infection occurred in 15.1% of patients. Removal of bicortical screw osteosynthesis material because of symptoms was indicated in 4.9% of patients. Relevant risk factors for complications are age (hypoaesthesia) and the presence of third molars during surgery (bad split). Show less
