Gertjan Mensink1, Peter J J Gooris2, Eelco J Bergsma3, Michael H Frank4, Jan T M van Gemert5, J P Richard van Merkesteyn6. 1. Consultant, Department of Oral and Maxillofacial Surgery, Amphia Hospital, Breda; Department of Oral and Maxillofacial Surgery, Leiden University Medical Centre, Leiden, The Netherlands. Electronic address: GMensink1@amphia.nl. 2. Consultant, Department of Oral and Maxillofacial Surgery, Amphia Hospital, Breda, The Netherlands; Affiliate Professor, Department of Oral and Maxillofacial Surgery, University of Washington, Seattle, WA. 3. Consultant, Epidemiologist, Department of Oral and Maxillofacial Surgery, Amphia Hospital, Breda, The Netherlands. 4. Consultant, Department of Oral and Maxillofacial Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands. 5. Consultant, Department of Oral and Maxillofacial Surgery, Amphia Hospital, Breda, The Netherlands; Department of Oral and Maxillofacial Surgery, University Medical Centre Utrecht, Utrecht, The Netherlands. 6. Department Head, Department of Oral and Maxillofacial Surgery, Leiden University Medical Centre, Leiden, The Netherlands.
Abstract
PURPOSE: Although the bilateral sagittal split osteotomy (BSSO) is a routinely performed procedure, exact control of the lingual fracture line remains problematic. The purpose of this study was to determine the various lingual splitting patterns in cadaveric human mandibles after a BSSO and the possible influence of the mandibular canal and mylohyoid groove on the lingual fracture line. MATERIALS AND METHODS: The investigators designed and implemented a case series to compare different lingual fracture lines. A standardized SSO was performed on 40 cadaveric hemimandibles using elevators and splitting forceps. The primary outcome variable during this study was the lingual fracture pattern possibly influenced by independent variables: the mandibular canal, the mylohyoid groove, and dental status. Descriptive and analytic statistics were computed for each study variable. RESULTS: Most lingual fractures (72.5%) ended in the mandibular foramen. Only 25% of fractures were "true" Hunsuck fractures, and no "bad splits" occurred. In addition, 35% of lingual fractures ran more than halfway or entirely through the mandibular canal, whereas only 30% of fractures ran along the mylohyoid groove. However, when the lingual fracture ran along this groove, it had a 6-fold greater chance of ending in the mandibular foramen. CONCLUSIONS: The hypothesis that the mandibular canal or mylohyoid groove would function as the path of least resistance was only partly confirmed. The use of splitters and separators did not increase the incidence of bad splits compared with the literature.
PURPOSE: Although the bilateral sagittal split osteotomy (BSSO) is a routinely performed procedure, exact control of the lingual fracture line remains problematic. The purpose of this study was to determine the various lingual splitting patterns in cadaveric human mandibles after a BSSO and the possible influence of the mandibular canal and mylohyoid groove on the lingual fracture line. MATERIALS AND METHODS: The investigators designed and implemented a case series to compare different lingual fracture lines. A standardized SSO was performed on 40 cadaveric hemimandibles using elevators and splitting forceps. The primary outcome variable during this study was the lingual fracture pattern possibly influenced by independent variables: the mandibular canal, the mylohyoid groove, and dental status. Descriptive and analytic statistics were computed for each study variable. RESULTS: Most lingual fractures (72.5%) ended in the mandibular foramen. Only 25% of fractures were "true" Hunsuck fractures, and no "bad splits" occurred. In addition, 35% of lingual fractures ran more than halfway or entirely through the mandibular canal, whereas only 30% of fractures ran along the mylohyoid groove. However, when the lingual fracture ran along this groove, it had a 6-fold greater chance of ending in the mandibular foramen. CONCLUSIONS: The hypothesis that the mandibular canal or mylohyoid groove would function as the path of least resistance was only partly confirmed. The use of splitters and separators did not increase the incidence of bad splits compared with the literature.