Clinical Paper Orthognathic Surgery CBCT-based predictability of attachment of the neurovascular bundle to the proximal segment of the mandible during sagittal split osteotomy J. O. Agbaje, Y. Sun, S. De Munter, S. Schepers, L. Vrielinck, I. Lambrichts, C. Politis: CBCT-based predictability of attachment of the neurovascular bundle to the proximal segment of the mandible during sagittal split osteotomy. Int. J. Oral Maxillofac. Surg. 2013; 42: 308–315. # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. J. O. Agbaje 1 , Y. Sun 1,2 , S. De Munter 2 , S. Schepers 1,3 , L. Vrielinck 1 , I. Lambrichts 2 , C. Politis 1,2 1 Oral and Maxillofacial Surgery, St. John’s Hospital, Genk, Belgium; 2 Faculty of Medicine, Hasselt University, Diepenbeek, Belgium; 3 Oral and Maxillofacial Surgery, Faculty of Medicine, Gent University, Belgium Abstract. Injury to the inferior alveolar nerve (IAN) during surgery is an important complication of bilateral sagittal split osteotomy. With cone beam computed tomography, the course of the nerve and its relationship to the surrounding structures can be assessed in three dimensions. This study aims to determine whether tomography can predict attachment of the neurovascular bundle to the proximal segment of the mandible during sagittal split osteotomy (SSO). Bilateral linear measurements were taken on cross-sectional tomography images. During osteotomy, it was noted for each patient whether the neurovascular bundle was attached to the proximal segment during the split. If attached, a bone-cutting instrument or a blunt instrument was needed to free the nerve. The nerve was attached at more than one-third of operation sites (170 sites). Of these, over 65% of attached nerves (108 sites) required a bone-cutting intervention to free them from the mandible. After correcting for confounding factors, the linear distances from the buccal cortical margin of the IAN canal to the inner and outer buccal cortical margins of the mandible were important predictors of whether the IAN will be attached to the proximal segment of the mandible during SSO. Key words: bilateral sagittal split osteotomy; cone beam computed tomography; inferior alveolar nerve; mandible; complications. Accepted for publication 3 July 2012 Available online 25 August 2012 Sagittal split osteotomy (SSO) is a basic orthognathic surgical procedure. Differ- ent complications 1–4 have been reported associated with bilateral sagittal split osteotomy (BSSO). Of importance among these complications is injury to the inferior alveolar nerve (IAN). 1 IAN injury during surgery largely results from manipulation of the nerve or struc- tures surrounding the nerve, or from direct injury to the nerve during the operation. 4–6 Int. J. Oral Maxillofac. Surg. 2013; 42: 308–315 http://dx.doi.org/10.1016/j.ijom.2012.07.012, available online at http://www.sciencedirect.com 0901-5027/030308 + 08 $36.00/0 # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.