bilateral sagittal split osteotomy

Several articles have discussed mandibular condyle position after bilateral sagittal split osteotomies (BSSO). However, previous studies have sought to establish a relationship between orthognathic surgery and the improvement of temporomandibular joint (TMJ) signs and symptoms. Also, they have been limited to two-dimensional evaluation of condylar position considering only the condylar “sag” or improper inferior seating of the condyle. The purpose of this study was to investigate a relationship between changes in condylar position using three-dimensional computed tomography and the negative clinical impact of BSSO on the temporomandibular joint. 

he presence of bifid mandibu¬lar canals is an unusual but not rare occurrence. The mandibular canal containing the inferior alveolar artery, vein, and nerve, originates from the mandibular foramen and terminates at mental foramen [1-4]. In radiology, mandibular canal’s appearance has been described as “a radiolucent dark ribbon between two white lines”[5]. White and Pharoah defined it as “dark linear shadow with thin radiopaque superior and inferior borders cast by the lamella of bone that bounds the canal” [6]. Understanding of its anatomic variations is very important due to its clinical implications in various oral and maxillofacial treatments like removal of wisdom teeth [7], mandibular implant placement [8], in bilateral sagittal split osteotomy procedures and during fixation of mandibular fractures. Presence of bifid or multiple mandibular canals forces the clinician to change the treatment plan. Ignoring this variation can cause several complications intra or postoperatively or even result in failure of treatment. For instance a bifid canal if ignored during surgical removal of third molar or dental implant placement can cause prolonged pain even after administering local anesthesia and also severe bleeding if the accessory canal is encroached [2]. Bifid mandibular canals may originate from the mandibular foramen independently or might bifurcate from a single canal during its course inside the mandible [8]. Bifid mandibular canals have been by classified by multiple authors according to anatomical location and configuration, on panoramic radiographs and computerized tomography. According to Carter and Keen [1], inferior alveolar nerve can be arranged as- Type I: single large bony canal, Type II: canal is lower down in the mandible and Type III: canal separates posteriorly into two large branches. Nortje, et al. [9] gave patterns of duplication as- Type I: duplicate canals from a single mandibular foramen which can be of same size/ lower canal smaller/ upper canal smaller. Type II: short upper canal up to the second molar areas. Type III: two canals from separate foramina, joining at molar area and Type IV: supplemental canals joining the main canals in the retromolar areas. This report describes a case of a bilateral Bifid Mandibular Canal suspected by a panoramic radiograph and confirmed by a CBCT prior to a dental treatment.