Postoperative Positional and Dimensional Changes of Mandibular Canal after Bilateral Sagittal Split Set-Back Osteotomy

Abstract

Objective: This preliminary study was planned to provide information about preoperative mandibular canal (MC) position and the postoperative positional changes of MC and length in three dimensions, with the purpose of providing some assistance in reducing inferior alveolar neurosensory disturbance (IAND).Methods: MC was examined on CBCT data using SimPlant Pro Standalone 13.0. MC locations were measured in all dimensions, with respect to mandibular bony borders. Results:The results showed that MC is frequently located in the midthird of the ramus anteroposteriorly and superoinferiorly and in the midthird of the corpus superoinferiorly. Postoperatively, ramus width was increased, ramus length was decreased significantly, and MC was repositioned laterally and inferiorly. MC length was decreased on both sides, non-correlated with the set-back amounts. Conclusion:Preoperative results may be beneficial for the prediction of MC position for surgeons, and postoperative results will be used for the following studies to correlate postoperative positional changes with IAND.

The Assessment of Neurosensory Disturbance Following Bilateral Sagittal Split Osteotomy With Subjective and Three-Dimensional Evaluation

“…According to the information obtained from the patient files, all the operations were performed by 2 plastic and reconstructive surgeons. A modified BSSO technique of Trauner and Obwegeser classical method by Dal Pont anteriorly positioned vertical cut and Epker complete osteotomy of the inferior mandibular cortex was used to prevent IAN injuries, enlarge bony surfaces between the segments, thus to improve rigid fixation and enhance postoperative healing 19 …”

“…The relationships between IAND and the position of the fixation screws to the MC, preoperative 3D measurements related to MC, and changes in MC lengths were also evaluated in the present study. The methodology of 3D measurements has been well documented in a previous study of the same authors 19 …”

“…3). 19 Actual (ACL) and shortest MC length (SCL) were also measured on 3D objects derived from ideal panoramic view (Fig. 4).…”

“…4). 19 For the assessment of the effects of fixation screws to IAND, the shortest distance from screws to MC was measured at all crosssectional slices and the patients were divided into 2 groups according to the presence or absence of screws in the MC (Fig. 5).…”

“…The methodology of 3D measurements has been well documented in a previous study of the same authors. 19 On the 3 cross-sectional slices (CS1: the most inferior point of the mandibular foramen, CSM: the midpoint between the mandibular foramen and the distal point of the mandibular second molar, CS7: the distal point of the mandibular second molar), ramus width (RW), medial cancellous bone length (MCL), and lateral cancellous bone length (LCL) were measured (Fig. 3).…”