Poster 33: Endoscopy Assisted Mandibular Sagittal Split Ramus Osteotomy

Abstract

Statement of the Problem: The prevalence of inferior alveolar nerve (IAN) parasthesia/dysthesia following a sagittal split osteotomy (SSO) ranges from 9% to 85%. Over zealous retraction and inappropriate positioning of surgical instrumentation often results in excess manipulation/damage of the soft tissues surrounding the IAN thereby inadvertently causing damage to the nerve. Intraoperative identification of the IAN has traditionally relied upon utilization of plain films and radiographic landmarks, tactile identification of the antilingula and IAN foramen utilizing a nerve hook, and direct visualization if possible. Unfortunately, in the absence of direct visualization, these methods lack the necessary precision and accuracy for reliable identification of IAN position. Radiographic determination of the position of the IAN foramen at best only provides a rough estimate of the nerve location. Aziz and coworkers demonstrated that tactile identification of the antilingula to infer position of the lingula is not always reliable. Thus, direct visualization is the most reliable way to identify IAN position. In the present study, a 30 degree Stryker endoscope was used to visualize the medial aspect of the ramus in order to determine IAN location following the initial dissection. We hypothesized that utilization of endoscopy to identify the IAN prior to creation of the medial horizontal osteotomy would limit manipulation of the soft tissues surrounding the IAN, preventing inappropriate positioning of surgical instrumentation, thereby reducing the incidence of parasthesia/dysthesia following an SSO.