IAN Injury After BSSO in Oral Clefts

Background and Purposes: Orthognathic surgery is necessary in more than 25% of patients with cleft lip and palate (CLP) to correct skeletal discrepancy and to obtain harmonious facial esthetics in the final phase treatment. A setback of mandible by bilateral sagittal split osteotomy (BSSO) along with maxillary osteotomy is usually performed when large skeletal discrepancies or associated mandibular deformities (e.g., asymmetries, canting of the mandibular occlusal plane) are present. Although the surgical technique of BSSO is well-developed, the neurosensory disturbances of the inferior alveolar nerve (IAN) remain one of the major postoperative complications. The purpose of this study is to identify the risk factors of IAN disturbances after BSSO and in turn to help clinicians to avoid such complication and to raise the satisfaction level of patients. Design: Prospective prognosis study. Setting: Chang Gung Craniofacial Center, Taoyuan. Patients: Two hundred Taiwanese patients with nonsyndromic CLP (age, \>16 for females, \>18 for males), who will undergo a BSSO as a part of the correction of their dentofacial deformities Measurements: All patients will undergo subjective (e.g., questionnaire) and objective (e.g., 2-point discrimination, light touch detection, and sharp/blunt detection) neurosensory assessments before surgery, and 1, 3, 6, 12 and 24 months after surgery. Cone beam computed tomography is performed before surgery and 1 week after surgery. Peri-operative factors including type of BSSO, extent of surgical correction, extent of split and fixation screws, concomitant genioplasty or third molar extraction are assessed. Patient-related factors including age, gender, bone quality of inferior alveolar canal are recorded as well. Data Analysis: Univariate and multivariate analyses will be performed. Statistical significance is assumed for a p value of less than 0.05.