Evaluation of Temporary Neurosensory Changes of Lower Lip Following Bilateral Sagittal Split Osteotomy

Orthognathic surgeries are used for correction of jaw discrepancies. One of the popular techniques in mandible is bilateral sagittal split osteotomy. The purpose of this study was to investigate sensory disturbance in lower lip up to 6 months after bilateral sagittal split osteotomy of mandible, and the effect of this sensory change on daily life of the patients as well as their level of satisfaction from the result of the operation. In this study, 22 patients (44 sides) with the average age of 21.4 years were operated with sagittal split osteotomy. For objective examination, 2-point discrimination test was done just before operation, and 3 and 6 months after the operation. For subjective examination, patients filled out questionnaires 3 and 6 months after the operation. Data were analyzed by Mc Nemar, Wilcoxon, t and Paired sample t-tests. In three month follow up, 63.3% and in six month follow up, 43.1% of cases had sensory changes. Wilcoxon test showed significant difference in the extent of anesthesia between three and six month follow ups (P=0.007) which showed recovery in regions with altered sense. The average result of 2-point discrimination test was 3.81 millimeters before operation, 6.9mm three months after operation and 5.2mm six months after the operation. In the six month follow up, the difference between right and left side was 1.04mm which was statistically significant (P=0.027). Despite the sensory changes in their lip, all patients were satisfied with the result of the operation. With passing the time (from 3 months to 6 months), the percentage of cases with sensory deficit decreased, which seems to be due to the spontaneous recovery of nerve. The results showed that sensory changes and their problems were not determinant factors in patient's satisfaction.