NEUROSENSORY RECOVERY FOLLOWING THE MANDIBULAR BILATERAL SAGITTAL SPLIT OSTEOTOMY

Purpose: This prospective study evaluated the neurosensory recovery pattern of the inferior alveolar nerve following the bilateral sagittal split osteotomy (BSSO). Patients and Methods: Forty-two consecutive patients undergoing BSSO were studied using five neurosensory tests: 1) static light touch, 2) moving touch discrimination, 3) two-point discrimination, 4) nociception, and 5) thermoreception. Intraoperative assessment of inferior alveolar nerve damage was made; other variables recorded included type of fixation, age, concomitant procedures, advancement vs setback, and magnitude of the movement. A subjective questionnaire was completed by the patient. Results: The variables that affected neurosensory function following BSSO were degree of nerve damage and the amount of time elapsed following surgery. Larger myelinated fibers (A-alpha) recovered slower and to a lesser degree at all time intervals up to 2 years when compared with small myelinated and unmyelinated nerve fibers. The magnitude of nerve damage directly correlated with early neurosensory deficit, but equalized over time. Conclusion: The long term (6 months and greater) chance for neurosensory recovery is good despite intraoperative nerve manipulation. Patients seem to adapt and report normal neurosensory function even though objective testing indicates continued neurosensory deficit.