Neurosensory changes following orthognathic surgery

Much variability exists among studies of neurosensory disturbance following facial surgery. This diversity of findings may be a function of the different surgical procedures and measurement methods used. The present study compared 3 methods of assessing neurosensory loss following surgical orthodontics. Two objective tests and 1 subjective test were administered to 24 patients preoperatively and 4 weeks postoperatively. These included measures of 2-point discrimination, pressure-pain thresholds, and perceived sensation changes in specific facial regions. Postoperatively, all patients needed greater separation on the 2-point discrimination test in the lower facial regions, but not in the upper regions. Bilateral sagittal split osteotomy patients, especially males, required greater separation on these lower sites. Pressure-pain thresholds were not significantly impaired in most patients. Those who underwent combined maxillary and mandibular procedures experienced lower thresholds on the lower lip, while bilateral sagittal split osteotomy patients reported lower thresholds on the upper lip. The 2-point discrimination test was consistent with patients' self-ratings of neurosensory problems using facial maps, but the pressure-pain test was not. The majority of patients reported changed sensation in the lower facial regions postoperatively, regardless of surgery type. Examiners were less likely to rate these same facial regions as different in sensory acuity. Male patients were more likely to report sensory loss or pain postoperatively. These findings suggest that self-reports of neurosensory change following orthognathic surgery are consistent with tests of 2-point discrimination and somewhat higher than examiner ratings, but the objective test of pressure-pain thresholds in this study was least sensitive to neurosensory changes.