Long-term neurosensory deficits associated with bilateral sagittal split osteotomy versus inverted 'L' osteotomy.

Ten cases of bilateral sagittal split osteotomies and nine cases of intraoral inverted "L" osteotomies were examined for postsurgical neurosensory disturbances. Neurosensory tests included brushstroke direction, temperature, and light touch. All patients completed a short questionnaire that elicited subjective information with respect to neurosensory symptoms and their perception of the surgical results. Analysis of the data obtained from the tests of neurosensory disturbances revealed no significant differences between the two surgical groups. The variance of the scores on each of the neurosensory disturbances measures was significantly greater (p < 0.01) for the BSSO group. Analysis of the data from the questionnaire indicated that BSSO patients were significantly more likely to report postsurgical hypoesthesia of the lip (p < 0.01) and chin (p < 0.001) than the intraoral inverted "L" osteotomies group. None of the intraoral inverted "L" osteotomies group reported a moderate level of hypoesthesia of the lower lip or the chin, 66% reported no lip hypoesthesia, and 89% indicated no hypoesthesia in the chin area. In contrast, 33% of the BSSO group reported moderate hypoesthesia of the lip, and 22% reported moderate hypoesthesia of the chin. All patients in both groups expressed satisfaction with the surgical outcome, and had not changed their opinion on having the surgery. Although the tests of neurosensory disturbances revealed some disparity between the groups, the differences were not statistically significant. However, the subjective impressions of the groups differed regarding postsurgical neurosensory disturbances; the BSSO group related significantly more symptoms.