Abstract
Twenty-three patients, who had undergone bilateral sagittal split ramus osteotomy (SSRO), and 21 who had undergone intraoral inverted L ramus osteotomy (ILRO), were examined for postsurgical neurosensory disturbances. The neurosensory tests employed included light touch, using a Semmes-Weinstein monofilament tester (SW tester); electrical stimulation, and a questionaire to determine changes in subjective sensations, at the time of each sensory evaluation, in comparison with before surgery. Neurosensory examinations were performed bilaterally (88 sides) at 1, 3, 6 and 12 months after surgery. Both thresholds for the two measurement techniques were lower in the ILRO group than in the SSRO group, at each measurement. The number of sides showing postoperative subjective symptoms was lower in ILRO patients than in SSRO patients, although the difference was not statistically significant. In the SSRO group, at each measurement point, the thresholds for the lower lip and chin were unrelated to the set-back (or advance) distance. By contrast, in the ILRO group, at the 1-month evaluation point, the thresholds for the lower lip and chin were significantly higher than the control level in patients whose set-back (or advance) distances were larger than average (p<0.05). In the ILRO group, whether these distances were large or small made little difference at the other evaluation poits.
