下顎枝矢状分割法術後の知覚障害に関する臨床的研究

Abstract

Sagittal splitting ramus osteotomy (SSRO) is the most common orthodontic procedure used to correct mandibular deformation. However there is a postoperative risk of neurosensory disturbance (NSD) of the mental nerve.A total of 84 patients underwent preoperative and postoperative bilateral examinations (total: 168 examinations). Subjective symptoms were assessed by interview, and constant-touch was evaluated by tactile-threshold tests with the use of a Semmes-Weinstein pressure aesthesiometer (SW test) and by static two-point discrimination tests (2 PD). Dynamic-touch was examined by vibratory sensibility tests.No significant differences were observed as compared with the preoperative scores on the SW test after 4 weeks. Furthermore, no change in the mean preoperative value on the 2 PD test was observed at the 8th postoperative week. A significant difference was detected between the preoperative score on the vibratory sensation test and the score after 24 weeks. Dynamic-touch assessment suggested that recovery was slow as compared with constant-touch recovery. The majority of patients scored 1.65 (the smallest sensible filament) on the SW test, and 83.2% of these patients showed an improvement in symptoms. A significant difference was noted between symptoms and the dispersion of vibratory sensibility test scores. The vibratory sensibility test could detect sensation recovery by slow regeneration of nerves, but the probability of not detecting sensation was high when only the SW test was used.Sensibility occurs via the function of various sensory units. Thus, a combination of tests should be performed to assess sensiblity associated with perceptual disorders.