Hypoesthesia associated with mandibular movement after sagittal split ramus osteotomy

Purpose: This retrospective study investigated the relationship between the degree of neurosensory disturbance (NSD) and mandibular movement distance after sagittal split ramus osteotomy (SSRO) and assessed sensory recovery. Methods: Lower lip hypoesthesia was evaluated at 1 week, 1 month, and 2 months after SSRO in 38 patients categorized according to the distance of mandibular movement: S group (0–7 mm; n = 17, 4 males and 13 females) and L group (7–14 mm; n = 21, 7 males, 14 females). Symptoms were evaluated by visual analog scale (VAS), tactile-threshold (SW) test, static 2-point discrimination (s-2PD) test, and current perception threshold (CPT) test. Results: The two groups did not differ significantly in gender and age. The Aβ fiber results of the CPT test differed significantly between the groups at 1 week and 1 month postsurgery (P < 0.05). There were no significant differences between the groups throughout the period in terms of VAS, SW, s-2PD, Aδ fiber, and C fiber of CPT. Conclusions: Post-SSRO, the incidence of NSD in terms of tactile sensation may be greater in the L group early postoperatively. This may assist surgeons in explaining postoperative hypoesthesia to patients preoperatively. © 2017, Springer-Verlag Berlin Heidelberg.