Bilateral sagittal split osteotomy versus distraction osteogenesis of the mandible: a randomized clinical trial

A randomized clinical trial was performed to evaluate differences in postoperative neurosensory disturbance (NSD) between two methods of mandibular advancement surgery. A total of 66 non-syndromal class II patients with mandibular hypoplasia were randomized for either distraction osteogenesis (DO) or bilateral sagittal split osteotomy (BSSO). Twenty-nine patients in the BSSO group and 34 patients in the DO group were available for evaluation. Objective assessment was performed by Semmes-Weinstein (SW) monofilament testing preoperatively and at least 1 year after surgery. Six of the 34 patients (17.6%) in the DO group experienced objective NSD, compared to 5/29 patients (17.2%) in the BSSO group. In the evaluation of nerve function by individual nerves, 8/68 nerves (11.8%) revealed objective NSD in the DO group, compared to 7/58 nerves (12.1%) in the BSSO group. A subjective NSD was reported in 11/34 patients (32.4%) in the DO group, compared to 9/29 patients (31.0%) in the BSSO group. In the evaluation of nerve function by individual nerves, a subjective NSD was reported for 13/68 nerves (19.1%) in the DO group, compared to 13/58 nerves (22.4%) in the BSSO group. None of the differences was significant. No differences in neurosensory disturbance could be found between the two study groups. Objective WS monofilament testing appeared to underestimate NSD compared to subjective patient report.