Does the use of a piezoelectric saw improve neurosensory recovery following sagittal split osteotomy?

Neurosensory disturbance of the inferior alveolar nerve (IAN) is an adverse effect associated with sagittal split osteotomies (SSO). The purpose of this work was to evaluate neurosensory recovery of the IAN when SSOs were performed with piezoelectric (PZ) versus reciprocating (RP) saws. This was a prospective split-mouth study of patients undergoing bilateral SSO using a PZ saw on one side and an RP saw on the other. The primary outcome of interest was neurosensory recovery, as assessed using the functional sensory recovery (FSR) scale defined by the UK Medical Research Council. Descriptive, bivariate, and regression statistics were computed. Twenty patients (40 SSOs) with a mean age of 19.9 ± 3.2 years were included. The mean mandibular movement did not differ significantly (P = 0.50) between the PZ and RP groups. All patients achieved FSR within 1 year of surgery (range 34-249 days). The median time to FSR overall was comparable between the PZ and RP groups (94.5 days and 101.5 days, respectively; P = 0.20). However, at the time FSR was achieved, PZ SSO sites were more likely to have higher neurosensory scores when compared to RP SSO sites (hazard ratio 2.3, 95% confidence interval 1.1-4.9, P = 0.04).

Is alteration of the occlusal plane stable with isolated nasomaxillary fixation of the Le Fort I osteotomy?

The purpose of this work was to evaluate the stability of maxillary position in the setting of occlusal plane rotations in bimaxillary surgery with rigid fixation of the mandible and bilateral nasomaxillary fixation at the Le Fort I level. This was a retrospective assessment of patients undergoing bimaxillary surgery for the correction of dentofacial deformities with occlusal plane alterations. Demographic measures assessed included age, sex, history of craniofacial anomaly, segmental maxillary osteotomy, and maxillary bone grafting. Cephalometric measures assessed included occlusal plane rotation (clockwise (CWR) or counterclockwise (CCWR)), angular measurements of maxillary and mandibular position (SNA, SNB, and ANB), and occlusal plane angle (occlusal plane to corrected Frankfort horizontal); these were assessed preoperatively (T0) and immediately (T1), 6 weeks (T2), and 1year postoperative (T3). Descriptive and bivariate statistics were computed; P≤0.05 was considered significant. Thirty-six patients were included as study subjects (mean age 18.6±1.8 years; 17 (47.2%) female); 27 (75%) had a primary diagnosis of craniofacial anomaly. Eleven patients (30.6%) had segmental maxillary osteotomies; 10 patients (27.8%) had simultaneous maxillary bone grafting. Twelve patients underwent CCWR; 24 patients underwent CWR. No patient required repeat surgery for malocclusion or relapse; there were no malunions or non-unions during follow-up. For CCWR patients, the mean occlusal plane change from preoperative to postoperative was 5.8±2.8°, remaining stable at 1 year postoperative (ΔT3-T1 1.6±1.0°, P>0.05). For CWR patients, the mean occlusal plane rotation was 4.5 ± 2.2°, remaining stable at 1 year postoperative (ΔT3-T1 1.1±0.9°, P>0.05). In patients undergoing bimaxillary surgery for occlusal plane rotation, two-point fixation of the Le Fort I osteotomy resulted in a stable maxillary position at 1 year postoperative.