Bilateral Sagittal Split Ramus Osteotomy Versus Distraction Osteogenesis for Advancement of the Retrognathic Mandible

The aim of the present study was to identify significant differences in skeletal stability and neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) between bilateral sagittal split ramus osteotomy (BSSO) and distraction osteogenesis (DO) for mandibular advancement surgery.

We performed a systematic and electronic search of several databases using specific keywords, a reference search, and a manual search through November 2014. The inclusion criteria were clinical human studies, including randomized controlled trials (RCTs), controlled clinical trials (CCTs), and retrospective studies, with the aim of comparing BSSO and DO (predictor variables) after mandibular advancement surgery with regard to skeletal stability and NSD of the IAN (outcome variables). Both linear and angular measurements of the horizontal and vertical positions of the mandible were analyzed. For binary outcomes, we calculated a standard estimation of the risk ratio using the random-effects model if heterogeneity was detected; otherwise, a fixed effects model, with a 95% confidence interval (CI), was used. Weighted mean differences or standard mean differences were used to construct forest plots of continuous data. In addition, the number needed to treat, with the 95% CIs, was calculated for NSD of the IAN.

Our initial PubMed search identified 215 studies, of which 9 met our inclusion criteria-3 RCTs, 1 CCT, and 5 retrospective studies. No statistically significant difference was found between the 2 groups regarding skeletal stability in either the vertical (P = .34) or horizontal (P = .88) direction. A statistically significant difference was found between BSSO and DO with regard to NSD of IAN function (P = .004).

The results of the present meta-analysis have shown that DO significantly reduced the incidence of NSD of the IAN after lengthening of the retrognathic mandible compared with the BBSO.