Is There a Difference in Stability or Neurosensory Function Between Bilateral Sagittal Split Ramus Osteotomy and Intraoral Vertical Ramus Osteotomy for Mandibular Setback?

Abstract

Bilateral sagittal split ramus osteotomy (BSSO) and intraoral vertical ramus osteotomy (IVRO) are used for mandibular setbacks. The purpose of this study was to determine differences in skeletal stability and neurosensory disturbance (NSD) of the mental nerve after mandibular setback using these operations. A systematic review and meta-analysis on these topics was performed. An electronic search of several databases with specific keywords, a reference search, and a manual search from database inception to December 2014 was performed with inclusion criteria of clinical human studies, randomized controlled trials (RCTs), controlled clinical trials (CCTs), and retrospective studies, with the predictor variable being BSSO or IVRO after mandibular setback surgery. The outcome variables of horizontal and vertical relapse using cephalometrics and NSD using trigeminal somatosensory-evoked potential and subjective tests were statistically analyzed. The initial PubMed search identified 716 studies of which 13 met the inclusion criteria—4 RCTs, 3 CCTs, and 6 retrospective studies. No statistically significant difference was found between the 2 groups regarding horizontal skeletal stability, but the BSSO group had more stability in the vertical dimension (P = .02). There was a statistically significant difference between BSSO and IVRO with regard to NSD of the inferior alveolar nerve (IAN; P = .001). The results of this meta-analysis suggest that BSSO and IVRO have good stability when used to set back the mandible. Furthermore, the results showed that IVRO statistically decreased the incidence of NSD of the IAN after mandibular setback surgery compared with BSSO.