Does Orthognathic Surgery Cause or Cure Temporomandibular Disorders? A Systematic Review and Meta-Analysis

Purpose: There is still controversy about whether orthognathic surgery negatively or positively affects temporomandibular disorders (TMDs). The purpose of this study was to determine whether orthognathic surgery has a beneficial or deleterious effect on pre-existing TMDs. Materials and Methods: A systematic review and meta-analysis were conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched 3 major data-bases to locate all pertinent articles published from 1980 to March 2016. All subjects in the various studies were stratified a priori into 9 categories based on subdiagnoses of TMDs. The predictor variables were those patients with pre-existing TMDs who underwent orthognathic surgery in various subgroups. The outcome variables were maximal mouth opening and signs and symptoms of a TMD before and after orthognathic surgery based on the type of osteotomy. The meta-analysis was performed using Comprehensive Meta-Analysis software (Biostat, Englewood, NJ). Results: A total of 5,029 patients enrolled in 29 studies were included in this meta-analysis. There was a significant reduction in TMDs in patients with a retrognathic mandible after bilateral sagittal split osteotomy (BSSO) (P = .014), but no significant difference after bimaxillary surgery (BSSO and Le Fort I osteotomy) (P = .336). There was a significant difference in patients with prognathism after isolated BSSO or intraoral vertical ramus osteotomy and after combined BSSO and Le Fort I osteotomy (P = .001), but no significant difference after BSSO (P = .424) or bimaxillary surgery (intraoral vertical ramus osteotomy and Le Fort I osteotomy) (P = .728). Conclusions: Orthognathic surgery caused a decrease in TMD symptoms for many patients who had symptoms before surgery, but it created symptoms in a smaller group of patients who were asymptomatic before surgery. The presence of presurgical TMD symptoms or the type of jaw deformity did not identify which patients' TMDs would improve, remain the same, or worsen after surgery. (C) 2017 American Association of Oral and Maxillofacial Surgeons