Persistent Neurosensory Disturbance Following Sagittal Split Osteotomy: A Systematic Review and Meta-Analysis of One-Year Outcomes and Risk Factors.

Background: Sagittal split osteotomy (SSO) is widely performed for mandibular repositioning; however, inferior alveolar nerve injury may result in persistent neurosensory disturbance (NSD) that affects quality of life. The true 1-year incidence and associated risk factors remain uncertain.

Purpose: The study purpose was to estimate the 1-year incidence of persistent NSD after SSO and to evaluate risk factors.

Data sources: We systematically searched PubMed and Embase (1998 to February 2025). Eligible human studies (randomized, prospective, retrospective) reporting NSD outcomes after SSO and possible risk factors in English language were included.

Study selection: Randomized controlled trials and prospective and retrospective cohort studies with a minimum follow-up of 3 months, reporting NSD incidence and potential predictors, were included. Nonhuman studies, case reports, and studies with alternative osteotomy techniques or incomplete NSD assessment were excluded. Study selection was performed by 2 independent reviewers.

Data extraction and synthesis: Following PRISMA, we extracted study characteristics, variable definitions, NSD assessment methods, and 1-year outcomes. "Persistent NSD" was defined as any NSD reported or assessed at 12 months postoperatively. Random- and fixed-effects models estimated pooled 1-year incidence; heterogeneity (I²) and small-study effects were assessed.

Results: The final sample comprised 47 studies (5,406 patients). The pooled 1-year incidence of persistent NSD was 21% (95% CI, 13%-32%). Older age (statistically significant in 5 out of 9 studies), greater mandibular advancement (significant in 2 out of 2 studies), and intraoperative nerve exposure/manipulation (significant in 2 out of 3 studies) were statistically significantly associated with a higher risk of persistent NSD across contributing adequately powered studies. Across the available evidence, persistent NSD was not significantly associated with sex (8/9 studies), skeletal class (4/5), fixation method (1/2), third molar presence (1/1), or concomitant genioplasty (3/5).

Conclusions and relevance: NSD following SSO persists in 1 in 5 patients at 1 year. Larger mandibular advancements and nerve manipulation increase persistent NSD risk. Standardized NSD assessments and adequately powered studies are essential to refine risk stratification and optimize surgical techniques.