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 (I) 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.