Altered sensation of the inferior alveolar nerve in sagittal spilt osteotomies: a review of cases at a major UK centre over 10 years.

Inferior alveolar nerve (IAN) injuries are common complications of orthognathic surgery, with incidences reported from 0% to 85% due to inconsistent definitions, assessment methods and follow-up protocols. These limitations hinder comparisons, emphasising the need for standardised evaluation. This 10-year retrospective cohort study investigates IAN injury rates following mandibular osteotomies, focusing on medium-long term outcomes and risk factors. A retrospective cohort study was conducted at a tertiary orthognathic centre (2014-2024) on sagittal split osteotomies, performed either as stand-alone or as part of bimaxillary surgeries. Altered sensation was assessed via patient-reported outcomes during clinical follow ups (0-60+ months). While a final review was typically conducted at 6 months, extended follow ups addressed nerve symptoms, revision surgeries, or COVID-19 disruptions. Chi squared tests, Fisher's exact test and odds ratios evaluated associations with demographics, split quality, and nerve injuries. The primary outcome was altered sensation at ≥6 months. Of 221 procedures, 75.6% (n = 167) had follow ups ≥6 months, with 44.3% (n = 74/167) reporting altered sensation, primarily in the lower lip. Rates were 49% (n = 49/100) at 6-12 months, 50% (n = 13/26) at 13-18 months, and 29.2% (12/41) beyond 18 months. Females (OR = 1.07) and the 41-50 age group (50%, n = 2/4) showed slightly increased sensory changes, although they were not statistically significant. Unsatisfactory splits had higher altered sensation rates (60%, n = 6/10) compared with satisfactory splits (43.9%, n = 65/148) although these were not statistically significant (p = 0.15). Among documented nerve injuries, 100% (n = 7) resulted in sensory changes at ≥6 months. Altered sensation affected 44.3% (74/167); non-standardised follow up limits interpretation and supports standardised neurosensory reporting.