Evaluating Lingual Nerve Repair Outcomes: A Systematic Review

The lingual nerve (LN) is susceptible to injury during oral and maxillofacial procedures, leading to neurosensory deficits. Advances in microsurgical techniques necessitate a comprehensive review of overall effectiveness and influencing factors.

A systematic review was performed via Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies. Inclusion criteria were full text availability, studies written in english, and studies published after 2000 reporting LN repair. The primary outcome was sensory improvement defined via functional sensory recovery (FSR) or neurosensory testing (NST). Sex, time from injury to repair, method of repair, and graft length were examined to see if each influenced outcomes.

A sample of 786 subjects across 17 studies was examined. Most patients were female (73.3%) and suffered injuries from third molar extractions (72.8%). Of the studies, 10 defined improvement by FSR with a total of 88.8% (500/563) of nerves achieving such. Of those achieving FSR, 91% did so within a year. The remaining 7 studies defined sensory improvement by individually setting various NST thresholds, with the combined improvement rate being 88.6% (203/229). Positive outcomes were achieved with graft lengths up to 70 mm. Results on time to repair were mixed. The methods of repairs were not different based on statistical analysis short of performing an equivalence trial.

Conclusions made from studies using FSR were similar to studies using NST, meaning the method of measuring outcomes does not seem to be a confounder. FSR is the superior scale due to being objective and standardized. LN repair produced high rates of sensory improvement, which is expected to occur within 1 year postoperative. Sex and graft length did not influence outcomes. More research is needed to determine the effect of time to repair on efficacy. Most methods of repair produced similar outcomes, suggesting multiple valid techniques exist.