Effect of exposed inferior alveolar neurovascular bundle during surgical removal of impacted lower third molars.

PURPOSE: In this prospective study, we sought to determine the incidence of inferior alveolar nerve (IAN) paresthesia in patients with an exposed IAN bundle seen intraoperatively. PATIENTS AND METHODS: We included consecutive patients undergoing third molar surgery in whom an exposed IAN bundle was seen in the third molar socket intraoperatively. Data recorded from patients included radiographic findings, variations in surgical method, intraoperative findings, complications, and postoperative sequelae. Patients were reviewed 1 week after surgery and evaluated subjectively and objectively to determine the incidence of paresthesia when the IAN bundle was exposed. Patients with paresthesia were followed for 2 years or until it resolved.
RESULTS: An exposed IAN bundle was seen in 192 operation sites in 170 patients over a 5-year period, of which 166 patients with 187 operation sites were included in this study. Thirty-eight operation sites (20.3%) showed paresthesia at 1 week after surgery (95% confidence interval, 14.5% to 26.1%); 20 sites (15.0%) showed abnormal objective assessment results. By 3 months from surgery, 57.9% of nerves had recovered to normal sensation, 65.8% of nerves recovered by 6 months, and 71.1% of nerves recovered by 1 year. Eight patients were lost to follow-up. Logistic regression showed that the operator, male gender, older age, and root curvature were significant risk factors for paresthesia.
CONCLUSIONS: Sighting an exposed intact IAN bundle during third molar surgery indicates its intimate relationship with the third molar and carries a 20% risk of paresthesia, with a 70% chance of recovery by 1 year from surgery.