Management of endodontic injuries to the inferior alveolar nerve

Objective: Functional sensory recovery from microsurgical intervention for inferior alveolar nerve (IAN) injuries resulting from endodontic treatment were evaluated using a retrospective chart review. Other variables assessed included time from injury to surgery as well as other factors which improved functional neurosensory recovery (FSR). Method and Materials: This case series of seven patients evaluated the outcome of IAN microsurgery following endodontic-related nerve injuries. All patients were referred, evaluated, and operated on by the primary investigator (VBZ). Surgical intervention consisted of external and/or internal neurolysis with irrigation of the mandibular canal and decompression of the affected IAN as well as allogeneic nerve graft in one patient. Preoperative and postoperative sensory levels were recorded and FSR was assessed using the Medical Research Council scale. Results: Seven subjects with a mean age of 35.57 years (range 22 to 55 years old) opted to undergo trigeminal nerve microsurgery for management of their IAN injury resulting from endodontic treatment of mandibular molar teeth. Six women and one man were included in this population. The majority of subjects presented with an initial chief complaint of dysesthesia and hypoesthesia. The mean interval between nerve injury and surgical treatment was 15 weeks (range 1 to 40 weeks). All patients had preoperative sensory level of S0, S1, or S2+, and achieved FSR following surgery. Two patients had postoperative sensory level of S3, four patients had a postoperative sensory level of S3+, and one had a postoperative sensory level of S4 (complete recovery). Conclusions: The results of this study suggest that trigeminal nerve microsurgery for the surgical treatment of endodontic injuries to the IAN can improve neurosensory function. Surgical intervention in this study was beneficial to alleviate neurosensory deficits and symptoms for those injuries to the IAN caused by endodontic treatment. Keywords: endodontic injuries, external neurolysis, inferior alveolar nerve repair, internal neurolysis