Microsurgical Repair of Peripheral Trigeminal Nerve Injuries From Maxillofacial Trauma

Abstract

Injuries to the peripheral branches of the trigeminal nerve from maxillofacial trauma can have distressing sensory or functional sequelae. The present study reports the results of trigeminal microneurosurgical repair in a series of patients with maxillofacial trauma. A retrospective chart review was completed of all patients who had undergone microneurosurgical repair of peripheral trigeminal nerve injuries caused by maxillofacial trauma and who had been treated by one of us (R.A.M.) from March 1986 through December 2005. A physical examination, including standardized neurosensory testing, was completed on each patient preoperatively. All patients were followed up periodically after surgery for at least 1 year with neurosensory testing repeated at each visit. Sensory recovery was evaluated using the guidelines established by the Medical Research Council. The following data were collected and analyzed: patient age, gender, nerve injured, etiology (location of fracture), chief sensory complaint (ie, numbness or pain, or both), interval from injury to surgical intervention, intraoperative findings, surgical procedure, and neurosensory status at the final evaluation. A total of 42 patients (25 males and 17 females) with average age of 37.1 years (range 11 to 61) and a follow-up of at least 12 months were included in the study. The most commonly injured/repaired nerve was the inferior alveolar nerve caused by mandibular angle fracture (n = 21), followed by the mental nerve due to mandibular parasymphysis fracture (n = 12), the infraorbital nerve from zygomaticomaxillary complex fracture (n = 7), and lingual nerve and long buccal nerve from mandibular body fracture (n = 1 each). In 17 patients, the chief sensory complaint was numbness, and 25 patients complained of pain with or without mention of numbness. The average interval from nerve injury to repair was 12.5 months (range 2 to 24). The most common intraoperative finding was a compression injury (n = 19), followed by partial nerve severance (n = 9). The most frequent surgical procedure was external decompression/internal neurolysis (n = 20). Ten injured nerves required reconstruction of a discontinuity defect with an autogenous nerve graft (donor sural or great auricular nerve), all of which were associated with mandibular angle or parasymphysis fractures. After a minimum of 1 year of follow-up, neurosensory testing demonstrated that 6 nerves (14%) showed no sign of recovery, 23 nerves (55%) had regained "useful sensory function," and 13 nerves (31%) showed full recovery as described by the Medical Research Council scale. Microsurgical repair of peripheral branches of the trigeminal nerve injured by maxillofacial trauma produced significant improvement or complete recovery in 36 (86%) of 42 patients. These results compare favorably with the microsurgical repair of peripheral trigeminal nerve injuries resulting from other causes.