A Bioabsorbable Collagen Nerve Cuff (NeuraGen) for Repair of Lingual and Inferior Alveolar Nerve Injuries: A Case Series

Abstract

This study describes the results of using NeuraGen (Integra LifeSciences, Plainsboro, NJ) as a nerve cuff for repair of lingual and inferior alveolar nerve injuries following third molar surgery. Eight female patients received a total of 9 NeuraGen cuffs for repair of lingual (6) or inferior alveolar (3) nerves. All injuries were treated within 3 to 7 months following injury. All patients were evaluated by mechanoceptive and nociceptive testing via brush directional discrimination, pin-prick pressure and thermal sensation. Lateral trap-door osteotomy of the mandible was utilized to access the inferior alveolar nerve. The lingual nerve was approached via a lingual gingival sulcus incision. Following external neurolysis and primary neurorrhaphy, NeuraGen was split longitudinally, and encased the nerve with at least a 1.5 cm margin. One or 2 6-0 prolene horizontal mattress sutures were used to reapproximate the NeuraGen edges and Healon (hyaluronic acid; Advanced Medical Optics, Santa Ana, CA) was applied to the perineural tissues. Five injuries resulted in objective anesthesia preoperatively with the other 4 having varying degrees of hypoesthesia. Six of the nerve injuries also resulted in dysesthesia. Four patients were followed for at least 1 year and the other 4 patients for about 2.5 years. The most recent data was used for this study. Postsurgical outcome was assessed utilizing some of the criteria proposed by Pogrel to classify patients as having good improvement, some improvement, no improvement, or worsening of symptoms. Four cases were found to have good improvement, 4 with some improvement and 1 had no improvement. None of the cases had worsening of symptoms. While reports of the use of other alloplastic materials for nerve repair were found to be variable, NeuraGen seems to have good preliminary results. Bioresorption is complete which decreases the likelihood of interneural scarring. Also, NeuraGen is not associated with episodes of compression neuropathy reported with other rigid non biodegradable materials. Its use in hand surgery literature and in experimental animal studies showed no statistical significance in outcome when compared to end-to-end anastomosis or nerve grafts. The reported advantage of NeuraGen was the elimination of problems associated with graft harvesting. In this small series, 8 out of 9 nerve repairs showed sensory improvement which suggests a favorable role of NeuraGen as a nerve cuff and protective barrier around the nerve injury site. While primary end-to-end anastomosis has comparable results, a nerve cuff has the advantage of preventing axonal escape at suture lines, it minimizes scar ingrowth and nerve entrapment, and it concentrates growth factors at the injury site.