Use of Sleeve Neurrorhaphy at the Brainstem for Facial Nerve Reconstruction

Introduction: Neurorrhaphy at the brainstem for reconstruction of the facial nerve remains a technical challenge. Traditional suture techniques prove increasingly difficult with the tendency toward approaches with more limited dissection and when resection of the nerve extends proximally close to the brainstem. A method for secure approximation of the proximal end of the remaining nerve and the graft not requiring the placement of suture would be beneficial in these difficult cases. Methods: Case report. Results: A 30 year old man was found to have a facial nerve schwannoma upon workup for asymmetric sensorineural hearing loss and elected for surgical resection. Following removal of the tumor via translabyrinthine approach the nerve was deficient several millimeters from the brainstem to the second genu in the mastoid. Devitalized cadaveric allograph (Avance Nerve Graft, AloGen, Inc., Alachua, FL, USA) was placed and sutured to the distal end of the nerve. Given the limited remaining proximal portion at the brainstem and the anatomical constraints it was elected to perform a sleeve neurorrhaphy to secure the graft to the remaining nerve. The graft and remaining nerve were approximated and wrapped with commercially available porcine submucosa extracellular matrix (AxoGuard Nerve Protector, AloGen, Inc., Alachua, FL, USA). Gelfilm was then placed between the repair and the brainstem, the dura was closed around the graft and the mastoid defect filled with fat. Discussion: Suture neurorrhaphy remains a technical challenge especially at the brainstem and the cerebellopontine angle. The depth of repair, anatomical constraints of the craniotomy, and generally limited length of proximal remaining nerve add to the difficulty of placing sutures using traditional techniques. The use of a wrap to secure the ends of the nerve and graft to each other also acts to protect the microenvironment which may promote growth of the axons. This case report describes the use of such a wrap to approximate and secure the residual stump of facial nerve at the brainstem with devitalized cadaveric nerve graft. Conclusion: The use of sleeve neurorrhaphy provides an alternative to traditional sutures for reconstruction of the facial nerve at the brainstem. This report serves as a technical description and long term follow up of a larger cohort of patients will be required to adequately compare this technique with the current suture technique.