Use of a Novel Ultrasonic Surgical System for Decompression of the Facial Nerve

Abstract

The middle cranial fossa approach has been used to explore and decompress the facial nerve in patients with Bell's palsy and facial nerve tumors. Unfortunately, this approach is technically challenging and has a significant risk of injury to the facial nerve and to the cochleovestibular organs. One way to minimize the risk may be with the use of the Sonopet Omni ultrasonic aspirator (Synergetics Inc., St Charles, MO) instead of an otologic drill. In this prospective study using cadaveric temporal bones, a total of 17 temporal bone specimens were used. Seven cadaveric temporal bones were used (4-left, 3-right) for the initial feasibility study. At a second session, an additional 10 temporal bones (5-left, 5-right) underwent decompression of the facial nerve from the fundus of the internal auditory canal (IAC) to the geniculate ganglion (ie, labyrinthine segment). The average time to decompress the labyrinthine segment was measured. The temporal bones were then examined for evidence of any injury. None of the 17 temporal bones showed any sign of injury to the superior semicircular canal or the cochlea. However, one specimen did have penetration of the IAC dura; another specimen did have penetration of the epineurium of the facial nerve. However, in neither case was there any evidence of injury to the facial nerve itself. At the first session, the average time for decompression of the labyrinthine segment was 10 minutes and 12 seconds. At the second session, the average time for decompression was 5 minutes and 0 seconds. The ultrasonic surgical system may be used as an alternative to the surgical drill for decompression of the facial nerve. Although a learning curve does exist, as with any new surgical tool or device, our results indicate that the device can be used safely and in a reasonable amount of time. However, before proceeding with intraoperative use of this device for otologic and neurotologic procedures, familiarization is first recommended on cadaveric temporal bone specimens.