HSC Section 3 - Trauma, Critical Care and Sleep Medicine

Surgical Management of Acute Facial Palsy

Fig. 8. Intraoperative image of complete exposure of the facial nerve with the arachnoid (dural) band being lysed, in a patient with Bell palsy. AB, arachnoid band.

most likely location of facial nerve injury based on imaging data. The perigeniculate re- gion is the most commonly injured and surgical decompression proceeds similarly to that in Bell palsy. Preoperative hearing assessment is crucial because, in contrast with Bell palsy, otic capsule–involving temporal bone fractures may result in profound sensorineural hear- ing loss, in which case a translabyrinthine approach may be undertaken. In addition, surgeons should be prepared for neurorrhaphy or interposition grafting based on intra- operative assessment of the traumatic nerve injury. Translabyrinthine Approach The translabyrinthine approach should only be used in patients who are confirmed to have complete hearing loss in the ipsilateral ear. Using the translabyrinthine approach to access cerebellopontine angle lesions has been described in detail elsewhere, 41 and a similar technique is used for facial nerve decompression. A complete mastoid- ectomy is done with identification of the middle and posterior fossa dural plates, sino- dural angle, sigmoid sinus, digastric ridge, incus, and lateral semicircular canal. The vertical segment of the facial nerve can be localized using the horizontal semicircular canal, chorda tympani, and the digastric ridge. The facial recess is then opened, providing access to the tympanic segment of the nerve. The incus and head of the malleus are removed. Labyrinthectomy is performed by removing the entire bony labyrinth; the SSCC ampulla is removed last and used as a landmark to locate the labyrinthine segment of the facial nerve. The posterior fossa is decompressed and the IAC is skeletonized. The superior trough is developed from medial to lateral and the labyrinthine segment, Bill bar, and superior vestibular nerves are identified. The labyrinthine segment is then followed to the GG. Targeted electrical stimulation is then performed to localize the site of the conduc- tion block. The entire intratemporal course of the nerve is inspected for traumatic injury. Focal endoneural herniation may be relieved by carefully incising the surround- ing epineurium with a 59-10 blade. Frank transection requires repair via primary neuro- rrhaphy if a tension-free anastomosis can be achieved, or an interposition graft. Either the great auricular or sural nerve may be used for grafting. Neural coaptation is

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