Facial Nerve Neuroma: Surgical Concept and Functional Results

ABSTRACT

This study reviewed the management and outcomes of 11 facial nerve neuromas treated in our institution during the past two decades with particular emphasis on surgical concepts and functional outcomes. All patients underwent complete surgical resection of their tumor. Eight patients (73%) were followed on an outpatient basis. A retrospective chart review for pre- and postoperative clinical and radiological data was performed. All facial neuromas were multisegment tumors. All segments of the facial nerve were represented, but 54% involved the geniculate ganglion and 45% involved the labyrinthine or tympanic portions of the nerve, or both. Depending on the extent of sensorineural hearing loss, surgical removal was performed through the middle cranial fossa or translabyrinthine approach. To obtain adequate nerve reconstruction, we combined intra- and extracranial approaches (e.g., the transmastoidal and transtemporal routes). Regardless of the type of nerve reconstruction, the best recovery achieved was moderate facial weakness (House-Brackmann Grade III) in 75% of the patients, even in a patient who was Grade IV preoperatively. The choice of treatment for facial neuromas and surgical approach depends on the extent of tumor, grade of facial palsy, and hearing function. When facial palsy is present, complete resection is clearly indicated. In patients without facial dysfunction, a conservative strategy consisting of clinical and radiological observation should be considered as a treatment option.

KEYWORDS

Facial nerve neuroma - facial nerve tumor - facial schwannoma - facial nerve surgery - facial nerve function

REFERENCES

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Facial nerve neuromas are extremely rare skull base lesions that typically affect the geniculate ganglion and temporal and labyrinthine segments of the facial nerve. Patients present with a variety of symptoms ranging from sensorineural hearing loss to facial palsy. Tumors with multiple segments are common. Surgical resection of these lesions always results in facial palsy. As the authors have pointed out, the maximal improvement that can be expected is House-Brackmann Grade III. Surgical resection should only be undertaken after a detailed discussion with the patient at which informed consent is obtained. Whether surgical palsy is an appropriate trade-off for hearing preservation is a decision that must be made between physician and patient. Although there are no controlled series using gamma knife or fractionated radiosurgery with the Cyberknife, one would expect the results to be similar to those from acoustic neuroma series. However, fractionated radiosurgery to maximize function of the nerve may be more attractive to patients with partial facial nerve palsy.

I thank the authors for sharing this well-written article.

This article reports a relatively large series of facial nerve neuromas treated at a single institution. In all cases, the neuroma was excised and facial nerve reconstruction was performed, typically with a nerve graft. A hypoglossal facial nerve anastomosis was performed only when the proximal facial nerve was unavailable for grafting. Both procedures represent the appropriate standard of care.

The authors discuss the option of observation, which as they note, increasingly is becoming the accepted initial treatment for these tumors. At the House Ear Clinic, we recommend observation as long as facial nerve function remains good. However, we discuss the risk of hearing loss with the patient because these tumors can erode into the cochlea and produce sensorineural hearing loss despite continued good facial nerve function.

When facial nerve function begins to deteriorate, surgical resection of the tumor with facial nerve grafting is recommended. The appropriate timing for surgery is a difficult decision. Surgery is usually delayed until the patient has significant facial nerve dysfunction, in the range of a House-Brackmann Grade III or IV. Waiting until the facial nerve completely degenerates compromises recovery, and the patient is urged not to wait too long to make the decision to undergo surgery.

Our experience is similar to that of the authors. When good facial function is present preoperatively, most patients receiving a facial nerve graft make a Grade III recovery. If the facial nerve has degenerated preoperatively, one usually expects only a Grade IV recovery, which is also expected with a hypoglossal facial anastomosis.

I congratulate the authors for their well-documented series and excellent discussion of this problem.