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Acoustic tumours (fwd)

Larry Lundy llundy at VOYAGER.NET
Tue May 14 06:53:57 EST 1996

>Ms Bailey,
>You raise many relevant points for the management of acoustic neuromas. In
>a young woman with a non hearing ear who now has evidence of trigeminal
>nerve compression (loss of feeling on that side of her face) and 3 cm
>tumor by MRI, it is very likely an acoustic neuroma. There are many
>excellent centers that treat these tumors in high volumes. I can give you
>some information from our group, with approximately 400 acoustic neuromas
>over the last 10 years, though I cannot make a direct comparison with
>other centers.
>The treatment of choice in her situation is a translabyrinthine resection
>of the tumor with intraoperative electromyographic monitoring of the
>facial and trigeminal nerve. Stereotactic radiotherapy is reserved for the
>medically infirm, elderly patients, or patients who absolutely refuse
>surgery. About 15-30% of patients with stereotactic radiotherapy will
>experience facial paralysis, and when followed for a few years, 10 - 20%
>will demonstrate further tumor growth (recall that stereotactic
>radiotherapy does not remove or "dissolve" the tumor, and practically
>speaking only halts its growth, though we don't know for how long). The
>National Institute of Health Consensus statement notes that surgery is the
>treatment of choice. (Acoustic Neuroma. NIH Consens Dev Conf Consens
>Statement 9 (4), 1991).
>The advent of intraoperative facial nerve monitoring has significantly
>improved the final facial nerve function, as about 75% of patients (all
>sizes of tumors included) will have normal or near normal (House-Brackman
>grade 1 or 2) facial nerve function post operatively (Kartush, JM, Lundy
>L: Facial nerve outcome in acoustic neuroma surgery. Otolaryngol Clin
>North Am 25: 623-647). The translabyrinthine approach offers the
>significant advantage of positive identification of the facial nerve
>laterally, especially in a tumor of this size. In our own experience of
>about 400 cases, when intraoperative monitoring is used, over 95% will
>have normal or near normal facial nerve function. Other factors also come
>into play, as discussed in the paper referenced.
>Unfortunately, when a tumor has reached this size and the hearing is lost
>preoperatively, there is no chance at restoring hearing. This is one
>reason the translabyrinthine approach is chosen, since hearing is already
>lost, and this approach has lower morbidity (facial nerve function,
>cerebellar function, headaches, etc). Hearing preservation, not
>restoration, is attainable if the tumor is small and is diagnosed and
>operated on early enough, usually by a middle fossa craniectomy approach.
>Incidentally, I see no medical reason to wait 4-6 months for surgery.
>There are some good general reference materials recently.
>        Acoustic Neuroma I & II, April & June 1992, Otolaryngologic
>Clinics of North America
>        NIH Consensus Statement, noted above
>        Neurotology (textbook), Jackler & Brackman, Mosby publisher, 1994
>        Acoustic Neuroma Association, a support/information group, who has
>a web page also
>                http://neurosurgery.mgh.harvard.edu/ana/
>        Otology Online, web page
>                http://ww.ears.com
>I know this is kind of a cursory overview, and there is much more
>information, as well as unresolved issues, but I hope this is of some
>Larry Lundy, MD
>Michigan Ear Institute
>llundy at voyager.net

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