Stereotactic radiosurgery failure in acoustic neuroma. (Editorial).The combined otolaryngologic spring meetings held May 10-14, 2002, in Boca Raton, Florida Boca Raton ("bōkə rə-tōn") is a city in Palm Beach County, Florida incorporated in May 1925. As of the 2000 census, the city had a total population of 74,764; the 2006 population recorded by the U.S. Census Bureau was 86,396. , included a wide variety of subjects worthy of comment on this page. Of special interest to me, as one involved in the development of neurotologic surgery to routinely preserve normal facial nerve facial nerve n. Either of a pair of nerves that originate in the pons, traverse the facial canal of the temporal bone, and pass through the parotid gland, reach the facial muscles through various branches, control facial muscles, and relay sensation function, was a paper Daniel J. Lee, MID, and colleagues of the Johns Hopkins School of Medicine presented at the American Neurotology Society, entitled "Clinical and histopathological features of recurrent vestibular schwannoma (acoustic neuroma Acoustic Neuroma Definition An acoustic neuroma is a benign tumor involving cells of the myelin sheath that surrounds the vestibulocochlear nerve (eighth cranial nerve). ) following stereotactic radiosurgery stereotactic radiosurgery n. Stereotaxis in which tissue destruction is produced by ionizing radiation rather than by surgical incision. stereotactic radiosurgery ." The authors reported four cases of acoustic neuroma that continued to grow after radiosurgery radiosurgery /ra·dio·sur·gery/ (-ser´jer-e) surgery in which tissue destruction is performed by means of ionizing radiation rather than by surgical incision. All four patients had cranial nerve neuropathy after radiosurgery; one had trigeminal nerve paresthesia paresthesia /par·es·the·sia/ (par?es-the´zhah) morbid or perverted sensation; an abnormal sensation, as burning, prickling, formication, etc. par·es·the·sia or par·aes·the·sia n. and three had hemifacial spasm. All had salvage microsurgery microsurgery or micromanipulation Surgical technique for operating on minute structures, with specialized, tiny precision instruments under observation through a microscope, sometimes equipped with cameras to show the operation on a monitor. performed by the authors within two years of the radiosurgery treatment. They observed inconsistent radiation changes in the cerebellopontine angle and internal auditory canal. Fibrosis outside and within the tumor varied markedly, complicating microsurgical dissection. Light microscopy confirmed the presence of viable tumor in all cases. The authors pointed out that in an effort to avoid complications, the tumor dose of radiosurgery in recent years has been reduced so that long-term evaluation will be required to determine the failure rate with that form of therapy. With both low- and high-dose radiation therapy, there is increased risk of developing neoplasms of the central nervous system. The authors found six cases reported to have malignant degeneration after radiation therapy for a cerebellopontine angle tumor cerebellopontine angle tumor Acoustic neuroma, see there . There is little question that in some cases radiosurgery (gamma knife or fractionated stereotactic radiosurgery) might be indicated for the treatment of enlarging acoustic neuroma--for example, in a patient in poor medical condition whose risk with surgery is unacceptable. (1,2) On the other hand, the risk of malignant degeneration and other serious complications of radiosurgery clearly make surgical removal by a skilled, experienced neurotologic surgeon the treatment of choice. JACK L. PULEC, MD Editor-in-Chief EAR, NOSE & THROAT JOURNAL References (1.) Pulec JL, Giannotta SL. Acoustic neuroma surgery in patients over 65 years of age. Ear Nose Throat J 1995;74:21-7. (2.) Pulec JL. Acoustic neuroma surgery in geriatric patients. Ear Nose Throat J 1999;78:429-42 |
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