Unusual Audiometric and Histologic Findings in Bilateral Acoustic Neurinomas

Fh, Linthicum

doi:10.1177/000348947208100317

Cited by 41 publications

(12 citation statements)

References 4 publications

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“…It has been discussed in the past that patients with NF2 have tumors that infiltrate the fibers of the cochlear nerve without disrupting the continuity of the nerve, instead of impairing auditory function through compression similar to unilateral sporadic tumors. 33–37 All six of the patients with NF2 in the current study had surgery on the opposite ear in the past. It is also possible that in our patients with NF2 the “protective effect” may be artifact attributable to the earlier diagnosis of the more symptomatic tumors on the opposite side first.…”

Section: Discussionmentioning

confidence: 93%

Tumor Growth and Audiometric Change in Vestibular Schwannomas Managed Conservatively

et al. 2000

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Objective: To prospectively define the correlation between changes in tumor volume and audiometric function in vestibular schwannomas managed conservatively. Study Design: Prospective longitudinal study. Methods: Twenty-one patients (age range, 15-84 y; mean age, 63.3 y) with newly diagnosed vestibular schwannomas were enrolled between 1994 and 1999 in a protocol at The Ohio State University Hospital (Columbus, OH) to evaluate the correlation between tumor volume and audiometric change during a period of observation. Patients were evaluated yearly by clinical examination, a standardized internal auditory canal magnetic resonance imaging scan with gadolinium contrast for volumetric analysis, and audiometric function testing. Demographic data, historical features, neurofibromatosis type 2 (NF2) status, initial testing results, and serial testing results were recorded. Results: An increase in tumor volume occurred in 14 of the 21 patients (66%). The pattern of volumetric change was found to be extremely variable. Multiple regression analysis revealed significant correlations of changes in tumor volume with changes in pure-tone average and speech discrimination score (P < .0001 and P ‫؍‬ .0021, respectively). Change in tumor volume had greater effect on puretone average and speech discrimination score in patients initially with class D audiometric function when compared with those initially in class A (P ‫؍‬ .0083 and P ‫؍‬ .0245, respectively). The presence of NF2 had an independent protective effect against deterioration of the pure-tone average when compared with patients without NF2 (P ‫؍‬ .0125). Conclusions: This study demonstrated a significant correlation between a change in volume and auditory deterioration in vestibular schwannomas being managed with a trial of observation. A given change in tumor volume appeared to have a greater effect on pure-tone average and speech discrimination score as initial auditory classification declined.

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Section: Discussionmentioning

confidence: 93%

Tumor Growth and Audiometric Change in Vestibular Schwannomas Managed Conservatively

et al. 2000

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“…In unilateral schwannomas, the cochlear nerve is confined to the tumor surface. In NF2 tumors fascicles of the nerve may sometimes pass directly through the tumor [10]. This means that a high central dose may induce hearing loss in NF2 tumors even if the prescription dose at the tumor margin is in the range normally used for vestibular schwannomas or indeed even if it is lower than usual.…”

Section: Cochlear Nerve Complicationsmentioning

confidence: 99%

Long-Term Complications following Gamma Knife Radiosurgery of Vestibular Schwannomas

Norén¹

1998

Stereotact Funct Neurosurg

154

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Since its inception in 1969, Gamma Knife radiosurgery (GKR) for vestibular schwannomas has been documented as an efficient and safe procedure based on more than 8,000 treatments worldwide. The author’s personal experience comprises 669 treatments for patients with vestibular schwannoma between 1969–1997. This experience demonstrates long-term growth control, usually with shrinkage, in 95% of unilateral tumors. In the mid-1970s, early facial weakness occurred in 38% and facial numbness in 33%. This has gradually decreased to less than 2% in the 1990s. Preservation of hearing (unchanged or almost unchanged) is currently achieved in 65 to 70%. Tinnitus is rarely changed by the treatment. The risks of intracranial bleeding, infection and CSF leak are avoided because of the noninvasive nature of the treatment. Hydrocephalus directly induced by the tumor occurred in 9.2% of patients. On the other hand, a treatment%related peritumoral reaction sufficient to block the CSF circulation and require shunt insertion was seen in only 1.4%. Based on experiences worldwide, the incidence of secondary neoplasia seems to be 0.1%. The effectiveness of GKR together with its low complication rate makes it a suitable treatment for anyone, regardless of age and general health. With few exceptions, schwannomas with an intracranial size of up to approximately 3 cm are suitable for GKR.

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“…It has been suggested that these poor results may be due to infiltration of the cochlear nerve by tumours in NF2. 24 Hearing preservation in our patients was even more disappointing in that we were unable to preserve hearing in any of our patients.…”

Section: Discussionmentioning

confidence: 68%

A clinical study of vestibular schwannomas in type 2 neurofibromatosis

Kishore

O’Reilly

2000

Clin Otolaryngol

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All 13 patients with neurofibromatosis 2 (NF2) who presented over a period of 17 years at the Institute of Neurological Sciences, Glasgow were reviewed and compared to patients with sporadic vestibular schwannomas. The NF2 patients presented at a younger age than those with sporadic vestibular schwannomas. A significant number had normal pure tone audiograms and a small number also had normal auditory brainstem responses at presentation. Vestibular schwannomas in NF2 patients grow more often and more rapidly than sporadic unilateral ones. They are more liable to infiltrate the cochlear and facial nerves making hearing and facial nerve preservation more difficult to achieve. Because the relatives of these patients often have normal audiograms and normal auditory brain stem responses in the presence of a schwannoma, our recommended method of screening of relatives of NF2 patients is magnetic resonance image scanning with Gd-DTPA enhancement.

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Unusual Audiometric and Histologic Findings in Bilateral Acoustic Neurinomas

Cited by 41 publications

References 4 publications

Tumor Growth and Audiometric Change in Vestibular Schwannomas Managed Conservatively

Tumor Growth and Audiometric Change in Vestibular Schwannomas Managed Conservatively

Long-Term Complications following Gamma Knife Radiosurgery of Vestibular Schwannomas

A clinical study of vestibular schwannomas in type 2 neurofibromatosis

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