Correlation between auditory function and internal auditory canal pressure in patients with vestibular schwannomas

Lapsiwala, Samir; Pyle, G. Mark; Kaemmerle, Ann W.; Sasse, Frank J.; Badie, Behnam

doi:10.3171/jns.2002.96.5.0872

Cited by 49 publications

(42 citation statements)

References 20 publications

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“…17 A recent histopathological study of unresected unilateral acoustic neuromas showed that degenerative changes in the inner ear and atrophy of the stria vascularis and spiral ligament were present in addition to cochlear nerve degeneration when compared with control specimens. 17 Tumor adherence to the cochlear nerve in the IAC 3 as well as increases in IAC pressure from tumor 13 may be responsible for these changes, which have been shown to adversely affect hearing outcome.…”

Section: Hearing Preservationmentioning

confidence: 99%

Medial acoustic neuromas: clinical and surgical implications

Dunn

Erkmen³

et al. 2014

JNS

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Object Medial acoustic neuroma is a rare entity that confers a distinct clinical syndrome. It is scarcely discussed in the literature and is associated with adverse features. This study evaluates the clinical and imaging features, pertinent surgical challenges, and treatment outcome in a large series of this variant. The authors postulate that the particular pathological anatomy with its arachnoidal rearrangement has a profound implication on the surgical technique and outcome. Methods The authors conducted a retrospective analysis of 52 cases involving 33 women and 19 men who underwent resection of medial acoustic neuromas performed by the senior author (O.A.) over a 20-year period (1993–2013). Clinical, radiological, and operative records were reviewed, with a specific focus on the neurological outcomes and facial nerve function and hearing preservation. Intraoperative findings were analyzed with respect to the effect of arachnoidal arrangement on the surgeon's ability to resect the lesion and the impact on postoperative function. Results The average tumor size was 34.5 mm (maximum diameter), with over 90% of tumors being 25 mm or larger and 71% being cystic. Cerebellar, trigeminal nerve, and facial nerve dysfunction were common preoperative findings. Hydrocephalus was present in 11 patients. Distinguishing intraoperative findings included marked tumor adherence to the brainstem and frequent hypervascularity, which prompted intracapsular dissection resulting in enhancement on postoperative MRI in 18 cases, with only 3 demonstrating growth on follow-up. There was no mortality or major postoperative neurological deficit. Cerebrospinal fluid leak was encountered in 7 patients, with 4 requiring surgical repair. Among 45 patients who had intact preoperative facial function, only 1 had permanent facial nerve paralysis on extended follow-up. Of the patients with preoperative Grade I–II facial function, 87% continued to have Grade I–II function on follow-up. Of 10 patients who had Class A hearing preoperatively, 5 continued to have Class A or B hearing after surgery. Conclusions Medial acoustic neuromas represent a rare subgroup whose site of origin and growth patterns produce a distinct clinical presentation and present specific operative challenges. They reach giant size and are frequently cystic and hypervascular. Their origin and growth pattern lead to arachnoidal rearrangement with marked adherence against the brainstem, which is critical in the surgical management. Excellent surgical outcome is achievable with a high rate of facial nerve function and attainable hearing preservation. These results suggest that similar or better results may be achieved in less complex tumors.

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Section: Hearing Preservationmentioning

confidence: 99%

Medial acoustic neuromas: clinical and surgical implications

Dunn

Erkmen³

et al. 2014

JNS

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“…Perhaps direct damage to primary sensory cells, radiation damage to the cochlear nerve, or direct damage to the nerve or internal auditory artery caused by the lesion result in compression or thrombosis with consequent ischemic damage to the cochlea. 6,27 There are only a few studies in the literature that analyze hearing preservation exclusively in patients with normal or subnormal hearing (GR Class I). Studies regarding the possibility of retaining functional hearing are increasing in number.…”

Section: Hearing Function After Gksmentioning

confidence: 99%

Evaluation of hearing function after Gamma Knife surgery of vestibular schwannomas

Franzin¹,

Spatola²,

Serra³

et al. 2009

FOC

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Object Due to technological advances in neuroradiology in recent years, incidental diagnoses of vestibular schwannomas (VSs) have increased. The aim of this study was to evaluate the hearing function after treatment with Gamma Knife surgery (GKS) for VSs in patients adequately selected with “good” or “useful” hearing before treatment and to assess the possible predictive factors for hearing function preservation. Methods Of all patients treated in the authors' hospital between 2001 and 2007, they retrospectively studied 50 patients with a unilateral VS in whom there was serviceable hearing (Gardner-Robertson [GR] Class I or II). Additional inclusion criteria were: no Type 2 neurofibromatosis, no previous treatment, and at least 6 months' follow-up of neuroradiological and audiological data. The median patient age was 54 years (range 24–78 years). The median tumor volume was 0.73 ml (range 0.03–6.6 ml), and the median radiation dose to the tumor margin was 13 Gy (range 12–16 Gy) with an isodose of 50%. Results Patient age, tumor volume, and presenting symptoms were found to correlate with hearing function. At a median of 36 months after radiosurgery, tumor growth control was 96% and no patient required any other additional treatment. Serviceable hearing was preserved in 34 patients (68%): 21 (62%) with GR Class I hearing and 13 (38%) with GR Class II hearing. The remaining 16 patients had poor hearing function:15 with GR Class III and 1 with GR Class IV hearing function. In 19 (58%) of 33 patients with GR Class I function before GKS the same class was maintained posttreatment; 29 (88%) maintained functional hearing (GR Class I or II). In all patients with an intracanalicular lesion, functional hearing was maintained. Significant prognostic factors for maintaining serviceable hearing were GR Class I function before treatment, symptoms at presentation, patient age younger than 54 years, and Koos Stage T1 disease. Conclusions The results of the study show that the probability of preserving functional hearing in patients undergoing GKS treatment for unilateral VSs is very high. Patients with GR Class I, age younger than 54 years, with presenting symptoms other than hearing loss, and a Koos Stage T1 tumor have better prognosis. The prescribed dose of 13 Gy appears to represent an excellent compromise between controlling the disease and preserving auditory function.

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“…In general, there are 4 patterns of hearing loss: 21,27,37,38,51,57,71,72,81,99 1) hearing deterioration in "growing" tumors, 2) hearing deterioration in "nongrowing" tumors, 3) early hearing loss, and 4) sudden hearing loss regardless of tumor growth. Vestibular schwannomas are histologically benign, slow-growing tumors that originate from the Schwann cells of the inferior vestibular nerve in most cases.…”

Section: Mechanism Of Hearing Loss In Vsmentioning

confidence: 99%

“…81 This compromise of the vascular supply can be a result of an increase in intracanalicular pressure or due to direct compression caused by the laterally invading tumor. 7,51 Compression of labyrinthine vessels has been shown to cause degeneration in the organ of Corti and the spiral ganglion (cochlear dysfunction). 22,37,43,71 Of note, the progression of hearing loss in VS is most often gradual, 39,96 although sudden deterioration is also possible.…”

Section: Hearing Loss In Patients With Growing Tumorsmentioning

confidence: 99%

“…Further, due to the anatomical distribution of the blood supply to the cochlea, vascular compromise should result in low-frequency hearing loss in these patients, whereas mostly higher-frequency loss is reported in such cases. 51,52 Tumor characteristics, including accelerated tumor growth and an increased number of intratumoral hemorrhages, are thought to cause sudden hearing loss through nerve compression and rapid accumulation of biochemical toxins. 99 A higher incidence of high-to mid-frequency hearing loss correlates well with the nerve compression theory, 32 but otoacoustic emissions in such patients do not reflect purely retrocochlear hearing loss 71 and suggest that both cochlear and retrocochlear components contribute to sudden hearing loss in such patients.…”

Section: Sudden Hearing Lossmentioning

confidence: 99%

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An update on unilateral sporadic small vestibular schwannoma

Thakur¹,

Banerjee

Khan³

et al. 2012

FOC

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Advances in neuroimaging have increased the detection rate of small vestibular schwannomas (VSs, maximum diameter < 25 mm). Current management modalities include observation with serial imaging, stereotactic radiosurgery, and microsurgical resection. Selecting one approach over another invites speculation, and no standard management consensus has been established. Moreover, there is a distinct clinical heterogeneity among patients harboring small VSs, making standardization of management difficult. The aim of this article is to guide treating physicians toward the most plausible therapeutic option based on etiopathogenesis and the highest level of existing evidence specific to the different cohorts of hypothetical case scenarios. Hypothetical cases were created to represent 5 commonly encountered scenarios involving patients with sporadic unilateral small VSs, and the literature was reviewed with a focus on small VS. The authors extrapolated from the data to the hypothetical case scenarios, and based on the level of evidence, they discuss the most suitable patient-specific treatment strategies. They conclude that observation and imaging, stereotactic radiosurgery, and microsurgery are all important components of the management strategy. Each has unique advantages and disadvantages best suited to certain clinical scenarios. The treatment of small VS should always be tailored to the clinical, personal, and social requirements of an individual patient, and a rigid treatment protocol is not practical.

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Correlation between auditory function and internal auditory canal pressure in patients with vestibular schwannomas

Abstract: Tumor growth into the IAC results in elevation of ICaP and may play a role in hearing loss in patients with VS. The relevance of these findings to the surgical treatment of these tumors is discussed.

Cited by 49 publications

References 20 publications

Medial acoustic neuromas: clinical and surgical implications

Medial acoustic neuromas: clinical and surgical implications

Evaluation of hearing function after Gamma Knife surgery of vestibular schwannomas

An update on unilateral sporadic small vestibular schwannoma

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