Length of Tumor-Cochlear Nerve Contact and Hearing Outcome after Surgery for Vestibular Schwannoma

Object Tumor size is likely to be a major determinant of hearing preservation after surgery for vestibular schwannoma. Findings in some large case series have not supported this concept, possibly due to variation in the technique used for tumor measurement. The authors sought to determine if the length of tumor–cochlear nerve contact was predictive of hearing outcome in adults undergoing resection of a vestibular schwannoma. Methods Patients who underwent a hearing-preserving approach for resection of a vestibular schwannoma at one institution by a neurosurgeon/neurotologist team between 2001 and 2005 were screened. Patients with American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) Class A or B hearing preoperatively were included. Magnetic resonance images were reviewed and used to calculate the length of tumor–cochlear nerve contact. Tumors were also measured according to AAO-HNS guidelines. Results Thirty-one patients were included, 8 (26%) of whom had hearing preservation. Univariate analysis revealed that extracanalicular length of tumor–cochlear nerve contact (p = 0.0365), preoperative hearing class (p = 0.028), I–V interpeak latency of the brainstem auditory evoked potential (p = 0.021), and the interaural I–V interpeak latency difference (p = 0.018) were predictive of hearing outcome. Multivariate analysis confirmed the predictive value of extra-canalicular length of contact and preoperative hearing class (p = 0.041 and p = 0.0235, respectively). Conclusions Vestibular schwannomas with greater lengths of tumor–cochlear nerve contact increase a patient's risk for hearing loss after surgery with attempted hearing preservation. Involvement of the internal auditory canal produces a constant risk of hearing loss. Data from the experience of a single surgical team can be used to estimate the probability of good hearing outcome for any given patient with serviceable hearing and a vestibular schwannoma.

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Developing Intraoperative Cochlear Nerve Monitoring during Vestibular Schwannoma Surgery

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0032-1314184 ◽

2012 ◽

Vol 73 (S 02) ◽

Author(s):

A. Kasbekar ◽

Y. Tam ◽

R. Carlyon ◽

J. Deeks ◽

N. Donnelly ◽

...

Keyword(s):

Vestibular Schwannoma ◽

Cochlear Nerve ◽

Nerve Monitoring

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Vestibular schwannoma surgery: Intraoperative cochlear nerve action potential monitoring

Otolaryngology ◽

10.1016/s0194-5998(97)80454-8 ◽

1997 ◽

Vol 117 (2) ◽

pp. P204-P204

Author(s):

J ROBERSONJR ◽

J MCAULEY

Keyword(s):

Action Potential ◽

Vestibular Schwannoma ◽

Cochlear Nerve ◽

Nerve Action ◽

Potential Monitoring

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Intraoperative Monitoring of the Cochlear Nerve during Neurofibromatosis Type-2 Vestibular Schwannoma Surgery and Description of a “Test Intracochlear Electrode”

Journal of Neurological Surgery Reports ◽

10.1055/s-0038-1673649 ◽

2019 ◽

Vol 80 (01) ◽

pp. e1-e9 ◽

Cited By ~ 2

Author(s):

Anand Kasbekar ◽

Yu Chuen Tam ◽

Robert Carlyon ◽

John Deeks ◽

Neil Donnelly ◽

...

Keyword(s):

Cochlear Implant ◽

Vestibular Schwannoma ◽

Intraoperative Monitoring ◽

Neurofibromatosis Type ◽

Auditory Brainstem ◽

Cochlear Nerve ◽

Auditory Brainstem Responses ◽

Tertiary Referral Center ◽

Objective Evidence ◽

Brainstem Response

Objectives A decision on whether to insert a cochlear implant can be made in neurofibromatosis 2 (NF2) if there is objective evidence of cochlear nerve (CN) function post vestibular schwannoma (VS) excision. We aimed to develop intraoperative CN monitoring to help in this decision. Design We describe the intraoperative monitoring of a patient with NF2 and our stimulating and recording set up. A novel test electrode is used to stimulate the CN electrically. Setting This study was set at a tertiary referral center for skull base pathology. Main outcome measure Preserved auditory brainstem responses leading to cochlear implantation. Results Electrical auditory brainstem response (EABR) waveforms will be displayed from different stages of the operation. A cochlear implant was inserted at the same sitting based on the EABR. Conclusion Electrically evoked CN monitoring can provide objective evidence of CN function after VS excision and aid in the decision-making process of hearing rehabilitation in patients who will be rendered deaf.

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Hearing outcomes of vestibular schwannoma patients managed with ‘wait and scan’: predictive value of hearing level at diagnosis

The Journal of Laryngology & Otology ◽

10.1017/s0022215109992611 ◽

2010 ◽

Vol 124 (5) ◽

pp. 490-494 ◽

Cited By ~ 32

Author(s):

S-E Stangerup ◽

M Tos ◽

J Thomsen ◽

P Caye-Thomasen

Keyword(s):

Vestibular Schwannoma ◽

Predictive Value ◽

High Frequency ◽

Pure Tone ◽

Hearing Level ◽

Speech Discrimination ◽

Resonance Imaging ◽

Hearing Outcome ◽

Hearing Outcomes ◽

Better Than

AbstractAims:This study aimed to evaluate the predictive value of both hearing level (at various frequencies) and speech discrimination for forecasting hearing outcome after a period of observation, in patients with vestibular schwannoma.Subjects:Over a 33-year period, 1144 patients with vestibular schwannoma were allocated to ‘wait and scan’ management, with annual magnetic resonance imaging and audiological examination. Two complete pure tone and speech discrimination audiograms were available for 932 patients.Results:The predictive value of initial hearing level better than 10 dB for forecasting hearing outcome after observation increased from 59 per cent at 250 Hz to 94 percent at 4000 Hz. At diagnosis, hearing level of 10 dB or better at 4000 Hz was found in only 18 of the 932 VS ears, while good speech discrimination was found in 159 patients (17 per cent). Of the latter patients, 138 maintained good hearing after observation.Conclusion:In vestibular schwannoma patients, good high frequency hearing and good speech discrimination at diagnosis are useful tools in predicting good hearing after observation.

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Stability of hearing preservation and regeneration capacity of the cochlear nerve following vestibular schwannoma surgery via a retrosigmoid approach

Journal of Neurosurgery ◽

10.3171/2015.10.jns15926 ◽

2016 ◽

Vol 125 (5) ◽

pp. 1277-1282 ◽

Cited By ~ 10

Author(s):

Christian Scheller ◽

Andreas Wienke ◽

Marcos Tatagiba ◽

Alireza Gharabaghi ◽

Kristofer F. Ramina ◽

...

Keyword(s):

Vestibular Schwannoma ◽

Strong Association ◽

Pure Tone Audiometry ◽

Hearing Preservation ◽

Cochlear Nerve ◽

Speech Discrimination ◽

Regeneration Capacity ◽

Postoperative Course ◽

Link Type ◽

Hearing Abilities

OBJECTIVE The purpose of this research was to examine the stability of long-term hearing preservation and the regeneration capacity of the cochlear nerve following vestibular schwannoma (VS) surgery in a prospective study. METHODS A total of 112 patients were recruited for a randomized multicenter trial between January 2010 and April 2012 to investigate the efficacy of prophylactic nimodipine treatment versus no prophylactic nimodipine treatment in VS surgery. For the present investigation, both groups were pooled to compare hearing abilities in the early postoperative course and 1 year after the surgery. Hearing was examined using pure-tone audiometry with speech discrimination, which was performed preoperatively, in the early postoperative course, and 12 months after surgery and was subsequently classified by an independent otorhinolaryngologist using the Gardner-Robertson classification system. RESULTS Hearing abilities at 2 time points were compared by evaluation in the early postoperative course and 1 year after surgery in 102 patients. The chi-square test showed a very strong association between the 2 measurements in all 102 patients (p < 0.001) and in the subgroup of 66 patients with a preserved cochlear nerve (p < 0.001). CONCLUSIONS There is no significant change in cochlear nerve function between the early postoperative course and 1 year after VS surgery. The result of hearing performance, as evaluated by early postoperative audiometry after VS surgery, seems to be a reliable prognosticator for future hearing ability. Clinical trial registration nos.: 2009-012088-32 (clinicaltrialsregister.eu) and DRKS 00000328 (“AkNiPro,” drks-neu.uniklinik-freiburg.de/drks_web/)

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Tumor origin and hearing preservation in vestibular schwannoma surgery

Journal of Neurosurgery ◽

10.3171/2011.7.jns102092 ◽

2011 ◽

Vol 115 (5) ◽

pp. 900-905 ◽

Cited By ~ 9

Author(s):

Jens Rachinger ◽

Stefan Rampp ◽

Julian Prell ◽

Christian Scheller ◽

Alex Alfieri ◽

...

Keyword(s):

Vestibular Schwannoma ◽

Tumor Size ◽

Hearing Preservation ◽

Vestibular Nerve ◽

Cochlear Nerve ◽

Nerve Function ◽

Nerve Preservation ◽

Tumor Origin ◽

Inferior Vestibular Nerve ◽

Vs Removal

Object Preservation of cochlear nerve function in vestibular schwannoma (VS) removal is usually dependent on tumor size and preoperative hearing status. Tumor origin as an independent factor has not been systematically investigated. Methods A series of 90 patients with VSs, who underwent surgery via a suboccipitolateral route, was evaluated with respect to cochlear nerve function, tumor size, radiological findings, and intraoperatively confirmed tumor origin. All patients were reevaluated 12 months after surgery. Results Despite comparable preoperative cochlear nerve status and larger tumor sizes, hearing preservation was achieved in 42% of patients with tumor originating from the superior vestibular nerve, compared with 16% of those with tumor originating from the inferior vestibular nerve. Conclusions Tumor origin is an important prognostic factor for cochlear nerve preservation in VS surgery.

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