Retrolabyrinthine Vestibular Neurectomy with Simultaneous Monitoring of Eighth Nerve and Brain Stem Auditory Evoked Potentials

Silverstein, Herbert; McDaniel, Alan B.; Wazen, Jack J.; Norrell, Horace

doi:10.1177/019459988509300607

Cited by 39 publications

(16 citation statements)

References 9 publications

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“…In 1980, the retrolabyrinthine approach was described as the “direct”[23] route to the CP angle, being well-liked by otologists and neurosurgeons alike, in the treatment of Meniere's disease,[22] petroclival meningiomas,[12] vestibular schwannomas,[47] and in the placement of auditory brainstem implants. [5] In the early 2000s, the retrolabyrinthine approach was described as “the unsung hero of skull base surgery.”[18] When compared to a retrosigmoid approach, the presigmoid exposure provides the benefits of a shorter working distance and less cerebellar retraction.…”

Section: Discussionmentioning

confidence: 99%

Radiographic assessment of the presigmoid retrolabyrinthine approach

Wong¹,

Stamates²,

Bhansali³

et al. 2017

Surg Neurol Int

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Background:Lesions of the petroclival fissure are difficult to access surgically. Both retrosigmoid and presigmoid retrolabyrinthine approaches have been described to successfully treat these complex tumors. The retrosigmoid approach offers quick and familiar access, whereas the presigmoid retrolabyrinthine approach reduces the operative distance and the need for cerebellar retraction. The presigmoid retrolabyrinthine approach, however, is constrained by anatomical limits that can be subject to patient variation. We sought to characterize the surgically relevant variation to guide preoperative assessment.Methods:One hundred and seventy-seven high-resolution computed tomography scans of the head (without preexisting pathology) were reviewed. Three hundred and fifty-four temporal bone scans were analyzed for level of aeration, size of Trautmann's triangle dura, and petrous slope. Petrous slope is the angle between the anterior sigmoid sinus and the petroclival fissure at the level of the internal acoustic canal.Results:Trautmann's triangle area had a mean of 185.15 mm2 (range 71.4–426.7 mm2). Petrous slope had a mean value of 149° (range 106–178°). Increasing aeration was found to be correlated with decreasing petrous slope and decreasing Trautmann's triangle area.Conclusion:The presigmoid retrolabyrinthine approach is uniquely confined. Variations in temporal bone anatomy can have dramatic impacts on the operative time, risk profile, and final exposure. Preoperative assessment is critical in guiding the surgeon on the appropriateness of approach. Preoperative measurement of Trautmann's triangle, petrous slope, and aeration can help to reduce surgical morbidity.

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Section: Discussionmentioning

confidence: 99%

Radiographic assessment of the presigmoid retrolabyrinthine approach

Wong¹,

Stamates²,

Bhansali³

et al. 2017

Surg Neurol Int

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“…Monopolar recording of CNAPs from the auditory nerve is useful in acoustic tumor removal when hearing preservation is desired (4,5). These potentials are extremely sensitive in detecting inner ear and CN damage, but CNAPs can be recorded when the electrode does not have close contact with the cochlear trunk.…”

Section: Discussionmentioning

confidence: 99%

“…Intraoperative monitoring of auditory evoked potentials is a very useful tool for hearing preservation during cerebello-pontine angle (CPA) surgery (1)(2)(3)(4)(5)(6). Brainstem auditory evoked potentials ( BAEPs) are often utilized for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Electrophysiologic Identification of the Cochlear Nerve Fibers during Cerebellopontine Angle Surgery

Colletti

Fiorino

1993

Acta Oto-Laryngologica

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To facilitate identification and preservation of the auditory nerve during cerebello-pontine angle surgery, bipolar recording of cochlear nerve compound action potentials (CNAPs) was performed. Two silver wires insulated with teflon up to the exposed ends were utilized as electrodes. They were twisted together, the distance between the two tips being 1 mm or less. Rarefaction polarity clicks (31/s) ranging from the psychoacoustical threshold to 120 dB pe SPL were used as stimuli. The investigation was performed in three groups of patients. The first group consisted of 9 patients submitted to vestibular neurectomy and 4 patients operated on by microvascular decompression of the eighth nerve. The second group comprised 8 patients with acoustic tumors smaller than 2 mm and serviceable hearing. Postoperative audiometric results in the subjects in the second group were compared with those obtained in well-matched homogeneous controls consisting of patients with acoustic neuroma operated on without the aid of CNAP recording. Bipolar recording from the eighth nerve was extremely selective, a good response being obtained only when positioning the electrode on the cochlear portion of the eighth nerve. During removal of the acoustic neuroma, repeated bipolar probing of the tumor and eighth nerve facilitated the task of distinguishing the cochlear nerve from other nervous structures and from the tumor, and contributed to preserving hearing in most patients.

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“…So erfasst sie zwar eine (z. B. durch Läsion der A. labyrinthi bedingte) hypoxische Funktionsreduktion dieser Strukturen, nicht jedoch eine durch direkte Irritation zentraler Anteile des Nervs bedingte Schädigung [30]. Diese wird sowohl im Rahmen der BERA erkannt (welche als "Far-field-Monitoring" das ZNS miterfasst) als auch durch eine hirnstammnahe direkte Ableitung vom Hörnerven, die in der vorliegenden Untersuchung nicht geprüft wurde.…”

Section: N Cochlearisunclassified