Hearing Preservation after Acoustic Neuroma Surgery with Intraoperative Direct Eighth Cranial Nerve Monitoring: Part II. A Classification of Results

1986 ◽  
Vol 95 (3_part_1) ◽  
pp. 285-291 ◽  
Author(s):  
Herbert Silverstein ◽  
Alan Mcdaniel ◽  
Horace Norrell
Keyword(s):  
Intraoperative Monitoring ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Class Iii ◽  
Tumor Removal ◽  
Eighth Cranial Nerve ◽  
Nerve Monitoring ◽  
Eighth Nerve ◽  
Auditory Evoked Response ◽  
Acoustic Neuromas

Since the advent of brainstem auditory evoked response audiometry and computerized tomography, small acoustic neuromas are more frequently found. Often the patient has serviceable hearing, which we would like to preserve during complete tumor removal. Since 1978, sixteen patients with acoustic neuromas have been operated upon through the retrosigmoid suboccipital approach, with the goal of hearing preservation. In 1983, we began using intraoperative direct eighth nerve monitoring, which produced a rapid assessment of cochlear nerve function during the excision of small acoustic neuromas. The tumors varied in size from intracanalicular lesions to one lesion with a 3.0 cm protrusion medial to the porus acousticus. In eight of sixteen cases, intraoperative monitoring was used, and in four of the patients hearing was preserved. In eight cases, intraoperative monitoring was not used, and hearing was preserved in only two patients. The overall success rate—in total tumor removal with hearing preservation—was 37%. Hearing was preserved in six of eight patients who had tumors which measured less than 1.5 cm. In this group of cases, two of the patients had a Class I good hearing result (PTA 0 to 30 dB and 70 to 100% discrimination), one patient had Class III nonserviceable hearing, (PTA 65 to 75 dB and 25 to 45% discrimination), and three patients had Class IV poor hearing, (PTA 80 to 100 dB and 0 to 20% discrimination). We found that continuous monitoring of direct eighth-nerve-evoked action potentials were extremely valuable and rapidly indicated reversible cochlear nerve trauma.

scholarly journals Cochlear Nerve Monitoring During Cerebellopontine Angle Operations

1988 ◽  
Vol 15 (1) ◽  
pp. 68-72 ◽  
Author(s):  
D.W. Rowed ◽  
J.M. Nedzelski ◽  
M.Z. Cashman ◽  
S. Stanton ◽  
R.V. Harrison
Keyword(s):  
Acoustic Neuroma ◽  
Action Potentials ◽  
Intraoperative Monitoring ◽  
Cerebellopontine Angle ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Nerve Function ◽  
Vestibular Neurectomy ◽  
Nerve Monitoring ◽  
Small Arteries

ABSTRACT:The authors present their experience with intraoperative monitoring of cochlear nerve action potentials (AP) in 30 adult patients. Operative procedures were acoustic neuroma excision with attempted hearing preservation and selective vestibular neurectomy in patients with incapacitating Meniere's disease and serviceable hearing (SRT<50 db, discrimination >60%). Loss of AP is detected rapidly and has been demonstrated after manipulation of the cochlear nerve and after coagulation of small arteries on the tumour capsule. Presence of an AP at the end of the procedure usually correlates with postoperative preservation of hearing. AP monitoring appears to be a reliable means of detecting potentially reversible changes in cochlear nerve function intraoperatively.

Preservation of hearing in patients undergoing excision of acoustic neuromas and other cerebellopontine angle tumors

1985 ◽  
Vol 63 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Charles H. Tator ◽  
Julian M. Nedzelski
Keyword(s):  
Tumor Size ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Consecutive Series ◽  
Speech Discrimination ◽  
Content Type ◽  
Acoustic Neuromas ◽  
Fine Print

✓ Microsurgical techniques have made it possible to identify and preserve the cochlear nerve from its origin at the brain stem and along its course through the internal auditory canal in patients undergoing removal of small or medium-sized acoustic neuromas or other cerebellopontine angle (CPA) tumors. In a consecutive series of 100 patients with such tumors operated on between 1975 and 1981, an attempt was made to preserve the cochlear nerve in 23. The decision to attempt to preserve hearing was based on tumor size and the degree of associated hearing loss. In cases of unilateral acoustic neuroma, the criteria for attempted preservation of hearing were tumor size (2.5 cm or less), speech reception threshold (50 dB or less), and speech discrimination score (60% or greater). In patients with bilateral acoustic neuromas or tumors of other types, the size and hearing criteria were significantly broadened. All patients were operated on through a suboccipital approach. Hearing was preserved postoperatively in six (31.6%) of the 19 patients with unilateral acoustic neuromas, although the cochlear nerve was preserved in 16. Of the six patients with postoperative hearing, three retained excellent hearing, and the other three had only sound awareness and poor discrimination. Hearing was preserved in three cases with other CPA tumors, including an epidermoid cyst and small petrous meningiomas in the internal auditory canal. Of the two cases with bilateral tumors, hearing was preserved in one. Of the 23 patients in whom hearing preservation was attempted, nine (39.1%) had some postoperative hearing, which in six was equal to or better than the preoperative level. Thus, it is worthwhile to attempt hearing preservation in selected patients with CPA tumors.

Hearing preservation in medial vestibular schwannomas

2008 ◽  
Vol 109 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Christian Strauss ◽  
Barbara Bischoff ◽  
Johann Romstöck ◽  
Jens Rachinger ◽  
Stefan Rampp ◽  
...  
Keyword(s):  
Growth Pattern ◽  
Auditory Evoked Potentials ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Neck Surgery ◽  
Underlying Disease ◽  
Cochlear Nerve ◽  
Vestibular Schwannomas ◽  
Consecutive Series ◽  
Tumor Removal

Object Vestibular schwannomas (VSs) with no or little extension into the internal auditory canal have been addressed as a clinical subentity carrying a poor prognosis regarding hearing preservation, which is attributed to the initially asymptomatic intracisternal growth pattern. The goal in this study was to assess hearing preservation in patients who underwent surgery for medial VSs. Methods A consecutive series of 31 cases in 30 patients with medial VSs (mean size 31 mm) who underwent surgery between 1997 and 2005 via a suboccipitolateral route was evaluated with respect to pre- and postoperative cochlear nerve function, extent of tumor removal, and radiological findings. Intraoperative monitoring of brainstem auditory evoked potentials was performed in all patients with hearing. Patients were reevaluated at a mean of 30 months following surgery. Results Preoperative hearing function revealed American Academy of Otolaryngology–Head and Neck Surgery Foundation Classes A and B in 7 patients each, Class C in 4, and D in 9. Four patients presented with deafness. Hearing preservation was achieved in 10 patients (Classes A–C in 2 patients each, and Class D in 4 patients). Tumor removal was complete in all patients with hearing preservation, except for 2 patients with neurofibromatosis. In 4 patients a planned subtotal excision was performed due to the individual's age or underlying disease. In 1 patient a recurrent tumor was completely removed 3 years after the initial procedure. Conclusions The cochlear nerve in medial VSs requires special attention due to the atypical intracisternal growth pattern. Even in large tumors, hearing could be preserved in 37% of cases, since the cochlear nerve in medial schwannomas may not exhibit the adherence to the tumor capsule seen in tumors with comparable size involving the internal auditory canal.

Preservation of hearing in surgery for acoustic neuromas

1993 ◽  
Vol 78 (6) ◽  
pp. 864-870 ◽  
Author(s):  
Michael E. Glasscock ◽  
James W. Hays ◽  
Lloyd B. Minor ◽  
David S. Haynes ◽  
Vincent N. Carrasco
Keyword(s):  
Hearing Preservation ◽  
Middle Cranial Fossa ◽  
Senior Author ◽  
Speech Discrimination ◽  
Content Type ◽  
Auditory Evoked Response ◽  
Surgical Access ◽  
Acoustic Neuromas ◽  
Cranial Fossa ◽  
Fine Print

✓Preservation of hearing was attempted in 161 cases of histologically confirmed acoustic neuroma removed by the senior author between January 1, 1970, and September 30, 1991. There were 136 patients with unilateral tumors: 22 patients had bilateral tumors (neurofibromatosis 2) and underwent a total of 25 procedures. Hearing was initially preserved in 35% of patients with unilateral tumors and in 44% of those with bilateral tumors. Results are reported in terms of pre- and postoperative pure tone average and speech discrimination scores. Surgical access to the tumor was obtained via middle cranial fossa and suboccipital approaches. The latter has been used more often over the past 5 years because of a lower associated incidence of transient facial paresis. Persistent postoperative headaches have been the most common complication following the suboccipital approach. The results of preoperative brain-stem auditory evoked response (BAER) studies were useful in predicting the outcome of hearing preservation attempts. Patients with intact BAER waveform morphology and normal or delayed latencies had a higher probability of hearing preservation in comparison to those with abnormal preoperative BAER morphology.

Preservation of hearing after surgery for acoustic schwannomas: correlation between cochlear nerve function and operative findings

1994 ◽  
Vol 80 (5) ◽  
pp. 844-848 ◽  
Author(s):  
Hiromichi Umezu ◽  
Tadashi Aiba
Keyword(s):  
Tumor Size ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Hearing Level ◽  
Tumor Removal ◽  
Content Type ◽  
Acoustic Schwannoma ◽  
Operative Findings ◽  
Total Tumor Removal ◽  
Results Of Surgery

✓ The results of surgery in 66 patients with acoustic schwannoma in whom total tumor removal was accomplished are reviewed in terms of the relationships among tumor size, preoperative hearing level, operative findings (including the shape and location of the cochlear nerve at the tumor surface), and the extent of post-operative hearing preservation. Both tumor size and the preoperative hearing level were correlated with the shape of the cochlear nerve, which more frequently formed a solid bundle when the tumor was small or the preoperative hearing was excellent. Hearing was retained postoperatively only in cases in which the nerve formed a solid bundle and could be differentiated and separated from the tumor capsule without difficulty. These findings suggest that tumor size and preoperative hearing level, which have been reported to be the main prognostic factors of postoperative hearing preservation, may influence the results of surgery for acoustic schwannoma through the shape of the cochlear nerve.

Hearing preservation in acoustic neuroma surgery: importance of adhesion between the cochlear nerve and the tumor

2002 ◽  
Vol 97 (2) ◽  
pp. 337-340 ◽  
Author(s):  
Takuzou Moriyama ◽  
Takanori Fukushima ◽  
Katsuyuki Asaoka ◽  
Pierre-Hugues Roche ◽  
David M. Barrs ◽  
...  
Keyword(s):  
Acoustic Neuroma ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Significant Prognostic Factor ◽  
Speech Discrimination ◽  
Middle Fossa ◽  
Content Type ◽  
Middle Fossa Approach ◽  
Acoustic Neuromas ◽  
Fine Print

Object. To evaluate the possible prognostic factors for hearing preservation, the authors retrospectively reviewed the results of 30 consecutive acoustic neuroma operations in which hearing preservation was attempted, in a total series of 63 acoustic neuromas. Methods. Intracanalicular tumors or those that extended less than 3 mm outside the porus acusticus (10 cases) were resected via the middle fossa approach. The retrosigmoid approach was used for tumors exceeding the limits for the middle fossa approach (20 cases). Overall, hearing was preserved (pure tone average ≤ 50 dB and speech discrimination score ≥ 50%) in 21 patients (70%). There were 11 patients with severe adhesion between the cochlear nerve and tumor capsule, and 19 without. Hearing was preserved postoperatively in only two (18.2%) of 11 patients with severe adhesion, whereas all 19 without severe adhesion had hearing preservation. Conclusions. The presence or absence of severe adhesion in the interface between the cochlear nerve and the tumor might be the most significant prognostic factor for hearing preservation postsurgery.

scholarly journals Does Attempt at Hearing Preservation Microsurgery of Vestibular Schwannoma Affect Postoperative Tinnitus?

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Martin Chovanec ◽  
Eduard Zvěřina ◽  
Oliver Profant ◽  
Zuzana Balogová ◽  
Jan Kluh ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Vestibular Schwannoma ◽  
Hearing Preservation ◽  
Cochlear Nerve ◽  
Hearing Level ◽  
Eighth Cranial Nerve ◽  
A Prospective Study ◽  
Tumor Consistency ◽  
Neurovascular Structures ◽  
New Onset

Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery via the retrosigmoid-transmeatal approach with special reference to the postoperative tinnitus outcome.Material and Methods. A prospective study was performed in 89 consecutive patients with unilateral vestibular schwannoma indicated for microsurgery. Patient and tumor related parameters, pre- and postoperative hearing level, intraoperative findings, and hearing and tinnitus handicap inventory scores were analyzed.Results. Cochlear nerve integrity was achieved in 44% corresponding to preservation of preoperatively serviceable hearing in 47% and useful hearing in 21%. Main prognostic factors of hearing preservation were grade/size of tumor, preoperative hearing level, intraoperative neuromonitoring, tumor consistency, and adhesion to neurovascular structures. Microsurgery led to elimination of tinnitus in 66% but also new-onset of the symptom in 14% of cases. Preservation of useful hearing and neurectomy of the eighth cranial nerve were main prognostic factors of tinnitus elimination. Preservation of cochlear nerve but loss of preoperative hearing emerged as the main factor for tinnitus persistence and new onset tinnitus. Decrease of THI scores was observed postoperatively.Conclusions. Our results underscore the importance of proper pre- and intraoperative decision making about attempt at hearing preservation versus potential for tinnitus elimination/risk of new onset of tinnitus.

Intraoperative Cochlear Nerve Monitoring for Vestibular Schwannoma Resection and Simultaneous Cochlear Implantation in Neurofibromatosis Type 2: A Case Series

2021 ◽  
Author(s):  
Margaret J Butler ◽  
Cameron C Wick ◽  
Matthew A Shew ◽  
Michael R Chicoine ◽  
Amanda J Ortmann ◽  
...  
Keyword(s):  
Vestibular Schwannoma ◽  
Cochlear Implantation ◽  
Case Series ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Cochlear Nerve ◽  
Tumor Removal ◽  
Nerve Monitoring ◽  
Brainstem Response

Abstract BACKGROUND Neurofibromatosis type 2 (NF2) often results in profound hearing loss and cochlear implantation is an emerging hearing rehabilitation option. However, cochlear implant (CI) outcomes in this population vary, and intraoperative monitoring to predict cochlear nerve viability and subsequent outcomes is not well-established. OBJECTIVE To review the use of intraoperative electrically evoked cochlear nerve monitoring in patients with NF2 simultaneous translabyrinthine (TL) vestibular schwannoma (VS) resection and cochlear implantation. METHODS A retrospective review was performed of 3 patients with NF2 that underwent simultaneous TL VS resection and cochlear implantation with electrical auditory brainstem response (eABR) measured throughout tumor resection. Patient demographics, preoperative assessments, surgical procedures, and outcomes were reviewed. RESULTS Patients 1 and 3 had a reliable eABR throughout tumor removal. Patient 2 had eABR pretumor removal, but post-tumor removal eABR presence could not be reliably determined because of electrical artifact interference. All patients achieved auditory percepts upon CI activation. Patients 1 and 2 experienced a decline in CI performance after 1 yr and after 3 mo, respectively. Patient 3 continues to perform well at 9 mo. Patients 2 and 3 are daily users of their CI. CONCLUSION Cochlear implantation is attainable in cases of NF2-associated VS resection. Intraoperative eABR may facilitate cochlear nerve preservation during tumor removal, though more data and long-term outcomes are needed to refine eABR methodology and predictive value for this population.

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