Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications

Youssef, A. Samy; Downes, Angela E.

doi:10.3171/2009.8.focus09144

Cited by 75 publications

(73 citation statements)

References 35 publications

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“…4,7 Patients received intraoperative electrophysiological monitoring and lower radiation doses (12 Gy to the 50% isodose line), techniques that are shown to have a better prognosis of facial nerve preservation, which may contribute to the efficacy of our facial nervesparing technique. 21,22 Combining surgery for good control of tumor growth with GKS for tumor expansion prevents facial nerve deficits in patients who might otherwise have a significant risk of facial nerve dysfunction.…”

Section: Discussionmentioning

confidence: 99%

“…17,18 Intraoperative monitoring of the facial nerve is the key for optimal facial nerve preservation, even though not all patients' clinical courses correlate with their intraoperative electrophysiological results. 18,22 Radiosurgical dosing of < 13 Gy also correlates with decreased risk of facial palsy, which is a useful consideration in Gamma Knife therapy for VSs. 21 Treatment failure is a significant concern in treating VS.…”

mentioning

confidence: 99%

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Efficacy of facial nerve–sparing approach in patients with vestibular schwannomas

Haque

Wojtasiewicz²,

Gigante³

et al. 2011

JNS

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Object. The goal of this article was to show that a combination of facial nerve-sparing microsurgical resection and Gamma Knife surgery (GKS) for expansion of any residual tumor can preserve good facial nerve function in patients with recurrent vestibular schwannoma (VS).Methods. Records of individuals treated by a single surgeon with a facial nerve-sparing technique for a VS between 1998 and 2009 were retrospectively analyzed for tumor recurrence. Of the 383 patients treated for VS, 151 underwent microsurgical resection, and 20 (13.2%) of these patients required postoperative retreatment for a significant expansion of residual tumor after microsurgery. These 20 patients were re-treated with GKS.Results. The rate of preservation of good facial nerve function (Grade I or II on the House-Brackmann scale) in patients treated with microsurgery for VS was 97%. Both subtotal and gross-total resection had excellent facial nerve preservation rates (97% vs 96%), although subtotal resection carried a higher risk that patients would require retreatment. In patients re-treated with GKS after microsurgery, the rate of facial nerve preservation was 95%.Conclusions. In patients with tumors that cannot be managed with radiosurgery alone, a facial nerve-sparing resection followed by GKS for any significant regrowth provides excellent facial nerve preservation rates. (DOI: 10.3171/2011.7.JNS101921) key WoRDs • vestibular schwannoma • facial nerve • Gamma Knife surgery • tumor recurrence • peripheral nerve 917Abbreviations used in this paper: GKS = Gamma Knife surgery; GTR = gross-total resection; HB = House-Brackmann; IAC = internal auditory canal; NF2 = neurofibromatosis Type 2; STR = subtotal resection; VS = vestibular schwannoma.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Efficacy of facial nerve–sparing approach in patients with vestibular schwannomas

Haque

Wojtasiewicz²,

Gigante³

et al. 2011

JNS

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“…Lower final stimulus thresholds, higher CMAP response amplitudes, and lower ratios of proximal to distal stimulation thresholds have been correlated with better postoperative facial nerve outcomes. 12,18 Recently, Prell et al 15 found that a real-time CMAP measure of train potential time (the A train) is relevant to facial nerve outcomes. Specifically, they found that if the total accumulated A train potential time was greater than 2.5 seconds, consideration should be given to limiting further dissection, because postoperative facial nerve weakness was more likely.…”

Section: Facial Nerve Outcomesmentioning

confidence: 99%

Pitfalls in intraoperative nerve monitoring during vestibular schwannoma surgery

Kircher

Kartush²

2012

FOC

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Despite the widespread acceptance of intraoperative neurophysiological monitoring in skull base surgery over the last 2 decades, surgeon training in the technical and interpretive aspects of nerve monitoring has been conspicuously lacking. Inadequate fundamental knowledge of neurophysiological monitoring may lead to misinterpretations and an inability to troubleshoot system errors. Some surgeons perform both the technical and interpretive aspects of monitoring themselves while others enjoin coworkers (surgical residents, nurses, anesthetists, or a separate monitoring service) to perform the technical portion. Regardless, the surgeon must have a thorough understanding to avoid potential medical and legal pitfalls because poor monitoring is worse than no monitoring. A structured curriculum and protocol in both the technical and interpretive aspects of monitoring is recommended for all personnel involved in the monitoring process. This paper details the technical, interpretive, and surgical correlates necessary for optimal intraoperative nerve monitoring during vestibular schwannoma surgery with an emphasis on electromyographic monitoring for facial and recurrent laryngeal nerves. Just as the American Society of Anesthesiologists' 1986 “Standards for Basic Anesthetic Monitoring” became a useful tool for both patients and anesthesiologists, impending guidelines in intraoperative neurophysiological monitoring should likewise become an important instrument for optimizing intraoperative neurophysiological monitoring.

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“…[3][4][5][6]15,23,25,45,49,56,58,61,65,67,112,115,117,118,124,130,131 However, IONM may demonstrate improvements in structural and functional preservation of the cranial nerves during these operations. 139,148 Several IONM techniques have been developed and evaluated with particular focus on CN VII and VIII preservation. Among these methods, the most frequently Intraoperative neuromonitoring techniques in the surgical management of acoustic neuromas used are EMG for the facial nerve and BAEP monitoring for the vestibulocochlear nerve.…”

mentioning

confidence: 99%

Intraoperative neuromonitoring techniques in the surgical management of acoustic neuromas

Oh¹,

Nagasawa²,

Fong³

et al. 2012

FOC

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Unfavorable outcomes such as facial paralysis and deafness were once unfortunate probable complications following resection of acoustic neuromas. However, the implementation of intraoperative neuromonitoring during acoustic neuroma surgery has demonstrated placing more emphasis on quality of life and preserving neurological function. A modern review demonstrates a great degree of recent success in this regard. In facial nerve monitoring, the use of modern electromyography along with improvements in microneurosurgery has significantly improved preservation. Recent studies have evaluated the use of video monitoring as an adjunctive tool to further improve outcomes for patients undergoing surgery. Vestibulocochlear nerve monitoring has also been extensively studied, with the most popular techniques including brainstem auditory evoked potential monitoring, electrocochleography, and direct compound nerve action potential monitoring. Among them, direct recording remains the most promising and preferred monitoring method for functional acoustic preservation. However, when compared with postoperative facial nerve function, the hearing preservation is only maintained at a lower rate. Here, the authors analyze the major intraoperative neuromonitoring techniques available for acoustic neuroma resection.

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Intraoperative neurophysiological monitoring in vestibular schwannoma surgery: advances and clinical implications

Cited by 75 publications

References 35 publications

Efficacy of facial nerve–sparing approach in patients with vestibular schwannomas

Efficacy of facial nerve–sparing approach in patients with vestibular schwannomas

Pitfalls in intraoperative nerve monitoring during vestibular schwannoma surgery

Intraoperative neuromonitoring techniques in the surgical management of acoustic neuromas

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