A-train clusters and the intermedius nerve in vestibular schwannoma patients

Rampp, Stefan; Illert, Jörg; Krempler, Katja; Strauß, Christian; Prell, Julian

doi:10.1016/j.clinph.2019.02.014

Cited by 7 publications

(8 citation statements)

References 25 publications

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“…Our previous studies demonstrated that a separate NI can give rise to an exceeding amount of A-trains not related to postoperative palsy [ 6 , 11 ], which limits outcome estimation based on free-running EMG alone. Since observation of a separate intermedius is related to tumor size [ 11 ], which itself yields predictive information [ 4 , 17 , 18 ], we hypothesized that considering this interaction could improve outcome estimation.…”

Section: Discussionmentioning

confidence: 99%

“…Extending automated marking [ 3 ], on- and offsets of individual A-trains were marked. In addition, A-train clusters [ 11 ] were identified visually. Subsequently, the durations of all A-train events were summed up per channel, yielding a total of 9 traintime values for each patient.…”

Section: Methodsmentioning

confidence: 99%

“…Potentially due to the low functional importance of intermedius motor fibers, this is frequently not accompanied by respective deficits [ 6 ]. Unfortunately, characteristics of “intermedius” A-trains are not significantly different from “facial” A-trains [ 11 ], which prevents differentiation of the two entities. Instead, so-called A-train “clusters”, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…Instead, so-called A-train “clusters”, i.e. A-trains occurring in most recording channels within a short time are more frequent in patients with separate NI on a group level [ 11 ]. In addition, the observation of a separate NI increases with larger tumor size, however is rare in cases with very large tumors [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

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Neural networks for estimation of facial palsy after vestibular schwannoma surgery

Rampp

Holze

Scheller

et al. 2022

J Clin Monit Comput

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Purpose Facial nerve damage in vestibular schwannoma surgery is associated with A-train patterns in free-running EMG, correlating with the degree of postoperative facial palsy. However, anatomy, preoperative functional status, tumor size and occurrence of A-trains clusters, i.e., sudden A-trains in most channels may further contribute. In the presented study, we examine neural networks to estimate postoperative facial function based on such features. Methods Data from 200 consecutive patients were used to train neural feed-forward networks (NN). Estimated and clinical postoperative House and Brackmann (HB) grades were compared. Different input sets were evaluated. Results Networks based on traintime, preoperative HB grade and tumor size achieved good estimation of postoperative HB grades (chi2 = 54.8), compared to using tumor size or mean traintime alone (chi2 = 30.6 and 31.9). Separate intermediate nerve or detection of A-train clusters did not improve performance. Removal of A-train cluster traintime improved results (chi2 = 54.8 vs. 51.3) in patients without separate intermediate nerve. Conclusion NN based on preoperative HB, traintime and tumor size provide good estimations of postoperative HB. The method is amenable to real-time implementation and supports integration of information from different sources. NN could enable multimodal facial nerve monitoring and improve postoperative outcomes.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neural networks for estimation of facial palsy after vestibular schwannoma surgery

Rampp

Holze

Scheller

et al. 2022

J Clin Monit Comput

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“…Presently, electrophysiological monitoring is used routinely to protect the facial nerve during acoustic neuroma operations (1)(2)(3)(4). Protecting the facial nerve comprises locating it and predicting its functioning (5,6).…”

Section: Introductionmentioning

confidence: 99%

Electrophysiological mapping and assessment of facial nerve functioning during acoustic neuroma operations

Li¹,

Bao²,

Liang³

et al. 2021

Ann Transl Med

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Background: Electrophysiological monitoring is used routinely to protect the facial nerve during acoustic neuroma surgery. This study aimed to clarify the relationship between the facial nerve's electrophysiological monitoring parameters and its function after surgery.Methods: Fifty-two patients with acoustic neuroma who underwent surgery were included. After localizing the facial nerve, its monitoring results during surgeries performed at our center were analyzed. Postoperative nerve functioning was correlated with the stimulation threshold of the facial nerve's proximal segment, proximal-to-distal amplitude ratio of the facial nerve, and proximal stimulation amplitude. Receiveroperating characteristic curves of the three parameters were calculated.Results: Electrical stimulation accurately described the facial nerve's anatomic distribution after the depth of anesthesia was assessed via accessory nerve stimulation. The data recorded after resection showed that a higher proximal-to-distal amplitude ratio was associated with better facial nerve functioning (P=0.037). A lower stimulation threshold of the proximal segment correlated with better facial nerve functioning (P=0.038). Conclusions:The most sensitive index to predict postoperative nerve functioning is the facial nerve's proximal-to-distal amplitude ratio. Accessory nerve stimulation can determine the appropriate depth of anesthesia, Electromyography (EMG) monitoring of the facial nerve during acoustic neuroma surgery can protect it effectively.

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