Continuous dynamic mapping to avoid accidental injury of the facial nerve during surgery for large vestibular schwannomas
- 230 Downloads
In vestibular schwannoma (VS) surgery postoperative facial nerve (CN VII) palsy is reducing quality of life. Recently, we have introduced a surgical suction device for continuous dynamic mapping to provide feedback during tumor resection without switching to a separate stimulation probe. The objective was to evaluate the reliability of this method to avoid CN VII injury. Continuous mapping for CN VII was performed in large VS (08/2014 to 11/2017) additionally to standard neurophysiological techniques. A surgical suction-and-mapping probe was used for surgical dissection and continuous monopolar stimulation. Stimulation was performed with 0.05–2 mA intensities (0.3 msec pulse duration, 2.0 Hz). Postoperative CNVII outcome was assessed by the House-Brackmann-Score (HBS) after 1 week and 3 months following surgery. Twenty patients with Koos III (n = 2; 10%) and Koos IV (n = 18; 90%) VS were included. Preoperative HBS was 1 in 19 patients and 2 in 1 patient. Dynamic mapping reliably indicated the facial nerve when resection was close to 5–10 mm. One week after surgery, 7 patients presented with worsening in HBS. At 3 months, 4 patients’ facial weakness had resolved and 3 patients (15%) had an impairment of CN VII (HBS 3 and 4). Of the 3 patients, near-total removal was attempted in 2. The continuous dynamic mapping method using an electrified surgical suction device might be a valuable additional tool in surgery of large VS. It provides real-time feedback indicating the presence of the facial nerve within 5–10 mm depending on stimulation intensity and may help in avoiding accidental injury to the nerve.
KeywordsElectrical nerve stimulation Facial nerve House-Brackmann score Intraoperative neurophysiological monitoring Motor evoked potential Vestibular schwannoma
We thank Anja Giger and Chantal Zbinden for medical illustration/editing the figures and Susan Kaplan for editing the manuscript.
Compliance with ethical standards
Conflict of interest statement
The mapping-suction device was developed by two of the authors (AR and KS). The University of Bern receives royalties from Inomed. The other authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
This study was approved by the local ethics committee (Project ID 2017–02325).
All patients signed the necessary consent forms.
- 2.Barzilai O, Lidar Z, Constantini S, Salame K, Bitan-Talmor Y, Korn A (2017) Continuous mapping of the corticospinal tracts in intramedullary spinal cord tumor surgery using an electrified ultrasonic aspirator. J Neurosurg Spine 27:161–168. https://doi.org/10.3171/2016.12.spine16985 CrossRefPubMedGoogle Scholar
- 4.Chen Z, Prasad SC, Di Lella F, Medina M, Piccirillo E, Taibah A, Russo A, Yin S, Sanna M (2014) The behavior of residual tumors and facial nerve outcomes after incomplete excision of vestibular schwannomas. J Neurosurg 120:1278–1287. https://doi.org/10.3171/2014.2.jns131497 CrossRefPubMedGoogle Scholar
- 5.Daniel RT, Tuleasca C, George M, Pralong E, Schiappacasse L, Zeverino M, Maire R, Levivier M (2017) Preserving normal facial nerve function and improving hearing outcome in large vestibular schwannomas with a combined approach: planned subtotal resection followed by gamma knife radiosurgery. Acta Neurochir 159:1197–1211. https://doi.org/10.1007/s00701-017-3194-0 CrossRefPubMedGoogle Scholar
- 7.Dong CC, Macdonald DB, Akagami R, Westerberg B, Alkhani A, Kanaan I, Hassounah M (2005) Intraoperative facial motor evoked potential monitoring with transcranial electrical stimulation during skull base surgery. Clin Neurophysiol 116:588–596. https://doi.org/10.1016/j.clinph.2004.09.013 CrossRefPubMedGoogle Scholar
- 17.Prell J, Rachinger J, Scheller C, Alfieri A, Strauss C, Rampp S (2010) A real-time monitoring system for the facial nerve. Neurosurgery 66:1064–1073; discussion 1073. https://doi.org/10.1227/01.neu.0000369605.79765.3e CrossRefPubMedGoogle Scholar
- 18.Prell J, Strauss C, Rachinger J, Alfieri A, Scheller C, Herfurth K, Rampp S (2014) Facial nerve palsy after vestibular schwannoma surgery: dynamic risk-stratification based on continuous EMG-monitoring. Clin Neurophysiol 125:415–421. https://doi.org/10.1016/j.clinph.2013.07.015 CrossRefPubMedGoogle Scholar
- 27.Sameshima T, Morita A, Tanikawa R, Fukushima T, Friedman AH, Zenga F, Ducati A, Mastronardi L (2013) Evaluation of variation in the course of the facial nerve, nerve adhesion to tumors, and postoperative facial palsy in acoustic neuroma. J Neurol Surg B Skull Base 74:39–43. https://doi.org/10.1055/s-0032-1329625 CrossRefPubMedGoogle Scholar
- 32.Seidel K, Beck J, Stieglitz L, Schucht P, Raabe A (2012) The warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors. J Neurosurg 118:287–296. https://doi.org/10.3171/2012.10.jns12895 CrossRefPubMedGoogle Scholar
- 34.Shiban E, Krieg SM, Obermueller T, Wostrack M, Meyer B, Ringel F (2015) Continuous subcortical motor evoked potential stimulation using the tip of an ultrasonic aspirator for the resection of motor eloquent lesions. J Neurosurg 123:301–306. https://doi.org/10.3171/2014.11.jns141555 CrossRefPubMedGoogle Scholar
- 35.Starnoni D, Daniel RT, Tuleasca C, George M, Levivier M, Messerer M (2018) Systematic review and meta-analysis of the technique of subtotal resection and stereotactic radiosurgery for large vestibular schwannomas: a “nerve-centered” approach. Neurosurg Focus 44:E4. https://doi.org/10.3171/2017.12.focus17669 CrossRefPubMedGoogle Scholar
- 38.Yang SY, Kim DG, Chung HT, Park SH, Paek SH, Jung HW (2008) Evaluation of tumour response after gamma knife radiosurgery for residual vestibular schwannomas based on MRI morphological features. J Neurol Neurosurg Psychiatry 79:431–436. https://doi.org/10.1136/jnnp.2007.119602 CrossRefPubMedGoogle Scholar
- 39.Yingling CD, Gardi JN (1992) Intraoperative monitoring of facial and cochlear nerves during acoustic neuroma surgery. Otolaryngol Clin N Am 25:413–448Google Scholar
- 40.Zou P, Zhao L, Chen P, Xu H, Liu N, Zhao P, Lu A (2014) Functional outcome and postoperative complications after the microsurgical removal of large vestibular schwannomas via the retrosigmoid approach: a meta-analysis. Neurosurg Rev 37:15–21. https://doi.org/10.1007/s10143-013-0485-7 CrossRefPubMedGoogle Scholar
- 41.Zumofen DW, Guffi T, Epple C, Westermann B, Krahenbuhl AK, Zabka S, Taub E, Bodmer D, Mariani L (2018) Intended near-total removal of Koos grade IV vestibular Schwannomas: reconsidering the treatment paradigm. Neurosurgery 82:202–210. https://doi.org/10.1093/neuros/nyx143 CrossRefPubMedGoogle Scholar