J Neurol Surg B Skull Base 2021; 82(04): 456-460
DOI: 10.1055/s-0040-1713103
Original Article

Facial Nerve Adherence in Vestibular Schwannomas: Classification and Radiological Predictors

Gustavo Simiano Jung
1  Department of Neurosurgery, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil
,
Guilherme Ramina Montibeller
1  Department of Neurosurgery, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil
,
Gabriel Schier de Fraga
2  Medicine Student, Faculdades Pequeno Príncipe, Curitiba, Paraná, Brazil
,
Thais dos Santos Rohde
3  Medicine Student, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
,
Ricardo Ramina
1  Department of Neurosurgery, Neurological Institute of Curitiba, Curitiba, Paraná, Brazil
› Author Affiliations

Abstract

Background Facial nerve palsy is one of the most frequent complications after resection of vestibular schwannomas (VS). Several mechanisms have been implicated in the poor postoperative facial nerve outcome. Adherence between the facial nerve and tumor capsule is one of the most relevant factors. There is no clear preoperative parameter permitting identification of these adhesions.

Objective The aim of this study was to identify the correlation between the grade of adherence of the facial nerve to the tumor capsule and its functional outcome after VS resection.

Methods A total of 26 patients with sporadic VS (tumor sized T3, T4A, and T4B according to Hannover classification) were evaluated. Grade of adherence of the facial nerve to the tumor capsule was checked during surgery and graduated according to a proposed scale into 1 to 3 different grades. Facial nerve function was assessed postoperatively and after 1-year follow-up. Size of tumor according to Hannover classification, presence of cystic components, “cerebrospinal fluid (CSF) cleft sign,” and the contour of tumor capsule were tested as radiological predictors of grade of adherence to the facial nerve.

Results and Conclusion Only Grade 2 (11 cases) and 3 (15 cases) of adherence were seen in large VS. Lower grade of adherence was associated with good facial nerve outcome after 1-year follow-up (p = 0.029). Presence of the “CSF cleft sign” and regular contour of tumor capsule were independent predictors of adherence. When both factors were associated, sensitivity and specificity of this method were 83 and 80%, respectively.

Authors' Contributions

G.S.J. supported in drafting the article or revising it critically for important intellectual content. G.S.J., G.R.M., G.S.F., and T.S.R. dedicated in substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data. R.R. prepared final approval of the version to be published.




Publication History

Received: 05 November 2019

Accepted: 12 April 2020

Publication Date:
01 July 2020 (online)

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