Surgical management of intraoperatively diagnosed facial nerve schwannoma located at internal auditory canal and cerebellopontine angle – our experiences of 14 cases

Abstract

Background

Facial nerve schwannomas located at internal auditory canal and cerebellopontine angle (IAC/CPA FNS) were diagnosed intraoperatively, it poses a therapeutic dilemma to the surgeon.

Objective

To report our experience in managing IAC/CPA FNS and to propose a treatment strategy.

Methods

A total of 14 patients with IAC/CPA FNS who were diagnosed intraoperatively and treated by operation between 2015 and 2019 were retrospectively studied.

Results

Unilateral hearing loss was the most common symptom and all these patients had normal facial nerve function preoperatively. Surgical approaches used in these patients including translabyrinthine (2 cases), retrosigmoid (RS) (11 cases), and middle cranial fossa (MCF) approach (1 case). Eight patients underwent partial resection, three patients underwent subtotal resection and three patients had complete tumor removal with facial nerve reconstruction. All partial resection patients and two patients underwent subtotal resection achieved a long-term HB grade I facial nerve function. The long-term facial nerve function of patients underwent complete resection and nerve grafting was no better than HB grade III.1 of the eight patients underwent partial resection experienced tumor regrowth during the follow-up.

Conclusions

Partial or subtotal resection for IAC/CPA FNS may provide an opportunity of retaining excellent facial nerve function. Regular postoperative imaging is helpful to monitor the recurrence.

Chinese abstract

背景：术中诊断出位于内耳道和桥小脑角的面神经神经鞘瘤（IAC / CPA FNS）, 给外科医生带来了治疗上的难题。

目的：报告我们在处理IAC / CPA FNS方面的经验并提出治疗策略。

方法：回顾性分析2015年至2019年间在手术中被诊断出并经手术治疗的14例IAC / CPA FNS患者。

结果：单侧听力减退是最常见的症状。所有这些患者术前均具有正常的面神经功能。对这些患者采用的手术方法包括经迷路（2例）, 乙状窦后（RS）（11例）和中颅窝（MCF）入路（1例）。 8例患者接受了部分切除, 3例接受了次全切除, 3例患者接受了全切除并接受面神经重建术。所有部分切除的患者和两名次全切除的患者均达到了长期的HB级I类面神经功能。全切除并接受神经移植的患者的长期面神经功能不超过HB III.1级。部分切除的8例患者在随访期间出现了肿瘤再生。

结论：IAC / CPA FNS的部分或次全切除术可能为保留优良的面神经功能提供了机会。定期术后影像检查有助于监测复发情况。

Keywords:

• Facial nerve schwannoma
• internal auditory canal
• cerebellopontine angle
• management

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by Youth Fund of National Natural Science Foundation of China [Grant No. 81900932, No. 81400460], and Clinical Research Plan of SHDC [Grant No. SHDC2020CR1049B].