Awake craniotomy for assisting placement of auditory brainstem implant in NF2 patients

Abstract

Objectives: Auditory brainstem implants (ABIs) may be the only opportunity for patients with NF2 to regain some sense of hearing sensation. However, only a very small number of individuals achieved open-set speech understanding and high sentence scores. Suboptimal placement of the ABI electrode array over the cochlear nucleus may be one of main factors for poor auditory performance. In the current study, we present a method of awake craniotomy to assist with ABI placement.

Methods: Awake surgery and hearing test via the retrosigmoid approach were performed for vestibular schwannoma resections and auditory brainstem implantations in four patients with NF2. Auditory outcomes and complications were assessed postoperatively.

Results: Three of 4 patients who underwent awake craniotomy during ABI surgery received reproducible auditory sensations intraoperatively. Satisfactory numbers of effective electrodes, threshold levels and distinct pitches were achieved in the wake-up hearing test. In addition, relatively few electrodes produced non-auditory percepts. There was no serious complication attributable to the ABI or awake craniotomy.

Conclusions: It is safe and well tolerated for neurofibromatosis type 2 (NF2) patients using awake craniotomy during auditory brainstem implantation. This method can potentially improve the localization accuracy of the cochlear nucleus during surgery.

Chinese abstract

目的：听觉脑干植入体（ABIs）可能是NF2患者恢复某种听觉感受的唯一机会。然而, 只有极少数的人获得了开放情境下的言语理解和高句子评分。 ABI电极阵列在耳蜗核上的近优放置可能是听觉表现不佳的主要因素之一。在该研究中, 我们提出一种清醒状态开颅手术来辅助ABI的放置。

方法：对4例NF2患者进行了前庭神经鞘瘤切除术和听神经脑干植入术, 采用乙状窦法进行了清醒状态手术和听力检查。术后评估了听觉结果及并发症。

结果：4例在ABI手术期间接受清醒状态开颅手术的患者中有3例在术中获得可重复听力感觉。在醒后听力测试中, 取得令人满意的有效电极数量、阈值水平和明显的音高。另外, 相对较少的电极产生非听觉感知。无严重并发症源于ABI或清醒状态开颅手术。

结论：2型神经纤维瘤病（NF2）患者在听觉脑干植入期间接受清醒状态开颅手术, 这很安全且可忍受性良好。这种方法可以潜在地改善手术期间耳蜗核的定位准确性。

Keywords:

• Neurofibromatosis type 2
• auditory brainstem implant
• awake craniotomy

Acknowledgments

We thank Ruquan Han, Dexiang Wang and Shuo Zhang for their invaluable help. This work has been funded by the following grants: The National Science Foundation of China (grant number: 7112049), the National Science and Technology Support Program of the 12th Five-Year Plan of China (grant number: 2012BAI12B03), Beijing Program Foundation for the Talents (grant number: 2016000021469G216) and the Capital Health Development and Research Special Projects of Beijing (grant number: 2011-1015-01).

Disclosure statement

The authors declare no competing financial interests.