Background: The combination of intralabyrinthine schwannoma (ILS) removal and cochlear implantation is the standard of care after surgical resection for audiological rehabilitation. Intracochlear ILS is not only the most frequent tumor in this group of schwannomas, but it is also, to some degree, surgically the most challenging because of its position behind the modiolus. Recent developments in the knowledge of implant position, implant magnet choice, and magnetic resonance imaging (MRI) sequences make an MRI follow-up after surgical removal possible. Thus far, no results are known about the surgical success and residual rate of these kind of tumors. The aim of the present study was to perform an early MRI follow-up for the evaluation of residual or recurrent intracochlear ILS after surgical removal and cochlear implantation. Methods: In a retrospective study, we evaluated seven patients after an intracochlear ILS removal and single-stage cochlear implantation with a mean period of 13.4 months post surgery with a 3T T1 GAD 2 mm sequence for a residual ILS. Patients were operated on using an individualized technique concept. Results: In six out of seven cases, 3 T T1 GAD 2 mm MRI follow-up showed no residual or recurrent tumor. In one case, a T1 signal indicated a tumor of the upper inner auditory canal (IAC) at the MRI follow up. Conclusion: MRI follow-up as a quality control tool after ILS removal and cochlear implantation is highly important to exclude residual tumors. Long-term MRI evaluation results are needed and can be obtained under consideration of implant position, implant magnet, and MRI sequence choice. A preoperative MRI slice thickness less than 2 mm can be recommended to visualize possible modiolar and IAC expansion.

中文翻译：

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耳蜗内迷路神经鞘瘤切除和人工耳蜗植入术后的质量控制

背景：迷路内神经鞘瘤 (ILS) 切除和人工耳蜗植入相结合是听力康复手术切除后的护理标准。耳蜗内 ILS 不仅是这组神经鞘瘤中最常见的肿瘤，而且在某种程度上，由于其位置在耳轮后面，因此在手术上也是最具挑战性的。植入物位置、植入物磁铁选择和磁共振成像 (MRI) 序列知识的最新发展使手术切除后的 MRI 随访成为可能。迄今为止，尚无关于此类肿瘤的手术成功率和残留率的结果。本研究的目的是进行早期 MRI 随访，以评估手术切除和人工耳蜗植入后残留或复发的耳蜗内 ILS。方法：在一项回顾性研究中，我们评估了 7 名接受耳蜗内 ILS 移除和单阶段人工耳蜗植入的患者，术后平均时间为 13.4 个月，使用 3T T1 GAD 2 mm 序列治疗残余 ILS。使用个性化技术概念对患者进行手术。结果：在七分之六的病例中，3 T T1 GAD 2 mm MRI 随访显示没有残留或复发的肿瘤。在一个案例中，T1 信号表明在 MRI 随访中存在上内耳道 (IAC) 肿瘤。结论：作为 ILS 移除和人工耳蜗植入后质量控制工具的 MRI 随访对于排除残留肿瘤非常重要。需要长期的 MRI 评估结果，可以在考虑植入物位置、植入物磁铁和 MRI 序列选择的情况下获得。