Department of Otolaryngology, Far Eastern Memorial Hospital, New Taipei, Taiwan.
Departments of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
J Neurol Sci. 2019 Apr 15;399:30-35. doi: 10.1016/j.jns.2019.02.008. Epub 2019 Feb 6.
This study reviewed our experience in treating patients with vestibular schwannoma (VS) who had acute sensorineural hearing loss (ASHL) early after radiosurgery.
Seventy VS patients underwent cyberknife radiosurgery. Of them, 6 patients had ASHL early (<6 m) after radiosurgery (Group A), accounting for 8.6% prevalence. The remaining 64 patients without ASHL were assigned to Group B. Another 10 VS patients with tiny tumor and serviceable hearing adopted observation policy (Group C). All patients underwent a test battery for inner ear function, and tumor size was measured via MR imaging.
The mean hearing level of Group A was 39 ± 16 dB before radiosurgery, which deteriorated to 67 ± 14 dB at the onset of ASHL after radiosurgery. Three months after treatment for ASHL, hearing improvement was noted in only one patient (17%). Mean tumor volumes of Group A before and after ASHL were 1.54 ± 1.48 cc and 1.33 ± 1.04 cc, respectively, showing non-significant difference. Receiver operating characteristic curve analysis revealed that the optimal cutoff value for tumor size was 1.45 cm for predicting absence of ASHL, with a sensitivity of 96% and a specificity of 67%. In contrast, Group C with mean tumor size of 0.64 ± 0.15 cm adopted observation policy, and none of them had ASHL two years after diagnosis.
Prevalence of ASHL in VS patients early after radiosurgery is 8.6%, likely due to radiation injury to the cochlear nerve. Thus, when tumor size is <1.45 cm, serviceable hearing is the criteria for determining whether observation policy (with serviceable hearing) or radiosurgery (lack of serviceable hearing) is given. For those tumor sizes ranged 1.45-3.0 cm, radiosurgery is indicated regardless of hearing level.
本研究回顾了我们在颅神经外科手术中治疗早期出现前庭神经鞘瘤（VS）伴急性感觉神经性听力损失（ASHL）患者的经验。
70 例 VS 患者接受了 Cyberknife 放射外科手术。其中，6 例患者在放射外科手术后早期（<6 个月）出现 ASHL（A 组），占 8.6%的患病率。其余 64 例无 ASHL 的患者被分配到 B 组。另外 10 例肿瘤较小且听力尚可的 VS 患者采用观察策略（C 组）。所有患者均接受内耳功能测试，并通过磁共振成像测量肿瘤大小。
A 组患者在放射外科手术前的平均听力水平为 39±16dB，放射外科手术后 ASHL 发作时恶化至 67±14dB。在 ASHL 治疗 3 个月后，仅 1 例（17%）患者听力有所改善。A 组患者在 ASHL 前后的平均肿瘤体积分别为 1.54±1.48cc 和 1.33±1.04cc，无显著差异。受试者工作特征曲线分析显示，肿瘤大小的最佳截断值为 1.45cm，预测 ASHL 不存在的灵敏度为 96%，特异性为 67%。相比之下，采用观察策略的 C 组患者平均肿瘤大小为 0.64±0.15cm，两年后无一人出现 ASHL。
VS 患者放射外科手术后早期出现 ASHL 的患病率为 8.6%，可能是由于耳蜗神经受到放射损伤所致。因此，当肿瘤大小<1.45cm 时，听力是否可保留是决定采用观察策略（听力可保留）还是放射外科手术（听力丧失）的标准。对于肿瘤大小在 1.45-3.0cm 之间的患者，无论听力水平如何，均建议行放射外科手术。
