Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery.
Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery.
复制标题
伽玛刀手术治疗前庭神经鞘瘤患者的听力保留。
作者：
A. Baschnagel;Peter Y. Chen;D. Bojrab;D. Pieper;J. Kartush;O. Didyuk;I. Naumann;A. Maitz;I. Grills
对象
前庭神经鞘瘤患者伽玛刀手术（GKS）后的听力损失与耳蜗的辐射剂量有关。本研究的目的是评估接受 GKS 治疗的 VS 患者的可用听力保留，并确定可用听力损失是否与耳蜗剂量相关。
方法
40 名听力正常的前庭神经鞘瘤患者接受了 GKS 治疗，中位边缘剂量为 12.5 Gy（范围 12.5-13 Gy）至 50% 等剂量体积。在 GKS 之前和之后第 1、3 和 6 个月前瞻性地进行听力测定，此后每 6 个月进行一次。听力保护基于纯音平均 (PTA) 和言语辨别 (SD)。可用听力定义为 PTA 小于 50 dB，SD 大于 50%。
结果
中位耳蜗最大剂量和平均剂量分别为 6.9 Gy（范围 1.6-16 Gy）和 2.7 Gy（范围 0.7-5.0 Gy）。中位听力学随访时间为 35 个月（范围 6-58 个月），维持可用听力的 1 年、2 年和 3 年精算率分别为 93%、77% 和 74%。平均耳蜗剂量低于 2 Gy 的患者均未出现可用听力损失 (p = 0.035)。接受平均耳蜗剂量低于 3 Gy 的患者的 2 年听力保留率为 91%，而接受平均耳蜗剂量为 3 Gy 或更高的患者的 2 年听力保留率为 59% (p = 0.029)。超过 25% 的耳蜗接受 3 Gy 或以上辐射的人听力损失率较高 (p = 0.030)。可用听力损失与年龄、肿瘤大小、GKS PTA 前、GKS SD 前、GKS Gardner-Robertson 分级前、最大耳蜗剂量或接受 5 Gy 的耳蜗体积百分比之间不存在统计学显着相关性。在多变量分析中，平均耳蜗剂量为 3 Gy 或更高时，可用听力损失呈显着趋势 (p = 0.074)。 24 个月时局部控制率为 100%。没有患者出现面部或三叉神经功能障碍。
结论
中位平均耳蜗剂量为 2.7 Gy，大多数听力可用的患者在 GKS 后 3 年后仍保留可用听力。平均耳蜗剂量低于 3 Gy 与较高的可用听力保留相关。
OBJECT
Hearing loss after Gamma Knife surgery (GKS) in patients with vestibular schwannoma has been associated with radiation dose to the cochlea. The purpose of this study was to evaluate serviceable hearing preservation in patients with VS who were treated with GKS and to determine if serviceable hearing loss can be correlated with the dose to the cochlea.
METHODS
Forty patients with vestibular schwannoma with serviceable hearing were treated using GKS with a median marginal dose of 12.5 Gy (range 12.5-13 Gy) to the 50% isodose volume. Audiometry was performed prospectively before and after GKS at 1, 3, and 6 months, and then every 6 months thereafter. Hearing preservation was based on pure tone average (PTA) and speech discrimination (SD). Serviceable hearing was defined as PTA less than 50 dB and SD greater than 50%.
RESULTS
The median cochlear maximum and mean doses were 6.9 Gy (range 1.6-16 Gy) and 2.7 Gy (range 0.7-5.0 Gy), respectively. With a median audiological follow-up of 35 months (range 6-58 months), the 1-, 2-, and 3-year actuarial rates of maintaining serviceable hearing were 93%, 77%, and 74%, respectively. No patient who received a mean cochlear dose less than 2 Gy experienced serviceable hearing loss (p = 0.035). Patients who received a mean cochlear dose less than 3 Gy had a 2-year hearing preservation rate of 91% compared with 59% in those who received a mean cochlear dose of 3 Gy or greater (p = 0.029). Those who had more than 25% of their cochlea receiving 3 Gy or greater had a higher rate of hearing loss (p = 0.030). There was no statistically significant correlation between serviceable hearing loss and age, tumor size, pre-GKS PTA, pre-GKS SD, pre-GKS Gardner-Robertson class, maximum cochlear dose, or the percentage of cochlear volume receiving 5 Gy. On multivariate analysis there was a trend toward significance for serviceable hearing loss with a mean cochlear dose of 3 Gy or greater (p = 0.074). Local control was 100% at 24 months. No patient developed facial or trigeminal nerve dysfunction.
CONCLUSIONS
With a median mean cochlear dose of 2.7 Gy, the majority of patients with serviceable hearing retained serviceable hearing 3 years after GKS. A mean cochlear dose less than 3 Gy was associated with higher serviceable hearing preservation.