Department of Neurosurgery and Gamma Knife Radiosurgery, IRCCS San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 60, 20132, Milan, Italy.
Neuroimaging Research Unit, Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy.
Neurosurg Rev. 2021 Oct;44(5):2797-2808. doi: 10.1007/s10143-021-01474-9. Epub 2021 Jan 12.
Gamma Knife radiosurgery (GKRS) is a well-established safe and effective treatment for trigeminal neuralgia (TN) with high initial success rate (80-90%). Why the pain relief is progressively decreased with time is a matter of considerable debate. To investigate factors related to long-lasting pain relief, the authors conducted a retrospective analysis focusing on anatomical and radiosurgical related parameters, chosen according to literature review. One hundred and twelve patients with classical trigeminal neuralgia and follow-up longer than 12 months were selected from our institutional consecutive series of patients treated by GKRS. Patients were followed for a mean period of 61.5 ± 3.5 months (range, 12-126 months) to evaluate, as endpoints, long-term pain relief and hypoesthesia onset. The median maximum radiation dose was 80 Gy (range 70-90 Gy). Factors related to poor long-term pain relief were prescription dose < 80 Gy (p = 0.038), calibration dose rate < 2.5 Gy/min (p = 0.018), and distance between isocenter and trigeminal nerve emergence > 8 mm (p < 0.001). When analyzing patients who received 80 Gy as maximum dose without any sector blocking, we notice that ID < 2.7 mJ was predictive for longer period of pain control (p = 0.043). It was experienced also among patients in which a small volume of the nerve (< 35%) received more than 80% of the maximal dose, compared to those in which a larger volume of the nerve was irradiated with maximal dose (p 0.034). This last result was significant if the shot was 8 mm or less from the pons. Several single-patient anatomical and radiosurgical parameters should be considered to improve GKRS effectiveness.
伽玛刀放射外科（GKRS）是一种成熟的、安全有效的三叉神经痛（TN）治疗方法，初始成功率高（80-90%）。为什么疼痛缓解会随着时间的推移而逐渐下降，这是一个相当有争议的问题。为了研究与长期疼痛缓解相关的因素，作者进行了一项回顾性分析，重点关注根据文献综述选择的解剖学和放射外科相关参数。从我们机构连续接受 GKRS 治疗的患者系列中选择了 112 例具有典型三叉神经痛且随访时间超过 12 个月的患者进行回顾性分析。对这些患者进行了平均 61.5±3.5 个月（范围 12-126 个月）的随访，以评估长期疼痛缓解和感觉迟钝的发生作为终点。中位最大辐射剂量为 80 Gy（范围 70-90 Gy）。与长期疼痛缓解不良相关的因素包括处方剂量<80 Gy（p=0.038）、校准剂量率<2.5 Gy/min（p=0.018）和中心点与三叉神经出口之间的距离>8 mm（p<0.001）。当分析接受 80 Gy 作为最大剂量且无任何扇形阻断的患者时，我们注意到 ID<2.7 mJ 可预测更长的疼痛控制时间（p=0.043）。在神经体积较小（<35%）接受超过 80%最大剂量的患者中也观察到了这种情况，而在神经体积较大（>35%）接受最大剂量照射的患者中则没有（p=0.034）。如果照射距离脑桥 8 mm 或更近，这种结果更显著。应考虑几个单个患者的解剖学和放射外科参数，以提高 GKRS 的效果。
