Lars Leksell Center for Gamma Surgery, Department of Neurological Surgery, University of Virginia Health Sciences System, Charlottesville, Virginia 22908, USA.
Neurosurgery. 2010 Jul;67(1):55-64; discussion 64. doi: 10.1227/01.neu.0000370204.68711.ac.
The causes of failure after an initial Gamma procedure were studied, along with imaging and clinical outcomes, in a series of 140 patients with cerebral arteriovenous malformations (AVMs) treated with repeat Gamma Knife surgery (GKS).
Causes of initial treatment failure included inaccurate nidus definition in 14 patients, failure to fill part of the nidus as a result of hemodynamic factors in 16, recanalization of embolized AVM compartments in 6, and suboptimal dose (<20 Gy) in 23. Nineteen patients had repeat GKS for subtotal obliteration of AVMs. In 62 patients, the AVM failed to obliterate despite correct target definition and adequate dose. At the time of retreatment, the nidus volume ranged from 0.1 to 6.9 cm3 (mean, 1.4 cm3), and the mean prescription dose was 20.3 Gy.
Repeat GKS yielded a total angiographic obliteration in 77 patients (55%) and subtotal obliteration in 9 (6.4%). In 38 patients (27.1%), the AVMs remained patent, and in 16 patients (11.4%), no flow voids were observed on magnetic resonance imaging. Clinically, 126 patients improved or remained stable, and 14 experienced deterioration (8 resulting from a rebleed, 2 caused by persistent arteriovenous shunting, and 4 related to radiation-induced changes).
By using repeat GKS, we achieved a 55% angiographic cure rate. Although radiation-induced changes as visualized on magnetic resonance imaging occurred in 48 patients (39%), only 4 patients (3.6%) developed permanent neurological deficits. These findings may be useful in deciding the management of AVMs in whom total obliteration after initial GKS was not achieved.
对 140 例脑动静脉畸形（AVM）患者进行重复伽玛刀治疗的初步伽玛刀治疗失败的原因、影像学和临床结果进行研究。
初始治疗失败的原因包括 14 例患者的病灶定义不准确、16 例因血流动力学因素未能完全填充病灶、6 例栓塞的 AVM 部分再通、23 例剂量不足（<20Gy）。19 例患者因 AVM 次全闭塞而行重复伽玛刀治疗。62 例患者尽管正确定义了靶区并给予了足够的剂量，但 AVM 仍未闭塞。在重复治疗时，病灶体积为 0.1~6.9cm3（平均 1.4cm3），平均处方剂量为 20.3Gy。
重复伽玛刀治疗后，77 例患者（55%）完全闭塞，9 例（6.4%）次全闭塞。38 例患者（27.1%）AVM 仍保持通畅，16 例患者（11.4%）磁共振成像未见血流空影。临床方面，126 例患者改善或保持稳定，14 例患者病情恶化（8 例因再出血，2 例因持续动静脉分流，4 例与放射诱导变化有关）。
通过重复使用伽玛刀，我们获得了 55%的血管造影治愈率。尽管磁共振成像上显示 48 例（39%）患者出现放射性改变，但仅有 4 例（3.6%）患者出现永久性神经功能缺损。这些发现可能有助于决定对初次伽玛刀治疗后未能完全闭塞的 AVM 患者的治疗。
