Choi Hyuk Jai, Choi Seok Keun, Lim Young Jin
Department of Neurosurgery, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea.
J Korean Neurosurg Soc. 2012 Dec;52(6):534-40. doi: 10.3340/jkns.2012.52.6.534. Epub 2012 Dec 31.
Brainstem arteriovenous malformation (AVM) is rare and radiosurgical management is complicated by the sensitivity of the adjacent neurological structures. Complete obliteration of the nidus is not always possible. We describe over 20 years of radiosurgical procedures for brainstem AVMs, focusing on clinical outcomes and radiosurgical techniques.
Between 1992 and 2011, the authors performed gamma knife radiosurgery (GKRS) in 464 cerebral AVMs. Twenty-nine of the 464 patients (6.3%) reviewed had brainstem AVMs. This series included sixteen males and thirteen females with a mean age of 30.7 years (range : 5-71 years). The symptoms that led to diagnoses were as follows : an altered mentality (5 patients, 17.3%), motor weakness (10 patients, 34.5%), cranial nerve symptoms (3 patients, 10.3%), headache (6 patients, 20.7%), dizziness (3 patients, 10.3%), and seizures (2 patients, 6.9%). Two patients had undergone a previous nidus resection, and three patients had undergone a previous embolization. Twenty-four patients underwent only GKRS. With respect to the nidus type and blood flow, the ratio of compact type to diffuse type and high flow to low flow were 17 : 12 and 16 : 13, respectively. In this series, 24 patients (82.8%) had a prior hemorrhage. The mean target volume was 1.7 cm(3) (range 0.1-11.3 cm(3)). The mean maximal and marginal radiation doses were 38.5 Gy (range 28.6-43.6 Gy) and 23.4 Gy (range 18-27 Gy), and the mean isodose profile was 61.3% (range 50-70%).
Twenty-four patients had brainstem AVMs and were followed for more than 3 years. Obliteration of the AVMs was eventually documented in 17 patients (70.8%) over a mean follow-up period of 77.5 months (range 36-216 months). With respect to nidus type and blood flow, the obliteration rate of compact types (75%) was higher than that of diffuse types (66.7%), and the obliteration rate of low flow AVMs (76.9%) was higher than that of high flow AVMs (63.6%) (p<0.05). Two patients (6.9%) with three hemorrhagic events suffered a hemorrhage during the follow-up period. The annual bleeding rate of AVM after GKRS was 1.95% per year. No adverse radiation effects or delayed cystic formations were found.
GKRS has an important clinical role in treatment of brainstem AVMs, which carry excessive surgical risks. Angiographic features and radiosurgical techniques using a lower maximal dose with higher isodose profiles are important for lesion obliteration and the avoidance of complications.
脑干动静脉畸形（AVM）较为罕见，放射外科治疗因邻近神经结构敏感而变得复杂。病灶完全闭塞并非总是可行。我们描述了20多年来针对脑干AVM的放射外科手术，重点关注临床结果和放射外科技术。
1992年至2011年期间，作者对464例脑AVM进行了伽玛刀放射外科手术（GKRS）。在464例接受评估的患者中，有29例（6.3%）患有脑干AVM。该系列包括16名男性和13名女性，平均年龄30.7岁（范围：5 - 71岁）。导致诊断的症状如下：意识改变（5例患者，17.3%）、运动无力（10例患者，34.5%）、颅神经症状（3例患者，10.3%）、头痛（6例患者，20.7%）、头晕（3例患者，10.3%）和癫痫发作（2例患者，6.9%）。2例患者曾接受过病灶切除术，3例患者曾接受过栓塞治疗。24例患者仅接受了GKRS。就病灶类型和血流情况而言，致密型与弥散型以及高流量与低流量的比例分别为17∶12和16∶13。在该系列中，24例患者（82.8%）曾有过出血。平均靶体积为1.7 cm³（范围0.1 - 11.3 cm³）。平均最大和边缘辐射剂量分别为38.5 Gy（范围28.6 - 43.6 Gy）和23.4 Gy（范围18 - 27 Gy），平均等剂量曲线为61.3%（范围50 - 70%）。
24例患有脑干AVM的患者接受了超过3年的随访。在平均77.5个月（范围36 - 216个月）的随访期内，最终有17例患者（70.8%）的AVM实现了闭塞。就病灶类型和血流情况而言，致密型的闭塞率（75%）高于弥散型（66.7%），低流量AVM的闭塞率（76.9%）高于高流量AVM（63.6%）（p<0.05）。2例患者（6.9%）发生了3次出血事件，在随访期间再次出血。GKRS后AVM的年出血率为每年1.95%。未发现不良放射效应或延迟性囊肿形成。
GKRS在治疗具有极高手术风险的脑干AVM中具有重要的临床作用。血管造影特征以及使用较低最大剂量和较高等剂量曲线的放射外科技术对于病灶闭塞和避免并发症很重要。
