Radiosurgical retreatment for brain arteriovenous malformation

OBJECTIVE: To analyze our experience with a second radiosurgical treatment for brain arteriovenous malformations (BAVMs) after an unsuccessful first radiosurgical treatment. METHODS: Between 1993 and 2000, 242 patients were treated by the Toronto Sunnybrook Regional Cancer Center using a LINAC system. Fifteen of these patients required a second radiosurgical intervention due to the failure of the first procedure. Data was collected on baseline patient characteristics, BAVM features, radiosurgery treatment plan and outcomes. Brain arteriovenous malformation obliteration was determined by follow-up MRI and angiography and the obliteration prediction index (OPI) calculated according to a previously established formula. RESULTS: The median interval between the first and second treatment was 46 months (range 39-109). The median follow-up after the second procedure was 39 months (range 26 to 72). The mean BAVM volume before the first treatment was 8.9cm3 (range 0.3-21) and before the second treatment was 3.6cm3 (range 0.2-11.6). The mean marginal dose during the first treatment was 18Gy (range 12-25) and during the second treatment was 16Gy (range 12-20). After the second treatment, nine patients had obliteration of their BAVM confirmed by angiography and one patient had obliteration confirmed by MRI, resulting in an obliteration rate of 66.6%, which is very comparable to that predicted by the OPI (65%). After the second treatment two patients had a radiation-induced complication (13.3%). CONCLUSION: Retreatment of BAVM using a second radiosurgery procedure is a safe and effective option that offers the same rate of success as the initial radiosurgery and an acceptable risk of radiation-induced complication.     

Treatment for arteriovenous malformation of the brain——Comparison between microsurgery and gamma knife

BACKGROUND: Microsurgery and gamma knife are the mainly ways to treat arteriovenous malformation of brain in grade Spetzler-Martin Ⅰ–Ⅲ; however, therapeutic effects of them need to be further studied. OBJECTIVE: To compare the therapeutic effects between microsurgery and gamma knife on the treatment of arteriovenous malformation of brain in grade Spetzler-Martin Ⅰ–Ⅲ. DESIGN: Retrospective analysis. SETTING: Department of Neurosurgery, the Third Hospital Affiliated to Sun Yat-sen University; Guangdong Microinvasion Center. PARTICIPANTS: A total of 86 patients with arteriovenous malformation of the brain were selected from the Department of Neurosurgery, the Third Hospital Affiliated to Sun Yat-sen University and Guangdong Microinvasion Center from January 1997 to February 2007. After DSA, CT and/or MRI examinations, patients were evaluated in grade Spetzler-Martin Ⅰ–Ⅲ. All patients were divided into microsurgery group (n = 34) and gamma knife group (n =52). There were 22 males and 12 females in the microsurgery group and their mean age was 26 years, while there were 34 males and 18 females in the gamma knife group and their mean age was 28 years. The grade of Spetzler-Martin was comparable in the two groups. All their relatives provided the confirmed consent and the study was allowed by ethics committee of our hospital. METHODS: Under complete anesthesia, patients were given microsurgery and the operative approach was chosen based on diseased regions. Firstly, feeding artery was blocked; secondly, it was separated along band of gliosis between malformation vessel mass and brain tissue; finally, draining vein was cut off and malformation vessel mass was resected. On the other hand, patients in the gamma knife group received Leksell-2300B gamma knife treatment. Leksell-G stereotaxis headframe was installed; GE1.5TMR scanning device was used for localization; r-Plan5.2 workstation was used for target design and dosage program; Leksell B gamma knife was used during the whole operative procedure. The target was 1–4 and peripheral dosage was 12–28 Gy. At 0.5, 1 and 2 years after operation, angiography was used to detect vascular occlusion in the two groups. Meanwhile, focal hemorrhage and new neurological function defect (including hemiplegic paralysis, language disorder, cerebellar function disorder, increasing frequency of epilepsy, etc.) were also observed. MAIN OUTCOME MEASURES: Rate of vascular occlusion, focal hemorrhage and neurological function defect at different time points after operation. RESULTS: All 86 patients were involved in the final analysis. Vascular nest of patients in the microsurgery group disappeared completely; while, two patients (6%, 2/34) had new neurological function defect but did not have rehaemorrhagia and death after operation. On the other hand, vascular nest of 43 patients (83%, 43/52) in the gamma knife group disappeared completely, and 8 (15%, 8/52) had new neurological function defect. There was significant difference between the two groups (χ2=2.63, P < 0.05). Six patients (12%, 6/52) in the gamma knife group had rehaemorrhagia after operation, and one (2%, 1/52) died. CONCLUSION: Both microsurgery and gamma knife have great effects on the treatment of arteriovenous malformation of brain in grade Spetzler-Martin Ⅰ–Ⅲ; however, the therapeutic effects of microsurgery are superior to those of gamma knife.     

Risk factors for hemorrhage of brain arteriovenous malformation

Patients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.     

深部脑动静脉畸形的显微手术治疗

目的 探讨深部脑动静脉畸形(BAVM)的显微手术技巧及效果. 方法 吉林大学中日联谊医院自2001年1月至2008年6月对收治入院的70例深部BAVM患者采用显微手术治疗,其中70例患者脑部畸形血管团属小型(直径＜3 cm)31例,中型(直径3～6 cm)36例,巨大型(直径＞6 cm)3例;按Spetzler-Martin分级:Ⅰ级11例,Ⅱ级12例,Ⅲ级23例,Ⅳ级16例,Ⅴ级8例,对术中的显微手术技巧及术后疗效进行总结分析. 结果 70例患者深部畸形血管团术中均完整切除,27例复查MRI、8例复查DSA证实.1例Spetzler-MartinⅤ级患者术后发生正常灌注压突破.所有患者随访6个月～3年,均无复发及再次出血.8例术前脑疝患者术后3例重残,2例中残,3例生活能自理.10例癫痫患者术后服用抗癫痫药物症状得到控制.余患者术后未遗留明显神经功能障碍. 结论 深部BAVM血管构筑复杂,手术全切除最为彻底.高流量BAVM行术前栓塞及口服β受体阻滞剂,术中降低动脉压、延长麻醉苏醒时间,术后减少液体摄入及应用脱水疗法,可降低正常灌注压突破的发生率.     

脑干动静脉畸形的特点及治疗

目的 探讨脑干动静脉畸形的临床表现、脑血管影像特点及治疗效果.方法 12例患者在数字减影血管造影(DSA)监视下进行全脑血管造影,了解畸形血管团的位置、大小、供血动脉及引流静脉情况,然后给予血管内栓塞治疗或放射治疗.结果 12例患者应用漂浮导管技术行血管内栓塞治疗;AVM完全消失4例(含栓塞加X刀1例);减少70%以上2例,40%～70%2例,40%以下4例.2例行X刀治疗,4例临床治愈,1例因治疗时间短未复查.结论 脑干动静脉畸形,发病年龄不等,出血危险性大,畸形团小,位置深,供血动脉多,引流静脉单一,栓塞治疗效果确实.     

脑动静脉畸形动物模型的初步建立

目的：建立脑动静脉畸形（ＡＶＭ）动物模型。方法：以中国实验用小型猪的颅底微血管网（ｒｅｔｅｍｉｒａｂｉｌｅ）为畸形团，经颈动静脉吻合等建立脑ＡＶＭ动物模型；用ＮＢＣＡ胶和Ｅｍｂｏｓｐｈｅｒｅ颗粒分别栓塞；模型建立和栓塞前后行血管造影。结果：成功构建了具有供血动脉、畸形团和引流静脉的ＡＶＭ模型；造影动脉期显示血液经畸形团向引流静脉分流；栓塞时，胶在畸形团（微血管网）里弥散、聚合良好，颗粒可使其显影逐渐变淡、直至消失。结论：本方法对建立脑ＡＶＭ急性期动物模型更简单经济省时，并且可靠；该模型在血管结构，造影影像和栓塞行为上与人脑ＡＶＭ相似，适用于有关的研究和介入医师的培训。     

Angiographically occult and spontaneously thrombosed large brain arteriovenous malformation

Treatment for brain arteriovenous malformations (AVM) include combinations of surgery, radiosurgery and embolization. Very rarely, spontaneous obliteration may occur, especially among small lesions with single superficial vein drainage and prior bleeding. We report the case of a large symptomatic AVM, without history of hemorrhage or prior treatment, in which self-obliteration was noted at surgery. Although MRI suggested the presence of an AVM, no evidence of arterial anomaly was observed in the brain angiography. At surgery, a large cortical nidus with tortuous arterial vessels, resembling that of an AVM but without blood flow, was identified. Complete resection was easily performed without relevant bleeding. The histopathologic study confirmed the diagnosis of a thrombosed AVM. Despite the low probability of recanalization, surgical resection of a suspected spontaneously obliterated AVM may be warranted, in order to reach a definitive diagnosis and to avoid the risk of an eventual bleeding, especially among younger patients.     

Dural arteriovenous malformation occurring after craniotomy for pial arteriovenous malformation.

The etiology of dural arteriovenous malformation (AVM) is still uncertain, and the occurrence of postoperative dural AVM has rarely been proved angiographically. The authors present a case of dural AVM in the jugular and the sigmoid sinuses, which developed 1 year after resection of a pial AVM via the craniotomy. A possible mechanism underlying this case of dural AVM is discussed.     

Review of treatment and therapeutic targets in brain arteriovenous malformation

Brain arteriovenous malformations (bAVM) are an important cause of intracranial hemorrhage (ICH), especially in younger patients. The pathogenesis of bAVM are largely unknown. Current understanding of bAVM etiology is based on studying genetic syndromes, animal models, and surgically resected specimens from patients. The identification of activating somatic mutations in the Kirsten rat sarcoma viral oncogene homologue (KRAS) gene and other mitogen-activated protein kinase (MAPK) pathway genes has opened up new avenues for bAVM study, leading to a paradigm shift to search for somatic, de novo mutations in sporadic bAVMs instead of focusing on inherited genetic mutations. Through the development of new models and understanding of pathways involved in maintaining normal vascular structure and functions, promising therapeutic targets have been identified and safety and efficacy studies are underway in animal models and in patients. The goal of this paper is to provide a thorough review or current diagnostic and treatment tools, known genes and key pathways involved in bAVM pathogenesis to summarize current treatment options and potential therapeutic targets uncovered by recent discoveries.     

脑动静脉畸形血管内治疗并发症探讨

目的　通过对３２７ 例脑动静脉畸形血管内治疗的分析, 探索导致各种并发症的相关因素, 以避免或减少血管内治疗并发症的发生。方法　对６０８ 例次采用不同栓塞材料进行血管内栓塞治疗产生不同并发症的分析, 其中胶栓塞后出血４ 例、水肿１５ 例、误栓４ 例、血管痉挛３ 例, 线段栓塞出血２ 例、水肿１２ 例、误栓２ 例、血管痉挛１９ 例, 探讨栓塞治疗中出现不同并发症的因素。探索避免或减少并发症的有效措施。结果　脑动静脉畸形血管内治疗并发症不仅与栓塞技术有关, 更与选用不适当的栓塞材料和栓塞材料的用量有明显关系, 其中线段多导致术中、术后血管痉挛; 多聚体类（ＩＢＣＡ、ＮＢＣＡ） 使用难度较大, 多引起脑水肿及脑出血并发症。结论　要提高脑动静脉畸形栓塞治疗的治愈率, 减少并发症, 除了有熟练的操作技术外还应根据病变的具体情况, 选择合适的栓塞材料、及其用量, 必要时与γ刀、Ｘ刀联合治疗。     

Behcet's disease with sinus thrombosis and arteriovenous malformation in brain

Summary A 55-year-old man suffered from Behcet's disease with bilateral sigmoid sinus thrombosis and dural arteriovenous malformation has been studied clinically and pathologically. A possible causal relationship between Behcet's disease and sigmoid sinus thrombosis is discussed.

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Zusammenfassung Bei einem 55jährigen Patienten mit Behcetscher Krankheit fand sich sowohl eine Thrombose des Sinussigmoides wie auch eine arteriovenöse Mißbildung der Dura und des Gehirnes. Es wird über das Ergebnis der klinischen und pathologisch-anatomischen Untersuchung dieses Falles berichtet und die möglichen Beziehungen zwischen den obengenannten Besonderheiten des Falles untereinander kommentiert.

     

Hemorrhage risk after partial endovascular NBCA and ONYX embolization for brain arteriovenous malformation

Abstract

Objective: To estimate for hemorrhage risk of partially endovascularly embolized brain arteriovenous malformation (BAVM).

Methods: We retrospectively reviewed 147 consecutive patients with BAVM-treated mainly with endovascular N-butyl cyanoacrylate (NBCA) and ONYX embolization. In Kaplan–Meier survival analysis, the index date was the dated of initial endovascular embolization; cases were censored at time of subsequent intracranial hemorrhage (ICH), or loss to follow-up, and multivariate proportional-hazards regression models included age of presentation (?30 years old), clinical presentations, and other potential confounders.

Results: We reviewed 147 patients with BAVM (58·8% male; mean age±SD at treatment: 27·5±11·1 years) treated with endovascular embolization. One hundred and forty-four NBCA and 76 ONYX embolizations were performed. Complete obliteration of BAVMs was achieved in 29 patients (19·7%). Thirty-two (21·8%) patients were treated with additional Gamma-knife radiosurgery. During 499·5 years of follow-up, 15 partially treated patients suffered a further hemorrhage, which caused four deaths. The crude annual risk of hemorrhage was 3·0% and the annual death rate was 0·8%. Among partially treated patients with hemorrhage at initial presentation, the risk of hemorrhage was 3·8%, while the risk of hemorrhage for patients without hemorrhage at initial presentation was 2·5%. The annual rate of subsequent hemorrhage was 2·6% for non-ICH and 4·2% for ICH in the partial NBCA embolization group compared with 2·4% for non-ICH and 2·4% for ICH in the partial ONYX embolization group.

Conclusions: The effect of partial AVM embolization with liquid embolic agents may still be unclear as for risk reduction of annual hemorrhage rate of cerebral AVM.     

脑动静脉畸形血流动力学分析

目的 报告脑动静脉畸形(arteriovenous malformation, AVM)血流动力学参数的临床实测与理论分析结果,探讨其变化的原因和意义.方法 对37例脑AVM患者和同期15例非心脑血管病患者的大脑前、中和后动脉的阻力、压力、流速、流量、直径和血管壁面切应力进行测量或测算及统计处理.并以电学和优化原理进行推导和解释.结果 病例组参与脑AVM供血的动脉与未参与供血的动脉相比,流速加快,流量增大,压力降低;病例组参与脑AVM供血的动脉与对照组的同名动脉相比,阻力降低,直径增粗,血管壁面切应力趋向守恒;上述变化可由电学原理推导证明或优化理论解释.结论 动静脉直接交通足脑AVM低阻力的结构基础,并导致AVM血管高流速和流量,而参与脑AVM供血的动脉直径增粗和血管壁面切应力趋向守恒是遵循能耗优化普遍性原理的适应性改变.     

脑动静脉畸形出血相关因素探讨

目的以本组脑AVM 120例,出血就诊85例为基础探讨脑AVM出血相关因素。方法随临床机遇脑AVM 120例。男82例,女38例,年龄8～62岁。病程5h～14年。以SAH及脑出血就诊85例(71.0%),二次及三次出血21例,占出血病例24.7%。DSA 115例,110例显见AVM(95.7%),隐匿性出血5例(4.4%)。据DSA、MRA检查,以综合分级,结合文献探讨脑AVM出血的相关或危险因素。结果Ⅰ、Ⅱ级(中、小型AVM)99例,出血79例,占出血组92.2%,Ⅲ、Ⅳ级(大型、超大型AVM)21例,出血6例,占7.1%。Ⅰ、Ⅱ级中、小型引流静脉数目少,引流简单,出血率最高。而Ⅲ、Ⅳ级大型、超大型引流静脉数目多,引流复杂,出血率低。结论脑AVM出血基础是病变血管的构筑及其形成的特殊血液动力学因素相互作用的结果,出血非为单一因素所决定。涉及出血相关因素或危险因素越多,出血率越高。脑AVM破裂出血与年龄、性别、AVM部位、供应动脉数目等并无明显关系。其中最主要的是与AVM大小、AVM构筑、引流静脉数目、大小流向、管壁损伤、缺陷程度、血流动力变化密切相关。动脉与静脉比较,引流静脉是AVM破裂主要因素。