颅内动静脉畸形手术前后血管团周围脑皮质局部血流量变化及病理学观察

Changes of focal cortical blood flow around the nidus of intracranial arteriovenous malformation before and after surgery and its pathological observations

目的观察颅内动静脉畸形（AVM）手术切除前、后,血管团周围组织血-脑屏障超微结构及脑皮质局部脑血流量的变化。方法选择34例AVM行手术切除术的患者,依据Spetzler-Matin分级标准,将AVM分为小型（直径〈3.0cm）16例、中型（3-6cm）12例及大型（直径〉6cm）6例。分别于AVM手术切除前及切除后1、2、3、4和24h,使用激光多普勒血流仪（LDF）对AVM周围1.5cm范围内皮质血流量进行监测,并对病灶周围脑组织进行病理学观察。术后7-12d行头部CT检查,了解脑水肿程度。结果1例患者术后出现异常脑水肿。①局部脑血流变化：畸形团切除后即刻及1、2、3、24h,中、小型（直径〈6cm）AVM局部皮质脑血流量较切除前分别增加（53±17）、（77±26）、（38±12）、（29±9）、（8±5）%;切除后4h减少（7±3）%,与切除前比较,切除后即刻及1、2h差异均有统计学意义（P〈0.05）;大型AVM（直径≥6cm）畸形团切除后即刻及1、2、3、4、24h局部皮质脑血流量较切除前分别增加（130±45）、（112±32）、（100±37）、（116±35）、（147±36）、（120±39）%,与切除前比较,差异均有统计学意义（P〈0.05）。②病理学观察：电镜观察全部标本,可见病灶周边脑组织的血-脑屏障3层结构有不同程度的变性、破坏,内皮细胞之间紧密连接缝隙增宽,星形胶质细胞足突明显水肿,甚至消失。结论AVM切除前后脑血流动力学变化是AVM术后诱发异常脑水肿的重要因素;AVM周边脑组织血-脑屏障的结构改变可能是AVM术后发生异常脑水肿的病理生理学基础。

Objective To observe the ultrastructure of blood brain-barrier around the nidus and the changes of focal cortical blood flow before and after cerebral arteriovenous malformation （AVM） resection.Methods Thirty-four patients with underwent AVM resection were selected according to the Spetzler-Martin Grade. The AVM were divided into small （n=16, diameter 〈3 cm）, medium （n=12, diameter 3~6 cm）, and large （n=6, diameter ≥ 6 cm） groups. The cortical blood flow within 1.5 cm around the AVM nidus were detected with laser Doppler flowmetry monitoring before the AVM resection, and 1, 2, 3, 4, 24 hours after the resection. The pathological observations after cerebral tissue around the nidus were performed. CT scan was performed 7-12 days after the operation to assess the severity of edema.Results One patient developed obvious brain edema after the operation. ①The regional cerebral flow：compared with the pre-resection around the nidus of medium and small sized AVM（diameter〈6 mm）at immediaterly after and 1,2,3,24 hours after resection was increased 53±17%,77±26%,38±12%,29±9%,8±5%,respectively,and decreased 7±3% at 4 hour after resection. The blood flow immediaterly after the resection, 1 and 2 hours after the resection had statistically significance higher than that before the resection （P〈0.05） While the regional cerebral flow of the AVM（diameter≥6mm）was increased 130±45%,112±32%,100±37%,116±35%,147±36%,120±39% at immediaterly after and 1,2,3,4,24 hours, respectively. There were significantly higher than that before resection （P〈0.05）.②Pathological observation revealed the ultrastructures of the 3 layers of brainblood barrier in the brain tissue arround the nidus developed different degree of degeneration and damage. The tight junctions between endothelial cells widened. Astrocytic foot processes were obviously swollen, and even disappeared.Conclusions The ultrastructure changes of blood brain-barrier in brain tissue around AVM may be the pathological base of abnormal edema after the AVM surgery. The hemodynamics changes before and after AVM resection are the important factors in inducing abnormal edema after AVM surgery.