Alén José F, Lagares Alfonso, Campollo Jorge, Ballenilla Federico, Kaen Ariel, Núñez Angel P, Lobato Ramiro D
Department of Neurosurgery, 12 de Octubre University Hospital, Madrid, Spain.
Neurosurgery. 2008 Dec;63(6):1106-11; discussion 1111-2. doi: 10.1227/01.NEU.0000335777.14055.71.
In the past, several possible explanations for idiopathic subarachnoid hemorrhage (ISAH) have been proposed; however, neuroimaging studies have never provided conclusive data about the structural cause of the bleeding. The aim of this study is to determine whether there are anatomic differences in the deep cerebral venous drainage in patients with ISAH compared with those with aneurysmal subarachnoid hemorrhage (ASAH) and those without intracranial hemorrhage.
We reviewed the venous phase of carotid digital angiograms of 100 consecutive patients who had a final diagnosis of ISAH. We also analyzed the angiograms of a control group of 112 patients with ASAH and the angiograms of a nonhemorrhagic group of 25 patients having incidental aneurysms. The anatomic variants of the basal vein of Rosenthal (BVR) on both sides were classified into the following types: Type A (normal continuous), in which the BVR is continuous with the deep middle cerebral veins and drains mainly into the vein of Galen; Type B (normal discontinuous), in which there is discontinuous venous drainage, anterior to the uncal vein and posterior to the vein of Galen; and Type C (primitive), which drains mainly to veins other than the vein of Galen. We calculated the proportions to analyze the differences in the type of venous drainage between patients with ISAH, patients with ASAH, and patients without hemorrhage. chi2 statistics were used to search for differences.
Types A and C venous drainage were present in 23.8 and 32.3%, respectively, of patients with ISAH compared with 58.7 and 15.4%, respectively, in the ASAH group and 57.5 and 5%, respectively, in the nonhemorrhagic group (P < 0.001). A primitive variant was present in at least 1 hemisphere in 38 patients with ISAH (41.8% of the cases) compared with 24 patients with ASAH (21.4%) and 2 patients (8%) in the nonhemorrhagic group (P < 0.001).
In patients with ISAH, deep cerebral venous drainage more commonly drains directly into dural sinuses instead of via the vein of Galen compared with patients with ASAH and patients without intracranial hemorrhage. The way in which this venous configuration might influence bleeding remains unknown.
过去曾提出几种关于特发性蛛网膜下腔出血（ISAH）的可能解释；然而，神经影像学研究从未提供关于出血结构原因的确凿数据。本研究的目的是确定与动脉瘤性蛛网膜下腔出血（ASAH）患者和无颅内出血患者相比，ISAH患者的大脑深部静脉引流是否存在解剖学差异。
我们回顾了100例最终诊断为ISAH的连续患者的颈动脉数字血管造影静脉期。我们还分析了112例ASAH患者的对照组血管造影以及25例有偶然动脉瘤的非出血组患者的血管造影。双侧Rosenthal基底静脉（BVR）的解剖变异分为以下类型：A型（正常连续型），其中BVR与大脑中深静脉连续，主要引流至大脑大静脉；B型（正常间断型），其中静脉引流在钩静脉前方和大脑大静脉后方间断；C型（原始型），主要引流至大脑大静脉以外的静脉。我们计算比例以分析ISAH患者、ASAH患者和无出血患者之间静脉引流类型的差异。使用卡方统计来寻找差异。
ISAH患者中分别有23.8%和32.3%存在A型和C型静脉引流，而ASAH组分别为58.7%和15.4%，非出血组分别为57.5%和5%（P<0.001）。38例ISAH患者（占病例的41.8%）至少有1个半球存在原始变异，而ASAH患者有24例（21.4%），非出血组有2例（8%）（P<0.001）。
与ASAH患者和无颅内出血患者相比，ISAH患者的大脑深部静脉引流更常见于直接引流至硬脑膜窦，而非经大脑大静脉。这种静脉构型可能影响出血的方式尚不清楚。
