Eguchi Seiichiro, Aihara Yasuo, Hori Tomokatsu, Okada Yoshikazu
Department of Neurosurgery, Tokyo Women's Medical University, Tokyo, Japan.
Pediatr Neurosurg. 2011;47(2):125-32. doi: 10.1159/000330543. Epub 2011 Sep 2.
External hydrocephalus, introduced by Dandy and Blackfan in 1914 [Am J Dis Child 1914;8:406-482], is used to describe the clinical condition of cerebrospinal fluid (CSF) accumulation in the subarachnoid space with its space expansion and increased intracranial pressure in pediatric patients. Benign subdural effusion, subdural hygroma and pseudohydrocephalus are some terms used to describe some conditions, not clearly defined at the moment as separate pathological entities. We report 3 pediatric cases which had CSF collections after craniotomy. Neuroimaging investigations revealed CSF collection after surgery. All 3 cases had a poor clinical course with resolution after shunting. This report analyzes the mechanisms and pathophysiology of postoperative extra-axial CSF collections (PECC), indicating that CSF accumulations in the extra-axial spaces (inside or outside the arachnoid) after surgery have a common pathophysiology. Therefore, the treatment protocol can be specific.
Three pediatric cases, aged from 11 months to 6 years, had large tumors located from their suprasellar region to the hypothalamus and third ventricle. The tumors were excised surgically through either an anterior interhemispheric translamina-terminalis or a transsylvian translamina-terminalis approach or both. The surgery conducted created a wide opening of the anterior interhemispheric or the sylvian fissures, dissecting the lamina terminalis and Liliequist's membrane resulting in a new artificial CSF tract from the basal cisterns to the subdural space. Clinical symptoms such as deterioration of consciousness level developed within a few weeks after surgery, and a follow-up computed tomography image confirmed subdural CSF collection. Symptoms improved after ventriculoperitoneal (V-P) shunting.
External hydrocephalus, subdural effusion and the other entities mentioned above are frequently observed in children, and little is known about their pathophysiology. To differentiate from the whole entity of CSF accumulation within the subdural and subarachnoid space, we use the term PECC to specify the main pathophysiological condition resulting from a wide dissection and opening of the arachnoid membrane and communication with the basal cisterns.
We present the occurrence of CSF collections in the extra-axial space after surgery as the specific condition of PECC. Broadly dissecting the arachnoid membrane, with a communication remaining with the ventricles, is the main factor contributing to PECC, and patients have shown that V-P shunting is an effective procedure preventing progression and effectively treating PECC.
外部性脑积水由丹迪（Dandy）和布莱克范（Blackfan）于1914年首次提出[《美国小儿疾病杂志》1914年；8：406 - 482]，用于描述小儿患者蛛网膜下腔脑脊液（CSF）积聚、蛛网膜下腔扩张及颅内压升高的临床状况。良性硬膜下积液、硬膜下蛛网膜囊肿和假性脑积水是用于描述某些目前尚未明确界定为独立病理实体的病症的术语。我们报告3例开颅术后出现脑脊液积聚的儿科病例。神经影像学检查显示术后存在脑脊液积聚。所有3例临床病程均不佳，分流术后病情缓解。本报告分析了术后轴外脑脊液积聚（PECC）的机制和病理生理学，表明术后蛛网膜外间隙（蛛网膜内或蛛网膜外）的脑脊液积聚具有共同的病理生理学。因此，治疗方案可以是特定的。
3例儿科病例，年龄从11个月至6岁，肿瘤位于鞍上区域至下丘脑及第三脑室。通过经终板前半球间入路或经侧裂经终板入路或两者联合手术切除肿瘤。手术造成了较宽的半球间前部或侧裂开口，分离终板和 Liliequist 膜，形成了一条从基底池到硬膜下间隙的新的人工脑脊液通道。术后几周内出现意识水平恶化等临床症状，后续计算机断层扫描图像证实硬膜下有脑脊液积聚。脑室腹腔（V - P）分流术后症状改善。
外部性脑积水、硬膜下积液及上述其他病症在儿童中较为常见，但其病理生理学鲜为人知。为了与硬膜下和蛛网膜下腔内脑脊液积聚的整体情况相区分，我们使用术语PECC来明确由蛛网膜膜广泛分离和开放以及与基底池相通所导致的主要病理生理状况。
我们将术后蛛网膜外间隙脑脊液积聚作为PECC的特定情况呈现。广泛分离蛛网膜膜且保持与脑室相通是导致PECC的主要因素，并且患者已表明V - P分流是预防病情进展和有效治疗PECC的有效方法。
