Second Department of Neurosurgery, Aristotle University of Thessaloniki, General Hospital of Thessaloniki Hippokratio, Thessaloniki, Greece.
Department of Anatomy and Surgical Anatomy, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Eur Neurol. 2022;85(4):313-325. doi: 10.1159/000523709. Epub 2022 Apr 11.
According to the classical hypothesis, the cerebrospinal fluid (CSF) is actively secreted inside the brain's ventricular system, predominantly by the choroid plexuses, before flowing unidirectionally in a cranio-caudal orientation toward the arachnoid granulations (AGs), where it is reabsorbed into the dural venous sinuses. This concept has been accepted as a doctrine for more than 100 years and was subjected only to minor modifications. Its inability to provide an adequate explanation to questions arising from the everyday clinical practice, in addition to the ever growing pool of experimental data contradicting it, has led to the identification of its limitations. Literature includes an increasing number of studies suggesting a more complex mechanism than that previously described. This review article summarizes the proposed mechanisms of CSF regulation, referring to the key clinical and experimental developments supporting or defying them.
A non-systematical literature search of the major databases was performed for studies on the mechanisms of CSF homeostasis. Gray literature was additionally assessed employing a hand-search technique. No restrictions were imposed regarding the time, language, or type of publication.
CSF secretion and absorption are expected to take place throughout the entire brain's capillaries network under the regulation of hydrostatic and osmotic gradients. The unidirectional flow is defied, highlighting the possibility of its complete absence. The importance of AGs is brought into question, potentiating the significance of the lymphatic system as the primary site of reabsorption. However, the definition of hydrocephalus and its treatment strategies remain strongly associated with the classical hypothesis.
根据经典假说，脑脊液（CSF）在脑室内系统中被主动分泌，主要由脉络丛分泌，然后单向沿颅尾方向流向蛛网膜颗粒（AGs），在那里被重吸收到硬脑膜静脉窦中。这一概念已经被接受了 100 多年，只是做了一些小的修改。它无法为日常临床实践中提出的问题提供充分的解释，加上与它相矛盾的实验数据不断增加，这导致了它的局限性被识别。文献中越来越多的研究表明，其机制比以前描述的更为复杂。本文综述了 CSF 调节的提出机制，提到了支持或反驳这些机制的关键临床和实验进展。
对有关 CSF 稳态机制的主要数据库进行了非系统性文献检索。此外，还采用手工检索技术对灰色文献进行了评估。不限制时间、语言或出版物类型。
CSF 的分泌和吸收预计将在整个大脑的毛细血管网络中进行，受液压和渗透梯度的调节。单向流动受到质疑，这凸显了其完全不存在的可能性。AGs 的重要性受到质疑，使淋巴系统作为主要重吸收部位的意义更加突出。然而，脑积水的定义及其治疗策略仍然与经典假说密切相关。
