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Neurology
Published in Roy Palmer, Diana Wetherill, Medicine for Lawyers, 2020
The soft brain is separated from the hard skull by a space containing fluid—cerebrospinal fluid (CSF)—itself contained within a series of membranes, of which the innermost is called the arachnoid and the outermost, a tough, fibrous layer densely applied to the skull, the dura mater. CSF is manufactured inside the ventricles, deep-lying caverns within the brain, which link to expel the spinal fluid near the base of the skull, whence it passes up in the subarachnoid space (and also down the spinal canal) to be absorbed at the top of the skull (Figure 14.2). Obstruction of the flow of CSF in the ventricular system leads to a condition known as hydrocephalus (water on the brain), which can cause progressive neurological impairment, culminating in death if not recognized and treated.
Blood–Brain Barrier and Cerebrospinal Fluid (CSF)
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
CSF is formed in the brain by a combination of ultrafiltration and active secretion and circulates through the subarachnoid space and the ventricular system. The ventricular system includes the two lateral ventricles, third ventricle, aqueduct of Sylvius, fourth ventricle and central canal of the spinal cord. In humans, the rate of CSF formation is 0.35–0.4 mL/min, or 500 mL/day. The total volume of CSF (60 mL within the cranium and 60 mL around the spinal cord) is exchanged approximately four times a day.
Corpus Callosotomy
Published in Stanley R. Resor, Henn Kutt, The Medical Treatment of Epilepsy, 2020
The surgical technique for callosotomy as elaborated by Wilson et al. was modified following an unacceptable number of perioperative complications including one death in the first series of eight patients (12). Avoiding entry into the ventricular system was adopted and may be the reason for a decreased report of ventriculitis and hydrocephalus (12,47,52). One-stage total callosotomy was replaced by a two-stage operation starting with either the posterior half or anterior one half to three quarters of the callosum (12,29,47). Most centers have now adopted anterior callosotomy as the first step (29,36,47). Completion of callosotomy is carried out if generalized seizure control is inadequate after an observation period of 4 or more months. Some centers have restricted surgery to anterior callosotomy alone (17,23,27), or a partial callosotomy related to intraoperative electrical studies (37). A recent review (53) of the results of anterior one half to three quarters callosotomy alone versus two-stage completion section revealed that the complete procedure has been successful in markedly decreasing or eliminating generalized seizures (generalized tonic-clonic, tonic, atonic and absence spells) in 80 to 90% of patients, whereas partial section has been similarly effective in 50% or less. Recent reviews by Roberts (47,52) elaborate the technical aspects of callosotomy.
Blood-cerebrospinal fluid barrier opening by modified single pulse transcranial focused shockwave
Published in Drug Delivery, 2023
Yi Kung, Chueh-Hung Wu, Meng-Ting Lin, Wei-Hao Liao, Wen-Shiang Chen, Ming-Yen Hsiao
Aside from the BBB, the blood-cerebrospinal fluid barrier (BCSFB) at the boundary between the choroid plexuses and the ventricular system also prevents direct communication between the CNS and CSF. Compared with the BBB, the choroidal vessels in the BCSFB are extremely permeable. In addition the vessels are not surrounded by the pericytes and astrocytic foot processes (Yao et al., 2018). Once BCSFB is disrupted, drugs in the blood immediately enter the CSF encircling the entire CNS, thus potentially providing widespread and quick drug delivery (Montagne et al., 2020). It has been shown to effectively increase drug concentrations in the CSF to alleviate epilepsy (Kung et al., 2021, 2022). Furthermore, the FSW was administered to the lateral ventricle instead of brain parenchyma to induce BCSFB opening, offering lesser risk of adverse effect (Mestre et al., 2018). The method could potentially be used to treat CNS diseases which require widespread drug diffusion, such as meningitis, encephalitis, and neurogenerative diseases including Alzheimer’s disease.
Association between subarachnoid hemorrhage-induced hydrocephalus and hydromyelia: pathophysiological changes developed in an experimental model
Published in Neurological Research, 2023
Some studies have shown that abnormalities in the ependymal cells of the central channel vary depending on the cause of ventricular dilation in patients with hydrocephalus [20,21]. The central channel dilation is a consequence of hydrocephalus. The central channel acts as a complementary compartment of the ventricular system. Any changes in one will reflect in other compartments. However, in the hydrocephalus pathology, the integration between the ventricular system and the central channel, subependymal membrane rupture, and ventricular dilation-related ependymal cell degenerations has not been discussed sufficiently. Spinal SAH can lead to hydrocephalus and is characterized by normal or increased ICP [21,22].− Intraspinal epidural pressure is a reliable index of pathologies that increased the ICP such as SAIH and SAH [23,24]. This index reflects the pressure in the SAS, ventricular system, operative cavities, spinal canal, and other connecting compartments [21]. The SAH-induced spinal subdural hematoma can trigger hydromyelia [22].
Dural venous sinus stenting in patients with idiopathic intracranial hypertension: report of outcomes from a single-center prospective database and literature review
Published in Expert Review of Ophthalmology, 2022
Matthew J Kole, Juan Carlos Martinez-Gutierrez, Francisio Sanchez, Rosa Tang, Peng Roc Chen
Given excess of CSF drives IIH pathophysiology, diversion of CSF by surgical shunt placement has been used for IIH treatment for decades. While the concept of draining CSF to an innocuous cavity is simple, surgical technology offers an evolving array of techniques. The proximal end of a shunt necessitates contact with the subarachnoid space which limits its options to the ventricular system of the brain or the lumbar subarachnoid space. The distal component of the shunt can be placed in a number of places most frequently the abdominal peritoneum, thoracic pleural space or right atrium of the heart. A comparison of ventriculoperitoneal (VP) and lumboperitoneal (LP) shunts found the former to be the better option in this patient population due to higher rates of obstruction in the LP shunt population [63]; however, other studies have shown conflicting results [64,65]. Though effective at lowering ICP, CSF diversion by any method is associated with high rates of early failure requiring revision in 36% of VP shunts and 46% in LP shunts; 87.5% of which occur within the first year [66,67]. A small study did show that bilateral proximal catheter placement may lower the frequency of proximal shunt occlusion; however, a larger number of patients would be required to corroborate these findings [68]. Elevated BMI may also be associated with an elevated rate of VP shunt failure.