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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 circulates through the ventricular system and the subarachnoid space from the formation sites to the absorption sites and has a hydrostatic pressure of 6.5–20 cmH2O (or 5–15 mmHg). Ciliary movements of the ependymal cells propel the CSF towards the fourth ventricle and the foramina of Luschka and Magendie into the cisterna magna. From the cisterna magna, CSF passes superiorly into the subarachnoid space around the cerebellar hemispheres, caudally into the spinal subarachnoid space, and cephalad to the basilar cisterns (around the premedullary pontine and interpeduncular cisterns). From the basilar cisterns, CSF flows through the pre-chiasmatic cistern and Sylvian fissure to the lateral and frontal cortical regions, and by a second route to the medial and posterior part of the cerebral cortex (Figure 5.2). Respiratory oscillations and arterial pulsations of the cerebral arteries and choroid plexus provide additional momentum for the movement of CSF.
Craniopharyngioma
Published in Dongyou Liu, Tumors and Cancers, 2017
The sellar region is the area around the sella turcica, which is a saddle-shaped, bony depression (or hollow) within the sphenoid bone at the skull base, and in which the pituitary gland is situated. Above the sellar region lies the suprasellar cistern (or chiasmatic cistern), with several vital structures traversing the area (e.g., the circle of Willis, optic nerves, optic chiasm, hypothalamus, pituitary stalk, and the infundibular and suprachiasmatic recesses of the third ventricle).
Post-operative vision loss: analysis of 587 patients undergoing endoscopic surgery for pituitary macroadenoma
Published in British Journal of Neurosurgery, 2022
John W. Rutland, Jonathan T. Dullea, Eric K. Oermann, Rui Feng, Dillan F. Villavisanis, Shivee Gilja, William Shuman, Travis Lander, Satish Govindaraj, Alfred M. C. Iloreta, James Chelnis, Kalmon Post, Joshua B. Bederson, Raj K. Shrivastava
Occasionally during ETS, the diaphragm sellae is opened surgically either in a planned manner to facilitate access to the superior component of a tumour, or incidentally as it descends during the latter stages of the surgery when resecting an adherent tumour capsule. The outflow of CSF and decompression of the suprasellar space presents both an opportunity, as well as a potential hazard. The newly expanded suprachiasmatic access afforded by a diaphragmatic opening can allow large tumours to fall down into the sella, and facilitate direct visualization of the superior margins, especially the optic chiasm using an angled scope. On the other hand, the diaphragm often functions as a natural barrier and physiological buffer between the sella turcica and chiasmatic cistern.25 As part of graft placement, materials packed into the sellar cavity may unexpectedly extravasate and possibly compress the optic nerves or chiasm in the immediate post-operative period without the diaphragma (Figures 1,2). In addition to the risk of CSF leak and subsequent infection associated with opening the diaphragma, we also believe that its opening is associated with rare post-operative visual loss. Furthermore, without the diaphragma sellae, the optic nerves and chiasm may be vulnerable to mechanical compression during surgery, which may have also contributed to observed visual loss.
The pros and cons of motor, memory, and emotion-related behavioral tests in the mouse traumatic brain injury model
Published in Neurological Research, 2022
Ruoyu Zhang, Junming Wang, Leo Huang, Tom J. Wang, Yinrou Huang, Zefu Li, Jinxin He, Chen Sun, Jing Wang, Xuemei Chen, Jian Wang
Traumatic subarachnoid hemorrhage (tSAH) is a negative prognostic factor [159]. Spontaneous SAH is one of the most common causes of severe acute brain injury in the clinic [160]. By using the endovascular perforation model and the pre-chiasmatic cistern single blood injection model of SAH [148], researchers found that SAH increased the ‘compulsive-like’ behaviors and stereotyped motor behaviors without affecting cognition (memory and learning) or emotion (depression- and anxiety-like behaviors) [161]. The behavioral tests evaluated in the TBI models, for example, NOR, FST, open field, NSS, and rotarod test are commonly used in the SAH models [161–170]. Other behavioral tests such as neurologic severity scoring, the SHIRPA (SmithKline Beecham, Harwell, Imperial College, Royal London Hospital, phenotype assessment) score, beam balance, and flex field analyses are also used [163]. To our knowledge, the tSAH model has not been established, which implies an unexplored area of research.
Retinal nerve fibre and ganglion cell inner plexiform layer analysis by optical coherence tomography in asymptomatic empty sella patients
Published in International Journal of Neuroscience, 2020
Ali Yilmaz, Mustafa Gok, Hilal Altas, Timur Yildirim, Sukran Kaygisiz, Hasan Serdar Isik
Anatomic variations and incomplete development of the sellar diaphragm are the most commonly accepted underlying pathologies in ES. The aforementioned anomalies open up a “free pathway” between the chiasmatic cistern and hypophyseal fossa, and the pulsatile action of cerebrospinal fluid (CSF) causes herniation of suprasellar structures toward the sella turcica. In this progressive process, compression of the pituitary gland and rhinorrhoea due to sellar base bone erosion may occur [6]. These pathophysiological events are reflected in the clinical setting as headaches, visual disturbances, hypophyseal hormonal anomalies, and rhinorrhoea (i.e. primary empty sella [PES] syndrome). Pituitary gland radiotherapy and surgery are the most common causes of secondary ES syndrome [7]. Visual loss and rhinorrhoea are indications for surgical interventions in PES patients.