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Paper 1
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
Mega cisterna magna is usually an incidental diagnosis which causes the appearances of a cystic midline posterior fossa lesion located posteriorly and displacing the cerebellum. It follows cerebrospinal fluid (CSF) on all MRI sequences. An arachnoid cyst would be another possible differential as it has the same signal characteristics, although the position is suggestive of mega cisterna magna. This appearance can be detected antenatally and in these cases can be associated with infections such as cytomegalovirus or chromosomal abnormalities.
Intracranial Cysts
Published in Amar Bhide, Asma Khalil, Aris T Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan, Problem-Based Obstetric Ultrasound, 2019
Amar Bhide, Asma Khalil, Aris T Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan
Cystic structures in the posterior fossa include: Enlarged cisterna magna when it is >10 mm in the transverse cerebellar view. Detailed ultrasound is needed to demonstrate this is isolated and that the cerebellum and vermis are normal. It can be associated with ventriculomegaly, but if it remains isolated and does not progress, prognosis is generally good.Blake's pouch cysts represent a communication between the 4th ventricle into the cisterna magna and appear as a unilocular cyst without any Doppler flow. Careful assessment is mandatory to ensure the remainder of the brain—in particular cerebellum and vermis—are normal. This is usually isolated, and most will resolve spontaneously.In Dandy-Walker malformation there is dilation of the fourth ventricle in the posterior fossa and that extends into the cisterna magna. The cerebellar vermis will be hypoplastic or absent. The condition is often associated with chromosomal abnormalities (mainly trisomy 18 and 13) or genetic syndromes. Coexisting abnormalities are very common, as is severe ventriculomegaly. The outlook is guarded.
Cheryl
Published in Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner, The Integrated Nervous System, 2017
Walter J. Hendelman, Peter Humphreys, Christopher R. Skinner
There is a circulation of CSF within the ventricles, with the flow being from lateral ventricles to the third ventricle, and then via a narrow aqueduct in the midbrain to the fourth ventricle in the pontine region (black arrows in Figure 9.5). At the lower end of this ventricle, CSF ‘escapes’ into the subarachnoid space, the cerebello-pontine cistern, known generally as the cisterna magna. Cisterns are enlargements of the subarachnoid space, and several others are found around the brainstem; the largest of these is the cisterna magna, located behind the brainstem and below the cerebellum, in the posterior cranial fossa, just above the foramen magnum (see Figure 9.5).
Pure endoscopic resection of pineal region tumors through supracerebellar infratentorial approach with ‘head-up’ park-bench position
Published in Neurological Research, 2023
Wei Hua, Hao Xu, Xin Zhang, Guo Yu, Xiaowen Wang, Jinsen Zhang, Zhiguang Pan, Wei Zhu
Patients were placed in the modified left ‘head-up’ park-bench position, with the upper body elevated and the head slightly extended instead of anteflexion. The head was then secured in place with a Mayfield three-pin head clamp and slightly flexed. Neuronavigation was registered in the Stryker Navigation System (Stryker, Kalamazoo, Michigan) and used to determine the optimal ‘head-up’ angle. An occipital midline skin incision and craniotomy approximately 3 × 3 cm in size were made (Figure 1 d and e). A U-shaped dural incision was made, and the cerebrospinal fluid of the cisterna magna was slowly released to further decrease the intracranial pressure. Through the combination of gravity assistance and reduced pressure, the corridor between the cerebellum and the tentorium could be easily opened.
Systematic scoping review of papilledema in vestibular schwannoma without hydrocephalus
Published in British Journal of Neurosurgery, 2023
Rakesh Mishra, Subhas Kanti Konar, Adesh Shrivastava, Amit Agrawal, Suresh Nair
Kumar et al.4 reported that cisterna magna CSF protein levels (CMCP) levels were significantly higher in VS patients (456.3 ± 213.6 mg/dL) than in the control population with other pathologies (96.3 ± 74.3 mg/dL).4 They also found that patients with visual loss had higher levels of CMCP (561.4 ± 186.9 mg/dL) than patients without visual complaints (314.2 ± 160.8 mg/dL).4 However, the majority of these patients had HCP, and therefore it cannot be inferred with a conclusion if HCP is responsible for visual disturbance or increased proteins. Further, seven patients in that series had a visual loss in the absence of HCP, but the individual patient data for these cases was missing. Therefore, a focussed study on ICP and CSF proteins is required to understand the mechanism responsible for the development and resolution of papilledema in VS patients without HCP
Experience with revision craniovertebral decompression in adult patients with Chiari malformation type 1, with or without syringomyelia
Published in British Journal of Neurosurgery, 2022
Adikarige Silva, Gopiga Thanabalasundaram, Ben Wilkinson, Georgios Tsermoulas, Graham Flint
Under magnification, the cerebellar tonsils are routinely reduced with bipolar coagulation. If judged to be necessary, in order to open Magendie, the tonsillar residues are also hitched superiorly and laterally, using fine silk sutures (usually one each side), passing from the tonsillar pia to the adjacent, cut dural edge. The use of silk sutures in this setting is owing to surgeon preference although an alternative fine non-absorbable suture can also suffice. Any arachnoid adhesions or webs, such as are sometimes encountered underneath the tonsils, are divided. The overall aim of these manoeuvres is to create an artificial cisterna magna, into which the 4th ventricle opens directly and which itself communicates freely with the basal cisterns and spinal subarachnoid channels. Duraplasty is not performed. Nor is any cranioplasty attempted. Wound closure consists of apposition of nuchal muscles in two layers, followed by fascia, fat and skin.