Arachnoid cysts are common, accounting for approximately 1% of intracranial mass lesions. Most are congenital, clinically silent, and remain static in size. Occasionally, they increase in size and produce symptoms due to mass effect or obstruction. The mechanism of enlargement of arachnoid cysts is controversial. One-way slit valves are often hypothesized as the mechanism for enlargement. The authors present 4 cases of suprasellar prepontine arachnoid cysts in which a slit valve was identified. The patients presented with hydrocephalus due to enlargement of the cyst. The valve was located in the arachnoid wall of the cyst directly over the basilar artery. The authors believe this slit valve was responsible for the net influx of CSF into the cyst and for its enlargement. They also present 1 case of an arachnoid cyst in the middle cranial fossa that had a small circular opening but lacked a slit valve. This cyst did not enlarge but surgery was required because of rupture and the development of a subdural hygroma. One-way slit valves exist and are a possible mechanism of enlargement of suprasellar prepontine arachnoid cysts. The valve was located directly over the basilar artery in each of these cases. Caudad-to-cephalad CSF flow during the cardiac cycle increased the opening of the valve, whereas cephalad-to-caudad CSF flow during the remainder of the cardiac cycle pushed the slit opening against the basilar artery and decreased the size of the opening. Arachnoid cysts that communicate CSF via circular, nonslit valves are probably more likely to remain stable.
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http://dx.doi.org/10.3171/2013.4.PEDS12609 | DOI Listing |
Children (Basel)
November 2024
Neurosurgery Department, University Hospital of Heraklion, School of Medicine, University of Crete, 71003 Heraklion, Crete, Greece.
Background/objectives: Intracranial arachnoid cysts (ACs) may be congenital, primary, or secondary due to trauma. These cysts are benign, contain cerebrospinal fluid (CSF), and are classified based on location, size, and their clinical symptomatology. They are uncommon lesions in children, rarely leading to severe mass-effect neurological symptomatology.
View Article and Find Full Text PDFInt J Obstet Anesth
December 2024
Department of Anesthesiology, Perioperative and Pain Medicine, Brigham & Women's Hospital, Harvard Medical School, United States.
Eur Spine J
January 2025
Department of Neurosurgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.
Background: Spinal epidural arachnoid cysts (SEACs) are rare, non-neoplastic pathologies that can cause compressive myelopathy. Preoperative identification of the exact fistula location is crucial for minimally invasive management.
Methods: This single-center retrospective study included 27 patients with SEACs who underwent "double-needle puncture myelography" to precisely localize the fistula before minimally invasive surgery.
Clin Neurol Neurosurg
December 2024
Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bengaluru, India. Electronic address:
Purpose: Arachnoid cysts constitute approximately 1 % of intracranial mass lesions, with quadrigeminal cistern arachnoid cysts being 5-18 % of those. This study presents a series of 31 cases of quadrigeminal cistern arachnoid cysts, constituting the most extensive series reported to date.
Methods: A retrospective analysis was conducted on 31 patients diagnosed with quadrigeminal cistern arachnoid cysts, focusing on clinical presentation, demographics, treatment approaches, and outcomes.
J Vet Intern Med
December 2024
Department of Clinical Science and Services, Royal Veterinary College, University of London, London, UK.
Background: Spinal arachnoid diverticulum (SAD) is considered a rare disease in cats. Previous reports mainly classified SAD in cats as acquired.
Hypothesis/objectives: The aim of this study was to describe the signalment, clinical presentation, diagnostic imaging findings, and outcome in a group of cats with SAD.
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