{"id":"c28831ab-df84-4cea-907c-0a1a6f1e8bc8","slug":"endoscopic-fenestration-of-an-acquired-arachnoid-cyst-causing-a-trapped-lateral-ventricle-two-dimensional-operative-video","title":"Endoscopic fenestration of an acquired arachnoid cyst causing a trapped lateral ventricle: Two-dimensional operative video","authors":["William M. Burns","Redi Rahmani","Rohin Singh","Gurkirat S. Kohli","Jonathan J. Stone"],"abstract":"Background: Arachnoid cysts are commonly congenital but they can also be acquired in the setting of surgery, trauma, hemorrhage, or infection. The pathophysiology of arachnoid cysts may involve adhesive arachnoiditis secondary to arachnoid tissue injury, leading to cerebrospinal fluid accumulation. While often asymptomatic, arachnoid cysts can produce symptoms due to mass effect or hydrocephalus. Intraventricular or periventricular cysts can lead to ventricular entrapment. Case Description: In this video, we present a case of a 28-year-old female patient who developed an intraventricular arachnoid cyst following resection of a Grade I meningioma. This led to left lateral ventricular entrapment and associated hemianopia, headache, nausea, and fatigue. The arachnoid cyst was managed with endoscopic fenestration with the aid of stereotactic neuronavigation. The operative video reveals multiple veils of adhered arachnoid firmly associated with choroid plexus as well as with the lateral walls of the ventricle. Using blunt instruments, bipolar cautery, endoscopic microscissors, and a Fogarty balloon, a wide communication between the body of the lateral ventricle and the trapped temporal horn and atrium was achieved. The patient experienced complete resolution of preoperative symptoms. Follow-up imaging revealed interval reduction in the size of the left lateral ventricle without evidence of cyst recurrence. The patient consented to the procedure, and the Institutional Review Board approval was not required as all identifiable patient information is removed. Conclusion: While there are no significant differences in clinical or radiologic outcomes between different surgical strategies in managing arachnoid cysts, endoscopic cyst fenestration offers a balance between definitive treatment and avoidance of shunt dependence. 2:21 - MRI of arachnoid cyst 2:42 - Treatment options and rationale 4:05 - Surgical plan and equipment 4:41 - Operative video 6:02 - Disease background 7:13 - Postoperative course 7:31 - Postoperative MRI The Institutional Review Board approval is not required. The authors certify that they have obtained all appropriate patient consent. There are no conflicts of interest. The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI. https://doi.org/10.25259/SNI_414_2025 The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.","thumbnailUrl":"https://sni-digital-videos.s3.amazonaws.com/placeholders/specialty/neuroendoscopy.png","publishDate":"2025-09-12T00:00:00.000Z","doi":"10.25259/SNI_414_2025","categories":["Neuroendoscopy","Video Abstract"],"fullTextUrl":"https://surgicalneurologyint.com/api/articles/c28831ab-df84-4cea-907c-0a1a6f1e8bc8/pdf"}