Endoscopic Management of Lateral Ventricle Arachnoid Cysts-Case Series with Proposed Classification.

Background: We present a case series of 7 patients with intraventricular arachnoid cysts of lateral ventricle managed with endoscopic treatment with proposed classification of the cyst based on anatomic extent.

Methods: In all patients, the lateral ventricle arachnoid cyst was primarily located in the trigone and body of the lateral ventricle. Proposed classification is based on extension of the arachnoid cyst. Type 1 is an arachnoid cyst located in the lateral ventricle only, type 2 is a lateral ventricle arachnoid cyst extending to the quadrigeminal cistern, and type 3 is the lateral ventricle arachnoid cyst extending to the velum interpositum cistern.

Results: Two patients were managed with multiple fenestration and septostomy, and in 1 patient where the cyst was not adherent to the ventricular wall it was excised completely. Two patients who had a lateral ventricle cyst located in the atrium but extending to quadrigeminal cyst were managed with 3 fenestrations. Two patients with a lateral ventricle arachnoid cyst located into the atrium of lateral ventricle and extending to the velum interpositum cistern through the choroid fissure were managed with 3 endoscopic fenestrations. Postoperatively, patients were followed clinically and by radiologic imaging. None of the patients reported recurrence until the latest follow-up.

Conclusions: Multiple endoscopic fenestrations for lateral ventricle arachnoid cyst according to its location and anatomic extension help to reduce recurrence and good outcome. Cyst excision is recommended only when the cyst wall is easily separable from the lateral ventricle wall. Intraoperative use of thulium light amplification by stimulated emission of radiation helps in achieving early hemostasis and easy perforation of the thick cyst wall.