Quadrigeminal cistern arachnoid cyst treated by endoscopic ventriculocystostomy through the trigonal region.

Background: When symptomatic, quadrigeminal cistern arachnoid cysts (QCACs), comprising 5 to 10% of all intracranial arachnoid cysts, are treated by open fenestration or shunt placement and in recent decades by endoscopic techniques. We introduce a novel endoscopic technique that may be used for surgery of QCACs.

Methods: A 52-year-old woman with a known history of QCAC (treated twice previously by open procedures) presented with symptoms, signs, and radiologic indicators of shunt malfunction and cyst recollection. Because of high-riding pineal gland and distortion of anatomy that resulted from the last surgeries, and loss of a suitable visual angle, a satisfactory ventriculocystostomy was not possible through the third ventricle. Therefore, the cyst was approached by entering the trigonal region of the lateral ventricle, allowing to perform ventriculocystostomy.

Conclusions: Postoperative imaging and follow-up visits proved this approach to be efficacious. This report, for the first time, introduces the so-called transtrigone lateral ventricle cystostomy as an alternative for cases of QCAC for which the ventriculocystostomy via the third ventricle is not suitable.