Symptomatic cysts of the cavum septi pellucidi and cavum vergae: the role of endoscopic neurosurgery in the treatment of four consecutive cases.

Cavum septi pellucidi and cavum vergae are generally asymptomatic fluid collections between the leaves of the septum pellucidum and are present in approximately 15 % of adult brains. These cavities rarely enlarge and become symptomatic causing significant neurological dysfunction as a result of obstruction of the interventricular foramina, distortion of the vascular structures of the deep venous system or compression of the hypothalamoseptal triangle. The authors present a series of four patients with symptoms related directly to pressure effects from the cyst wall to the neighbouring deep brain structures. There were two females and two males with a mean age of 47.5 years. All four patients underwent endoscopic cyst fenestration with a rigid endoscope. In 2 patients frameless neuronavigation was accomplished with the optical tracking system (Radionics, Burlington, USA). All symptoms related to pressure effect resolved after surgery. Endoscopic pellucidotomy of symptomatic cysts of the septum pellucidum produces immediate relief of the mass effect of the cyst and resolution of associated symptoms. Additionally, frameless neuronavigation is a useful tool in planning and realizing the approach and improving intraoperative orientation.