Endoscopic Fenestration of Middle Fossa Arachnoid Cysts: A Technical Description and Case Series

Abstract

Background: Arachnoid cysts are intra-arachnoidal cerebrospinal fluid collections most frequently seen in the middle cranial fossa. The optimal method of treatment for symptomatic arachnoid cysts remains controversial and includes cyst shunting, open craniotomy and endoscopic fenestration. All these techniques, however, have been associated with the development of postoperative subdural fluid collections. We describe a new endoscopic transcortical technique that attempts to avoid this complication. Methods: Six patients with middle cranial fossa arachnoid cysts were treated with endoscopic fenestration at our institution between January 2002 and December 2005. Three cases were approached directly through the cyst, while the other 3 were approached by passing the endoscope through the rim of adjacent cortex. Results: All six endoscopic fenestrations were successful in treating the arachnoid cysts. Among the 3 patients treated via a direct cyst entry, 2 cases developed significant subdural hygromas, 1 of which required aspiration. On the other hand, 1 of the 3 cases treated using a transcortical technique developed an insignificant postoperative extra-axial collection that resolved at 3 months without intervention. Conclusion: Endoscopic fenestration is an effective treatment for symptomatic arachnoid cysts. Endoscopic fenestration via a transcortical approach attempts to minimize cerebrospinal fluid drainage into the subdural space, avoiding the development of significant postoperative extra-axial collections, while promoting flow into the basal cisterns.

Management of subdural hygromas associated with arachnoid cysts

“…In reported series, surgical fenestration of arachnoid cysts has resulted in iatrogenic postoperative subdural hygroma in approximately 4% to 29% of cases. 11,13,18,21,22,25,30,36,44,48,60,66,69,70,72,84 The incidence of asymptomatic subdural collections following surgical fenestration may be even higher. 66 As with idiopathic or posttraumatic hygromas, these postoperative hygromas may cause symptoms of elevated ICP, 72 leading Maixner et al 47 to term this phenomenon "pseudotumor syndrome following surgery for arachnoid cysts."…”

Middle Cranial Fossa Arachnoid Cyst Presenting With Subdural Effusion and Endoscopic Detection of Tear of the Cyst -Case Report-

“…2) Recently, advances in neuroendoscopic surgery have allowed treatment by endoscopic cyst fenestration. [3][4][5][7][8][9]14,16) Simple burr hole drainage has often been used in middle cranial fossa arachnoid cyst combined with subdural hematoma. However, various approaches have been selected in cases associated with subdural effusion.…”

Surgical Decompression of Supratentorial Arachnoid Cysts in Pediatric Patients Younger than One Year

“…Endoscopic treatment of arachnoid cysts has been reported increasingly in the last decade, mostly focusing on patients with middle fossa or suprasellar cysts [29, 30]. Microsurgical fenestration carries potential morbidity and shunt placement could be technically difficulty for midline supratentorial arachnoid cysts related to the third ventricle, such as in case 3.…”