Advances in the endoscopic management of suprasellar arachnoid cysts in children

Abstract

Object: Suprasellar arachnoid cysts present unique management problems. The authors retrospectively reviewed six cases, in which endoscopic ventriculocystocisternotomy was performed, to identify specific neuroimaging features that aid both the accurate diagnosis of this entity and the postoperative assessment of fenestration patency.

Methods: Six consecutive children underwent treatment for suprasellar arachnoid cysts. Consistent radiographic features in all cases were identified. Through a single entry site, endoscopic fenestration was performed at both the apical and basal cyst membranes. Outcome was assessed using clinical examination, quantitative changes in cyst size, and triplanar magnetic resonance (MR) imaging with flow-sensitive (long TR) sequences. In every case, the suprasellar cysts displayed three diagnostic MR imaging features: 1) vertical displacement of the optic chiasm/tracts; 2) upward deflection of the rostral mesencephalon and mammillary bodies; and 3) effacement of the ventral pons. Two patients initially underwent placement of a ventriculoperitoneal shunt before the cysts were recognized, but MR images obtained after shunt placement revealed the cysts. In a mean follow-up period of 26.2 months, all patients improved clinically. Postoperative imaging revealed a mean cyst volume decrease of 52.7% and a return to more normal suprasellar and prepontine anatomy. Flow-sensitive MR imaging confirmed pulsation artifact at all 12 fenestration sites. There was no surgery-related death and no additional cerebrospinal fluid diversion procedure was required.

Conclusions: To aid in the accurate diagnosis of prepontine arachnoid cysts, the authors identified several pathognomonic features on sagittal MR images: vertical deflection of the optic chiasm and mammillary bodies, as well as pontine effacement. Dual endoscopic fenestration into the intraventricular compartment and basal cistern is safe, and it effectively provides symptomatic relief by decreasing the cyst size. Triplanar flow-sensitive MR imaging sequences can confirm fenestration patency without the need for cine-mode MR imaging.