Endoscopic removal of a suprasellar arachnoid cyst: an anatomical study with special reference to skull base

Abstract

Suprasellar arachnoid cysts are rare entities in adults, representing 10% of all cysts. Endoscopic treatment is now preferred for this pathology, allowing a new anatomical approach to skull base structures. The aim of this study is to present the relevant anatomy of the skull base viewed during an endoscopic procedure for a suprasellar arachnoid cyst. A 77-year-old man with 6 months history of walking disorder was referred for neurosurgical evaluation. Physical examination did not show any oculomotor or endocrine disorder. Sagittal T1-weighted MRI demonstrated a large suprasellar arachnoid cyst. The patient underwent a ventriculocystocisternostomy without complications. Postoperative neurologic examination showed an initial improvement of walking disorders. Cerebral CT scan showed a slight reduction in cyst dimensions. During the endoscopic procedure, the anatomical view of the skull base was demonstrative. From the interior of the cyst we were able to identify the following structures: the clivus, pituitary stalk, pituitary gland, basilar artery, posterior cerebral arteries, posterior communicating arteries, oculomotor nerves and the superior wall of cavernous sinus. We identified a slit valve mechanism in the arachnoid next to the basilar artery. Ventriculocystocisternostomy is a useful procedure in treating arachnoid cyst. Moreover, during this procedure, the endoscope allows for better and safer visualization of skull base structures.