Endoscopic treatment of adult idiopathic obstruction of the foramen of Monro.

Background: Adult idiopathic membranous obstruction of the foramen of Monro is an extremely rare condition that can be effectively treated with endoscopic foraminoplasty. A unilateral or bilateral foraminoplasty is performed if one or both of the foramina of Monro are obstructed, respectively. Endoscopic septum pellucidotomy is usually used in combination with the foraminoplasty.

Blake's pouch cyst.

Background: In 1900, Joseph Blake described a transient posterior evagination of the tela choroidea of the fourth ventricle in the normal 130-day old human embryo. He was the first to recognize and fully elucidate on the real nature of the foramen of Magendie as an aperture, which develops within a saccular expansion of the embryonic fourth ventricular cavity. The persistence of this temporary fourth ventricular outpouching into the postnatal period and its significance either as separate entity or as an entity within the Dandy-Walker continuum has over the years been one of the most controversial topics in both neurosurgical and neuroradiological literature.