Conventional shunting of isolated fourth ventricle is notorious for leading to frequent and severe complications. We present four patients with isolated fourth ventricle who have been treated with open posterior fossa surgery together with either outlet fenestration alone or outlet fenestration and a fourth ventricle-spinal subarachnoid space (SSS) shunt. A survey of the relevant literature did not yield any other case reports of fourth ventricle shunting to the SSS under such circumstances. This paper discusses the reasons for choosing this mode of treatment. The main advantage of this technique is that the catheter is inserted along the anatomical long axis of the fourth ventricle. This positioning lessens the possibility of irritating or penetrating the brain stem. Moreover, as a more physiological solution, the shunt does not require a valve system. Because of these advantages, internal fourth ventricle-SSS shunting is proposed as a valid alternative to the "classic" fourth ventriculo-peritoneal shunt.

Clinical features, therapeutic approaches and prognosis of this rare tumour are discussed with regard to the known 30 cases in the literature.

We report a 1 1/2-year-old child with an ependymoma in the posterior cranial fossa. As the computed tomographic scan showed evidence of marked triventricular hydrocephalus, the patient underwent ventriculoperitoneal shunting. Two hours after operation, he developed a fatal intratumoral hemorrhage. The indications and contraindications of ventricular external or internal drainage before posterior cranial fossa tumor removal are briefly discussed.

The authors report two pediatric cases of transient mutism that occurred after surgical removal of a medulloblastoma and a pilocytic astrocytoma of the vermis and discuss the pathophysiology of this syndrome. Transient mutism has been described for the first time quite recently, even in cases where these tumors were also surgically removed before. Perhaps improvement in imaging and in surgical techniques made neurosurgeons more daring and some interventions that were judged impossible are routinely performed today. If this is the case, postoperative transient cerebellar mutism might be considered the price that must be paid in order to cure more patients with cerebellar tumors.

A case of aqueductal stenosis following mumps infection is reported, to the authors' knowledge the 12th case in the literature. The pathogenetic events are discussed and the literature reviewed.