The correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a "real" Dandy-Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

The correct interpretation of the modern neuroradiologic techniques may help in selecting adequate treatment between the two main options (third ventriculostomy or shunting). In the last decades, endoscopic third ventriculostomy has become the first-line treatment of aqueductal stenosis; however, some issues, such as the cause of failures in well selected patients, long-term outcome in infant treated with ETV, and effect of persistent ventriculomegaly on neuropsychological developmental, remain unanswered.

Endoscopic third ventriculostomy should be considered as an alternative procedure to ventriculo-peritoneal shunting and external ventricular draining for the emergency control of severe hydrocephalus caused by posterior fossa tumors, since it can quickly eliminate symptoms, and hence, can delay surgery scheduling if required. Even though ETV does not prevent postoperative hydrocephalus in all cases, it does protect against acute postoperative hydrocephalus due to cerebellar swelling. In addition, it eliminates the risks of cerebrospinal fluid (CSF) infection related to external drainage and minimizes the risk of overdrainage because it provides more physiological CSF drainage than the other procedures. Since postoperative hydrocephalus is very often physically obstructive, ETV should always be considered a possible treatment procedure.

Endoscopic placement of a stent in the aqueduct is more effective in preventing the repeated occlusion of the aqueduct than aqueductoplasty alone and should be indicated as the initial treatment in each case of compatible anatomy.

The high ICP observed in a group of patients in the early postoperative days is probably related to the slow permeation of the subarachnoid spaces by the cerebrospinal fluid flowing out of the third ventriculostomy. Management of intracranial hypertension after ETV remains a matter of controversy. The role of the lumbar puncture in the faster normalization of the ICP is examined in this article. By increasing the compliance and the buffering capacities of the spinal subarachnoid spaces, it probably decreases the cerebrospinal fluid outflow resistance from the ventricular system, facilitating the decrease of the ventricular volume and allowing faster permeation of the intracranial subarachnoid spaces. High postoperative ICP can account for persistent symptoms of intracranial hypertension and ventricular dilatation on computed tomographic scans after third ventriculostomy. A cycle of one to three lumbar punctures should always be performed in patients who remain symptomatic and who show increasing ventricular dilatation after ETV, before ETV is assumed to have failed and an extracranial cerebrospinal fluid shunt is implanted.

Object In this paper, the authors' goal was to evaluate the role of neuroendoscopy in the treatment of arachnoid cysts of the quadrigeminal cistern. Methods Between March 1995 and February 2008, 14 patients affected by arachnoid cysts of the quadrigeminal cistern were treated endoscopically. The cysts were classified according to their anatomical and radiological appearance. The most frequent form (Type I) extended infratentorially and supratentorially with a dumbbell shape. Type II cysts were confined to the infratentorial space and were associated with the most severe and acute form of hydrocephalus. Type III cysts presented a significant asymmetric expansion toward the temporal fossa. Ten patients underwent an endoscopic procedure as primary treatment and 4 as an alternative to shunt revision. In 6 cases, the first endoscopic procedure was ventriculocystostomy (VC) together with endoscopic third ventriculostomy (ETV). In the other 8 cases, the first endoscopic procedure was VC alone. Results In the 6 cases in which VC was performed with an ETV, the procedure was successful, and the patients did not require further surgery. Of the 8 cases in which the first endoscopic procedure performed was VC without ETV, 7 underwent reoperation. Four of these patients underwent endoscopic procedures (by reopening the obstructed VC and performing ETV or cystocisternostomy) 2, 4, 4, and 5 months later with final success in all cases. Three patients (all of whom were previously treated using ventriculo- or cystoperitoneal shunts) required shunt reimplantation (complete failure). Subdural collection developed in 1 case, which was managed by transient insertion of a subduroperitoneal shunt. Neurological and developmental outcomes were good except for 1 patient who did not show improvement in preoperative developmental delay. No transient or permanent morbidity or mortality was observed. Conclusions The analysis of this series suggests that arachnoid cysts of the quadrigeminal cistern and the associated hydrocephalus can be effectively treated by endoscopy; this approach allows the patient to be shunt independent in more than 78% of the cases. If endoscopy is used as first option, the success rate of endoscopic procedures observed in this series was 90%. Endoscopic third ventriculostomy should be associated with a VC to offer the highest success rate with a single procedure.

Pseudotumor cerebri is an avoidable cause of visual loss, both in adults and children. Few diagnostic measures are usually sufficient to determine the correct diagnosis. Since pseudotumor cerebri is a diagnosis of exclusion, the differential diagnosis work out is of special importance. Modern neuroimaging techniques, especially magnetic resonance imaging and magnetic resonance venography may clarify the role of obstruction to venous outflow in each case. Various therapeutic options are available: medical, surgical, and endovascular procedures may be used to prevent irreversible visual loss. Treatment is usually effective, and most patients will experience complete resolution of symptoms without persistent deficits.

OBJECTIVE Neuroendoscopic removal of intraventricular tumors is difficult and time consuming because of the lack of an effective decompression system that can be used through the working channel of the endoscope. The authors report on the utilization of an endoscopic ultrasonic aspirator in the resection of intraventricular tumors. METHODS Twelve pediatric patients (10 male, 2 female), ages 1–15 years old, underwent surgery via a purely endoscopic approach using a Gaab rigid endoscope and endoscopic ultrasonic aspirator. Two patients presented with intraventricular metastases from high-grade tumors (medulloblastoma, atypical teratoid rhabdoid tumor), 2 with subependymal giant cell astrocytomas (associated with tuberous sclerosis), 2 with low-grade intraparaventricular tumors, 4 with suprasellar tumors (2 craniopharyngiomas and 2 optic pathway gliomas), and 2 with pineal tumors (1 immature teratoma, 1 pineal anlage tumor). Hydrocephalus was present in 5 cases. In all patients, the endoscopic trajectory and ventricular access were guided by electromagnetic neuronavigation. Nine patients underwent surgery via a precoronal bur hole while supine. In 2 cases, surgery was performed through a frontal bur hole at the level of the hairline. One patient underwent surgery via a posterior parietal approach to the trigone while in a lateral position. The endoscopic technique consisted of visualization of the tumor, ventricular washing to dilate the ventricles and to control bleeding, obtaining a tumor specimen with biopsy forceps, and ultrasonic aspiration of the tumor. Bleeding was controlled with irrigation, monopolar coagulation, and a thulium laser. RESULTS In 7 cases, the resection was total or near total (more than 90% of lesion removed). In 5 cases, the resection was partial. Histological evaluation of the collected material (withdrawn using biopsy forceps and aspirated with an ultrasonic aspirator) was diagnostic in all cases. The duration of surgery ranged from 30 to 120 minutes. One case was complicated by subdural hygroma requiring a subduro-peritoneal shunt implant. CONCLUSIONS In this preliminary series, endoscopic ultrasonic aspiration proved to be a safe and reliable method for achieving extensive decompression or complete removal in the management of intra- and/or paraventricular lesions in pediatric patients.