**7. Complications**

successful when performed in patients with intraventricular hemorrhage (IVH) and previous shunting; it is also highly successful in patients with primary aqueductal stenosis, while patients with history of both hemorrhage and infection are poor candidates for ETV

Some authors recommended the use of temporary CSF diversion, such as Ommaya reservoir in the acute stage of IVH, and performed the ETV when evidence of ventricular dilatation is obvious [75]. Moreover, in adult patients with IVH, studies showed that endoscopic third ventriculostomy may be an option in cases of acute intracranial hemorrhage with intraventricular extension in which there is clearly established CSF outflow obstruction, with special

The question of in which cases a reclosure of the ETV opening occurs is still not answered. The recent data indicate that failure of ETV may occur immediately after the primary procedure, where the main cause is poor indication of remaining membranes or even years after where it is due to scarring [77, 78]. A redo ETV is supported before deciding to do other CSF diversion procedures whenever a failure was encountered, at which the ETVSS predicts the chance of successful redo ETV. Failure of the ETV and thus redo ETV can be also predicted by the presence of excessive prepontine arachnoid membranes in addition the use of external ventricular

In such cases, hydrocephalus is caused by a large posterior fossa cyst in cases of Dandy-Walker malformation. ETV alone, with aqueductal stent, or with fenestration of the cyst can

Cystoventricular stent placement with endoscopic third ventriculostomy is a promising alternative in patients with Dandy-Walker malformation with aqueductal obstruction [26].

ETV has been recently introduced as a treatment option for normal pressure hydrocephalus. Gangemi et al. mentioned an overall success rate of 72%, in a series of 25 patients [31]. In a larger multicentric study, the clinical improvement reached 69.1%, where the improvement was correlated to the short clinical history, better neurological score before the operation, and the intraoperative appearance of normal cerebral pulsations [82]. Hailong et al. reported an 82.35% success rate and claimed that the preoperative Kiefer score and the patient's age are significant prognostic factors for ETV dysfunction [30]. However, the criteria of patients' selection and the small sample size in most previous literature would justify the actual deficiency of solid evidence that supports ETV as a treatment option in normal pressure hydrocephalus. Large-scale clinical studies are needed to reach better evidence and define the role

[72, 73].

**6.3. Redo success rate**

102 Hydrocephalus: Water on the Brain

drain EVD [78, 79].

**6.4. Dandy-Walker malformation**

**6.5. Normal pressure hydrocephalus**

of ETV in the management of INPH [83].

be sufficient in some cases to control hydrocephalus [80, 81].

concern paid toward the surgeon experience [76].

In a previous literature review, the overall complication rate was 8.5%; among the individual series, the rate ranged from 0 to 31.2%. Complications reported in the immediate postoperative period were mainly hemorrhagic, infectious, subdural collections and CSF leak [84]. These complications represent actually the same complications that can be encountered with the ventricular shunting in exclusion of the hardware-related complications with variable incidence rates that can differ according to the variable age groups.

In conclusion, although ETV is considered a reliable resort to control the hydrocephalus without implanting a shunt, the debate on its success rate is still not finalized especially in young children and communicating hydrocephalus. So that more studies covering those types are warranted.
