Complex hydrocephalus (combination of communicating and obstructive type): an important cause of failed endoscopic third ventriculostomy

Seventy one patients of obstructive hydrocephalus who underwent ETV in our institution were included in this study. Aetiology of hydrocephalus included congenital aqueductal stenosis in 42 and tubercular meningitis (TBM) in 29 patients. Failure of ETV was seen in 15 (21%) patients. These 15 patients included 6 (14.3%) from the congenital group and 9 (31.0%) patients from the TBM group. Iohexol CT ventriculography confirmed a patent stoma (suggesting a complex hydrocephalus) in 10 (66.7%) out of the 15 failed ETV cases. The incidence of complex hydrocephalus was more common in TBM group (8/29 patients, 27.60%) compared to congenital group (2/42 patients, 4.8%). The complex hydrocephalus patients with a patent ETV stoma were successfully managed by a lumbar peritoneal (LP) shunt.Ten out of the 71 patients (14%) with obstructive hydrocephalus who underwent an ETV had a complex hydrocephalus, which was the major (66.7%) cause for failure of ETV. Improving methods to detect the exact type of hydrocephalus pre-operatively could increase success rate of ETV and avoid an unnecessary operative procedure (ETV).Hydrocephalus can be communicating, obstructive, or a combination of both. Understanding the basic pathology or the combination of pathologies leading to hydrocephalus in a given patient is essential to decide the best treatment option [1]. Patients with communicating hydrocephalus can be managed with a lumbar peritoneal (LP) shunt [2]. While, in purely obstructive hydrocephalus, an endoscopic third ventriculostomy (ETV) is a preferred option, as an alternative to ventriculoperitoneal (VP)/ventriculoatrial (VA) shunting [1,3]. In some cases, despite a functioning/patent stoma after an ETV, there is no clinical improvement and patients present with persistently raised intracranial pressure (ICP). In such cases, a combination of obstruction with defective absorption may be responsible for their clinical features. This entity with combination of pathologies is referred to