Placement of Ommaya reservoir following endoscopic third ventriculostomy in pediatric hydrocephalic patients: A critical reappraisal

Purpose: Endoscopic third ventriculostomy (ETV) has become standard for obstructive hydrocephalus. Even a successful ETV can obstruct, leading to recurrence of symptoms and even death. A possible solution to this problem is leaving an Ommaya reservoir (OR) following the ETV. OR can be tapped in an emergency and for diagnostic purposes. No specific complications have been attributed to OR in this setting. We present our experience with OR in children undergoing ETV for hydrocephalus. Materials and methods: A retrospective study was conducted in hydrocephalic children that underwent ETV with OR insertion over 13 years (1997-2010) from a single institution. Data were collected from charts and follow-ups. Results: Twelve patients (from 200 patients who had an ETV) underwent placement of OR with ETV. OR was reserved for a subgroup of patients in whom we anticipated complications-in children that presented with acute hydrocephalus and were in deteriorating condition, for pathologies believed to have a low predicted ETV success rate, or when the surgeon felt that the ETV procedure was suboptimal. OR was tapped in eight patients. Complications occurred in four patients: two cases of subdural effusion, one case of chronic subdural hematoma, and one CSF leak. Four ORs were removed due to complications, and four were converted to shunts. Conclusions: OR should be considered in selected patients undergoing ETV. Despite its obvious advantages, OR may be associated with a relatively high risk of extraaxial fluid collections. This association requires further investigation.