Intraventricular pressure dynamics in ventriculocholecystic shunting: a telemetric study.

Extracranial cerebrospinal fluid shunting is the current mainstay of therapy for hydrocephalus. The generally preferred extracranial site for cerebrospinal fluid absorption is the peritoneal space; however, the cardiac atrium and the pleura are also commonly used. On occasion other CSF recipient sites, such as the gallbladder, are used secondarily when the more common absorptive spaces are unavailable or unsuitable. The gallbladder, though, exhibits its own pressure dynamics in response to physiological stimuli. The effects of gallbladder contraction on intraventricular pressure (IVP) in the presence of a ventriculocholecystic (VGB) shunt are unknown. We had the opportunity to place a VGB shunt in a 4-year-old child who was coupled to a noninvasive telemonitor. After a period of acclimation, we examined the IVP dynamics of that shunting system both pre- and postprandially. We found that before ingestion of food, the gallbladder provides a CSF recipient site similar to that of the peritoneal space. However, after ingestion of a meal containing fat, we found that IVP rose more than 10 cm water in a stereotypic fashion consistent with postprandial gallbladder contraction. The increase in IVP lasted for several hours reaching a peak at approximately 75 min postprandially. We conclude that the VGB shunt is a viable alternative for extracranial cerebrospinal fluid shunting; however, one must be aware of the peculiar dynamics of this shunt in relation to food ingestion and the potential for unusually high IVPs.