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Shunt removal or replacement based on intraventricular infusion tests
1Department of Neurosurgery, Ullevål University Hospital, Oslo, Norway.
Insights
Ventricular infusion tests help determine if children with shunts need ongoing treatment. This method accurately assesses shunt dependence and function, aiding clinical decisions.
Area of Science:
- Neurosurgery
- Pediatric Neurology
- Medical Devices
Background:
- Hydrocephalus management in children often involves shunts.
- Assessing shunt dependence and function can be challenging using clinical signs and imaging alone.
Purpose of the Study:
- To evaluate the utility of ventricular infusion testing in children with uncertain shunt dependence.
- To differentiate between shunt malfunction and true hydrocephalus requiring continued treatment.
Main Methods:
- Ventricular outflow resistance (R0) was measured using steady-state infusion of artificial cerebrospinal fluid (CSF) in 14 children with shunts.
- Cerebral perfusion pressure (CPP) was maintained above 30 mmHg during the procedure.
- Shunt patency was assessed by unclamping the shunt at plateau pressure.
Main Results:
- Four children with normal R0 values had shunts removed and showed positive clinical outcomes.
- Three children with pathological R0 values that normalized upon unclamping had functioning shunts.
- Seven children with persistently elevated R0 values required shunt revision, with 6 experiencing clinical improvement.
Conclusions:
- Ventricular infusion testing provides a valuable method for assessing shunt dependence and function in complex pediatric cases.
- This technique can guide decisions regarding shunt removal or revision, improving patient management.
Abstract:
In 14 children with indwelling ventriculoatrial or ventriculoperitoneal shunts, the need for continued shunt treatment was judged to be uncertain based on clinical symptoms and signs and CT scans. Ventricular outflow resistance (R0) was determined by implantation of a ventricular catheter and steady state infusion of artificial cerebrospinal fluid (CSF) according to the formula R0 = (Pp - P0)/Infusion rate, where P0 is the opening pressure in the lateral ventricle and Pp the plateau pressure recorded at that particular infusion rate. R0 was determined during general anesthesia and steady state ventilation was ensured by mechanical ventilator. Ventricular fluid pressure (VFP) and arterial blood pressure (ABP) were recorded by standard fluid pressure transducers. The cerebral perfusion pressure (CPP = ABP - VFP) was kept above 30 mmHg by reducing the infusion rate in cases of unacceptable increase in VFP. R0 was determined with the shunt clamped. During steady state infusion at the plateau pressure the shunt was unclamped to test shunt patency. Four children had normal R0 values with the shunt clamped. Their shunts were removed. They have done well clinically, and control CT scans have not demonstrated increased ventricular size. Three children demonstrated pathologic R0 values (above 12 mmHg/ml per min) that normalized after shunt unclamping; i.e. each had a well-functioning shunt. Seven children demonstrated increased R0 values even after shunt unclamping. Their shunts were replaced, and clinical improvement has been observed in 6 of them. Ventricular infusion tests appear useful to evaluate shunt dependence and function in difficult cases.