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Symptomatic progressive ventriculomegaly in hydrocephalics with patent shunts and antisiphon devices
Insights
The antisiphon device (ASD) may cause complications like headaches and neurological issues in some patients with cerebrospinal fluid shunts. Adjusting ASD placement or using alternative valves might prevent these adverse effects.
Area of Science:
- Neurosurgery
- Biomedical Engineering
Background:
- Antisiphon devices (ASDs) are used to prevent cerebrospinal fluid shunt overdrainage and negative intracranial pressure.
- They are recommended for preventing slit ventricles and extreme shunt dependency.
Observation:
- The study involved 40 pediatric and young adult patients with cerebrospinal fluid shunts incorporating ASDs.
- Nine patients experienced adverse symptoms despite documented shunt patency.
- Four patients developed severe neurological symptoms, including coma and headaches.
Findings:
- Patients with ASDs experienced progressive ventriculomegaly in an erect position, despite shunt patency in a horizontal position.
- Symptoms resolved, and ventricular size normalized after switching to alternative valve systems without ASDs.
- The study theorizes that ASD placement downstream from cerebral ventricles could prevent these issues.
Implications:
- The findings suggest potential complications associated with ASDs in certain cerebrospinal fluid shunt systems.
- Alternative shunt valve configurations or ASD placement may be necessary to optimize patient outcomes.
- Further research is needed to refine the use of ASDs and prevent adverse events in hydrocephalus management.
Abstract:
The antisiphon device (ASD) was designed to prevent excessive negative intracranial pressure and overdrainage with cerebrospinal fluid shunts. It has been recommended for prevention of slit ventricles and extreme shunt dependency. It was used by the author in 40 children and young adults who had low pressure headaches or were judged to be at risk for the development of subdural hematomas because of extreme hydrocephalus, relatively fixed head size, or tall stature. Nine patients encountered problems with adverse symptoms in spite of shunt patency. Four had alarming neurological symptoms of coma or severe headaches after incorporation of ASDs in ventriculoperitoneal shunt systems. With patients in the horizontal position, shunt patency was documented but computed tomography revealed progressive ventriculomegaly when they were kept erect. Symptoms abated and ventricular size diminished after conversion to proximal medium pressure diaphragm or spring-ball valve systems without ASDs. Because long shunt systems with ASDs require adequate hydrostatic columns to initiate flow when patients are erect, it is theorized that such symptoms could have been prevented by placing ASDs farther downstream from the cerebral ventricles.