What it is
A ventriculoperitoneal (VP) shunt is a system of catheters and a one-way valve implanted under the skin. A catheter is placed into one of the brain's ventricles (fluid-filled chambers), connected to a programmable pressure valve behind the ear, and tunneled under the skin down to the abdomen where the distal catheter drains into the peritoneal cavity. The fluid is then absorbed by the peritoneum, bypassing the normal circulation pathway that is either blocked or impaired.
The valve is programmable — its opening pressure can be adjusted non-invasively with a magnet after implantation, which allows fine-tuning of drainage without additional surgery.
What to expect
Shunt placement is performed under general anesthesia and typically requires an overnight hospital stay. The majority of patients notice improvement in symptoms — particularly gait and cognition in NPH — within days to weeks of surgery.
Shunts are mechanical devices and can malfunction. The most common issues are obstruction (the catheter tip becomes blocked) and infection. Shunt revisions — to replace a malfunctioning component — are not uncommon over a patient's lifetime. Patients with shunts should know the symptoms of shunt malfunction: return of original hydrocephalus symptoms, severe headache, nausea, or altered mental status.
Alternatives
Endoscopic third ventriculostomy (ETV) is an alternative for obstructive hydrocephalus that avoids implanted hardware entirely. Whether ETV is appropriate depends on the cause of hydrocephalus, patient age, and prior surgical history.