Programmable Shunt Surgery for Hydrocephalus
A programmable shunt is a type of ventriculoperitoneal shunt (VPS) that is used for treatment for hydrocephalus. Hydrocephalus is a neurological disease literally meaning water on the brain and can be very disabling. This fluid (cerebrospinal fluid or CSF) is normally made then reabsorbed at certain rates and when these rates are not balanced, it can lead to an increase in fluid causing pressure and resulting in neurologic symptoms. CSF normally resides in cavities in the brain called ventricles. The purpose of a programmable shunt is to drain this excess fluid from the ventricle. This is achieved by placing a tube into the ventricle (in the brain) which drains the fluid to the abdomen. A programmable shunt has an adjustable valve which prevents the fluid from moving in the wrong direction and only lets fluid drain when the pressure is too high.
What is its goal?
The goal of a programmable shunt is to reduce the abnormally high pressure inside the brain. This is achieved by placing a catheter in the brain that allows drainage of excess fluid into the abdomen. A programmable shunt has an adjustable valve which allows you to modify the amount of fluid drained after the shunt is implanted.
How is it done?
The patient goes to sleep with general anesthesia. A small hole is made in the skull on the top of the head, behind the hairline. A small catheter is directed into the fluid filled cavity in the brain (ventricle). Tubing is tunneled to a place behind the ear where a valve is placed to regulate the flow of fluid. Tubing is again tunneled down to the belly (peritoneum) where the fluid can drain freely and be absorbed by the body. The surgery usually takes around an hour and a half to perform.
What are the risks?
The major risks of the procedure are bleeding, infection, damage to normal brain tissue and need for future operation. The risk of bleeding is immediate and will be detected while the patient is still in the hospital. If there is excessive bleeding, a larger surgery may be required to prevent brain damage. When the shunt is placed, the catheter must pass through normal brain tissue to reach the fluid cavity (ventricle). The shunt is usually placed in a part of the brain that can tolerate this manipulation, but rarely patients can develop weakness, sensory or visual changes, and speech difficulty. The risk of infection and obstruction is the most common problem with VPS. The shunt tubing is a foreign object in the body which can make it impossible for the body to kill the bacteria growing on the tubing. If a shunt becomes infected, it needs to be removed and replaced with a entirely new system. If obstruction occurs, only the part of the shunt system that does not work needs to be replaced.
What is the success rate?
The success rates depend on the age of the patient and the reason why the shunt is needed. Generally, there is around a 50% failure rate for ventriculoperitoneal shunts. The shunt tubing can become infected or obstructed requiring surgical revision. Endoscopic third ventriculosotomy (ETV) is an alternative treatment that has a higher success rate but only available for select patients (see endoscopic third ventriculosotomy).
How long will I stay in the hospital?
Depending on the clinical situation, patients are able to go home 2-7 days after surgery.
What is special about the way we deliver this treatment?
The Rochester Neurosurgery Partners shunt failure rates are among the lowest in the country. They are currently performing a study to calculate their exact revision rate and to determine which factors lead to a good outcome. The materials and technology used for this procedure are the newest and most advanced. This includes the use of antibiotic coated shunt catheters and MRI guided neuronavigation.