Definition & Overview
A ventriculoperitoneal shunt, or a VP shunt, is a medical device installed to relieve pressure on the brain and is recommended for people suffering from hydrocephalus. This condition is brought about by excessive cerebrospinal fluid (CSF) that leads to the rapid widening of the spaces in the brain (ventricles) causing undue pressure. If left untreated, this can ultimately lead to brain damage.
The CSF is a very important component of the nervous system as it creates a cushion for the brain tissue and provides means for the delivery of nutrients into the brain. It flows between the spine and the cranium to ensure there is sufficient intracranial blood volume. The CSF is continuously produced as it flows through the ventricles, nourishing the surface of the brain and spinal cord. It then exits into the base of the brain and gets reabsorbed into the bloodstream. However, due to abnormalities, the flow and balance of the CSF may be disrupted leading to its accumulation.
Ventriculoperitoneal shunt is the main treatment for hydrocephalus, which affects about 1 in every 500 children. It can either be congenital or acquired, and its most apparent indication is the abnormal increase in head circumference. In children, symptoms can be accompanied by downward deviation of the eyes and seizures. In adults, symptoms of hydrocephalus include headaches, nausea and vomiting, swollen optic nerve, blurred or double vision, irritability, lethargy, and changes in cognition or memory. The cause of this condition is yet to be fully understood.
Who Should Undergo and Expected Results
A VP shunt surgery is performed on patients with hydrocephalus. It is often immediately performed as soon as the condition is diagnosed to prevent serious complications.
To confirm hydrocephalus, certain tests such as ultrasound, magnetic resonance imaging (MRI) scan or computed tomography (CT) scan, are usually performed to rule out other conditions. Once confirmed, ventriculoperitoneal shunt is performed at the soonest possible time.
With surgery, excess CSF is drained out of the brain to restore normal volume. However, it is important to note that the procedure does not reverse brain damage if it has already occurred. Its main goal is to prevent any further damage that may otherwise occur if treatment is not immediately provided.
How is the Procedure Performed?
VP shunting is performed under general anaesthesia and it usually takes about an hour or two to finish. In general, the shunt serves as a drainage system that consists of a long tube equipped with a valve. This procedure is performed in the following order:
First, the hair in a pre-determined area of the head is shaved, which is usually at the top or back or behind the ear. The surgeon then makes incisions in strategic areas of the brain to accommodate a catheter that will be later placed in the ventricle. The surgeon also makes another surgical cut in the stomach area.
A hole is drilled in the skull, through which a thin tube (catheter) is inserted into a brain ventricle. Another catheter is positioned under the skin behind the ear and is inserted further into the neck and chest, right down to the belly area.
A fluid pump (valve) is then placed under the skin behind the area and is connected to both catheters. This is designed in such a way that when extra pressure builds up in the brain due to excess CSF, the valve automatically opens and excess fluid is drained through the catheter into the chest area. The shunt is implanted permanently and has to be monitored on a regular basis.
New surgical technology now allows this procedure to be done using an endoscope or through a computer-guided method.
After surgery, recovery usually takes about three to four days, with most patients able to leave the hospital within a week. During hospitalisation, patients are regularly monitored to ensure normal heart rate and blood pressure. Preventive antibiotics are also administered to avoid the development of infection.
Possible Risks and Complications
Ventriculoperitoneal shunt surgery is a very safe procedure with high success rates. However, just like any surgical procedure, there may be risks and complications involved. Surgical risks may include infection and excessive bleeding. Adverse reactions to anaesthesia such as blood pressure level changes and breathing difficulties are also some possible complications.
Complications that are specific to VP shunting are very rare but can be serious. These include:
- Infection of the shunt implant leading to infection of the brain
- Blood clotting
- Bleeding of the brain
- Swelling of the brain
- Damage to brain tissue related to the VP shunt
It is also very important to watch out for symptoms such as fever, abdominal pain, headache, and abnormal spikes in heart rate and blood pressure, which may indicate shunt malfunction.
Pinto FC, Saad F, Oliveira MF, Pereira RM, Miranda FL, Tornai JB, et al. Role of endoscopic third ventriculostomy and ventriculoperitoneal shunt in idiopathic normal pressure hydrocephalus: preliminary results of a randomized clinical trial.
Spiegelman L, Asija R, Da Silva SL, Krieger MD, McComb JG. What is the risk of infecting a cerebrospinal fluid-diverting shunt with percutaneous tapping?. J Neurosurg Pediatr.