Shunt system

Cerebral shunt
Intervention
A diagram of a typical brain shunt
MeSH	D002557
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Cerebral shunts are commonly used to treat hydrocephalus, the swelling of the brain due to excess buildup of cerebrospinal fluid (CSF). If left unchecked, the cerebrospinal fluid can build up leading to an increase in intracranial pressure (ICP) which can lead to intracranial hematoma, cerebral edema, crushed brain tissue or herniation. The cerebral shunt can be used to alleviate or prevent these problems in patients who suffer from hydrocephalus or other related diseases. Shunts can come in a variety of forms but most of them consist of a valve housing connected to a catheter, the end of which is usually placed in the peritoneal cavity. The main differences between shunts are usually in the materials used to construct them, the types of valve (if any) used, and whether the valve is programmable or not.

The location of the shunt is determined by the neurosurgeon based on the type and location of the blockage causing hydrocephalus. All brain ventricles are candidates for shunting. The catheter is most commonly placed in the abdomen but other locations include the heart and lungs. Shunts can often be named after the route used by the neurosurgeon. The distal end of the catheter can be located in just about any tissue with enough epithelial cells to absorb the incoming CSF. Below are some common routing plans for cerebral shunts.

A subgaleal shunt is usually a temporary measure used in infants who are too small or premature to tolerate other shunt types. The surgeon forms a pocket beneath the epicranial aponeurosis (the subgaleal space) and allows CSF to drain from the ventricles, creating a fluid-filled swelling on the baby's scalp. These shunts are normally converted to VP or other shunt types once the infant is big enough.

There are a number of complications associated with shunt placement. Many of these complications occur during childhood and cease once the patient has reached adulthood. Many of the complications seen in patients require immediate shunt revision (the replacement or reprogramming of the already existing shunt). The common symptoms often resemble the new onset of hydrocephalus such as headaches, nausea, vomiting, double-vision, and an alteration of consciousness. Furthermore, in the pediatric population, the shunt failure rate 2 years after implantation has been estimated to be as high as 50%.