Brain shunt surgery is a medical procedure that involves inserting a thin, flexible tube called a shunt into the brain to help drain excess cerebrospinal fluid (CSF) that has built up.
Shunts have been used to treat hydrocephalus since the 1950s. Shunting is a process of redirecting or rerouting something from its original path or destination to another location or pathway. In people with hydrocephalus, the shunt is typically placed in the brain ventricle, a fluid-filled space inside the brain, and it is then tunneled under the skin to another part of the body, usually the abdomen or the heart, where the excess fluid can be safely absorbed or eliminated.
The shunt has a one-way valve that regulates the flow of CSF and prevents it from flowing too quickly or too slowly. As the pressure of CSF increases inside the brain, the one-way valve opens and the excess fluid drains.
This surgery is usually performed under general anaesthesia, and patients may need to stay in the hospital for a few days after the procedure to monitor their condition and ensure proper healing.
Overall, while shunt surgery is generally considered safe and effective, it does carry some risks of complications.
Types of shunt surgery
Ventriculo-peritoneal (VP) shunt
This is the most common treatment, which shifts fluid from the brain into the peritoneal cavity (a fluid-filled gap between the walls of the abdomen and the organs in the abdomen).
Ventriculo-pleural (VPL) shunt
Shifts fluid from the brain into the pleural cavity (space between the two pleura of the lungs).
Ventriculo-atrial (VA) shunt or Vascular shunt
Shifts fluid from the brain to the right atrium of the heart.
Ventriculo-gallbladder (VGB) shunt
This shunt shifts fluid from the brain to the gallbladder. It is not common but may be used in cases when treatment with other shunt locations is not possible. This might be due to infection, previous shunt failure, or if there is a congenital abnormality in the more common shunt locations.
Subdural-peritoneal shunt (SDP)
This shunt shifts fluid from subdural space to the peritoneal cavity.
These shunts have the following additional features:
- Fixed pressure shunt (most common) – regulates the flow-rate of the fluid based on a predetermined pressure setting; it is used for specific situations in which fluid output needs to be regulated.
- Programmable shunt – adjusts how much fluid is drained by a patient’s VP shunt, even after that shunt has been placed, because it is externally adjustable by a magnetic device.
Shunt complications
While shunt surgery is generally safe and effective, there are several potential complications that may occur, including:
Infection
Shunt surgery increases the risk of developing an infection, either at the site of the surgery or along the shunt tubing. Signs of an infection may include fever, redness, swelling, and drainage from the incision site.
Malfunction or failure
Shunts can malfunction or fail, causing the patient's symptoms to return. The shunt may become blocked, dislodged, or broken. In some cases, additional surgery may be needed to fix the problem.
Overdrainage
Shunts can also cause overdrainage, in which too much CSF is removed from the brain. This can cause headaches, nausea, vomiting, and other symptoms.
Underdrainage
On the other hand, the shunt may not drain enough fluid, leading to a recurrence of symptoms such as headaches, nausea, and vomiting.
Bleeding
There is a risk of bleeding during or after shunt surgery, which may require additional surgery to stop the bleeding.
Migration
In rare cases, the shunt may migrate or move from its original position. This can cause discomfort or may require additional surgery to reposition the shunt.
Tissue overgrowth
Sometimes, tissue may grow over the shunt tubing, obstructing the flow of CSF. This can lead to symptoms such as headaches and nausea.