Endoscopic third ventriculostomy (ETV) is a neurosurgical procedure for hydrocephalus, a condition characterized by excessive cerebrospinal fluid (CSF) within the brain’s ventricles. This procedure restores the natural flow of CSF by creating an internal bypass, aiming to alleviate pressure on the brain.
Understanding Endoscopic Third Ventriculostomy
Endoscopic third ventriculostomy involves a minimally invasive technique to create a new pathway for cerebrospinal fluid within the brain. The “endoscopic” aspect refers to the use of an endoscope, a thin, flexible tube equipped with a light and a camera, which allows the neurosurgeon to visualize the inside of the brain on a monitor. The term “third ventriculostomy” signifies that the procedure creates an opening in the floor of the third ventricle, one of the fluid-filled chambers deep within the brain.
This opening allows trapped cerebrospinal fluid to bypass an obstruction and flow into surrounding spaces, where it can be naturally reabsorbed into the bloodstream. By diverting the fluid internally, ETV normalizes intracranial pressure without the need for an implanted shunt system.
Conditions Addressed by ETV
ETV primarily treats obstructive (non-communicating) hydrocephalus. In this type, a physical blockage prevents normal cerebrospinal fluid flow within the ventricular system. ETV creates a bypass around such obstructions, allowing fluid to circulate freely.
Common causes include aqueductal stenosis, a constriction of the passage connecting the third and fourth ventricles. Tumors near the third ventricle can also cause blockages. Hydrocephalus resulting from post-hemorrhagic or post-infectious complications, where inflammation or scarring obstructs CSF pathways, may also be treated. However, ETV is generally less effective for communicating hydrocephalus, a type where CSF flow within the ventricles is not obstructed, but absorption into the bloodstream is impaired.
Performing the ETV Procedure
The ETV procedure is a neurosurgical procedure performed under general anesthesia. A small section of hair on the scalp may be shaved to prepare the surgical site. A small incision is then made, followed by the creation of a tiny opening, known as a burr hole, in the skull, typically on the right side of the head.
Through this burr hole, the neurosurgeon inserts a thin endoscope, guiding it through brain tissue into a lateral ventricle and then into the third ventricle. The endoscope transmits real-time images to a monitor, providing the surgeon with a clear view of brain structures. Using specialized micro-instruments, an opening is created in the floor of the third ventricle.
This opening allows cerebrospinal fluid to bypass the obstruction and flow into the subarachnoid space, where it can be absorbed. Once the new pathway is confirmed, the endoscope is withdrawn, and the burr hole and incision are closed. The entire procedure typically takes one to two hours.
Recovery and Expected Outcomes
Following an ETV procedure, patients are monitored in a recovery area before being transferred to a hospital room. The typical hospital stay is one to two days. During the initial recovery period, common symptoms can include headaches, nausea, and vomiting, which are usually managed with medication and resolve within a day or two.
Long-term outcomes for ETV vary depending on the underlying cause of hydrocephalus and the patient’s age. For selected cases of obstructive hydrocephalus, particularly those caused by aqueductal stenosis or tumors, ETV has a success rate, with studies reporting overall success around 73.4%. Patients with aqueductal stenosis may see success rates as high as 88.9%. While the goal is to resolve hydrocephalus symptoms, ETV is a treatment, not a cure, and some patients may require further intervention if the created opening closes over time. Regular follow-up appointments, including imaging studies like MRI, are important to monitor the effectiveness of the procedure.
Potential Considerations
While endoscopic third ventriculostomy is generally considered a safe procedure, like any surgical intervention, it carries risks. Complications, though infrequent, can include infection, bleeding, or cerebrospinal fluid leakage from the surgical site. Serious bleeding is a rare but significant concern.
Neurological deficits are rare but have been reported. The overall complication rate for ETV ranges from 8.5% to 35.5% across various studies, with a low mortality rate of 0.21%. A primary consideration is the possibility of the opening closing, which would necessitate further treatment, potentially including a shunt placement.