Does the size of an Endoscopic Third Ventriculostomy (ETV) hole increase over time?

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By Aparna Srinivasan


Permanent shunts are the most common form of treatment for patients with hydrocephalus. However, if a patient has hydrocephalus due to blockage of cerebrospinal fluid (CSF) between the third ventricle and the basal cisterns, often referred to as non-communicating hydrocephalus, they may have an option of treatment without the placement of a shunt. 

This procedure is known as an endoscopic third ventriculostomy (ETV). During an ETV procedure, the surgeon makes a hole on the floor of the third ventricle through which the CSF can drain, bypassing the blockage. The success of this procedure is determined by whether or not the clinical symptoms of hydrocephalus improve. One way the ETV can fail is if the hole closes. However, no research group has looked at what happens to the hole in the months and years after the procedure. 

Dr. Miguel Trelles and his colleagues at Johns Hopkins University in Baltimore, used magnetic resonance (MR) imaging to determine how the area of the third ventriculostomy hole changes over time. In this study, researchers looked at 295 MR images from 84 patients who had undergone an ETV.


It was found that, for a majority of the patients in this study, the area of the ETV hole increased over a period of time. Immediately after the surgery, the average hole size was 4.6 mm2 which is a bit smaller than the tip of a lollipop stick. The first three months after surgery showed the greatest increase in the size of hole by approximately 0.037 mm2/day. Over the next three years the researchers found that the rate at which the size of the hole was increased, gradually declined. On average, the area of the hole increased by 7.5 mm2 a year (0.02 mm2/day). The one factor that correlated with the increase in the area of hole was the age of the patient at surgery. The size of the hole increased at a higher rate for older patients. The only two patients who had narrowing and subsequent closure of the hole were 19 and 22 years of age. 


This study is the first to evaluate the size of the ETV hole using MR imaging over a period of time. This research is important because it shows us how useful MR imaging can be to neurosurgeons who want to evaluate an ETV. The findings will help surgeons determine how often and when MR imaging is necessary for their patients. 

To read more about this study, click here.

Author Aparna Srinivasan is currently a high school senior. She enjoys playing the flute in her community orchestra and the school marching band. In the future, she hopes to pursue a career in medicine.

3 Comments for : Does the size of an Endoscopic Third Ventriculostomy (ETV) hole increase over time?
    • Giana
    • March 6, 2019

    I had an ETV almost 7 years ago.
    This studies seems to concern me. Is the hole getting too large an eventual issue for patients?

    • Vivian
    • March 4, 2019

    Blood thinners can change the flow, that happened to my husband, it was again adjusted and he was fine. We were told to watch for delirium …It presented it self as agitated ,wanting to sleep, ..he had type 2 diabetes, and was in hospital for a second amputation…was very jovial and friendly with everyone, that suddenly changed ,the doctors then told me they had no idea what was happening…Dr. M. Hamilton in Calgary and Dr. Urbanija were his Neurosurgeons ,when they were contacted they knew immediately the problem and it was fixed.

    • Tim Abernathy
    • February 5, 2019

    I had a shunt put in two years ago. I have had difficulty remembering things. Along with my gate while, walking and numbness on my left side at times. I have been anxious, edgier and more sleeping than normal is this normal?
    I had to go on disability because, of my memory and falling down. Is this considered a disability and can I ever return back to work?

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