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.