Results Summary

What was the research about?

Hydrocephalus, or water on the brain, affects 1 to 2 of every 1,000 babies born in the United States. Hydrocephalus occurs when the brain can’t absorb cerebrospinal fluid as quickly as it is made. This imbalance causes fluid to build up and increase pressure on the brain.

Placement of a shunt is the most common treatment for hydrocephalus. The shunt is a small plastic tube inserted under the scalp and into the brain to drain the excess fluid. When surgeons put in a shunt, they choose an entry site, or location on the head, where they can insert it. But some shunts get blocked and stop draining.

In this study, the research team wanted to learn whether the shunt’s entry site affects how long it will work. The study compared two commonly used shunt entry sites for children with hydrocephalus:

  • Anterior, or on the top of the head near the front
  • Posterior, or on the back of the head

The research team looked at how long it took for some shunts to stop working, children's quality of life, and side effects from surgery.

What were the results?

Among children whose shunt stopped working, the length of time before the shunt stopped working was similar between the two entry sites.

Among all children, quality of life and side effects from surgery didn’t differ between the entry sites.

Who was in the study?

The study included 453 children with hydrocephalus receiving care at one of 14 hospitals across North America. Among the children, 63 percent were White, 17 percent were Black, and 20 percent reported other race or didn’t report a race; 19 percent were Hispanic or Latino, and 15 percent didn’t report an ethnicity. Most children were under six months old, and 60 percent were boys.

What did the research team do?

The research team assigned children by chance to an anterior or posterior entry site. All children received usual care after surgery. Children had follow-up visits within three months of surgery and then once a year.

Parents completed surveys about quality of life before surgery and then one week and 12 to 18 months later. At 6, 18, 30, and 42 months, the research team asked about concerns with the shunt or if children went to another hospital for problems with the shunt. An independent group of doctors reviewed health records to determine if a shunt had stopped working.

Parents of children with hydrocephalus, staff from patient advocacy groups, and pediatric surgeons helped plan and design the study.

What were the limits of the study?

Only 52 percent of parents answered the quality of life survey at the start of the study. Results may have differed with more responses. After 18 months, fewer children had shunts that stopped draining than the research team expected. If the study had been longer, the team might have found differences between the entry sites.

Future research could compare results for the two entry sites for longer.

How can people use the results?

Surgeons and parents can consider these results when considering shunt entry sites for children with hydrocephalus.

Final Research Report

View this project's final research report.

Journal Citations

Related Journal Citations

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments. 

Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:

  • The reviewers noted that this trial comparing two techniques for inserting shunts to treat hydrocephalus in children found no significant difference in time to shunt failure, but the authors’ sensitivity analyses pointed to a higher failure rated in posterior shunt entry compared to anterior shunt entry. The reviewers suggested that the authors note this difference in their abstract conclusions but acknowledge that the difference could be due to chance. The researchers considered this suggestion but in their review of the data noted that the difference might be related more to the surgeons in the study rather than to shunt entry site. Therefore, the researchers felt that their original conclusion of no difference between groups was still the most accurate statement.
  • The reviewers pointed out the high rates of missing information about patient quality of life at both the baseline and the one-year assessments. They did not agree with the researchers’ contention that data were missing at random and recommended that the researchers use multiple imputation in a sensitivity analysis to account for the factors that contributed to the missing data. The researchers noted that the factors they believed to contribute to missing data were not related to the assessment or the intervention and were concerned about the validity of the multiple imputation approach given the substantial amount of missing data in this study. However, the researchers did impute the missing data using several available patient characteristics and conducted the recommended sensitivity analysis. They reported that the results of the sensitivity analysis were similar to the main analyses and that there was no difference between treatment groups in patient quality of life.
  • One reviewer asked the researchers to add a description of the valve types used in the surgeries and recommended that the researchers add valve type to their analyses. The researchers declined this addition because there is research evidence that valve type does not affect shunt survival in this population, and they preferred not to list the valve types so they would not appear to be endorsing a specific valve product.

Conflict of Interest Disclosures

Project Information

William Whitehead, MD, MPH
Baylor College of Medicine
A Randomized Controlled Trial of Anterior Versus Posterior Entry Site for Cerebrospinal Fluid Shunt Insertion

Key Dates

September 2014
June 2022

Study Registration Information


Has Results
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Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
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Last updated: January 3, 2023