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.
Professional Abstract
Objective
To compare the effectiveness of anterior versus posterior entry sites for ventriculoperitoneal (VP) cerebrospinal fluid shunts on prolonging time to shunt failure among pediatric patients with hydrocephalus
Study Design
| Design Element | Description |
|---|---|
| Design | Randomized controlled trial |
| Population | 453 pediatric patients under age 18 with hydrocephalus requiring a VP shunt |
| Interventions/ Comparators |
|
| Outcomes |
Primary: time to shunt failure Secondary: quality of life, length of surgery, number of intraoperative catheter passes to enter the ventricle, location of ventricular catheter tip, hospital length of stay, shunt revision rate, and major perioperative complications including pseudomeningoceles, cerebrospinal fluid leaks, subdural hygromas, intracranial bleeds, skull fractures, complications from peritoneal catheter insertion, new neurologic deficits, postoperative seizures, and epilepsy |
| Timeframe | At least 18-month follow-up for primary outcome |
This block-randomized controlled trial compared the effectiveness of two standard entry sites for placing a VP shunt on prolonging time to shunt failure among pediatric patients with hydrocephalus. The study also looked at patients’ complications from surgery and quality of life.
Researchers randomly assigned patients to either an anterior or posterior entry site for a VP shunt. Patients randomized to the anterior entry site had the shunt placed on the top of their heads. Patients randomized to the posterior entry site had the shunt placed on the back of their heads. For both entry sites, the shunt was positioned under the skin to drain excess cerebrospinal fluid into the peritoneum. Surgeons determined the type of shunt hardware and valve used in each procedure as well as postoperative care. Patients had follow-up visits within three months of shunt placement and then annually thereafter for up to three years.
The study included 453 children with hydrocephalus who received treatment at one of 14 hospitals across North America. Of these children, 63% were White, 17% were Black, and 20% reported other race or did not report a race; 19% were Hispanic or Latino, and 15% did not report an ethnicity. The median age was 1.3 months, and 60% were males.
Parents completed surveys about their child’s quality of life before surgery and again one week and 12 to 18 months after surgery. At 6, 18, 30, and 42 months, researchers called parents to find out if children had visited another hospital for shunt problems or if parents had any concerns about the shunts. Researchers also collected data from the children’s electronic health records. An independent, blinded committee reviewed clinical notes, data collection forms, and imaging studies to determine if children experienced shunt failure.
Parents of children with hydrocephalus, representatives from a hydrocephalus patient advocacy organization, and pediatric neurosurgeons helped plan and design the study.
Results
Time to shunt failure did not differ significantly between the two entry sites. Compared with patients with the anterior entry site, patients with the posterior entry site had a higher rate of shunt failure, although the difference was not statistically significant (hazard ratio=1.35; 95% confidence interval: 0.98, 1.85).
Secondary outcomes did not differ significantly between the two locations.
Limitations
Only 52% of parents completed quality of life surveys before surgery. Survey findings may have differed with more responses. After 18 months, fewer patients experienced shunt failure than expected; following patients for longer may have improved power to detect differences in shunt failure between the entry site locations.
Conclusions and Relevance
In this study, shunt failure, quality of life, and complication rates did not differ among patients with anterior and posterior shunt entry sites.
Future Research Needs
Future research could compare failure rates for anterior and posterior shunt entry sites among children with hydrocephalus for a longer time.
Final Research Report
View this project's final research report.
Journal Citations
Results of This Project
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.