Project Summary

This research project is in progress. PCORI will post the research findings on this page within 90 days after the results are final.

What is the research about?

Chiari type I malformation is a disorder where brain tissue extends into the spinal cord. Doctors usually diagnose this health problem in late childhood or early adulthood. Patients who have Chiari type I malformation and syringomyelia, a cyst or fluid-filled sac in the spinal cord, can have headaches and a hard time talking, swallowing, and breathing.

Doctors use two types of surgery to treat Chiari type I malformation and syringomyelia. In the first type, called posterior fossa decompression, the surgeon removes a small section of bone at the back of the skull to reduce pressure on the brain. In the second type of surgery, called duraplasty, the surgeon does the same procedure and opens the cover of the brain, called the dura. The surgeon then sews in a patch of tissue to make the dura bigger and relieve pressure on the brain.

One in five patients have complications from duraplasty, such as infection. To avoid complications, some patients opt not to have duraplasty. But if decompression without duraplasty does not ease symptoms, patients may need to have a second surgery.

Doctors don’t know whether either type of surgery is more effective for relieving symptoms. In this study, the research team is comparing decompression with and without duraplasty to see how well each type of surgery relieves symptoms and if either causes less harm. The team is also comparing the two approaches on quality of life after surgery.

Who can this research help?

Study results may help patients with Chiari type I malformation and syringomyelia make decisions with their doctors about surgery options.

What is the research team doing?

The research team is enrolling 148 patients ages 0 to 21 years with Chiari type I malformation and syringomyelia. The team is assigning patients, by chance, to have decompression surgery with or without duraplasty. Patients return to the surgeon’s office three times after surgery for a nervous system exam. At these visits, patients complete two surveys about their symptoms and quality of life. One year after surgery, patients have a brain and spine scan to measure the size of their cyst.

Clinicians, caregivers, and patients help plan and monitor the study and share results.

Research methods at a glance

Design Elements Description
Design Randomized controlled trial
Population Children and young adults ≤21 years old with Chiari malformation type I ≥5 mm tonsillar ectopia, syrinx between 3 mm and 6 mm, and Chiari Severity Index classification 1
  • Posterior fossa decompression surgery
  • Posterior fossa decompression surgery with duraplasty

Primary: complications of surgery (e.g., cerebrospinal fluid leaks, infections, meningitis)

Secondary: size of syrinx, quality of life

Timeframe 12-month follow-up for primary outcome

Project Information

David Limbrick, MD, MS, PhD
Washington University School of Medicine
Posterior Fossa Decompression with or without Duraplasty for Chiari Type I Malformation with Syringomyelia

Key Dates

September 2015
May 2023

Study Registration Information


Award Type
Health Conditions Health Conditions These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them. View Glossary
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
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
State State The state where the project originates, or where the primary institution or organization is located. View Glossary
Last updated: January 20, 2023