PFDD Versus PFDRT in Chiari Decompression Surgery

February 12, 2026 updated by: Xuanwu Hospital, Beijing

Type of Surgical Intervention for Chiari Malformation-syringomyelia: a Multicenter Randomized Controlled Study

The purpose of this study is to determine whether a posterior fossa decompression and duraplasty with or without tonsil manipulation results in better patient outcomes with fewer complications and improved quality of life in those who have Chiari malformation type I and syringomyelia.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Participants with Chiari Malformation type I and syringomyelia will be randomized to either have a posterior fossa decompression and duraplasty with or without tonsil manipulation. The participant will then return to the neurosurgeon's office at the following time points which are consistent with standard of care practice: 3-6 months, 12 and 24 months. At these visits, the clinician will complete a physical exam and the participant will report on the prognosis of symptoms and complete questionnaires. A spine MRI will be performed 3-6 months, 12 and 24 months after the surgery.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
250

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Beijing Municipality
      • Beijing, Beijing Municipality, China, 100053
        • Fengzeng Jian

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥14 years old
  • Chiari malformation type I ≥5 mm tonsillar ectopia
  • a syrinx with a width > 50% of the cross-sectional diameter of the spinal cord , and a length of at least 2 cervical and/or thoracic vertebral segments.
  • MRI of the brain and cervical and thoracic spine are required prior to surgery and must be available to be shared with the Data Coordinating Center

Exclusion Criteria:

  • included one or more of the following preexisting conditions: hydrocephalus; tumor; brain trauma; stroke; meningitis; abscess;
  • other congenital anomalies of the brain or skull base; vertebral anomalies (i.e., Klippel-Feil, atlas assimilation, etc.);
  • degenerative or demyelinating disease;
  • CM-I without syringomyelia;
  • syringomyelia with cerebellar tonsils in a normal position;
  • fibromyalgia;
  • chronic fatigue syndrome;
  • prior posterior fossa surgery.
  • Unable to share pre-decompression MRI of the brain and spine Patients who do not wish to participate

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Posterior fossa decompression with duraplasty
In brief, a midline incision was made from the inion to the C2 level. A piece of autologous fascia was harvested from the muscular fascia layer. Paraspinal muscles were dissected to expose the occipital bone, posterior arch of the atlas and axis, spinous process, and lamina. The inferior portion of the occipital bone and approximately 2 cm of the posterior arch of C1 were removed, achieving bony decompression (approximately 2.5-3 × 2.5-3 cm). Once the dura was exposed, the atlanto-occipital membrane was coagulated and dissected off the dura. The dura was then incised in a Y-shaped fashion, with care taken to preserve the underlying arachnoid. Watertight duraplasty was performed using the autologous fascia. The wound was closed in anatomical layers.
Procedure: Posterior fossa decompression with duraplasty
In brief, a midline incision was made from the inion to the C2 level. A piece of autologous fascia was harvested from the muscular fascia layer. Paraspinal muscles were dissected to expose the occipital bone, posterior arch of the atlas and axis, spinous process, and lamina. The inferior portion of the occipital bone and approximately 2 cm of the posterior arch of C1 were removed, achieving bony decompression (approximately 2.5-3 × 2.5-3 cm). Once the dura was exposed, the atlanto-occipital membrane was coagulated and dissected off the dura. The dura was then incised in a Y-shaped fashion, with care taken to preserve the underlying arachnoid. Watertight duraplasty was performed using the autologous fascia. The wound was closed in anatomical layers.
Experimental: PFDD with tonsillar resection/reduction
Briefly, a midline incision approximately 3-4 cm posterior to the foramen magnum is made. The incision is deepened layer by layer along the midline to reach the occipital bone, exposing the posterior margin of the foramen magnum and part of the occipital squama. The posterior edge of the foramen magnum is opened, and part of the occipital squama is removed up to the junction of the cerebellar vermis and cerebellar tonsils. The occipitoatlantal fascia is exposed and dissected. The dura mater and arachnoid mater are incised longitudinally and suspended bilaterally to provide a clear surgical field. The primary objectives of resection were: ensuring no significant obstruction of CSF circulation at the foramen magnum and the foramen of Magendie under natural conditions. Preventing occlusion of the foramen of Magendie caused by herniated cerebellar tonsils or any membranous structures under natural conditions. The dura is closed in situ.
Procedure: PFDD with tonsillar resection/reduction
Briefly, a midline incision approximately 3-4 cm posterior to the foramen magnum is made. The incision is deepened layer by layer along the midline to reach the occipital bone, exposing the posterior margin of the foramen magnum and part of the occipital squama. The posterior edge of the foramen magnum is opened, and part of the occipital squama is removed up to the junction of the cerebellar vermis and cerebellar tonsils. The occipitoatlantal fascia is exposed and dissected. The dura mater and arachnoid mater are incised longitudinally and suspended bilaterally to provide a clear surgical field. The primary objectives of resection were: ensuring no significant obstruction of CSF circulation at the foramen magnum and the foramen of Magendie under natural conditions. Preventing occlusion of the foramen of Magendie caused by herniated cerebellar tonsils or any membranous structures under natural conditions. The dura is closed in situ.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
improvement or resolution of the syrinx,
Time Frame: 3-6, 12 and 24 months
defined as > 50% improvement in length, maximal cross-sectional diameter, or both.
3-6, 12 and 24 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
complication rates
Time Frame: 12 months
Reoperation,Wound infection,Aseptic meningitis,CSF fistula,Subcutaneous hydrops,Other complications
12 months
blood loss
Time Frame: 12 months
blood loss
12 months
hospital stay
Time Frame: 12 months
hospital stay
12 months
cost for the hospitalisation.
Time Frame: 12 months
cost for the hospitalisation.
12 months
Chicago Chiari Outcome Scale (CCOS) scale
Time Frame: 12 months
for evaluating the spinal cord function after chiari decompression surgery, Each item is scored on a scale from 1 to 4, with 4 representing the best possible functional status.
12 months
visual analog scale (VAS)
Time Frame: 12 months
degree of the pain, 1-10, higher scores mean a worse outcome
12 months
Japanese Orthopaedic Association (JOA) scale
Time Frame: 12 months
Motor function， sensory， bladder function；for evaluating the spinal cord function；0-17， higher scores mean a better outcome
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Xuanwu Hospital, Beijing

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
The First Hospital of Hebei Medical University
Beijing Jiangong Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: fengzeng jian, Xuanwu Hospital, Beijing

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 31, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 12, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 12, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 20, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 9, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 12, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 17, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • DDCS

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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