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

Completed

Conditions

Intervention / Treatment

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

Interventional

Enrollment (Actual)

250

Phase

  • 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 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

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
Intervention / Treatment
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

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

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

Xuanwu Hospital, Beijing

Collaborators

The First Hospital of Hebei Medical University
Beijing Jiangong Hospital

Investigators

  • 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)

January 31, 2024

Primary Completion (Actual)

February 12, 2026

Study Completion (Actual)

February 12, 2026

Study Registration Dates

First Submitted

August 20, 2023

First Submitted That Met QC Criteria

October 9, 2023

First Posted (Actual)

October 12, 2023

Study Record Updates

Last Update Posted (Actual)

February 17, 2026

Last Update Submitted That Met QC Criteria

February 12, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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.

Clinical Trials on Tonsillectomy

Clinical Trials on Posterior fossa decompression with duraplasty

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Iran

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe