An interventional study of Atlas occipital decompression lateral joint release combined with occipital-neck fusion and Simple FMD with Outer Dural Delamination in Atlantoaxial Dislocation, Chiari Malformation and Basilar Invagination, sponsored by Southern Medical University, China. Completed at 1 site in China. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2026-04-28.
Sponsored by Southern Medical University, China · Not applicable, Interventional, and Treatment
The research background of this study is that Chiari malformation (CM) is a congenital malformation in the foramen magnum region, often associated with syringomyelia, basilar depression, odontoid dislocation and other craniocervical junction deformities. The traditional surgical method for Chiari malformation with skull basilar depression is simple decompression without fixation, so it cannot effectively maintain the stability of the cervical spine and reduce the compression of the brainstem and cervical cord, often resulting in poor curative effect and aggravated symptoms. The cervical spine is the most flexible and most mobile part of the spine, and the instability of the cervical spine will directly affect the quality of life of patients after surgery. Subsequently, with the continuous advancement of technology and the continuous development and improvement of surgical methods, Investigators can relieve spinal cord compression by using atlanto-occipital decompression and dissection followed by C1/2 lateral arthrolysis combined with occipitocervical fusion. So, is this surgical combination the most effective surgery for patients with Chiari malformation and type II skull basilar depression? How should doctors adjust to the best surgical approach to treat patients with Chiari malformation and type II skull basilar depression? These questions have long puzzled neurosurgeons. By conducting this research, investigators hope that participants can participate in it, and work with them to answer this question, and jointly promote the development and progress of doctors' careers, while benefiting more patients.
33 studies on the registry are indexed under Arnold-Chiari Malformation; 11 are open to participants now.
This study's enrollment of 64 is above the median of 41 across 17 interventional studies indexed under Arnold-Chiari Malformation.
Browse Arnold-Chiari Malformation studies →Southern Medical University, China is the lead sponsor of 31 studies on the registry; 6 are open to participants now.
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Exclusion Criteria:
All patients underwent preoperative dynamic CT scans in flexion, neutral, and extension positions, and all were treated surgically with atlanto-occipital decompression, CI/2 lateral articular release, combined with occipital-cervical fusion.
Procedure: Atlas occipital decompression lateral joint release combined with occipital-neck fusion
Patients in this arm will receive the traditional standard procedure, which consists of simple bony foramen magnum decompression combined with outer dural delamination (without opening the inner layer of the dura mater to reduce complications).
Procedure: Simple FMD with Outer Dural Delamination
A. Chiari malformation combined with type II Basilar invagination showed that the slope spinal canal angle decreased, and the position of the dentition moved up. The yellow fusion device in the picture is C1/2 lateral inter-articular Cage (the patent granted by the applicant for this project); B. After atlanto-occipital decompression, C1/2 lateral inter-articular release is performed, and a fusion device is implanted to move down the position of the tip of the tooth process to reduce the compression of the cervical medulla oblongata; C. Implantation of the posterior neck nail rod system; D. Improve the angle of the sloped spinal canal by posterior compression rod technique (Cantilever) to further reduce the compression on the superior cervical medulla oblongata.
This arm utilizes the traditional standard strategy, distinct from the comprehensive fusion in the experimental arm. The specific distinguishing details are: Performing strictly anatomical decompression ONLY. This involves bony foramen magnum decompression combined with outer dural delamination (without opening the inner layer of the dura mater). This arm specifically EXCLUDES C1/2 facet joint release, cage implantation, and any form of occipitocervical internal fixation or biomechanical reconstruction.
Chang of Chicago Chiari outcome score
The Chicago Chiari Malformation Prognosis Scale (CCOS) is a comprehensive quantitative scoring criterion for surgical prognosis in patients with Chiari malformations, first proposed by the Department of Neurosurgery of the University of Chicago School of Medicine. CCOS covered four scoring criteria, including improvement in pain symptoms, improvement in non-pain symptoms, ability to live, and surgery-related complications, with a single score of 1-4 for a total score of 4 to 16, and at the last follow-up, the higher the patient's score indicated the better the patient's postoperative prognosis.
Time frame: through study completion, an average of 1 year
Occurrence of complications
1)Minor complications such as pain, neck stiffness, and poor wound healing. 2)Serious complications such as vertebral artery injury, dyspnea, cerebrospinal fluid leakage, and severe intracranial infection.
Time frame: The second week after surgery
Chang of Magnetic Resonance Imaging
Measurements of radiographic improvement, such as cerebellar tonsillar hernia length.
Time frame: through study completion, an average of 1 year
Chang of Visual Analog Score for pain
Visual Analog Score stands for visual analogue scoring method and is one of the commonly used pain scoring criteria. The main thing is to draw a 10cm horizontal line on the paper, the beginning end is 0, the other end is 10, the middle part represents different degrees of pain, let the patient choose the degree of pain by himself. A score below 3 represents mild pain; 4-6 are divided into pain that interferes with sleep, but is tolerable; A score of 7-10 indicates unbearable pain.
Time frame: through study completion, an average of 1 year
Chang of Japanese Orthopaedic Association Scores
The patient's lumbar spine function and improvement were mainly evaluated from four aspects: subjective symptoms, daily activity ability, clinical signs, and bladder function. The scoring range is 0\~29 points, and the higher the total score, the milder the patient's condition.
Time frame: through study completion, an average of 1 year
Chang of Neck Disability Index
Neck Disability Index consists of 10 items, including: neck pain and related symptoms (pain intensity, headache, concentration and sleep) and activities of daily living (personal care, lifting heavy objects, reading, work, driving and playing). Each item has a minimum score of 0 and a maximum score of 5, with higher scores indicating greater levels of dysfunction.
Time frame: through study completion, an average of 1 year
Plan to share: No
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Southern Medical University, China