A Prospective Study of Surgical Treatment Strategies for Goal B Type Basilar Invagination

Study Overview
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Brief Summary
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The etiology of Goal B type basilar invagination (BI) is still not clear, and it may be related to platybasia and short slope. There is no unified standard surgical strategy for Goal B type BI, and different surgical strategies have a great influence on the surgical results of patients. The purpose of our prospective study in China is to (1) further clarify the etiology of Goal B type BI, and (2) improve the surgical outcome in these patients.

Official Title
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A Prospective Study of Surgical Treatment Strategies for Goal B Type Basilar Invagination in China

Conditions
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Basilar Invagination, Prospective Study, Surgical Outcome

Intervention / Treatment
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* Procedure: Posterior fossa decompression
* Procedure: Posterior Compression-Distraction-Reduction-Fixation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Goal B type basilar invagination (BI) Exclusion Criteria: Preoperative diagnosis was confirmed as not Goal B type basilar invagination (BI) The patient was not physically fit for surgery.
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Posterior fossa decompression<br>Posterior arch of atlas removal, reconstruction of cisterna magna, decompression of cerebellum, detection of magendie foramen. | Procedure: Posterior fossa decompression<br>* Posterior fossa decompression：Posterior arch of atlas removal, decompression of cerebellum, detection of foramen magnum.<br>|
| Experimental: Posterior Compression-Distraction-Reduction-Fixation<br>After subperiosteal dissection, the facet joint was exposed. A 2-mm joint scraper with sharp edge was inserted into the joint capsule and rotated to remove the articular cartilage. A blunt-edged rotating distractor was then inserted into the joint space, and the facet was sequentially opened with larger and larger blunt rotating distractors. After distraction on one side, an appropriate-sized trial was placed into the contralateral facet, holding the distraction open. This was repeated back and forth with larger trials. These steps were repeated, and the facet joints were distracted up to the pre-planned distance of the odontoid tip above Chamberlain's line. | Procedure: Posterior Compression-Distraction-Reduction-Fixation<br>* Posterior Compression-Distraction-Reduction-Fixation：After subperiosteal dissection, the facet joint was exposed. A 2-mm joint scraper with sharp edge was inserted into the joint capsule and rotated to remove the articular cartilage. A blunt-edged rotating distractor was then inserted into the joint space, and the facet was sequentially opened with larger and larger blunt rotating distractors. After distraction on one side, an appropriate-sized trial was placed into the contralateral facet, holding the distraction open. This was repeated back and forth with larger trials. These steps were repeated, and the facet joints were distracted up to the pre-planned distance of the odontoid tip above Chamberlain's line.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| JOA Score（Japanese Orthopaedic Association Scores） | Changes in JOA score，from 0 to 17, higher scores means better outcome | 1 months, 3 months, and 6 months postoperatively | 
| NDI Score | Changes in NDI score，from 0% to 100%，higher scores means worse outcome | 1 months, 3 months, and 6 months postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of Basilar Invagination | Radiographic assessment of the reduction of basilar invagination, using distance from odontoid tip to Chamberlain's line (DCL) | 1 months, 3 months, and 6 months postoperatively | 
| Change of CCA | Radiographic assessment of the change in clivus-canal angle (CCA) | 1 months, 3 months, and 6 months postoperatively | 
| Change of CVJ triangle area | Radiographic assessment of the reduction of CVJ triangle area | 1 months, 3 months, and 6 months postoperatively | 
| Change of CMA | Radiographic assessment of change of cervico-medullary angle (CMA) | 1 months, 3 months, and 6 months postoperatively | 
| Change of subarachnoid space | Radiographic assessment of the relief of width of subarachnoid space | 1 months, 3 months, and 6 months postoperatively |