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J Neurol Surg B Skull Base 2023; 84(06): 616-628
DOI: 10.1055/a-1932-8692
Original Article

A Novel Craniocervical Junction Compression Severity Index-Based Grading System for Multidirectional Quantification of the Biomechanics at Foramen Magnum of Chiari Malformation Type I

Yunsen He   *
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Ping Liu   *
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Mengjun Zhang
2   Department of Neuropsychology, Sichuan Provincial Center for Mental Health, Sichuan, People's Republic of China
,
Lili Guo
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Tao Zheng
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Yuanpeng Yao
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Qiang Zheng
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Mingbin Bao
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Chuan Jiang
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Bo Wu
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
,
Jinping Liu
1   Department of Neurosurgery, Sichuan Provincial People's Hospital Ringgold Standard Institution, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
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Abstract

Objective This study aimed to establish a novel grading system, based on the craniovertebral junction compression severity index (CVJCSI) for multidirectional quantification at the foramen magnum plane for Chiari malformation type I (CMI).

Methods The CVJCSI grading system was established to stratify patients based on the ventral (modified clivoaxial angle < 138°), dorsal (tonsil herniation), and central (brainstem herniation) CVJ (craniovertebral junction) compression, the CVJCSI grading system was established to stratify patients. The optimal surgical method for each grade was recommended by intragroup comparisons regarding the efficacy of the three operations. Finally, according to the CVJCSI grading system, a prospective validation trial was performed and surgically treated for internal validation.

Results Based on the retrospective study (n = 310), the CVJCSI included six grades: I: syrinx alone without compression; II: dorsal compression; III: dorsal and central compression; IV: ventral compression; V: dorsal and ventral compression; and VI: ventral, dorsal, and central compression. Among all available variables, only the CVJCSI and surgical methods significantly affected the CCOS. The CCOS scores, overall and for each CVJCSI grade, increased in the prospective cohort (n = 42) compared with that in the retrospective analysis.

Conclusions The CVJCSI can be used to stratify CMI patients. The higher the CVJCSI grade, the more severe the CVJ compression and the worse posterior fossa deformity. Meanwhile, the CVJCSI was negatively correlated with the CCOS. The lower the CVJCSI grade, the better the response to surgery, and the less-invasive surgical procedures were warranted. Finally, the prospective cohort study validated the proposed CVJCSI-based surgical protocols.

Keywords

Chiari malformations - craniovertebral junction - classification - grading system - CCOS - CM0 - CM1.5

* Yunsen He and Ping Liu contributed equally to the work and should be regarded as joint first authors.




Publication History

Received: 30 March 2022

Accepted: 23 August 2022

Accepted Manuscript online:
29 August 2022

Article published online:
02 December 2022

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