Coupling Failure as the Forth Category in the Classification of Congenital Spinal Deformity

Coupling Failure as the Forth Category in the Classification of Congenital Spinal Deformity

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Corresponding Author
Noriaki Kawakami
Department of Orthopaedics and Spine Surgery, Meijo Hospital

A B S T R A C T

Study Design: A retrospective study Objective: To analyze the discordant relationship between anterior and posterior structure in congenital spinal deformity (CSD). Summary of Background Data: Winter classified CSD into three categories, formation failureW,1 , segmentation failureW, and mixed type. While it has been widely used for analysis of CSD for more than 30 years, there are some types of CSD with atypical vertebral anomalies (VAs), which do not belong to any of the three categories. Methods: Three-dimensionally reconstructed CT images of 332 patients with CSD were evaluated to clarify the relationship between the anterior and posterior structure of each VA according to the algorism for evaluation of CSD presented by Kawakami. Those that belonged to the multiple complex types (MC) were analyzed to determine the presence of discordancy. Results: Of 332, 104 patients were classified as Solitary simple (SS), 69 as Multiple simple (MS), 35 as SF, and 124 as MC. 38 of the 124 patients with MC were subclassified into the Mismatch malformation type (MMC). Twelve of the 38 patients with the MMC exhibited three types of unusual VAs; 2 patients with a combination of a normal vertebral body (VB) with hemilaminae (Posterior mismatch type); 2 with normal laminae with contralateral hemivertebral bodies (Anterior mismatch type); and 8 with a discordant combination of multiple contralateral hemivertebral bodies and hemilaminae (Anteroposterior mismatch type). This study proposed to put these three types with mismatch phenomena together and was termed “Coupling failure”, which was regarded as a fourth category of CSD. Conclusion: Coupling failure is completely different from both formation failureW and segmentation failureW in terms of the developmental mechanisms and characteristics of discordancy. The addition of coupling failure facilitates the understanding of complicated CSD, which can then be classified clearly into four categories, including formation failureK, coupling failure, segmentation failureK, and Mixed failure.

Article Info

Article Type
Research Article
Publication history
Received: Mon 19, Mar 2018
Accepted: Mon 02, Apr 2018
Published: Fri 06, Apr 2018
Copyright
© 2023 Noriaki Kawakami. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Hosting by Science Repository.
DOI: 10.31487/j.RDI.2018.10.002