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03-01-2024 | Original Article

Usefulness of the preoperative thoracic inlet angle in comparison to the T1 slope for predicting cervical kyphosis after laminoplasty

Authors: Kenta Takakura, Eiji Takasawa, Tokue Mieda, Toshiki Tsukui, Kazuhiro Inomata, Yusuke Tomomatsu, Akira Honda, Hirotaka Chikuda

Published in: European Spine Journal | Issue 3/2024

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Abstract

Purpose

Thoracic inlet angle (TIA) is a sagittal radiographic parameter with a constant value regardless of posture and is significantly correlated with the sagittal balance of the cervical spine. However, the practical use of TIA has not been studied. This study aimed to investigate the usefulness of the preoperative TIA for predicting the development of kyphotic deformity after cervical laminoplasty in comparison to the preoperative T1 slope (T1S).

Methods

A total of 98 patients who underwent cervical laminoplasty without preoperative kyphotic alignment were included (mean age, 73.7 years; 41.8% female). Radiography was evaluated before surgery and at the 2-year follow-up examination. The cervical sagittal parameters were measured on standing radiographs, and the TIA was measured on T2-weighted MRI in a supine position. Cervical alignment with a C2–C7 angle of ≥ 0° was defined as lordosis, and that with an angle of < 0° was defined as kyphosis.

Results

Postoperative kyphosis occurred in 11 patients (11.2%). Preoperatively, the kyphosis group showed significantly lower values in the T1S (23.5° vs. 30.3°, p = 0.034) and TIA (76.1° vs. 81.8°, p = 0.042). We performed ROC curve analysis to clarify the impact of the preoperative TIA and T1S on kyphotic deformity after laminoplasty. The optimal cutoff angles for TIA and T1S were 68° and 19°, respectively, with similar diagnostic accuracy.

Conclusion

This study demonstrated the clinical utility of the preoperative TIA for predicting the risk of postoperative kyphotic deformity after cervical laminoplasty. These findings suggest the importance of the preoperative assessment of thoracic inlet alignment in cervical spine surgery.
Literature
Metadata
Title
Usefulness of the preoperative thoracic inlet angle in comparison to the T1 slope for predicting cervical kyphosis after laminoplasty
Authors
Kenta Takakura
Eiji Takasawa
Tokue Mieda
Toshiki Tsukui
Kazuhiro Inomata
Yusuke Tomomatsu
Akira Honda
Hirotaka Chikuda
Publication date
03-01-2024
Publisher
Springer Berlin Heidelberg
Published in
European Spine Journal / Issue 3/2024
Print ISSN: 0940-6719
Electronic ISSN: 1432-0932
DOI
https://doi.org/10.1007/s00586-023-08095-4