Greater cervical kyphosis during flexion increases the risk of kyphotic deformity after laminoplasty in patients with cervical spondylotic myelopathy

Takashi Fujishiro; Takuya Obo; Yuki Yamamoto; Yoshitada Usami; Sachio Hayama; Yoshiharu Nakaya; Atsushi Nakano; Masashi Neo

doi:10.1016/j.jocn.2024.05.003

Greater cervical kyphosis during flexion increases the risk of kyphotic deformity after laminoplasty in patients with cervical spondylotic myelopathy

J Clin Neurosci. 2024 May 10:125:24-31. doi: 10.1016/j.jocn.2024.05.003. Online ahead of print.

Authors

Takashi Fujishiro¹, Takuya Obo², Yuki Yamamoto³, Yoshitada Usami², Sachio Hayama², Yoshiharu Nakaya², Atsushi Nakano², Masashi Neo²

Affiliations

¹ Department of Orthopedic Surgery, Osaka Medical and Pharmaceutical University, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686 Japan; Department of Orthopedic Surgery, First Towakai Hospital, 2-17, Miyano-machi, Takatsuki, Osaka 569-0081, Japan. Electronic address: takashi.fujishiro@ompu.ac.jp.
² Department of Orthopedic Surgery, Osaka Medical and Pharmaceutical University, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686 Japan.
³ Department of Orthopedic Surgery, Osaka Medical and Pharmaceutical University, 2-7, Daigaku-machi, Takatsuki, Osaka 569-8686 Japan; Department of Orthopedic Surgery, First Towakai Hospital, 2-17, Miyano-machi, Takatsuki, Osaka 569-0081, Japan.

PMID: 38733900
DOI: 10.1016/j.jocn.2024.05.003

Abstract

Kyphotic deformity following the loss of cervical lordosis can lead to unfavourable neurological recovery after cervical laminoplasty (CLP); therefore, it is essential to identify its risk factors. Recent studies have demonstrated that the dynamic parameters of the cervical spine, based on baseline flexion/extension radiographs, are highly useful to estimate the loss of cervical lordosis after CLP. However, it remains unclear whether such dynamic parameters can predict kyphotic deformity development after CLP. Hence, the present study aimed to investigate whether the dynamic parameters could predict kyphotic deformity in patients with cervical spondylotic myelopathy (CSM) after CLP. This retrospective study included 165 patients, consisting of 10 and 155 patients with and without cervical kyphosis of C2-C7 angle ≤ -10° at the final follow-up period, respectively. Among the static and dynamic parameters of the cervical spine, greater cervical kyphosis during flexion (fC2-C7 angle) demonstrated the best discrimination between these two cohorts, with an optimal cutoff value of -27.5°. Meanwhile, greater gap range of motion (gROM = flexion ROM - extension ROM ) had the highest ability to predict a loss of ≥ 10° in C2-C7 angle after CLP, with an optimal cutoff value of 28.5°. This study suggests that in patients with CSM, fC2-C7 angle ≤ -25° on baseline radiographs is a potential risk for kyphotic deformity after CLP. In clinical practice, the patients with this criterion (fC2-C7 angle ≤ -25°) along with gROM ≥ 30° are at high risk of developing significant kyphotic deformity after CLP.

Keywords: Cervical laminoplasty; Cervical lordosis; Cervical spondylotic myelopathy; Gap ROM; Kyphotic deformity; Range of motion; gROM.