Evaluation of crankshaft phenomenon after posterior fusion for early onset scoliosis using an inverse trigonometric function: a multicenter retrospective cohort study.

IF 1.6 Q3 CLINICAL NEUROLOGY

Spine deformity Pub Date : 2024-11-01 Epub Date: 2024-05-28 DOI:10.1007/s43390-024-00900-4

Shun Okuwaki, Toshiaki Kotani, Yuki Taniguchi, Teppei Suzuki, Toru Yamaguchi, Satoru Demura, Kanichiro Wada, Ryo Sugawara, Katsushi Takeshita, Kei Watanabe, Tsutomu Akazawa, Noriaki Kawakami

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引用次数: 0

Abstract

Purpose: The crankshaft phenomenon (CSP) is a corrective loss after posterior surgery for early onset scoliosis (EOS). However, an accurate method for CSP evaluation has yet to be developed. In this study, we evaluated pedicle screw (PS) length and rotation angle using an inverse trigonometric function and investigated the prevalence of the CSP.

Methods: Fifty patients from nine institutions (mean age 10.6 years, male/female ratio 4:46) who underwent early definitive fusion surgery at ≤ 11 years of age were included. The rotation angle was calculated as arctan (lateral/frontal PS length) using radiography. Measurements were taken at the apex and lower instrumented vertebra (LIV) immediate, 2-, and 5-year postoperatively. CSP was defined as a rotation angle progression ≥ 5°. We divided patients into CSP and non-CSP groups and measured the demographic parameters, Risser grade, state of the triradiate cartilage, major coronal Cobb angle, T1-T12 length, T1-S1 length, and presence of distal adding-on (DAO). We compared these variables between groups and investigated the correlation between the measured variables and vertebral rotation. Logistic regression analysis investigated factors associated with CSP.

Results: The rotation angle progressed by 2.4 and 1.3° over 5 years for the apex and LIV, respectively. CSP occurred in 15 cases (30%), DAO in 11 cases (22%), and CSP and DAO overlapped in 4 cases (8%). In the CSP group, the T1-T12 length was low immediate postoperatively. The rotation angle was negatively correlated with preoperative height (r = - 0.33), T1-T12 length (r = - 0.35), and T1-S1 length (r = - 0.30). A lower preoperative T1-T12 length was associated with CSP (odds ratio: 0.996, p = 0.048).

Conclusions: CSP occurred in 30% of patients with EOS who underwent definitive fusion. The presence of CSP was associated with a lower preoperative T1-T12 length.

Level of evidence: Diagnosis, level IV.

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使用反三角函数评估早发脊柱侧凸后路融合术后的曲轴现象：一项多中心回顾性队列研究。

目的：曲轴现象（CSP）是早发脊柱侧凸（EOS）后路手术后的一种矫正损失。然而，目前尚未开发出精确的 CSP 评估方法。在这项研究中，我们使用反三角函数评估了椎弓根螺钉（PS）的长度和旋转角度，并调查了CSP的发生率：方法：纳入了来自 9 家机构的 50 名患者（平均年龄 10.6 岁，男女比例为 4:46），这些患者在 11 岁以下时接受了早期明确融合手术。旋转角度的计算公式为 arctan（侧方/前方 PS 长度），采用放射摄影技术。术后即刻、术后2年和术后5年分别在顶点和下部器械椎体（LIV）进行测量。CSP的定义是旋转角度进展≥5°。我们将患者分为CSP组和非CSP组，并测量了人口统计学参数、Risser分级、三椎体软骨状态、主要冠状面Cobb角、T1-T12长度、T1-S1长度和是否存在远端附加物（DAO）。我们比较了各组之间的这些变量，并研究了测量变量与椎体旋转之间的相关性。逻辑回归分析调查了与 CSP 相关的因素：结果：在 5 年时间里，顶点和 LIV 的旋转角度分别增加了 2.4 和 1.3°。15例（30%）发生了CSP，11例（22%）发生了DAO，4例（8%）发生了CSP和DAO重叠。在 CSP 组中，术后 T1-T12 长度较低。旋转角度与术前身高（r = - 0.33）、T1-T12 长度（r = - 0.35）和 T1-S1 长度（r = - 0.30）呈负相关。术前较低的 T1-T12 长度与 CSP 相关（几率比：0.996，P = 0.048）：结论：在接受最终融合术的EOS患者中，有30%的患者出现了CSP。结论：30%接受最终融合术的 EOS 患者存在 CSP，CSP 的存在与术前较低的 T1-T12 长度有关：证据级别：诊断，IV级。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Spine deformity

CiteScore

3.20

自引率

18.80%

发文量

167

期刊介绍： Spine Deformity the official journal of the?Scoliosis Research Society is a peer-refereed publication to disseminate knowledge on basic science and clinical research into the?etiology?biomechanics?treatment?methods and outcomes of all types of?spinal deformities. The international members of the Editorial Board provide a worldwide perspective for the journal's area of interest.The?journal?will enhance the mission of the Society which is to foster the optimal care of all patients with?spine?deformities worldwide. Articles published in?Spine Deformity?are Medline indexed in PubMed.? The journal publishes original articles in the form of clinical and basic research. Spine Deformity will only publish studies that have institutional review board (IRB) or similar ethics committee approval for human and animal studies and have strictly observed these guidelines. The minimum follow-up period for follow-up clinical studies is 24 months.