A new method for measuring torsional deformity in scoliosis

Toshio Doi,Umito Kuwashima,Katsumi Harimaya,Satoshi Kido,Kiyoshi Tarukado,Osamu Tono,Kenichi Kawaguchi,Yukihide Iwamoto,Yoshihiro Matsumoto

doi:10.1186/1748-7161-6-7

Toshio Doi, Umito Kuwashima + Show 7 more

Open Access

https://doi.org/10.1186/1748-7161-6-7

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Abstract

BackgroundThe importance of spinal rotational and torsional deformity in the etiology and the management of scoliosis are well-recognized. For measuring the posterior spinal component rotation, Ho's method was reported to be reliable. However, there is no practical method to measure the anterior spinal component rotation. Moreover, there is also no method to quantify the spinal torsional deformity in scoliosis. The goal of this study is to characterize scoliosis and its deformity to hypothesize the etiology and the development of scoliosis, and to establish a new method for the measurement of the vertebral body rotation and spinal torsional deformity in scoliosis using CT scans.MethodsPre-operative CT scans of 25 non-congenital scoliosis patients were recruited and the apical vertebral rotation was measured by a newly developed method and Ho's method. Ho's method adopts the laminae as the rotational landmark. For a new method to measure the apical vertebral rotation, the posterior point just beneath each pedicle was used as a landmark. For quantifying the spinal torsional deformity angle, the rotational angle difference between the two methods was calculated.ResultsIntraobserver and interobserver reliability analyses showed both methods to be reliable. Apical vertebral rotation revealed 13.9 ± 6.8 (mean ± standard deviation) degrees by the new method and 7.9 ± 6.3 by Ho's method. Right spinal rotation was assigned a positive value. The discrepancy of rotation (6.1 ± 3.9 degrees), meaning that the anterior component rotated more than the posterior component, was considered to express the spinal torsional deformity to the convex side.ConclusionsWe have developed an easy, reliable and practical method to measure the rotation of the spinal anterior component using a CT scan. Furthermore, we quantified the spinal torsional deformity to the convex side in scoliosis by comparing the rotation between the anterior and posterior components.

Highlights

The importance of spinal rotational and torsional deformity in the etiology and the management of scoliosis are well-recognized
Nash and Moe published a practical method for determing the vertebral rotation from the projection of the pedicle in frontal radiographs [11]
Aaro and Dahlborn introduced the use of Computed tomography (CT) scans to measure vertebral rotation [7,8], and Ecker et al used the sagittal angle, which was taken to be the angle between the sagittal plane and the line between the correct posterior mid-point of the vertebra canal and the center point of the corpus vertebrae, to determine the rotation [6]

Summary

Introduction

The importance of spinal rotational and torsional deformity in the etiology and the management of scoliosis are well-recognized. The goal of this study is to characterize scoliosis and its deformity to hypothesize the etiology and the development of scoliosis, and to establish a new method for the measurement of the vertebral body rotation and spinal torsional deformity in scoliosis using CT scans. Based on observations of 3D images or specimens of scoliosis, the anterior component, such as the vertebral body, has been determined to rotate more than the posterior component, such as the spinous process and laminae [9,10]. Ho’s method uses the laminae as the landmark [3,4] These numerous methods have been proposed for the vertebral rotation, it is difficult to find an anatomical landmark to measure the anterior component rotation [2,13], and few practical methods are available

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