Szabolcs Somoskeöy

Breakthrough in three-dimensional scoliosis diagnosis: significance of horizontal plane view and vertebra vectors

Scoliosis is a multifactorial three-dimensional (3D) spinal deformity with integral and directly related vertebral deviations in the coronal, sagittal and horizontal planes. Current classification and diagnostic methods rely on two-dimensional (2D) frontal and lateral X-ray images; no routine methods are available for the visualization and quantitative evaluation of deviations in the horizontal plane. The EOS 2D/3D system presented here is a new, low-dose, orthopedic radiodiagnostic device based on Nobel prize-winning X-ray detection technology with special software for 3D surface reconstruction capabilities that finally led to a breakthrough in scoliosis diagnosis with high-quality, realistic 3D visualization and accurate quantitative parametric analysis. A new concept introducing vertebra vectors and vertebra vector parametric calculations is introduced that furnishes simplified visual and intelligible mathematical information facilitating interpretation of EOS 2D/3D data, especially with regard to the horizontal plane top view images. The concept is demonstrated by a reported scoliotic case that was readily characterized through information derived from vertebra vectors alone, supplemented with the current angulation measurement methods in the coronal and sagittal planes and axial vertebral rotation measurements in the horizontal plane, with a calibrated 3D coordinate system suitable for inter-individual comparisons. The new concept of vertebra vectors may serve as a basis for a truly 3D classification of scoliosis.

Geometrical values of the normal and arthritic hip and knee detected with the EOS imaging system

PurposeEOS 2D/3D is an integrated, low-dose orthopedic digital radioimaging solution, which, due to its groundbreaking properties, has recently shown an increasing application in scoliosis surgery. Its integrated sterEOS 3D software allows creation of patient-specific three-dimensional (3D) lower limb models, and can produce geometrical parameters in 3D. Currently there are a limited number of reports on EOS for lower limb applications.MethodsThree-dimensional reconstructions of 256 hip and knee joints of 128 healthy subjects, as well as 53 hips and 46 knees of 69 patients with hip or knee arthritis, were evaluated based on orthogonal EOS two-dimensional (2D) images. Measurements for hips included femur and tibia length, total length of the extremity, femoral antetorsion and offset, femoral neck length, neck-shaft and hip-knee-shaft (HKS) angles. Lower limb alignment in both frontal and sagittal planes were determined in normal and arthritic knees. Values were compared with those obtained by standard methods published by others.ResultsNormal hip and knee geometrical parameters were found in our healthy subjects. In osteoarthritic cases, values for neck-shaft angle, femoral antetorsion, femur length and total length of the extremity were shown to decrease non-significantly. Evaluation of lower limb alignment in healthy and arthritic knees showed normal values in healthy subjects apart from three cases with an average six degrees varus. Arthritic knees were most frequently found to have a varus angulation, with the exception of 11 cases with normal or valgus alignment.ConclusionEOS 2D/3D with its sterEOS 3D reconstruction is useful for a comprehensive 3D examination of the lower limb. In the near future it may be suitable for daily routine diagnostics of orthopedic lower limb deformities as a primary examination method.

Comparison of scoliosis measurements based on three-dimensional vertebra vectors and conventional two-dimensional measurements: advantages in evaluation of prognosis and surgical results

PurposeA new concept of vertebra vectors based on spinal three-dimensional (3D) reconstructions of images from the EOS system, a new low-dose X-ray imaging device, was recently proposed to facilitate interpretation of EOS 3D data, especially with regard to horizontal plane images. This retrospective study was aimed at the evaluation of the spinal layout visualized by EOS 3D and vertebra vectors before and after surgical correction, the comparison of scoliotic spine measurement values based on 3D vertebra vectors with measurements using conventional two-dimensional (2D) methods, and an evaluation of horizontal plane vector parameters for their relationship with the magnitude of scoliotic deformity.Methods95 patients with adolescent idiopathic scoliosis operated according to the Cotrel-Dubousset principle were subjected to EOS X-ray examinations pre- and postoperatively, followed by 3D reconstructions and generation of vertebra vectors in a calibrated coordinate system to calculate vector coordinates and parameters, as published earlier. Differences in values of conventional 2D Cobb methods and methods based on vertebra vectors were evaluated by means comparison T test and relationship of corresponding parameters was analysed by bivariate correlation. Relationship of horizontal plane vector parameters with the magnitude of scoliotic deformities and results of surgical correction were analysed by Pearson correlation and linear regression.ResultsIn comparison to manual 2D methods, a very close relationship was detectable in vertebra vector-based curvature data for coronal curves (preop r 0.950, postop r 0.935) and thoracic kyphosis (preop r 0.893, postop r 0.896), while the found small difference in L1–L5 lordosis values (preop r 0.763, postop r 0.809) was shown to be strongly related to the magnitude of corresponding L5 wedge. The correlation analysis results revealed strong correlation between the magnitude of scoliosis and the lateral translation of apical vertebra in horizontal plane. The horizontal plane coordinates of the terminal and initial points of apical vertebra vectors represent this (r 0.701; r 0.667). Less strong correlation was detected in the axial rotation of apical vertebras and the magnitudes of the frontal curves (r 0.459).ConclusionsVertebra vectors provide a key opportunity to visualize spinal deformities in all three planes simultaneously. Measurement methods based on vertebral vectors proved to be just as accurate and reliable as conventional measurement methods for coronal and sagittal plane parameters. In addition, the horizontal plane display of the curves can be studied using the same vertebra vectors. Based on the vertebra vectors data, during the surgical treatment of spinal deformities, the diminution of the lateral translation of the vertebras seems to be more important in the results of the surgical correction than the correction of the axial rotation.

Computer-Generated, Three-Dimensional Spine Model From Biplanar Radiographs: A Validity Study in Idiopathic Scoliosis Curves Greater Than 50 Degrees

STUDY DESIGN Reproducibility study of SterEOS 3-dimensional (3D) software in large, idiopathic scoliosis (IS) spinal curves. OBJECTIVE To determine the accuracy and reproducibility of various 3D, software-generated radiographic measurements acquired from a 2-dimensional (2D) imaging system. SUMMARY OF BACKGROUND DATA SterEOS software allows a user to reconstruct a 3D spinal model from an upright, biplanar, low-dose, X-ray system. The validity and internal consistency of this system have not been tested in large IS curves. METHODS EOS images from 30 IS patients with curves greater than 50° were collected for analysis. Three observers blinded to the study protocol conducted repeated, randomized, manual 2D measurements, and 3D software generated measurements from biplanar images acquired from an EOS Imaging system. Three-dimensional measurements were repeated using both the Full 3D and Fast 3D guided processes. A total of 180 (120 3D and 60 2D) sets of measurements were obtained of coronal (Cobb angle) and sagittal (T1-T12 and T4-T12 kyphosis; L1-S1 and L1-L5; and pelvic tilt, pelvic incidence, and sacral slope) parameters. Intra-class correlation coefficients were compared, as were the calculated differences in values generated by SterEOS 3D software and manual 2D measurements. The 95% confidence intervals of the mean differences in measures were calculated as an estimate of reproducibility. RESULTS Average intra-class correlation coefficients were excellent: 0.97, 0.97, and 0.93 for Full 3D, Fast 3D, and 2D measures, respectively (p = .11). Measurement errors for some sagittal measures were significantly lower with the 3D techniques. Both the Full 3D and Fast 3D techniques provided consistent measurements of axial plane vertebral rotation. CONCLUSIONS SterEOS 3D reconstruction spine software creates reproducible measurements in all 3 planes of deformity in curves greater than 50°. Advancements in 3D scoliosis imaging are expected to improve our understanding and treatment of idiopathic scoliosis.

[Principles of the EOS™ X-ray machine and its use in daily orthopedic practice].

The EOS™ X-ray machine, based on a Nobel prize-winning invention in Physics in the field of particle detection, is capable of simultaneously capturing biplanar X-ray images by slot scanning of the whole body in an upright, physiological load-bearing position, using ultra low radiation doses. The simultaneous capture of spatially calibrated anterioposterior and lateral images allows the performance of a three-dimensional (3D) surface reconstruction of the skeletal system by a special software. Parts of the skeletal system in X-ray images and 3D-reconstructed models appear in true 1:1 scale for size and volume, thus spinal and vertebral parameters, lower limb axis lengths and angles, as well as any relevant clinical parameters in orthopedic practice could be very precisely measured and calculated. Visualization of 3D reconstructed models in various views by the sterEOS 3D software enables the presentation of top view images, through which one can analyze the rotational conditions of lower limbs, joints and spine deformities in horizontal plane and this provides revolutionary novel possibilities in orthopedic surgery, especially in spine surgery.

[Evaluation of the usefulness of the EOS 2D/3D system for the measurement of lower limbs anatomical and biomechanical parameters in children].

INTRODUCTION Lower limbs anatomical and biomechanical parameters are essential in several paediatric orthopaedic disease, which makes their exact measurement necessary. AIM The aim of the author was to evaluate the reliability of the EOS 2D/3D System, a 3D reconstruction capable imaging device in children. METHOD 3D reconstructions were performed in 523 cases aged between 2 and 16 years in whom no abnormality influencing lower limbs biomechanics was observed. For statistical analysis intraclass correlation, paired-samples t-test, Spearman-correlation and Welch-test were used. RESULTS Excellent results were found for all parameters in reliability test used by the operator. The step-forward position used during the examination influenced the sagittal tibiofemoral angle only. All examined parameters showed significant correlation with age and gender. Height correlated with neck-shaft angle, hip-knee shift, femoral and tibial torsion only. CONCLUSIONS The EOS technology proved to be an appropriate method to measure lower limbs anatomical parameters in children. Changes in these parameters during development correlated with age and gender.