Evaluating the Rotation Correction of the Main Thoracic Curve in Severe Adolescent Idiopathic Scoliosis: Bending and Traction vs. Fulcrum – A Preliminary Report

Abstract

BackgroundFlexibility evaluation methods were only used to assess the changes of coronal Cobb angle in patients with adolescent idiopathic scoliosis (AIS). Little attention was attached to the vertebral rotation in these methods.Material/Method21 patients with severe adolescent idiopathic scoliosis were enrolled in this study. Coronal flexibility and rotation correction were compared on the supine bending, traction and fulcrum bending radiographs. The apical vertebral body rib ratio (AVB-R), and Perdriolle rotation angles were used to measure the rotation of the main thoracic curve. Statistical analysis was performed with one-way Analysis of Variance(ANOVA). Correlations between postoperative AVB-R and AVB-R in supine bending, traction and fulcrum bending radiographs were assessed utilizing the Linear Regression.ResultsThere were trends towards increased coronal flexibility in fulcrum bending versus traction versus supine bending, but there were no significant differences due to the limited sample size. And all were significantly lower than postoperative correction. The correction of AVB-R at traction and supine bending radiographs were significantly better than fulcrum bending, however, all were significantly lower than postoperative correction. Correction of Perdriolle rotation angle at traction radiograph was best among these methods. A univariant linear regression analysis showed a strong linear correlation between the postoperative AVB-R and the AVB-R in the traction radiograph.ConclusionsAs to patients with severe AIS, the coronal plane flexibility evaluated at the fulcrum bending radiograph is superior to that at the traction radiograph. This may be explained by the measurement errors induced by the better derotation capacity at the traction radiograph. Rotation correction evaluated at the traction radiograph proves better than the fulcrum bending radiographs, showing a linear correlation with the postoperative correction.

A Novel Multiple Screw Distraction Reducer System in the Treatment of Scoliosis with a Severe Rib Hump

“…On the one hand, the longitudinal distraction of the spine itself could produce a derotation effect. [17][18][19] Jhaveri et al reported that the overall mean AVR, as measured using the Nash-Moe scale, of the major structural curve was 3.1 AE 0.8 preoperatively, and it was reduced to 2.4 AE 0.6 intraoperatively following skeletal (skull femoral) traction for the correction of large-magnitude idiopathic and neuromuscular scoliosis. 20 The MSDR system performs internal longitudinal distraction on the scoliotic spine and may produce stronger traction that is more conducive to the correction of vertebral rotation.…”

Comparison Between Radiographic Methods of Measuring Flexibility in Scoliosis

“…2 In their classifications, King 3 and Lenke 4 highlighted the importance of the flexibility of the curves in the radiographical examination, formulating the concept of curve structurality and defining it as one of the most important parameters for surgical planning, responsible for the choice of arthrodesis levels and the number of corrective osteotomies. [5][6][7][8][9] Flexibility can be analyzed by several methods: bending in the standing or dorsal horizontal decubitus positions, fulcrum bending, traction, traction under general anesthesia, among others. [5][6][7][10][11][12] Currently, bending radiographs are considered the gold standard for flexibility assessment, because they are easy to perform and are one of the parameters included in the classifications.…”

“…[5][6][7][8][9] Flexibility can be analyzed by several methods: bending in the standing or dorsal horizontal decubitus positions, fulcrum bending, traction, traction under general anesthesia, among others. [5][6][7][10][11][12] Currently, bending radiographs are considered the gold standard for flexibility assessment, because they are easy to perform and are one of the parameters included in the classifications. 5,7,13,14 It is known that in curves greater than 60 degrees traction is better than the other methods.…”

“…[5][6][7][10][11][12] Currently, bending radiographs are considered the gold standard for flexibility assessment, because they are easy to perform and are one of the parameters included in the classifications. 5,7,13,14 It is known that in curves greater than 60 degrees traction is better than the other methods. 7,12 More recently, flexibility has begun to be assessed using the traction under anesthesia method.…”

“…5,7,13,14 It is known that in curves greater than 60 degrees traction is better than the other methods. 7,12 More recently, flexibility has begun to be assessed using the traction under anesthesia method. Some studies have demonstrated equivalence with the bending positions, with better correction due to muscle relaxation.…”