Curve severity and apical vertebral rotation and their association with curve flexibility in adolescent idiopathic scoliosis

Abstract

Purpose To determine the association between coronal Cobb's angle and Nash-Moe index in patients with adolescent idiopathic scoliosis. We also attempted to determine whether apical vertebral derotation depended upon the curve flexibility. Overview of literature The three-dimensional nature of adolescent idiopathic scoliosis (AIS) is well established. Knowledge of all components of this complex deformity is essential to formulate effective treatment strategies. Though the importance of quantifying all the components of the deformity, in AIS, has been analysed in detail, very few studies have been done to ascertain the relationship between the coronal plane deformity and apical vertebral rotation. Methods Digitalised standing and supine stretch anteroposterior (AP) radiographs of 158 patients with AIS were analysed. The standing and supine stretch AP radiographs were compared to calculate the percentage reduction of Cobb's angle to determine curve flexibility. The derotation of the apical vertebra on application of traction was also noted. The one-way repeated ANOVA was used to determine the association between Cobb's angle and Nash-Moe index. The independent sample t test was used to determine whether a statistically significant difference was present, in the age of the patient, severity of the curve and percentage reduction of Cobb's angle between those curves that derotated and those that did not, when stretched. Results The one-way repeated ANOVA revealed an association between Cobb's angle and Nash-Moe index on the standing and supine AP stretch radiographs (P < 0.01). The Independent sample t-test showed a statistically significant difference in percentage reduction of Cobb's angle between those curves that derotated compared to those that did not, on stretch (P < 0.01). Conclusions This study demonstrates that there is an association between apical vertebral rotation and the coronal plane deformity. It also demonstrates that flexible curves derotate to a greater extent compared to rigid curves, when stretched.

The Correlation Between Cobb’s Angle and Pedicle Rotation in Adolescent Idiopathic Scoliosis After Surgical Treatment

“…Nash-Moe method can be used to determine the rotational deformity of the vertebrae and this method is still widely used. 11 The present study investigated the correlation between Cobb's angle and pedicle rotation in AIS after surgical treatment.…”

“…10 The 3-dimensional nature of scoliosis was well understood based on radiography. 11 The Cobb angle is the gold standard for measuring lateral curve that could show how severe the deformity of the spine. Nash-Moe method can be used to determine the rotational deformity of the vertebrae and this method is still widely used.…”

Developing of a Mathematical Model to Perform Measurements of Axial Vertebral Rotation on Computer-Aided and Automated Diagnosis Systems, Using Raimondi’s Method

“…AVR is a necessary parameter in being able to correctly evaluate and provide a prognosis for monitor and treat scoliosis [ 1 – 7 ].…”

“…Axial vertebral rotation (AVR) is a basic parameter in the study of idiopathic scoliosis in adolescents [ 1 , 2 ]. Its measurement is necessary to evaluate the severity of scoliosis and quantify the risk of progression [ 1 , 3 – 7 ] for the selection of treatment [ 3 , 4 , 8 , 9 ] and for the analysis of orthopaedic surgery [ 1 , 6 – 8 , 10 , 11 ].…”

Clinical and radiological results of surgically treated patients with adolescent idiopathic scoliosis and the effects of pulmonary rehabilitation on respiration functions

“…The distance from the midpoint of the apical vertebral body to the central mid-sacral line was measured, and consequently, apical vertebral translation (AVT) was determined. [ 8 ] Using the Nash–Moe method, [ 8 ] the rotation of the apical vertebrae was measured. We used the Lenke classification system criteria to analyze the graphs of the patients.…”