Characterization of trunk motion in adolescents with right thoracic idiopathic scoliosis

Although standard radiography is currently used for deformity assessment in AIS patients, it is performed in a constrained position and probably not reflective of spinal balance during daily-life activities. Our main objective was to compare trunk motion in Lenke 1 and 2 AIS patients to healthy volunteers, using gait analysis.

Lenke 1 or 2 AIS patients planned for surgery were included. The day before surgery, they underwent radiographic evaluation and gait analysis. Among the gait parameters, sagittal vertical axis (Dyn-SVA), shoulder line rotation (Dyn-SL rotation), pelvis rotation (Dyn-P rotation) and acromion pelvis angle (Dyn-APA) were measured. AIS patients were compared to 25 asymptomatic controls.

A total of 57 patients were included in the study, with a mean Cobb angle of 55.4°. AIS patients had a lower Dyn-SVA when compared to controls (47.0 vs. 62.9 mm, p = 0.012). Dyn-APA and Dyn-SL rotation were negative in AIS patients, meaning that shoulder line was rotated towards the left (- 6.4 vs. 7.8° and - 7.5 vs. - 0.4°, p<0.001, respectively). On the other hand, Dyn-P rotation was positive, meaning that pelvis was rotated towards the right side during gait (1.1 vs. - 0.5, p = 0.026).

This is one of the largest series of gait analysis in AIS patients. We demonstrated that AIS patients have an abnormal gait pattern, with a decreased anterior tilt of the trunk and transverse plane abnormalities. We found that gait deviation was not related to radiographic measurements, pointing out that dynamic assessment provides new data about spinal posture. These slides can be retrieved under Electronic Supplementary Material.