Background: In patients with untreated scoliosis or in those with posterior spinal instrumented fusion (PSF), the movements of neither the thoracic cage (ThC) nor the abdomen (ABD) during quiet and deep breathing have been well defined in the literature. The purpose of this study was to evaluate kinematic variations in the ThC and ABD during quiet and deep breathing by optical reflective motion analysis (ORMA) in children with scoliosis.
Methods: The study included 6 healthy children (group A), 7 subjects with untreated scoliosis over 50 degrees (group B), and 8 patients with scoliosis treated by PSF (group C). After anthropometric measurements (standing height, sitting height, arm span, chest perimeter, body weight, body mass index, T1-T12, and L1-L5 length) were obtained, the movements of subjects during quiet and deep breathing were measured with a 10-camera 3-dimensional ORMA system (82 markers) with the subjects in a standard standing position.
Results: No significant differences were observed in sex, age, weight, height, or arm span (P>0.05). Significant differences were observed in the chest perimeter, Cobb angle, and body mass index (P<0.05). ThC and ABD movements during quiet and deep breathing decreased significantly in group B and C when compared with group A (P<0.05). Group B showed decreased expansion of the ThC (-52.4% to -58.3%) and relatively increased motion of the ABD compared with groups A and C (P<0.001). However, ABD expansion remained lower in group B than in groups A and C (-32.8% and -5.7%). PSF does not completely eliminate transverse plane kinematics, although a greater reduction was observed at instrumented than noninstrumented levels (-60.8% vs. -35.1%; P<0.05).
Conclusions: ORMA is a useful tool for assessing alterations in the kinematics of the ThC and ABD caused by severe scoliosis and/or PSF. Compared with normal subjects, patients with severe scoliosis had poorer and less effective kinematics of the ThC and ABD. In contrast, operated subjects had better and more effective kinematics of the ThC and ABD, breathing curves, thoracic expansion, and abdominal movements closer to normal compared with patients with severe, untreated deformity.
Level of evidence: Level III.