Three dimensional analysis of chest wall motion during breathing in healthy individuals and patients with scoliosis using an ultrasonography-based system.

Unlabelled: The mechanical inefficiency during respiration in scoliosis remains unclear.

Aim: To study the three-dimensional motion of the chest wall during deep breathing in healthy and scoliotic individuals.

Materials & Methods: Three-dimensional chest wall motion during breathing was studied in 17 scoliotic patients (right thoracic curvature) and 9 healthy individuals. Measurements were performed using a Zebris CMS 70P system (Zebris Medizintechnik Gmbll, Isny, Germany) which analyzes the time delay of ultrasound pulses emitted from markers placed on the chest wall. Nine markers were attached on the upper, the middle and the lower chest wall. Subjects were seated on a chair and asked to breathe deeply and slowly with no elevation of the shoulders for one minute.

Results: The amplitudes were symmetric between the two sides in healthy individuals while scoliotic patients exhibited asymmetric chest wall motion. The amplitudes of the right convex side of the chest wall exhibited less motion than those of the left concave side, especially on the lower chest wall.

Conclusion: Chest wall motion was asymmetric in the scoliotic patients with diminished motion of the right lower chest wall. This locally diminished ventilation may cause ventilation-perfusion inequality and result in hypoxemia.