Adolescent Idiopathic Scoliosis (AIS) Patient Positioning in EOS System®

Overview

The EOS® imaging system, a new imaging modality which offers low dose, weight bearing and full body X-ray imaging, requires a new standing position where patients put their hands and forearms on the wall vertically for stability. Although this method provides enough support for the patients during the extended X-ray acquisition time, its impact on the postural balance and sagittal profile of the spine and sacro-pelvic parameters has not been evaluated. The goal of this study is to identify the impact of patients' arm positioning on the sagittal profile and postural balance of the patient and subsequently propose a standardized method for full spine X-ray acquisition in the EOS® imaging system.

Spino-pelvic sagittal analysis and postural assessment are important parameters in adolescent idiopathic scoliosis (AIS) treatment and surgical planning.The three-dimensional (3D) shape of the spine is impacted by the patients' posture particularly in adolescents with flexible spinal curves. The latter highlights the importance of the patients' positioning during X-ray acquisition in order to avoid any misleading measurements that may adversely impact monitoring and surgical curve correction in AIS. Participating subjects will undergo two bi-planar X-rays in different positions. The positions will be instructed by the means of graphical presentation and verbal explanation by the radiology technician. The first standing position in the EOS® imaging system for full spinal X-ray acquisition will consist of putting both hands and forearms in front of the subject on the wall vertically. In the second position, knuckles are loosely placed on ipsi-lateral clavicles. Bi-planar X-rays will be taken in the EOS® imaging system for both positions. Moreover to compare the postural balance of the patient in the two described positions, a pressure mat will be placed in the EOS® system. The pressure mat will be calibrated with the EOS® system and permits to identify the position of the center of pressure (COP) with respect to the anatomical landmarks. The magnitude of pressure under the patients' feet will be measured during each X-ray and compared.

Conditions