Assessment of cervical disk prosthesis by means of video-fluoroscopy image processing

Many cervical spine pathologies involve degeneration of the stabilizing mechanisms of vertebrae segments and often cause pain. Abnormal intervertebral motion is an indication for surgery. Currently, spinal fusion surgery is widely adopted to fix the instable vertebral segments but recently, disk arthroplasty is more and more adopted as an alternative to restore normal kinematics and biomechanics of the sick segment and to reduce development of symptomatic adjacent-level degeneration. This study aims to measure intervertebral kinematics by means of image processing of X-ray fluoroscopy videos, which are able to screen patient's neck spontaneous movements of flexion-extension. Vertebrae trajectories are estimated by using image template matching techniques. Then, continuous-time intervertebral kinematics is computed by using spline interpolation. The results, obtained by using real fluoroscopy videos, reveal the possibility of obtaining in vivo information about the continuous evolution of motion of the implanted prosthesis and adjacent segments.