The purpose of this study was to establish a finite element stress analysis method of intervertebral discs in a rheumatoid arthritis (RA) patient with cervical involvement using a three dimensional (3D) computer model reconstructed from computer tomography (CT) and magnetic resonance (MR) images. Intervertebral disc 3D finite element models were created using point cloud data of endplates of cervical spine (C2-C7) vertebral bodies in three different positions; neutral, flexion, and extension positions. Transformations of each endplate in flexion and extension positions were determined using a volume merge method. Changes in stress/strain distribution during flexion and extension were analyzed using displacement data of the endplate as input data. Stress concentration was noted at both lateral regions in C2/3 and C3/4 intervertebral discs. However, no significant changes in stress distribution during motion were observed at C4/5, C5/6, and C6/7 intervertebral discs.
