Mechanical effects of continuous passive motion on the lumbar spine in seating

• Published in: Journal of biomechanics 2000-06, Vol.33 (6), p.695-699
• Main Authors: van Deursen, D.L., Lengsfeld, M., Snijders, C.J., Evers, J.J.M., Goossens, R.H.M.
• Format: Article
• Language: English
• Subjects: Algorithms; Axial rotation; Back Pain - therapy; Computer Simulation; Continuous passive motion; Dynamic sitting; Elasticity; Exercise Therapy; Forecasting; Humans; Intervertebral Disc - physiology; Ischium - physiology; Lumbar Vertebrae - physiology; Models, Biological; Motion Therapy, Continuous Passive; Musculoskeletal system; Pelvic Bones - physiology; Physiological models; Pliability; Posture - physiology; Reproducibility of Results; Rigid body analyses; Rotation; Spinal Diseases - therapy; Stiffness; Stress, Mechanical; Torsional stress; Vibration
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/S0021-9290(99)00231-6

The aim of this study was to develop a model which describes the mechanical spinal response to small alternating pelvic stimulation induced by an active rotational movement of a normal chair. The rotary continuous passive motion (RCPM) of the seat about a vertical axis of only 0.6° resulted in an increased in spinal length as opposed to the normal daily shrinkage, and back patients experienced pain relief. Passive and active exercies have been broadly applied for treating and healing spinal disorders. A rigid body package (ADAMS Android) was used to translate the stimulation of the ischial tubersoity in caudo-cranial handing-over visualisation. The parameters of the model were set so that the values of the global stiffness and geometry of the intervertebral discs could be changed. In vivo validation of the model was based on force and moment measurements using an internal AO fixator. The predicitons of the model concerning natural frequency (4.5 Hz) in vertical direction and the axial torsion response on small pelvic torsion are comparable with experimental data.