[Kinematic effects of discectomy on the lumbar spine: an experimental study]

By way of 3-dimensional measurement, the kinematics of the lumbar spine after discectomy were studied on 8 specimens of functional spinal units from cadavers. Each specimen was subjected to discectomy performed as on living body, the specimen was then, with proper load, fixed on a frame specially made for passive motion, imitating that of a person. Records of the 3-dimensional motions, before and after discectomy, were compared carefully. The data demonstrated that discectomy of lumbar spine did bring about definite ill-effect on kinematics of the spine, initiating immobility.