Intervertebral Disc Degeneration Reduces Vertebral Motion Responses.

Colloca, Christopher J.; Keller, Tony S.; Moore, Robert J.; Gunzburg, Robert; Harrison, Deed E.

In vitro and in vivo biomechanical studies have examined spine kinematics during posteroanterior loading mimicking spinal manipulation therapy (SMT), but few (if any) studies have quantified SMT loading-induced spinal motion responses in the degenerated intervertebral disc.  The objective of this study was to determine the effects of disc degeneration and variable pulse duration mechanical excitation on dorsoventral lumbar kinematic responses.  Fifteen sheep underwent a survival surgical procedure resulting in chronic disc degeneration of the L1-L2 disc. Ten age- and weight-matched animals served as controls. Uniform pulse dorsoventral mechanical forces (80 N) were applied to the L3 spinous processes using 10-, 100-, and 200-ms duration pulses mimicking SMT. L3 displacement and L2-L1 acceleration in the control group were compared with the degenerated disc group.  The results showed that dorsoventral displacements increased significantly with increasing mechanical excitation pulse duration in both groups. Displacements and L2-L1 acceleration transfer were significantly reduced in the degenerated disc group compared with control.  The authors conclude that dorsoventral vertebral motions are dependent on mechanical excitation pulse duration and are significantly reduced in animals with degenerated discs.

Spine, 2007,    32(19), E544-E550

Link to Abstract

Link to Full Text