The effect of repeated extensions on the discographic dye patterns in cadaveric lumbar motion segments

Little is known about the effect of mechanical treatment on the intervertebral disc in the management of low back pain, even though good clinical results are often claimed for this treatment. In order to understand the possible effects of this treatment, cadaveric lumbar motion segments were studied with discography at 103 levels in 19 lumbar spine specimens. Fifty-four motion segments were tested with repeated extension/compression moments and evaluation of the changes in discogram dye pattern was made. In 43% increased dye leakage was observed, while 31% of those studied showed some degree of increased bulging, and in 2% there was evidence of decreased bulging. The major effect of repeated extensions moments on the cadaveric lumbar motion segment appears to lie in forcing dye from the nucleus pulposus into the spinal epidural space, or some peridiscal space in many abnormal discs.