Nucleus pulposus replacement: an emerging technology.

Debilitating low back pain as a result of symptomatic lumbar disc degeneration places a significant burden on an industrial society. Traditionally surgical treatment involving fusion of the anterior and posterior spinal elements has resulted in unpredictable and frequently irreproducible results, especially with regard to return to work rates. A new surgical method of managing symptomatic disc degeneration recalcitrant to nonoperative measures involves the partial or complete removal of the intervertebral disc with replacement with a motion-sparing device. A review of the English-speaking literature will be discussed evaluating the historical development, design considerations, animal models, basic science studies, cadaveric research, and clinical outcomes of the partial removal of the intervertebral disc (nucleus pulposus) and replacement with a motion-sparing implant. An overview of traditional methods of surgical management of lumbar degenerative disc disease will then be followed by an introduction to the concept of motion-sparing implants (nucleus pulposus replacement) intended to remove the pain generator without the associated morbidity of a surgical fusion.