A new classification system for degenerative disc disease of the lumbar spine based on magnetic resonance imaging, provocative discography, plain radiographs and anatomic considerations.

Prior attempts to classify degenerative disc disease (DDD) of the lumbar spine have been based on magnetic resonance imaging (MRI) signal intensity. Internal disruption of the disc is not reliably diagnosed by MRI alone. No attempt has been made to include provocative discography and plain radiographs. The intervertebral joint is a three-joint complex consisting not only of the end plate-disc-end plate joint of the anterior column, but also the two facet joints of the posterior column. To date, no classification system for lumbar DDD has taken into account the state of degeneration of the facet joints. In the past this may not have been important with regard to arthrodesis. But as early experience indicates, the degree of degeneration of the facet joints is paramount to the clinical success of an artificial disc replacement. As we transition from intervertebral joint fusion to intervertebral joint replacement, it is imperative that the state of degeneration of the three-joint complex be classified in such a way that all can evaluate lumbar DDD using the same terminology. A new classification system for lumbar DDD is presented. The intervertebral segment is graded in two parts: the anterior column and the posterior column, based on MRI, discography and plain radiographs. The system will be validated through a blinded study of 100 patients requiring stand-alone anterior lumbar interbody fusion or circumferential fusion. Although the debate over which discs are best treated surgically with indication for total disc replacement, or with indication for fusion will continue for some time, the basic understanding of intervertebral disc and posterior facet joint pathology, classified and validated in a simple forthright manner, is essential as we move forward with artificial disc technology.