Natural course and prognosis of intervertebral disc diseases. International Society for the Study of the Lumbar Spine Seattle, Washington, June 1994.

The disc is an osmotic system that lives from motion. Because of the human sedentary nonmoving lifestyle, disc degeneration is progressive. The morbidity curve does not follow the degeneration curve. In patients between 40 and 50 years old, discs have highlights in their clinical course because of the biomechanical constellation, with the presence of tears and fissures in the anulus and maintained expansion power of nucleus material. In old discs, the nucleus is not willing to move. This is the comfortable rigidity of the aging spine. Not only during lifetime also in case of acute back pain and sciatica natural course is benign. If patients and their doctors wait long enough, most pain curves drop, so that initially planned surgery can be cancelled. This is the waiting list phenomenon. Few patients need a disc operation because of hard disc fragments, which can be identified on magnetic resonance imaging. Open disc surgery is the most frequent and important spine operation. Proper patient selection and good technique with a small approach by microsurgery can help avoid PDS, the worst course and prognosis of intervertebral disc disease.