[Pain following operations of the lumbar spine. The "failed back surgery syndrome"].

This is a follow up study of 61 patients with a 'failed back surgery syndrome' (FBSS). The mean follow up time is 5.4 years after the first operation on the lumbar spine. The diagnosis before the first operation was in 35 patients an entrapment disease (disc herniation or stenosis of the spinal canal), in 25 patients a segmental instability and once a deformity. The reason for the development of a 'failed back surgery syndrome' was in 18% a perioperative complication, in 24% a late unhappy consequence of the operation, in 40% an assessment- or treatment error. In 18% we were not able to figure out any reason for the failure. The correlating diagnosis were: postoperative infections 3, hematoma 1, disc herniation or instability on a second level 12, a second disc herniation at the same level 3, scarring or arachnoiditis 2, instability 18, lateral spinal stenosis 10. We emphasize the importance to distinguish between a clinical relevant and irrelevant diagnosis and to use special tests for this differentiation.