[Natural course in spondylolysis and spondylolisthesis].

The incidence of spondylolysis is approximately 5-6% in the white population. Males and females are equally affected. In about one third of the cases spondylolysis is associated with spondylolisthesis. For the etiology mechanical and genetic factors are important. At the L4 level mechanical factors play the dominant role, while at the L5 level genetic factors are equally important (size and orientation of the facet joints, dysplasia of the vertebral arch). Increased risk for low back pain is found in the presence of the following factors: spondylolisthesis exceeding 10 mm, a low lumbar index, increased lumbar lordosis, spondylolysis at the L4 level and early beginning of symptoms. In the absence of one of these factors the risk for low back pain in adulthood is not greater than in the normal population. This statement is supported by the fact that in a low back clinic with more than 2000 patients with low back pain, the incidence of patients with spondylolysis was not higher than in the normal population. In our own study we followed up 31 patients. The majority of them were symptomatic during adolescence. After a follow-up time of 28 years on average 20 of them stated that they had no pain since adolescence, 8 had only occasional pain and only 2 had undergone operative treatment because of significant low back pain.