Isthmic spondylolisthesis among patients receiving disability pension under the diagnosis of chronic low back pain syndromes.

OBJECTIVES: This study evaluated the incidence of lumbar isthmic spondylolisthesis among subjects permanently disabled because of low back pain syndromes. SUMMARY OF BACKGROUND DATA: Previous information pointed to whether spondylolisthesis is associated with more frequent or intensive low back pain than that found in the general population. One may expect severe deformity, neurologic deficits, and hence impairment and disability accompanying such a spinal disorder. However, natural history of spondylolisthesis has also been reported to be benign.
METHODS: Files from 952 subjects receiving temporary or permanent disability pension because of musculoskeletal disorders of the vertebral column were investigated; 81% had low back pain syndromes. From the radiologic report of the lumbar spine, which was available in 519 (70%) cases, the radiologic findings were recorded.
RESULTS: In 2.5%, isthmic lumbar spondylolisthesis was present. In more than half of the subjects, the location of the defect was on L4. Only minor neurologic findings were present.
CONCLUSIONS: The finding that the incidence corresponds well with the incidence in the normal population may suggest that lumbar isthmic spondylolisthesis does not invariably lead to severe impairment or disability, although location of the defect at the level proximal to L5 may be connected to an increased risk for permanent low back disability.