principal investigator has left the institution

The aim of the study is to evaluate the feasibility and validity of conventional radiographs of the lumbo-sacral spine when the patient is lying on a special table which facilitates maximal lumbo-sacral flexion. The results gained from the radiographs with the patient on the table will be compared with those gained from standard flexion-extension radiographs of the lumbo-sacral spine.

After enrollment in the study patients will complete a set of questionnaire concerning degree, extent and quality of their low back problem. Afterwards a lateral conventional radiograph of the lumbar spine with the patient on a custom made positioning table will be taken. The table facilitates optimal flexion of the lumbar spine. Afterwards sagittal translation and rotation are measured on the flexion-extension radiographs and the radiograph taken on the custom made table. Differences between the measurements will be determined.

Inclusion Criteria:

• chronic low back pain (≥ 3 months)
• clinical suspicion of lumbo-sacral instability
• functional conventional radiographs of lumbar spine
• pain intensity > 4 / 10 on visual analogue scale
• age 20-60 years

Exclusion Criteria:

• radicular pain
• pain at more than two locations
• lumbar spine surgery
• scoliosis
• lumbar spondylolysis
• lumbar spondylodiscitis
• anatomic aberrations of lumbar spine
• unconsolidated spine fractures
• neurologic deficits
• spine tumor
• neuromuscular disease
• rheumatic disease
• severe osteoporosis
• radiotherapy within the last 5 years
• pregnancy
• insufficient German language skills
• no informed consent

Patients suffering from chronic low back pain and clinical suspicion of lumbar instability.