F-2-22-02
PERSISTENCE OF LOW BACK PAIN IN THE YOUNG - A PROSPECTIVE EIGHT-YEAR FOLLOW-UP STUDY OF SUBJECTS WITH AND WITHOUT LOW BACK PAIN
Jouko J. Salminen, Ari Oksanen (University Hospital of Turku, Turku, Finland), Jaana Pentti (Turku Regional Institute of Occupational Health, Turku, Finland )
Abstract: In a questionnaire based survey of 14-year-old Finnish school children (n=1503) a subgroup (7.8%) with frequent low back pain (LBP) was found. We decised to follow a random sample of this subset (n=40) and equal number of initially pain free control subjects matched by age, sex, and schoolclass with special reference to LBP, leisure time physical activity, anthropometry, spinal mobility, trunk muscle strength, and magnetic resonance imaging findings of the lumbar spine.
Differences between the groups at baseline and at three-year follow-up were reported earlier. Among other findings we found more frequent and earlier development of degenerative changes in the lower lumbar intervertebral disks in original LBP group.
At three-year follow-up, subjects with LBP at baseline still reported LBP-ever (P<0.001), LBP in the past 12 months (P=0.001), and recurrent LBP (P=0.017) significantly more often than control subjects. At eight-year follow up still some persistence of LBP existed in the comparisons between the original LBP group and control subjects. One third of the original LBP group reported recurrent pain both at three- year and eight-year follow-up. Factors contributing to the persistence of recurrent pain will be analysed.
F-2-22-03
THE INFLUENCE OF THE LUMBAR DISC DEGENERATION THE BALANCE OF THE TRUNK MUSCLE STRENGTH
JH. Lee, K. Itoh, Y.Hoshino, Y. Kariya, K, Saita (Jichi Medical School, Tochigi, Japan)
Purpose: It is a commonly accepted conclusion that subjects with LBP have lower muscle strength than the normal population, but no agreement on the balance of the trunk muscle strength (extension/flexion ratio) has been reached so far. We studied to assess the influence of the lumbar intervertebral disc degeneration on that ratio in normal subjects.
Method: 175 volunteers without LBP were classified into normal disc (NOR) and degenerated disc (DEG) group (female NOR: n=33, 28.9±9.2 y.o., male NOR: n=48, 29.3±7.5, female DEG: n=37, 32.0±8.8, male DEG: n=57, 30.7±7.6) A sagittal MRI of the lumber spine was used for assessment of disc degeneration. Trunk muscle strength in extension and in flexion was measured isokinetically at the speed of 60 deg/sec, and the ratio of the peak torque was calculated as extension/flexion ratio.
Result: The ratio of the DEG group (female: 0.83±0.20, male: 0.92±0.22) demonstrated significantly lower values than the NOR groups (female: 0.99±0.28, male: 1.12±0.29, P<0.05).
Conclusion: Minor instability as s result of the disc degeneration may affect the trunk extensor muscles more than the abdominal muscles. This study revealed that the degeneration of the lumber intervertebral disc can be sttributable to an impaired trunk muscle balance.
