ONE-FOOTED AND EXTERNALLY DISTURBED 2-FOOTED POSTURAL CONTROL IN PATIENTS WITH CHRONIC LOW-BACK-PAIN AND HEALTHY CONTROL SUBJECTS - A CONTROLLED-STUDY WITH FOLLOW-UP

Study Design. A study of postural control during one-footed and extern ally disturbed two-footed stance among healthy control subjects and pa tients with chronic low back pain at the beginning of a functional bac k restoration program and 6 months later at follow-up examination. Obj ectives. To study postural control cross-sectionally among control sub jects and patients with low back pain, and to evaluate the effects of functional restoration on the postural control parameters in a follow- up examination. Summary of Background Data. Deficits of motor skills a nd coordination have been reported in association with musculoskeletal disorders. It has been found that patients with chronic low back pain have impaired psychomotor control, but the impairment is reversible w ith successful low back rehabilitation. It is insufficiently known how functional activation and intensive physical training affect postural control. Methods. Sixty-one healthy volunteers (32 men, 29 women) and altogether 99 patients with low back pain participated in the study. Sixty-eight patients (33 men, 35 women) had moderate and 31 (18 men, 1 3 women) had severe low back pain. Postural stability was measured wit h a force platform. In two-footed stance, vibration stimulation on cal f and back muscles was used to disturb the balance. Center point of fo rce-velocity (cmi sec), average position shift in anteroposterior dire ction (cm), and maximal position shift in lateral direction (cm) were used as the parameters. Results. Reliability of all tests was acceptab le, Center point of force-velocity was the most sensitive parameter an d the one-footed measurement the most sensitivetest for evaluating pos tural stability. At the beginning, the patients with severe low back p ain had poorer one-footed postural control compared with the control s ubjects (P = 0.0003). The subgroup of patients with moderate low back pain participated in the restoration program. The outcome of the resto ration program was considered good if the disability because of low ba ck pain (Oswestry index) decreased during the restoration program and poor if the disability increased or did not change. The one-footed pos tural stability remained primarily at the same level as the initial re sults in the control and good outcome groups, but became significantly poorer in the poor outcome group. The difference between poor outcome and control groups was statistically significant (P = 0.04). Conclusi ons. impaired postural stability seems to be one factor in multidimens ional symptomatology of patients with chronic low back trouble. Postur al stability is easily disturbed in case of impairment in strength, co ordination, or effective coupling of muscles in the lumbar and pelvic area. Patients with chronic low back pain seem to experience impairmen t in these functions, which should be taken into consideration when ba ck rehabilitation programs are planned.