Directional exercise helps relieve low back pain: better outcomes seen in randomized trial.
Current national guidelines state that physical activity is good for low back pain, and that there is insufficient evidence to recommend any specific exercises for management of this extremely common and costly problem.
That's no longer the case. A new multicenter randomized controlled trial shows that in most cases the specific type of exercise prescribed has a great impact upon patient outcome, said Dr. Donelson of Hanover, N.H.
New Zealand physical therapist Robin A. McKenzie developed a way to subgroup patients with low back pain (LBP) by having them repeatedly perform movements involving lumbar spinal flexion, extension, and lateral side glide. In about three-quarters of cases, this assessment identifies a single direction of movement--the patient's directional preference--that immediately improves the pain and/or centralizes it by moving the pain from the leg to the back, with the relief persisting after testing is finished.
Far and away the most common directional preference is extension, followed by lateral, then flexion. Many studies have shown that this mechanical assessment of directional preference in patients with LBP has strong interexaminer reliability. The minority of patients without a directional preference are likely to have a prolonged episode or nonrecovery.
Dr. Donelson reported on an 11-center trial without commercial sponsorship in which 12 physical therapists who were formally trained and credentialed in mechanical diagnosis and treatment assessed 312 patients with LBP. Among the 74% who had a directional preference to their pain--the study population--83% preferred lumbar extension, 10% lateral, and 7% flexion.
Randomized to one of three groups, the patients received either an exercise prescription that matched their directional preference--for example, exercises emphasizing lumbar extension for patients having an extension preference--or exercises opposite to their directional preference, or nondirectional exercise.
"All three groups were given advice to stay active, a rationale for their particular exercise assignment, and reassurance of likely recovery. This educational content, when added to the nondirectional exercises in group 3, strongly resembled guideline-based care," the physician noted.
At entry, 40% of the patients were unable to work due to LBP, and 24% had a work-related low back injury. The LBP was acute in 13%, subacute in 32%, and chronic (of more than 7 weeks duration) in 55%. Overall, 70% of patients had a history of prior LBP episodes. Also, 47% had LBP only, 18% also had referred pain above the knee, 17% had pain distal to the knee, and 17% had one positive neurologic sign.
The primary end point was self-assessed intensity of back and leg pain after 2 weeks. Pain was rated as better or resolved by 95% of patients in the matching-exercise group, 23% in the opposite-exercise group, and 42% in the nondirectional-exercise group.
Most strikingly, 35% of patients in the opposite group and 33% in the nondirectional group had to withdraw from the study early because their pain intensified or moved further distally, or their neurologic status worsened. Not a single patient in the directional group worsened or had to drop out.
Patients in the matched-exercise group also fared significantly better in all secondary study end points. They had twice as great an improvement in pain intensity scores as patients assigned to the other two groups. They had significantly greater mean reduction in depression scores. They had a fivefold greater functional improvement as assessed by the Roland-Morris Disability Questionnaire.
And among the 56% of study participants on pain medication at baseline, those in the matched-exercise group had a three-fold greater reduction in medication use after 2 weeks compared with those in the other two groups.
Most prior studies of exercise in patients with LBP have been done in patients with nonspecific LBP. These studies have generally yielded equivocal or conflicting results. The key to a successful exercise prescription, as shown in this trial and in contrast to previous studies, is first to divide patients into subgroups based upon the directional preference of the LBP, then provide matching exercises, Dr. Donelson stressed.
The hypothesized mechanism of benefit of matching the exercise prescription to the directional preference of a patient's LBP is that the various directions are likely compatible with vertebral disk pain.
"The disk has a nucleus pulposus that displaces in a direction opposite the bending load. And since we're a forward flex society, the disk most often goes out the back--we see that all the time. The theory would be that if it's overly displaced to the point of causing pain within the disk or the nerve root, then it's possible to move the patient in the opposite direction and through repeated loading reduce that displacement and have the nucleus retreat," Dr. Donelson explained.
"The nice thing about this approach is that when you're treating the patient you don't have to prove or disprove that it's the disk. We enjoy talking about that, but it doesn't matter for the patient. One of the very attractive things about this approach is it doesn't require you to make an anatomic diagnosis in order to find a very specific and effective treatment for a patient," he said.
VITAL SIGNS Total Health Expenditures per Capita Nearly Double From 1990 to 2002 1990 $2,738 1992 $3,184 1994 $3,534 1996 $3,847 1998 $4,179 2000 $4,670 2002 $5,440 Note: Based on data from the Centers for Medicare and Medicaid Services. Source: Kaiser Family Foundation Note: Table made from bar graph.
BY BRUCE JANCIN
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|Publication:||Internal Medicine News|
|Date:||Nov 15, 2004|
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