Exercise might not always be the best treatment approach for some low back pain sufferers. A new randomized trial shows no difference in pain, disability, or general health among patients with lower back pain and Modic changes (MCs) — edema or fatty degeneration in the vertebral endplate — who followed an exercise regime and those who adopted a routine of rest and load reduction.
The finding that rest results in the same small improvements as a more active treatment approach challenges the idea that exercise should be the "gold standard" for patients with low back pain and MCs, said lead author Rikke K. Jensen, MSc, from the Research Department, Spine Centre of Southern Denmark, in Middelfart. This article is part of her PhD thesis.
The results do not suggest that patients with MCs should not exercise, said Jensen "But I think clinicians should be careful; when patients come back and say this treatment didn't work, it's not because they did it the wrong way or they didn't do it enough. It's very possible that this treatment is just not very effective for this group of patients."
The study was published online February 29 in BioMed Central's open access journal BMC Medicine.
Inhibits Healing
Although MCs are fairly common, affecting some 40% of patients with low back pain (LBP), their precise cause is unknown. One theory has been that they are caused by mechanical stress, and that excessive loading may result in microfractures of the endplate causing inflammation in the vertebral endplate and the adjacent bone marrow.
The severe and persistent pain suffered by patients with MCs is often unresponsive to active treatment, possibly because weight-bearing exercises inhibit microfracture healing. "When you're jumping up and down on microfractures, they tend not to get better," said Jensen. "It was important for us to test the hypothesis that people don't improve with exercise if they have these MCs, and are there other treatment options that could prove to be more effective."
When you're jumping up and down on microfractures, they tend not to get better.
The study enrolled 100 adult patients with persistent LBP (at least 3 on an 11-point scale) and MC confirmed on magnetic resonance imaging that extended beyond the endplate into the vertebral body. The patients were referred from primary care and had had symptoms lasting from 2 to 12 months. They were allocated to either a rest group or an exercise group.
The rest group was instructed to avoid hard physical activity and to rest by lying down for an hour twice daily. They also used a flexible lumbar belt as needed for up to 4 hours a day. After 10 weeks, they were to gradually increase their physical activity. The duration of this intervention was supposed to allow time for microfracture healing.
Subjects in the exercise group did supervised 1-hour exercises once a week for 10 weeks. The regime included exercises for stabilizing muscles in the low back and abdomen, exercises for postural instability, and light physical fitness training. These patients were encouraged to do the same exercises at home 3 times a week and to maintain a "normal" level of activity.
Pain/Disability Assessment
All patients completed questionnaires at baseline, 10 weeks, and 12 months. The study assessed pain using a numerical rating scale (NRS) of back pain ranging from 0 to 10; disability using the 23-item Roland Morris Disability Questionnaire (RMQ) with scores ranging from 0 to 23; general health using the EuroQol, as well as global assessment and depression. Patients also reported any back problems or sick leave.
The study included data on 87 patients at 10 weeks and 96 patients at the end of the study.
After treatment, the mean pain NRS score was 5.0 in the rest group vs 4.5 in the exercise group (difference adjusted for baseline score, age, sex, smoking and physical workload: − 0.07; P = .9). At 1 year, the scores were 4.8 in the rest group and 4.3 in the exercise group (adjusted difference:− 0.3; P = .5).
For disability, the posttreatment NRS score was 11.0 in the rest group and 11.1 in the exercise group (adjusted difference: − 0.6; P = .5) and at 1 year, the scores were identical at 10.7 for both groups (adjusted difference: − 1.2; P = .3).
The study found no significant difference in general health scores. Also no serious problems or adverse events were reported in either group.
The study results do not add anything new to what is already known about the etiology of MCs, said Jensen. "We know that they are part of the degeneration process but we still don't know what causes them."
Spine-related pathoanatomic changes other than MCs, or psychosocial factors, might influence or cause pain, said the authors. And if MCs do cause pain and rest is useful, the amount of rest in the study may have been insufficient. It's also possible that subgroups of type, size, and location of MCs would have responded differently to treatment.
Although rest was not inferior to exercise in the study, it could carry the risk of unwanted behaviors such as poor coping strategies. However, the study found no difference in emotional functioning between the groups.
Jensen stressed that exercise generally has beneficial effects on overall health and well being for all patients. "I don't recommend exercise as a specific treatment for MCs but MCs are not a contraindication for exercise."
However, she added that the study does not bring researchers or clinicians any closer to an effective treatment for MCs. "Actually, we don't know what to do with these patients."
“Excellent” Study
Asked for comment on this study, Vera Bril, MD, from the Division of Clinical Investigation & Human Physiology, Toronto General Research Institute, in Canada, and a member of the American Academy of Neurology, was positive.
"I think that this is an excellent study that does not support the hypothesis that patients with different forms of back pain respond differently to treatment," she told Medscape Medical News. "So the presence of Modic changes at the endplate regions does not predict response to therapy for back pain.
"It is also interesting that both those advised to rest and those to be active had the same outcomes in this study," she added.
The authors have disclosed no relevant financial relationships.
BMC Medicine. 2012. Published online February 29, 2012. Abstract
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