Kim Bergholdt, DC, Rasmus N. Fabricius, DC, and Tom Bendix, MD, DrMedSci

RESUMO

Study Design. A “randomized”/stratified, singleblinded, parallel-group study.

Objective. To evaluate 3 structurally different mattresses relative influence on patients with chronic low back pain (CLBP).

Summary of Background Data. In several advertisements, it is proclaimed that certain mattresses have a positive effect on LBP, and especially a hard mattress is commonly believed to have a positive effect.

Methods. One hundred sixty CLBP patients were randomized to 1 of 3 groups, having a mattress/bed mounted in their sleeping room for 1 month. The beds were: (1)
waterbed (Akva), (2) body-conforming foam mattress (Tempur), and (3) a hard mattress (Innovation Futon). At baseline and after 4 weeks, a blinded observer interviewed
the patients on LBP levels (0 –10), daily function (activities of daily living, 0–30), and on the amount of sleeping hours/night.

Results. Because of dropout of 19 patients before baseline, the analyses were performed on 141 patients. During the 1-month trial period another 27 patients stopped ahead of time, which were accounted for by “worse case” as well as “no-change” analyses. Both the
waterbed and the foam mattress seemed superior to the hard mattress, especially when using the probably most relevant “worst case” data. There were no relevant difference
between the effects of the water bed and the foam bed.
Conclusion. The Waterbed and foam mattress  did influence back symptoms, function and sleep more positively as apposed to the hard mattress, but the differences were small.
Key words: low back pain, chronic, sleep, mattress.

Introduction
Among several factors potentially influencing the level of low back pain (LBP), mattresses are often discussed, and many patients report either advantage or disadvantage from specific mattresses.
Several believes exist on which some mattress may improve back pain more than others,1 especially for those who have the worst pain when they wake up in the morning. The facts are unfortunately very few and inconclusive.
Kovacs et al2 conducted a large trial with 313 adults who had chronic low back pain. They found that a mattress of medium firmness improved pain and disability slightly among the participants compared with a more firm mattress. Otherwise there have only been made a few studies on this subject.3–9 Most of these studie are small and weakened by shortcomings in the methods.
Several are not even controlled. Furthermore, they are difficult to compare because there have been a variety of mattresses, evaluation methods, and inclusion and exclusion
criteria. Although they have all indicated that some mattresses can have a positive or negative effect on back pain, no overall conclusion can be drawn.10,11
There are much more studies elucidating the influence on bed rest in postoperative pain or otherwise exceeding usual nightly sleep, etc. as an optional treatment for actual LBP   sciatica.11,12 That issue is, however, out of the frame of this study.
However, there are several aspects to consider when looking at the possible effects a mattress may have on LBP, especially:

● Better sleep at night leading to a greater sense of well being, which may affect the perception of pain during the day.

● The back should probably be kept more or less in a neutral position, so that long lasting end-range positions of 1 or more tender spinal joints are avoided. To obtain this demand, the mattress should be appropriately soft, conforming body curvatures by having a reasonable capacity to equalize the pressure. How close the spinal posture should mimic that of the standing posture 13 is unclear.

● The capability of easy turning from side to side to avoid a painful loaded twist in the back. An appropriately hard mattress seems optimal for this purpose.

● A specific mattress may influence intervertebral disc nutritional flow positively or negatively as a function of spinal movement, because movement affects the discal metabolism.14–18 It is likely that the significance of this factor varies between those being sedentary or physically active during the daytime.
The purpose of this study was to investigate the relative effect as regarding back pain, leg pain, activities of daily living (ADL) and hours of sleep of respectively a waterbed, a body-conforming, visco-elastisk foam mattress, and a more firm Futon mattress on patients with chronic LBP.

FONTE:
Kim Bergholdt, DC,
Rasmus N. Fabricius, DC, and
Tom Bendix, MD, DrMedSci

Veja o artigo completo em: Spine 2008;33:703–708