Back pain is the number one cause of disability worldwide. And we know that time has a fundamental impact on the development of persistent pain and inability to work. During the transition between the acute and chronic phases of low back pain, the psychosocial aspects become more important.

A recent review of the literature again confirmed that returning to work is good for recovery, whereas a prolonged period without work has the opposite effect. Gradual exposure to work makes it possible to avoid harming components of workers’ psychological and social well-being, such as self-esteem and sense of identity, and to maintain or recover the physical capacities needed for rapid reappropriation of their role within the company. Some workers, health care professionals and employers are afraid of an overly early return to work because of their own fears associated with pain or movement. Nevertheless, it is now acknowledged that workers who are recommended to remain as active as the pain permits have a lower risk of relapse than those who are prescribed rest until the symptoms disappear. 

How can we resolve this dilemma?

Christian Larivière, a biomechanics researcher at the IRSST, has been interested in this topic for a long time. “My research program has two focuses, which centre on a single question: What’s the best way to stabilize the lumbar spine? The first focus involves studying an active treatment method: a program of lumbar stabilization exercises. My other research focus is the use of lumbar support belts, a passive treatment method.

“It’s certain that we prefer workers to learn to use their muscles by doing lumbar stabilization exercises,” he continues. “The belt is a method that we suggest people use if necessary, for the short term, to reintegrate people who haven’t completed their exercise program back at work, for example. It doesn’t apply to chronic problems, but it’s definitely appropriate for more acute episodes.

 

 

The belt gives them some assurance and meets a necessary condition during this transition by ensuring more biomechanical security. Our study was designed to provide the first evidence to support that idea.”

A preparatory study

In fact, according to Christian Larivière, the final proof will have to be provided by a randomized, controlled trial (RCT), which will compare a control group to an experimental group. “This study had the aim of preparing for one, since an RCT is very expensive and the cost increases with the number of factors that have to be taken into consideration. First, which belt should we choose? Second, for which kinds of patients is this kind of treatment most effective? When we look at the effects of all kinds of treatments on back pain, we find that they’re generally modest.

“Then, some subjects don’t respond to the treatment at all while others respond very well. Our ultimate goal would therefore be to determine what kind of patient will benefit most from wearing a lumbar support belt. And thirdly, once we’ve established that a subgroup of patients responds well to this treatment, we want to know why. That’s where neuromechanical measures come into play. Our study has given us a good idea of the measures that are most sensitive to the effects we want to observe. That’s helping us make a selection for the RCT.”

Psychology and biomechanics

Given what we know about the winning factors for a return to and retention at work, we can’t ignore the role of psychosocial factors. Alessia Negrini, a researcher in psychological health at the IRSST, is a specialist in this area. “To the best of our knowledge, this is one of the few multidisciplinary studies carried out in Quebec that integrates a psychological component with the biomechanical aspects of employment rehabilitation.

“Do workers see wearing a belt as a good thing, or don’t they? Will I be able to make certain movements at work, and also in my daily life? When someone’s afraid of making a movement, is that just at work or also in their personal life? The project considers the whole person, helping us to understand what happens at work. We therefore adapted and used some questionnaires that will allow us to measure these factors in a future RCT.”

Another new aspect in a study of this kind is that it assessed anticipated social stigmatization. “What will other people think if I do or don’t wear my belt?” explains Alessia Negrini. “Other people’s opinion can influence our behaviour. Do my immediate superior, my colleagues, my clients, my family, my friends, my therapists encourage me or find it ridiculous? This evaluates an aspect that can potentially determine adherence to wearing a belt: other people’s judgment.”

In this regard, the researcher mentions a particularly significant result of the study: in general, people who felt that the lumbar support belt could help them carry out specific tasks also felt that their colleagues would approve of their using it. In addition, “people found the belt practical and easy to use. They were confident that it would help them carry out tasks at work and in their daily life.” All these indicators point in the same direction, supporting the use of a belt, just as the biomechanical results do.

Reactions to pain

Michael Sullivan, a professor and researcher in the Department of Psychology at McGill University, whose specialties include fear and catastrophizing of pain, took part in the psychological portion of the study.

 

 

That impedes recovery and leads gradually to a chronic condition and prolonged disability, and possibly the appearance of symptoms of psychological distress and depression.

Once they had accomplished some of the more difficult tasks in the neuromechanical evaluation, the subjects in the study were immediately asked to answer some questions on fear and dramatization of pain, while they still remembered the experiment, with or without the belt. “We were able to show that wearing a belt immediately reduced the pain and also seemed to reassure workers about their fear of executing certain activities. What’s interesting is that some reactions to pain changed when the subjects performed more demanding tasks, such as full forward flexion and handling loads,” reports the researcher.

One more tool to facilitate returning to or staying at work

Like Christian Larivière, Alessia Negrini believes that it’s important to continue the research by trying to find out whether specific sensations, perceptions and differences appear in different groups of people with back pain, depending on certain signs observed during the clinical examination and maybe on sex or age, among other factors. In that way, it would be possible to determine whether a belt should be prescribed for everyone or just for certain workers with specific clinical profiles, from specific industries or exposed to specific kinds of tasks.

“More and more,” believes Alessia Negrini, “research should consider the various players in the return to work. In my field, we consider that the success of a return may start even before the employee goes on leave. For example, if there’s good communication and support by the immediate superior, that can foster a healthy, sustainable return to work and contribute to preventing a potential relapse. Thus, a lumbar support belt could be one more tool to integrate into other measures to be considered throughout the process facilitating a return to work.”

Something brand-new in biomechanics

Christian Larivière is very proud of his achievements in biomechanics: “In our lab at the Institut de réadaptation Gingras-Lindsay-de-Montréal, we’ve implemented several types of neuromechanical assessments with leading-edge equipment. Some of our customized fixtures don’t exist anywhere else, or hardly anywhere. In relation to what’s being done around the world, we’re very well equipped for this kind of research. A neuromechanical study as comprehensive as this one has never been done to assess the effects of a lumbar support belt, and some of the assessments were the first ever.” Although they need to be validated in other studies, the preliminary results are promising.

Effects of the lumbar support belt

“There are three mechanisms underlying injuries and aggravation of pain on which we think lumbar support belts can have a positive effect,” according to Christian Larivière and Richard Preuss, of McGill University, another coauthor of this study. “First, there is lumbar and joint instability, which means that one vertebra moves in relation to another enough to cause an injury to a ligament or other structures in the lumbar spine. The study showed an increase in lumbar spine rigidity in subjects who wore a belt, which is associated with better lumbar stability. The second possible mechanism is when a person’s work means they have to bend forward often and for a long time, like roofers and gardeners. That can cause small tears in the posterior ligaments of the spinal column because they’re stretched a lot in this kind of task.

 

 

The third mechanism concerns workers whose pain is aggravated just by standing or sitting for a long time. It appears that this happens faster in people who activate the muscles surrounding the lumbar region more to protect it from pain and new injuries. This activation compresses the vertebral column. When you remain in this position for a long time, the intervertebral discs and other structures, such as the articular surfaces, are compressed and that can create pain in people with injuries that do not react well to this kind of loading of the lumbar spine. In our study, we showed that a lumbar support belt can help reduce this muscle activation.

“One might think that a lumbar support belt is suitable only for people who bend over often or have to perform very heavy tasks, but that’s not true at all. It can also be beneficial for people who do light manual tasks, in an office or on a computer,” explains Christian Larivière.