Return-to-work interventions for low back pain: a descriptive review of contents and concepts of working mechanisms.

Low back pain is a major medical and social problem associated with disability, work absenteeism and high costs. Given the impact of the problem, there is a need for effective treatment interventions in occupational healthcare that aim at the prevention of chronic disability and the realisation of return to work. These so-called return-to-work (RTW) interventions are becoming increasingly popular. As well as questions concerning the effectiveness of RTW interventions, there are also important questions on the actual content and underlying concepts of these multifactorial intervention strategies. The purpose of this review is to examine the literature on the content and underlying concepts of RTW interventions for low back pain. A systematic literature search identified 14 randomised controlled trials (RCTs) evaluating the effects of 19 RTW interventions. The content and concepts of these RTW interventions are described, compared and discussed in this review. Further, the contents of the RTW interventions are classified by the use of predefined components (physical exercises, education, behavioural treatments and ergonomic measures). The identified RTW interventions varied with respect to the disciplines involved, the target population and the number and duration of sessions. The classification showed that physical exercises were a component of most of the selected interventions, followed by education, behavioural treatments and ergonomic measures. The most prevalent combination of components was the combination of physical exercises, behavioural treatment and education. However, the types of physical exercises, behavioural treatment and education varied widely among the RTW interventions. The described concepts for the physical exercises were an increase of muscle strength, coordination, range of motion of the spine and cardiovascular fitness, and a decrease of muscle tension. Education as a part of RTW interventions is believed to increase the understanding of patients regarding their disorder and treatment. Behavioural treatments were mainly based on the gate control theory of pain (psychophysiological processes are involved in pain perception) and/or the operant conditioning hypothesis (pain behaviour is determined by its consequences). No concepts were described for ergonomic measures. Finally, the plausibility of the described concepts is discussed. Future RCTs on this topic should evaluate the underlying concepts of the RTW intervention in addition to its effectiveness.