Transition from acute to chronic pain: a misleading concept?

Abstract

C hronic pain is a major health problem and the leading cause of years lived with disability. 57 In the absence of disease-modifying therapies and adequate symptomatic treatment, prevention is important. In recent years, there has been a focus on "transition of acute to chronic pain" or "pain chronification." It has been postulated that some forms of chronic pain might be regarded as a continuum of acute pain, possibly with a transition point or period where acute pain progresses into chronic pain, sometimes also referred to as the shift from physiological to pathological pain 14,45,55,67 (Fig. 1A). Such terminology implies that one mechanistic type of pain transforms into another pain, for example, that acute pain caused by tissue damage and inflammation changes into a neuropathic pain, which is unlikely or at least not proven. In the following, we challenge the concept of "transition" of pain. Transition of pain or development of pain?For many years, there has been a focus on the phenomena of central sensitization, spinal amplification, and altered descending pain modulation as underlying mechanisms of chronic pain. 6,23,24,34 In an editorial in PAIN from 1988, Patrick Wall speculated that acute and chronic pain after surgery could be prevented by treatments, for example, nerve blocks or opioids, that would block nerve discharges caused by injury or preexisting pain, thereby reducing central sensitization. 68 Although there is ample evidence from preclinical and clinical studies that excessive afferent discharges consequential to tissue injury evoke a peripheral and central sensitization resulting in sensory hypersensitivity, 12,16,70 it has never been proven in humans that central sensitization is sustained after the tissue has healed and the afferent input has ceased and that it drives chronic pain. 24 Similarly, studies addressing clinical signs of central sensitization before surgery show some evidence for a link to chronic pain only for total joint arthroplasty, and with conflicting results. 52,54 Nevertheless, the association between severe acute and persistent postsurgical

Reply to Vlaeyen et al.

“…We appreciate the letter by Vlaeyen et al 2 as we hoped that our perspective 1 would contribute to a discussion. The network theory proposed by Vlaeyen et al is interesting and overcomes some of the limitations with the central sensitization construct.…”

Towards a dynamic account of chronic pain

“…We also agree that we need a better understanding of the link between acute and chronic pain, and that current constructs such as central sensitization have clear limitations. 8 On the other hand, we also believe that the pain type idea put forward by Finnerup et al, 4 albeit more diversified, may suffer from the same conceptual limitations as central sensitization: both share the common assumption that the behavioral manifestations of pain (the symptoms) are caused by a physiological event either at the central or at the peripheral nervous system (such as injury or inflammation). The consequence of this line of thought is a focus on the identification of the common cause, and when treated appropriately, the observable symptoms should disappear (Fig.…”

“…We propose to extend some of Finnerup et al's ideas 4 towards a more dynamic network approach of chronic pain. Specifically, what Finnerup et al 4 seem to be ignoring is that pain is not only a response to damaged tissue but also part of a larger plexus. Pain is an emotional experience 6 and considered part of a motivational system that alarms, directs, and energizes behavior to minimize bodily harm.…”

“…A different approach is needed. We propose to extend some of Finnerup et al's ideas 4 towards a more dynamic network approach of chronic pain. Specifically, what Finnerup et al 4 seem to be ignoring is that pain is not only a response to damaged tissue but also part of a larger plexus.…”

Pain interference in young adulthood and work participation

“…17 For example, in the United States, 10% of adults with chronic pain experience health problems that limit their ability to engage in paid work, whereas other people with chronic pain who remain employed may nevertheless experience increased use of sick leave and reduced performance at work, such as working more slowly, feeling fatigued, or losing concentration. 7,17,27,31,37 Acute pain, which may be a precursor or predictor of chronic pain, 11,13 could similarly limit people's engagement in paid work or cause workers to leave the labor force. Owing to the impact of pain on work participation, return to work or improvement of work performance are common goals of vocational rehabilitation for people with chronic pain.…”