Recently, an updated definition of pain has been proposed: “Pain is a distressing experience associated with actual or potential tissue damage with sensory, emotional, cognitive, and social components“. Psychosocial factors are thought to play a major role in the persistence of low back pain (LBP).

Fear avoidance beliefs may be the most important cognitive factor in the development of chronic disability in patients with LBP (Crombez, Vlaeyen, Heuts, and Lysens, 1999; Fritz, George, and Delitto, 2001). Coudeyre et al., 2006).

Chronic pain, is it different from acute pain?

Chronification and central sensitization

Pain chronification describes the process of transient pain progressing into persistent pain; pain processing changes as a result of an imbalance between pain amplification and pain inhibition; genetic, environmental and bio-psychosocial factors determine the risk, the degree, and time-course of chronification.’

As part of the Change Pain Chronic Advisory Board meeting of pain specialists, attendees generated and reached consensus agreement on the following overarching definition of `pain chronification’:

o Pain chronification describes the process of transient pain progressing into persistent pain.

o Pain processing changes as a result of an imbalance between pain amplification and pain inhibition.

o Genetic, environmental and bio-psychosocial factors determine the risk, the degree, and time-course of chronification.

Factors such as psychological distress, low mood, poor sleep, adverse beliefs and somatisation are important determinants of chronic musculoskeletal pain outcomes, with sleep problems more closely correlated as an independent predictor of greater disability in people with LBP than leg pain (Asih et al 2014; Zarrabian et al 2014; Vargas-Prada and Coggon 2015).

Hypersensitivity to noxious and non-noxious stimuli has been proposed in the development of medically-indistinct ‘Central Sensitivity Syndromes’ (e.g. fibromyalgia, chronic fatigue syndrome, IBS and headaches), where there is no evidence of a single, primary local tissue cause (Neblett et al 2013). The sensitisation process is also implicated in the lowering of thresholds and reduced tolerance for complaints, as well as self-reports of stress and may explain why some develop more SHC than others (Winkelstein 2004; Ursin and Eriksen 2006; Verkuil et al 2007). Furthermore, a state of sustained arousal may develop through cross-sensitisation.

Due to the fact that central sensitization results from changes in the properties of neurons in the CNS, pain associated with the chronification process is no longer linked, as in acute nociceptive pain, to the presence, intensity, or duration of noxious peripheral stimuli. On the contrary, central sensitization produces pain hypersensitivity by changing the sensory response elicited by normal inputs, including inputs that usually evoke innocuous sensations.

Multiple mechanisms contribute to these changes, with each one being subject to, or an expression of, neural plasticity (the capacity of neurons to change their function, chemical profile, or structure. In some pain syndromes, such as fibromyalgia and irritable bowel syndrome, no identifiable noxious stimulus nor lesion or disease of the somatosensory nervous system is present.

Early intervention plays an important role in preventing pain chronification, but what kind of intervention!!!

This RCT involved 240 veterans with chronic back pain or osteoarthritis of the knee or hip who had pain that was ongoing and intense. Half were treated with opioids and half with non-opioid medications — either common over-the-counter drugs like acetaminophen or naproxen, or prescription drugs like topical lidocaine or meloxicam. The aim of the study was to compare the effect of Opoid vs nonopoid medications on outcome was pain-related function, assessed with the 7-item Brief Pain Inventory (BPI) interference scale, over 12 months.

There was no significant difference in pain-related function between the 2 groups over 12 months.

At the beginning of the study, it was found that patients who were enrolled really thought that opioids were far more effective than non-opioid medications. But after as little as six months, the non-opioid group reported their pain was slightly less severe than the opioid group’s collective assessment. By the end of the year, there was really no difference between the groups in terms of pain interference with activities. And over time, the non-opioid group had less pain intensity, and the opioid group had more side effects such as constipation, fatigue and nausea. Also opoids carry the risk of dependence, addiction and overdose. Coming off of opioids gives patients who have developed a dependence flu-like symptoms that can last for days or weeks.

Listen to this, How do you understand a patient's pain when it doesn't seem to match tissue damage.

https://twitter.com/BJSM_BMJ/status/970451018361200640

Take away massages:

· Monotherapy often leads to insufficient therapeutic response:

In the absence of a specific spinal pathology, there is a consensus in international guidelines about the interest of reassuring patients about the benign nature of the pain and advising patients to remain physically active, continue normal activities, stay at or return to work and avoid bed rest and passive treatments (Airaksinen et al., 2006; Koes et al., 2001; van Tulder et al., 2006).

Müller-Schwefe and colleagues recently highlighted the need to change the focus of treatment for chronic low back pain to individually-tailored multimodal management (i.e. integrated multidisciplinary therapy with coordinated somatic and psychotherapeutic options) that reflects the underlying pain mechanisms.

Treatment with opioids was not superior to treatment with nonopioid medications for improving pain-related function over 12 months. Results do not support initiation of opioid therapy for moderate to severe chronic back pain or hip or knee osteoarthritis pain. Based on a 2013 Cochrane review, the available evidence for pharmacological prevention of chronic pain is limited and additional evidence from well-designed, large-scale trials is required.

· Practical education

There is a need for improved education and knowledge-sharing among health care practitioners involved in the management of pain patients, particularly primary care physicians, including increased awareness of how and where non-pain medicine specialists can find appropriate education opportunities.

The use of properly administered early interventions, including cognitive-behavioral therapy, potentially decreases sick leave and prevents chronic problems in patients with acute pain

References:

• Audrey Petit, Cyril Begue, Isabelle Richard & Yves Roquelaure (2018) Factors influencing physiotherapists’ attitudes and beliefs toward chronic low back pain: Impact of a care network belonging, Physiotherapy Theory and Practice.

• Musculoskeletal pain in Primary Care Physiotherapy: Associations with demographic and general health characteristics -Patrick C. Kennedy, Helen Purtill, Kieran O'Sullivan.

• Bart Morlion, Flaminia Coluzzi, Dominic Aldington, Magdalena Kocot-Kepska, Joseph Pergolizzi, Ana Cristina Mangas, Karsten Ahlbeck & Eija Kalso (2018): Pain chronification: what should a non-pain medicine specialist know?, Current Medical Research and Opinion.

• Krebs, E.E., Gravely, A., Nugent, S., Jensen, A.C., DeRonne, B., Goldsmith, E.S., Kroenke, K., Bair, M.J. and Noorbaloochi, S., 2018. Effect of Opioid vs Nonopioid Medications on Pain-Related Function in Patients with Chronic Back Pain or Hip or Knee Osteoarthritis Pain: The SPACE Randomized Clinical Trial. JAMA, 319(9), pp.872-882.