Chronic primary musculoskeletal pain: a new concept of nonstructural regional pain

Chronic primary musculoskeletal pain is a newly recognized condition (in 2022) that is categorized as nociplastic pain, occurring without identifiable tissue abnormality. This is a paradigm shift in management towards more centrally directed treatment strategies. Patients with myofascial pain may in fact suffer from this condition. Many questions remain, including validation of examination techniques, prevalence, ideal treatment, and acceptance by healthcare community. An article in Pain Reports aims to clarify the issue.

1. Chronic primary musculoskeletal pain

Chronic primary musculoskeletal pain is a type of chronic pain that persists for more than 3 months without tissue damage and can cause significant physical, emotional, and social impairment. It falls under the umbrella of “chronic primary pain” and cannot be accounted for by another condition. This type of pain is characterized by regional pain and tenderness and is modulated by psychosocial factors.

The diagnosis of chronic primary musculoskeletal pain requires regional pain present for at least 3 months that cannot be entirely explained by associated neuropathic or nociceptive pain, along with clinical examination demonstrating evoked pain hypersensitivity. A probable diagnosis also requires a history of pain sensitivity to touch, pressure, movement, or temperature, as well as the presence of hypersensitivity to sound or light or odours, sleep disturbances, fatigue, or cognitive problems.

2. Is chronic primary musculoskeletal pain different from myofascial pain syndrome?

Chronic primary musculoskeletal pain (MSK) and myofascial pain syndrome (MPS) share similarities in non-neuroanatomical pain distribution, central and constitutional symptoms, and modulation by psychosocial factors. However, there is controversy over the etiology, pathology, diagnostic criteria, and treatment of MPS, which is based on subjective physical abnormalities identified on muscle palpation. Chronic primary MSK pain introduces the concept that not all regional pain conditions are solely due to tissue abnormalities but can be mechanistically explained as sensitization of the nervous system. It may also require examination skills beyond the average clinician’s abilities to identify.

3. Challenges and value of diagnosing chronic primary musculoskeletal pain

The concept of chronic primary MSK pain proposes that many MSK conditions previously attributed exclusively to musculoskeletal tissue pathology may be at least partially due to abnormalities in pain processing. This raises questions such as when does pain mechanism cross the boundary from nociceptive to nociplastic pain, are there early predictors that influence transition to chronic pain sensitization, are some locations and people more susceptible to pain sensitization and chronicity, and how easily will physicians be able to distinguish primary from secondary MSK pain. The value of diagnosing chronic primary MSK pain is in establishing treatment paradigms.

(5) How willingly will patients and health care professionals accept treatments with a psychosocial rather than peripherally directed focus 

Patients and healthcare professionals may have resistance towards a biopsychosocial approach for chronic primary musculoskeletal pain management, as it is less operator-dependent and requires a shift towards centrally acting medications, self-management strategies, and psychological therapies. Resistance towards a biopsychosocial approach may also arise due to financial ramifications if payers refuse to authorize treatments. Patients may have difficulty understanding the central component of their pain condition and may be relieved to have a plausible explanation for their symptoms with education. Multimodal management is required for chronic primary musculoskeletal pain, whereas management for myofascial pain syndrome and chronic secondary musculoskeletal pain should be more peripherally focused.

Conclusions

The concept of nociplastic pain is still developing and requires further validation and acceptance from non-pain specialists. Chronic primary musculoskeletal pain can be seen as a type of “regional fibromyalgia,” although some may have issue with the term. The value of diagnosing this type of pain is to shift focus towards centrally directed treatments and reduce unnecessary investigations. The medical community needs to support and investigate this concept further to better understand prevalence and effective treatments.