400 Section - Beyond Palpation: Defining a Multidomain Assessment of Chronic Myofascial Pain

Chronic myofascial pain (cMP) is a common musculoskeletal disorder lacking universal diagnostic criteria. Assessment relies on palpation to identify myofascial trigger points (MTrPs) that are active (i.e., spontaneously painful) or latent (i.e., painful only upon compression), but often overlooks contributors to pain phenotypes commonly observed. We aimed to determine evaluations that better distinguish cMP phenotype.


Design:

We analyzed baseline data from a prospective observational study of people with neck/shoulder pain and pain-free individuals classified as active (spontaneously painful, n=34); latent (pain upon palpation, n=40); and pain-free (n=22). Assessments included: pain history, upper trapezius examination, patient-reported questionnaires: Pain intensity and interference (PEG); pain catastrophizing (PCS); PROMIS physical function (PF); sleep disturbance; anxiety (GAD-2); depression (PHQ-2); hypermobility (Beighton/Brighton); Objective measures: pressure pain threshold (PPT), quantitative sensory testing (QST). Group differences were evaluated using two-sample t-tests for continuous variables and Fisher’s exact test for proportions (significance level: α=0.05).

 








Results:

Physical examination and objective measures of pain/function differed across groups (p≤0.02). Pain history showed noteworthy differences (p< 0.01) between the active and latent/pain-free groups, while latent and pain-free groups were largely similar. Questionnaires captured important variation: PHQ, GAD-2, and PCS scores differed slightly between active and latent/pain-free groups, while PEG, PF, and sleep disturbance showed stronger separation (p< 0.01). GAD-2 differed between latent and pain-free groups (p=0.03), sleep disturbance did not reach significance (p=0.07). Presence of bilateral MTrPs was not different when comparing the active vs latent groups.


Conclusion:

The standard clinical assessments distinguish individuals with spontaneous pain from other groups but don't distinguish latent from pain free. Psychosocial symptoms (anxiety, sleep disturbance) do distinguish latent from pain-free individuals. Presence of bilateral MTrPs does not distinguish those who are active form latent. Adding PROs contributes to characterization of cMP.