Multidimensional Analysis of the Clinical Spectrum and Symptom Burden of Unexplained Myofascial Pain.

OBJECTIVE

To assess potential contributors to the variability in the clinical spectrum of unexplained neck/shoulder pain and its associated myofascial component(s).

DESIGN

Prospective cross-sectional study of adults reporting neck/shoulder pain and pain-free individuals.

SETTING

Participants were recruited from the community and assessed in a research laboratory.

PARTICIPANTS

Of the N=96 adults recruited for the study, 84 had complete records (mean age±SD, 32.7±13.2 y; 58.3% women). On physical examination, they were classified into an active group (those with spontaneous MP without provocation, n=25), a latent group (those with MP upon provocation, n=38), or a referent group (those with no MP in the neck and shoulder, n=21).

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: Pain intensity and interference; symptom burden measured using patient-reported outcomes and objective measures: Pain Catastrophizing Scale (PCS); Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function; sleep disturbance; anxiety; depression; hypermobility (Beighton/Brighton); objective measures in the medial upper trapezius using pressure pain threshold and quantitative sensory testing.

RESULTS

The symptom burden explained 75% of the variance in pain intensity and interference in the overall sample, 82% in the active group, and 92% in the referent group. PROMIS Physical Function and PCS were key predictors of pain intensity and interference. Network analysis identified unique symptom clusters in the active and latent groups.

CONCLUSIONS

Multidimensional symptom burden explains the variability in the clinical spectrum of pain intensity and interference in unexplained neck/shoulder MP. Network analysis can further improve clinical risk stratification. These findings represent a step toward the eventual goal of developing multidisciplinary clinical guidance for managing the whole patient, rather than the current emphasis on regional contributors to MP.