Background & Aims
Myofascial trigger points (MTrPs) are commonly found in musculoskeletal and chronic pain conditions1-4. A Delphi survey by Fernandez-de-las-Penas et al. established consensus on the definitions for latent and active trigger points, which reviewed the diagnostic criteria for MTrPs, highlighting variability and lack of a gold standard 5. The presence of latent and active MTrPs is not fully understood, with hypotheses suggesting various contributing factors. The study objectives were to: (i) assess the clinical prevalence of chronic pain causes and MTrPs, and (ii) explore the interaction between active and latent MTrPs with pressure-pain thresholds as a central sensitization indicator. It is hypothesized that our results will be in alignment with the Delphi criteria 5. The research addresses gaps in understanding and aims to enhance clinical diagnostic methods for MTrPs.
Methods
665 consecutive patients (67.2% female, mean age 61) were recruited from a tertiary pain medicine clinic. Academic clinicians developed a standardized assessment. The diagnostic criteria for active and latent MTrPs 5 were explained to clinic chiropractors and a standardized assessment was implemented. Pain-pressure thresholds (PPT) were obtained using a digital algometer. The force (Newtons) was reported at the transition from pressure to pain. PPT were obtained from the region of the MTrP and at predefined distal locations. These locations included the head, C7 cervical spinous process, L5 lumbar spinous process, right and left ACJ, wrists, upper and lower legs, and medial malleoli. Clinic patients were separated into active and latent MTrPs groups.
A priori statistical plan was developed to (i) perform descriptive statistics of the 665 clinic patients and (ii) perform Pearson’s r correlations between clinical test metrics and PPT values to compare MTrPs groups.
Results
The top five mechanistic chronic pain diagnoses are nociceptive (23.6%), neuropathic/nociplastic (17.5%), nociceptive/nociplastic (17.1%), nociceptive/neuropathic (16.7%), and nociplastic (14.3%)., We assessed the correlations between the individual variables of the pain diagram and the pressure-pain threshold. 184 pairs of variables were shown to be significant. No significant correlation was found between the extent of pain on the Michigan pain diagram and the number of active MTrPs (Pearson r=0.05, p=0.21). The sample was divided into two groups: those with active or latent MTrPs. The mean Central Sensitization Inventory (CSI) for the active MTrPs group was 40.98 (SD=16.42), while the latent MTrPs group had a mean CSI of 49.56 (SD=16.14). Tests indicated that CSI scores in both groups followed a normal distribution. A two-sample t-test revealed a significant group difference (p=4.55e-6). A significant correlation (r=0.14, p=0.048) for CSI > 40 and active MTrPs was also found.
Conclusions
The clinical methodology used was manual palpation of the region of discomfort and to detect attributes of a MTrP. For active MTrPs, reproduction of symptoms, hypersensitive spots, and taut bands were the most prevalent—present in 37.1% of our study sample. Our results did not confirm the presence of referred pain as a prevalent attribute. For latent MTrPs, the most prevalent attributes were hypersensitive spots and taut bands—present in 43.3% of the sample These findings align with the Delphi survey5 and consensus. We propose revising clinical criteria for diagnosing active and latent MTrPs. This study revealed a moderate correlation (0.42) between active MTrPs and pain extent using the Michigan pain diagram. Significant differences in CSI scores between active and latent MTrPs suggest an association with nociplastic pain.
References
1. Lluch E, et al. Prevalence, incidence, localization, and pathophysiology of myofascial trigger points in patients with spinal pain: a systematic literature review. J Manipulative Physiol Ther 2015;38:587-600.
2.Cardoso LR, et al. Myofascial pain syndrome after head and neck cancer treatment: Prevalence, risk factors, and influence on quality of life. Head Neck 2015;37:1733-1737.
3.Lin WC, et al. Increased risk of myofascial pain syndrome among patients with insomnia. Pain Med 2017;18:1557-1565.
4.Chiarotto A, et al. Prevalence of myofascial trigger points in spinal disorders: a systematic review and meta-analysis. Arch Phys Med Rehabil 2016;97:316-337.
5.Fernandez-de-Las-Penas C, Dommerholt J. International consensus on diagnostic criteria and clinical considerations of myofascial trigger points: a Delphi study. Pain Med 2018;19:142-150.
Presenting Author
Mahnaz Tajik
Poster Authors
Topics
- Assessment and Diagnosis