Objective sonographic measures for characterizing myofascial trigger points associated with cervical pain

Area of Science:

• Musculoskeletal Ultrasound
• Pain Medicine
• Biomedical Engineering

Background:

• Myofascial trigger points (MTPs) are a common cause of musculoskeletal pain.
• Distinguishing between active and latent MTPs is crucial for effective treatment.
• Current diagnostic methods for MTPs lack objective quantitative measures.

Purpose of the Study:

• To investigate the differences in physical properties and vascularity of active MTPs, latent MTPs, and normal muscle.
• To assess the utility of sonoelastography and Doppler imaging in characterizing MTPs.

Main Methods:

• Sonoelastography was used to measure the size (area) of stiff MTPs in the upper trapezius muscles of 44 patients with acute cervical pain.
• Triplex Doppler imaging was employed to analyze blood flow and calculate the pulsatility index (PI) near MTPs.

Main Results:

• Active MTPs exhibited significantly larger areas (0.57 cm²) compared to latent (0.36 cm²) and normal sites (0.17 cm²).
• Sonoelastography area measurements effectively distinguished between active, latent, and normal muscle sites.
• Vessels near active MTPs showed a higher pulsatility index (median 8.3) than those near normal sites (median 3.0).

Conclusions:

• Myofascial trigger points can be classified by size using sonoelastography.
• Trigger point area and pulsatility index are valuable metrics for assessing the progression of myofascial pain syndrome.