Abstract
Severe neck-shoulder pain induces functional limitations in both life and work. The purpose of this study was to determine the characteristics of shoulder microcirculation abnormality in workers. This study recruited 32 workers and patients, both n = 16. Questionnaires were administered, and Laser Doppler Flowmetry (LDF) was used to measure microcirculatory blood flow (MBF) at the myofascial trigger points (MTrPs) on the shoulders. The absolute-deviation(MMBF) represented the mean MBF (MMBF) variability among subjects. The differences in the life characteristics, shoulder pain level, and microcirculatory characteristics at MTrPs between the two groups were compared. It was found that shoulder pain level was significantly higher in the patient than in the control group (p < 0.001). Deviation of the MMBF value beyond the postulated "normal range" of 60-80 was significantly higher in the patient than in the control group (p < 0.001). The MMBF deviation was significantly correlated with shoulder pain level, pain duration, and the symptom effect (p < 0.01, n = 32). A normal range for the MMBF of 60-80 on the shoulder near MTrPs is hypothesized for the first time based on this study. Noninvasive LDF can be used to assess abnormality in the MBF on shoulder MTrPs at an early stage.