Exploring Myofascial Differences in Unilateral Neck Pain

Neck pain is a common ailment that afflicts a substantial portion of the global population, with nearly one-third of people experiencing it on an annual basis. To gain deeper insights into how pain affects the myofascial layers of the neck, a new study set out to investigate its impact on the upper trapezius muscle, particularly in individuals suffering from unilateral and more severe neck pain.

This research adopted a cross-sectional approach and involved the examination of forty patients, with an average age of 42.2 ± 14.7, who had received a confirmed diagnosis of unilateral neck pain. To assess the myofascial characteristics, the study employed durometry and indentometry, focusing on the stiffness, elasticity, and pressure pain threshold on both sides of the neck—the symptomatic side (SS) and the healthy side (HS). Additionally, the study quantified the range of motion of the cervical spine, specifically lateral flexion and rotation, using a digital goniometer.

The study’s results yielded intriguing findings. Notably, a significant difference in stiffness was observed between the two groups.

Durometry measurements indicated that the symptomatic side exhibited greater stiffness (SS-33.76 ± 7.78) compared to the healthy side (HS-29.75 ± 7.45). A similar pattern emerged in the indentometry results, where the symptomatic side displayed higher stiffness (SS-59.73 ± 33.93) compared to the healthy side (HS-4.18 ± 12.69).

In contrast, the study did not reveal significant distinctions in terms of elasticity between the two sides. The parameter of elasticity, as measured by the study, showed no meaningful difference between the symptomatic side (SS-0.101 ± 1.09) and the healthy side (HS–0.006 ± 0.29).

Similarly, cervical spine mobility, both in lateral flexion and rotation, exhibited no notable variations between the two sides. Lateral flexion results were SS-37.08 ± 8.15 and HS-37.73 ± 7.61, while rotation results were SS-73.55 ± 12.37 and HS-72.85 ± 11.10.

Additionally, pressure pain threshold measurements (algometry) showed no significant differences, with the symptomatic side (SS-36.41 ± 17.53) closely mirroring the healthy side (HS-37.22 ± 17.00).

It indicates that individuals experiencing more severe unilateral neck pain tend to exhibit noticeable differences in stiffness on the affected side. However, the elasticity of the upper trapezius muscle, cervical spine mobility, and pressure pain threshold showed no significant differences between the symptomatic and healthy sides.

The increased stiffness of the selected muscle can be attributed to several factors. One potential reason is the altered tissue morphology of the myofascia, which can result from aging processes or pathological changes in the posterior-lateral fascial chain. Additionally, passive transmission of forces from the muscles to the fascial tissue and fascia-triggered neuromuscular alterations may contribute to stiffness. Changes in the hydration and viscosity state of the fascia can also play a role.

Furthermore, an imbalance between different muscle parts of the trapezius and the prevertebral and spinal extensors is discussed as a relevant factor in increased stiffness. It’s worth noting that the upper trapezius muscle is anatomically predisposed to shortening due to its dominant posture-related function.

Age-related processes in the body can significantly impact elasticity. As individuals age, typically from around sixty years onwards, there is a decrease in the number, quality, and strength of muscle fibers, coupled with an increase in collagen content. These age-related changes lead to an overall increase in stiffness, and this effect tends to be more pronounced in women.

While these findings provide valuable insights, further research is needed to unravel the precise links and mechanisms underpinning these observations. Understanding these connections could potentially pave the way for more effective interventions and treatments for individuals grappling with neck pain, ultimately improving their quality of life.