Predictive factors for the efficacy of myofascial infiltration in chronic cervicalgia: implications for technique indication criteria

Chronic cervicalgia is a widespread condition that severely impacts patients' quality of life and often presents with a myofascial pain component, characterized by the presence of trigger points (MTrPs). In clinical practice, myofascial trigger point infiltration with local anesthetics and corticosteroids has been used extensively as an interventional treatment to alleviate pain. However, not all patients experience the same level of improvement, which has prompted research into the identification of predictive factors for treatment success. This prospective study investigates the clinical and demographic predictors of positive outcomes following myofascial trigger point infiltrations in patients with chronic cervicalgia. Seventy-four patients were recruited from a chronic pain management unit and underwent three ultrasound-guided infiltrations of lidocaine and corticosteroids into active MTrPs over a six-week period. Pain intensity, quality of life, and physical function were measured at baseline and four weeks after the final infiltration using the Visual Analog Scale (VAS), SF-36 Health Survey, and Patient Global Impression of Improvement (PGI-I). Results showed that 75.7% of patients reported significant improvement (PGI-I scores of 1-3) at four weeks post-treatment. Key predictors of positive outcomes included age greater than 50 years, a baseline VAS score of 5 or lower, and higher scores in the emotional role subscale of the SF-36. Conversely, younger age (<50 years), higher baseline pain intensity, and lower pressure pain thresholds (algometry scores <2500 g/cm²) were associated with poorer outcomes. These findings suggest that clinicians should consider patient age, baseline pain levels, and emotional well-being when selecting candidates for myofascial infiltrations to optimize treatment outcomes.