Local injection therapy in 107 patients with myofascial pain syndrome of the head and neck.

Myofascial pain syndrome of the head and neck is a frequent cause of facial pain and is characterized by tender trigger points. In a double-blind study of 107 patients, local injection therapy using one of three solutions was applied at the trigger points by intracutaneous injection of 0.3 ml solution followed by deep infiltration of the site. Results using bupivacaine 0.25%, lignocaine 1% and saline 0.9% were compared. There was no significant difference among groups with respect to reduction of pain and overall rating by patients of the therapeutic benefits. Fifty-three patients (49%) were free of symptoms after treatment, 40 patients (38%) reported substantial relief and in 14 patients (13%) symptoms remained unchanged. The findings suggest that relief of pain is mainly due to reflex mechanisms rather than to the pharmacological effects of the injected solutions. Physiological saline solution is recommended for use in local injection therapy.