Pretreatment anxiety and pain acceptance are associated with response to trigger point injection therapy for chronic myofascial pain

Background and Aim: This study examined the psychosocial profile of patients who responded or did not respond to trigger point injection therapy for chronic myofascial pain. Methods: Seventy one patients with a diagnosis of chronic myofascial pain of the paraspinous muscles completed a pretreatment questionnaire measuring demographic and social factors, and validated scales to assess pain intensity, pain interference (physical and emotional), and defined psychological characteristics (pain catastrophizing, pain acceptance, pain self-efficacy, mood and anxiety). Trigger point injection therapy of the affected areas of myofascial pain was performed and follow-up was conducted by telephone at one week (n=65) and one month (n=63) post intervention to assess treatment outcome (pain intensity and pain-related physical interference). Results: At one week follow-up and one-month follow-up, using pain-related physical interference as the outcome measure, we found that those who responded well to treatment were characterized by a lower level of pretreatment anxiety and a higher level of pain acceptance, with anxiety being the strongest predictor. Conclusion: These results suggest that responses to interventional pain management in chronic myofascial paraspinous pain may be influenced by psychological characteristics, especially pretreatment anxiety.