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

Gerard M Healy, David P Finn, David A O'Gorman, Chris Maharaj, Miriam Raftery, Nancy Ruane, Caroline Mitchell, Kiran Sarma, Marek Bohacek, Brian E McGuire

This study examined the psychosocial profile of patients who responded or did not respond to trigger point injection therapy for chronic myofascial pain. 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). 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. These results suggest that responses to interventional pain management in chronic myofascial paraspinous pain may be influenced by psychological characteristics, especially pretreatment anxiety.