Botulinum toxin A for the management of temporomandibular myofascial pain: A cohort study

Abstract

Myofascial pain represents the largest subgroup of temporomandibular disorders (TMD) that account for a common cause of non-dental orofacial pain. The management of TMD is complex due to the chronic nature of the condition, alongside acute episodes presenting to the clinician. A fundamental part of TMD management is consideration of the biopsychosocial element in its aetiology. First-line treatment of myofascial TMD includes early diagnosis, explanation and education, and conservative self-care measures. Botulinum toxin A (BTX-A) is now being used increasingly as an adjunct to conservative management of muskuloskeletal pain disorders due to its muscle-relaxant and analgesic properties. However, the scientific evidence regarding this is conflicting and it has been suggested that there is insufficient evidence to support the efficacy of BTX-A. To assess the effectiveness of masseteric BTX-A, a mixed methods analysis of a TMD-myofascial pain cohort who underwent BTX-A injections was therefore carried out. A total of 149 patients completed one round of treatment, and 61 of them completed an additional round. In total, 398 masseter muscles were injected. The mean preoperative visual analogue scale (VAS) pain score was 8/10, compared with a postoperative mean score of 3/10 six weeks after treatment. The mean percentage reduction in pain was 50%. Pain scores and quality of life scores improved considerably more in the severe pain group than in the mild group. Complete resolution of symptoms was reported in 21% of patients (n = 31). The treatment significantly improved patients' reported pain and quality of life scores, highlighting key beneficial effects for the myofascial pain subgroup of TMD.

Keywords: TMD; botulinum toxin; bruxism; myofascial pain; temporomandibular disorder.