Botulinum Toxin A for the management of temporomandibular myofascial pain - a cohort study

Abstract

Myofascial pain represents the largest subgroup of TMD (Temporomandibular Disorders), which accounts 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 bio-psycho-social element in the aetiology of TMD. First-line treatment of myofascial TMD includes; early diagnosis, explanation and education and conservative self-care measures. More recently, Botulinum Toxin A (BTX-A) is being used increasingly as an adjunct to conservative management of muskulo-skeletal 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. A mixed method analysis of a TMD-myofascial pain cohort who underwent BTX-A injections to assess the effectiveness of masseteric BTX-A was carried out. 149 patients completed one round of masseteric BTX-A treatment, of whom 61 completed an additional round of BTX-A. In total, 398 masseter muscles were injected. The average VAS pain score pre-operatively was 8/10, compared with a postoperative mean score of 3/10 at 6 weeks after treatment. The mean percentage reduction in pain was 50%. Pain scores were classified as mild (≤4) , moderate (≤7) or severe (≥8). Pain scores and quality of life scores were found to improve considerably more in the severe pain group in comparison to 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.