Poster 15: Botulinum toxin type a in the treatment of temporomandibular joint dislocation in an adult with anoxic brain injury: a case report

Abstract

Setting: Outpatient acute rehabilitation facility. Patient: A 20-year-old Japanese man with a medical history significant for cardiac arrest at age 15 leading to anoxic encephalopathy. Case Description: 5 years after the event, physical examination was significant for recurrent, spontaneous mandibular depression and protrusion leading to bilateral dislocation of the temporomandibular joints (TMJ). Functionally, the patient was nonverbal and unable to masticate. Nutrition was provided by placing food in the oral pharynx and manually elevating the mandible, increasing his risk for aspiration. Simple radiograph did not reveal TMJ abnormalities. Needle electromyography of the mastication muscles indicated continuous motor unit action potential activity in the position of rest. Using an intraoral approach, the bilateral pterygoids were each injected with 25U of botulinum toxin type A (Botox) using electromyographic guidance. No complications were experienced. Assessment/Results: By 7 days postinjection, improvements were noted in the patient’s ability to close his lips around a straw, which resulted in improved feeding. Functional electric stimulation of the masseters was also used for muscle strengthening, as well as speech therapy to improve vocalization. After this therapy, the patient improved his ability to drink and eat without manual assistance and was able to vocalize the “ee” phoneme. Discussion: This case demonstrates how a team approach to the treatment of spasticity in TMJ muscles can lead to the appropriate administration of botulinum toxin type A. Conclusion: The administration of botulinum toxin in the lateral ptyergoids for treating TMJ dislocation can lead to an increase in verbalization, mastication, and improved quality of life.