We report a case of severe trismus following traumatic brain injury (TBI), which was treated successfully with botulinum toxin A. Its effect evidenced long-term resolution, for over one year. A 36 year-old man with a multifocal intracranial hemorrhage was admitted for quadriplegia with dysphagia and trismus. During ten months, a nasogastric tube was placed for feeding after TBI, and at that time his upper- to-lower interincisal distance was only 1.2 cm upon voluntary mouth opening. Botulinum toxin A 450 U (DysportⰒ) was injected into both masseter, medial pterygoid and left temporalis muscles under electromyographic guidance. The interincisal distance began to improve one week after injection. He successfully underwent percutaneous endoscopic gastrostomy, dysphagia rehabilitation therapy, and dental prosthesis. More than one month after injection, oral feeding proved possible. After 1 year his interincisal distance was maintained at 2.9 cm. (J Korean Acad Rehab Med 2008; 32: 456-459)
