Medical treatment of recurrent temporomandibular joint dislocation using botulinum toxin A.

This paper describes a new technique for prophylactic treatment of recurrent mandibular dislocation using injection of botulinum toxin A (BtA) into the lateral pterygoid muscles. BtA temporarily weakens muscles by blocking acetylcholine release, and thus operates through a principle different from established treatments such as joint sclerosant therapy, eminectomy or Dautry's procedure. The patient suffered recurrent mandibular dislocations caused by tardive dystonia. We injected 75 mu BtA percutaneously into each lateral pterygoid muscle under electromyographic guidance. No further dislocations occurred over the subsequent 10 months, and follow-up continues. There were no immediate or delayed side effects. More experience is required before this becomes an established treatment. BtA is usually given in outpatients, and is less invasive or destructive than previous options. It may not be suitable if dislocation is due to lax ligaments or weak muscles. Operators must be aware that other BtA preparations require a different dose.