An effective case of glycerol injection into the trigeminal cistern against trigeminal neuralgia resulting from pontine infarction

Abstract

   We experienced an unique case of trigeminal neuralgia resulting from pontine infarction. The patient was a 68-year-old woman who had suffered from the hemifacial numbness in the mandible on the right side since 1985. The numbness gradually recovered in six months, but she suddenly felt spontaneous toothache-like pain on that region in 1988. She was finally diagnosed as trigeminal neuralgia in 1993. She administered carbamazepine and had several mandibular nerve blocks with local anestheticssince 1993. When she was introduced our hospital in 2002, she had been suffering from stabbing painin the mandible on the right side. Head MRI revealed only a wedge-shaped shadow on the right middlecerebellar peduncle. The patient was treated by an anhydrous glycerol injection of 0.25 ml into the right trigeminal cistern. Three days after the injection, she was discharged with complete pain relief. The mechanism of pain relief produced by the glycerol injection is still unknown. One possibleexplanation is that the glycerol injection into the trigeminal cistern could suppress the abnormal excitationof partly demyelinated nerve fibers and may be effective for secondary trigeminal neuralgia, suchas trigeminal neuralgia resulting from pontine infarction.