Trigeminal Neuralgia Due to Petrosal Bone Deformity.

BACKGROUND: There have been a few previous reports of trigeminal neuralgia caused by bony structures. We report a rare case of trigeminal neuralgia caused by petrous bone deformity. CASE DESCRIPTION: A-43-year-old man with facial pain in the left maxillary and mandibular divisions of the trigeminal nerve was referred to our hospital. Computed tomography showed bone hyperplasia protruding into the left cerebellopontine cistern, compressing the left trigeminal nerve. Administration of carbamazepine ameliorated facial pain, but the effect was unsatisfactory, and microvascular decompression was performed through the anterior transpetrosal approach. The protruding petrous bone was drilled out to release compression of the trigeminal nerve, thus straightening the deviated trajectory of the nerve. The superior cerebellar artery adjacent to the thickened petrosal bone seemed to have compressed the trigeminal nerve and was also transposed. The facial pain disappeared completely after microvascular decompression surgery.
CONCLUSIONS: The anterior transpetrosal approach is an appropriate and essential strategy for trigeminal neuralgia caused by petrous bone deformity of the petrous apex.