[Trigeminal neuralgia with the offending artery transfixing the trigeminal nerve: a case report].

We report a rare case of a patient manifesting trigeminal neuralgia with the offending artery transfixing the trigeminal nerve. A 67-year-old woman was admitted with typical episodes of trigeminal neuralgia on the right side. Magnetic resonance angiograms revealed the right superior cerebellar artery (SCA) compressing the nerve. Through a retromastoid suboccipital craniotomy on the right side, the right SCA was found to compress the root entry zone (REZ) and then penetrate the portio major of the trigeminal nerve. The nerve was dissected parallel to the axis, 7 mm distally from the transfixing point to facilitate transposition of the SCA. In addition to anchoring the distal portion of the SCA to the tentrium, a prosthesis was interposed between the proximal portion and the pons to secure the decompression. The pain was completely relieved immediately after operation with no neurological deficit. Procedures, such as the longitudinal rhizotomy employed in this case, must be carried out for microcompression, in response to individual anatomical variations in neurovascular structures.