Neural interconnections between portio minor and portio major at the porus trigeminus: application to failed surgical treatment of trigeminal neuralgia.

Recalcitrant trigeminal neuralgia following surgical treatment can be a life-altering condition. To explore alternative anatomic reasons for such a complication, the authors examined the potential for nerve connections between the sensory and motor roots of the trigeminal nerve at the opening of Meckel's cave (porus trigeminus). In 15 embalmed adult cadavers (30 sides), the authors performed microdissection of the skull base and specifically at the opening of Meckel's cave. Two sides (6.67%) were found to have interneural connections between the sensory and motor roots at Meckel's cave. These occurred in one male and one female cadaver, both on right sides. Both connections were histologically verified to be neural and were 0.5 mm in diameter and 2.2 and 3.2 mm in length, respectively. Both connections traveled in an oblique fashion from the portio major to the portio minor. On the basis of authors' findings, the sensory and motor components of the trigeminal nerve at the opening of Meckel's cave may be interconnected with a neural anastomosis. Such findings may be of use during the surgical treatment of trigeminal neuralgia or other surgery of the posterior fossa so that inadvertent transection or traction does not occur.