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[A case of basilar impression treated with mandible splitting transoral approach].

We report a case of basilar impression treated with mandible splitting transoral approach surgery. A 39-year-old man presented a ten-year history of gait disturbance. He had experienced acceleration of his spastic paraparesis for the past few years. Neurological examination on admission demonstrated tetraparesis (MMT4/5), severe hyperreflexia in his arms and legs, severe sensory loss below C2, urinary retention and inability to open his mouth widely. Radiological findings showed the dens and the body of C2 are deeply invaginated to the atlas and the foramen magnum and medulla and upper cervical cord were markedly compressed by this basilar invagination. After carrying out posterior decompression and occipito-cervical fixation, we attempted to remove the invaginated dens and the C2 vertebral body using a conventional transoral approach. But limitation of mouth opening made operative fields narrow. Consequently because of insufficient anterior decompression his neurological deficits could not be alleviated. Employment of mandible splitting procedure brought about a wide operative view so that complete removal of the residual dens and 70% drilling out of the C2 body was made possible. Postoperative complications were negligible. Finally, great alleviation of his deficits was achieved. Mandible splitting procedure is effective for obtaining a wide operative field on the anterior approach to the craniocervical junction.