Transoral approach and extended modifications for lesions of the ventral foramen magnum and craniovertebral junction.

OBJECTIVES: To describe our method of performing the transoral approach and the extended approaches to the ventral foramen magnum and craniovertebral junction and review the technical aspects and operative nuances.
DESIGN: Review.
RESULTS: The transoral approach provides direct midline exposure to access extradural disease located at the craniovertebral junction and ventral foramen magnum. The corridor of exposure is generally limited by the extent to which the patient can open his or her mouth. The location of the hard palate relative to the craniovertebral junction limits superior exposure, whereas the mandible and base of the tongue limit the inferior exposure. In most cases, exposure can be obtained from the inferior clivus to the middle to lower C2 vertebral body. Extended transoral approaches can be performed to increase exposure if necessary. These approaches include transmaxillary (Le Fort I maxillotomy), transmaxillary with a midline palatal split (extended "open-door" maxillotomy), transpalatal, and median labiomandibular glossotomy (transmandibular split).
CONCLUSIONS: The transoral approach effectively provides direct access to extradural midline lesions of the craniovertebral junction. A specialized retractor system can expose the inferior clivus to the C2 body. Extended approaches as described can access lesions that extend beyond these limits.