Use of Frameless Stereotactic Neuronavigation and O-arm for Transoral Transpalatal Odontoidectomy to Treat a Very High Basilar Invagination.

Frameless stereotactic neuronavigation system has been in wide use since many years for precise localization of cranial tumors and navigation for spinal instrumentation. We present its usage in the localization of odontoid process in a very high basilar invagination for a transoral transpalatal resection of the same. We discuss the technical aspects of assembly of neuronavigation system, O-arm and Mayfield head frame on Allen spine system to achieve precise and accurate localization of high riding odontoid process through an extremely narrow operative corridor.