Implantation of the anterior atlantoaxial lateral mass intervertebral cage using the transoral approach.

Abstract

The purpose of this study was to evaluate the possibility of implanting the anterior atlantoaxial lateral mass intervertebral cage, a new type of fixation, by the transoral approach. This study examined the possibility of implantation in vivo by the quantitative measurement on the dry atlantoaxial bone and implantation of the anterior atlantoaxial lateral mass intervertebral cage in specimens. Anterior atlantoaxial lateral mass intervertebral cages were implanted in 10 atlantoaxial joint specimens using the transoral approach. Eight anatomical parameters (width, the thickness, ordinates, abscissas, and declination angles of the mass) from each of the 30 dry atlas and axis bone specimens were measured. These parameters determined the size and the design of the cage and the way of implantation. The course of the vertebral artery forms the safe boundary for transoral surgery. The shape of the area of work exposure was an inverted trapezoid. In specimens, the anterior atlantoaxial lateral mass intervertebral cages could be successfully implanted using the transoral approach. The parameters of the human atlantoaxial lateral masses exposed anteriorly showed that there was enough space, for the safe anterior implantation of the cage. The surgery using the transoral atlantoaxial reduction and plate makes possible the implantation of the anterior cage. The implantation of anterior atlantoaxial lateral mass intervertebral cage through transoral approach is possible.