Abstract
We have developed a navigation system for the blood vessel prosthesis replacement of aortic aneurysms, and have used it in clinical practice. This system supports surgeons to identify a target intercostal artery by using patient image. The patient image and real body are matched by registration. Reference points of registration are anatomical landmarks of skeleton such as jugular notch, sternal angle, left anterior superior iliac spine, pubis, and spinous process. However, identification of spinous process was hard to doctors in operation. We developed a new registration method which X, Y and Z axis correspond to the Head-Foot, Right-Left and Anterior-Posterior directions. The specific feature is that identification of spinous process is not necessary. We evaluated errors with the new registration method using the retrospective 6 clinical data. We calculated fiducial localization error. As a result, errors of anterior points in the Head-Foot direction were less than 10 mm. We aimed to reduce the Head-Foot error as less than 20 mm because the ribs exist at intervals of approximately 40 mm in the Head-Foot direction. The new registration method was confirmed to be effective in the decision of approach to the target artery. Moreover, even when the point of the spinous process changed to the next spinous process of the set spinous processes, error was equivalent to the original point, therefore, using the present system, the identification of the spinous process can be unnecessary. It was concluded that newly-developed registration algorism is effective for doctors in identification of intercostal artery.
