AN IGSTK-BASED SURGICAL NAVIGATION SYSTEM CONNECTED WITH MEDICAL ROBOT Huoling Luo [1][2] , Fucang Jia *[1] , Zhizeng Zheng [1] , Qingmao Hu [1] ,Yongzhong Xu [2] [1] Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and the Chinese University of Hong Kong [2] China University of Mining and Technology, Xuzhou, Jiangsu Province, China *Corresponding Author, Email: fc.jia@siat.ac.cn ABSTRACT A surgical navigation system based on IGSTK (Image- Guided Surgical Toolkit) that guide medical robot to drill pedicle screw into vertebra precisely is presented. The surgical location device used is NDI Polaris Vicra ® optical tracking system and the assistance robot is KUKA ® Robot KR 5 sixx R650. Message communication between the navigation system and KUKA robot is implemented based on OpenIGTLink protocol client-server model. Multiple tracked tools can be tracked automatically by state-machine mechanism in a safe manner. To overcome the line of sight limitation of optical tracking system, a new instrument that we called it two-face instrument model has developed to enlarge the rotation angle of the tracked tool. The experiment showed that the navigation could guide robot to execute precise surgical operation in a simple and safe mode. Index Terms — surgical navigation, message communication, robot, two-face tool 1. INTRODUCTION Motivated by less trauma to the patient and lower overall costs, traditional open surgery is being replaced with minimally invasive techniques for many procedures [1] . Image-guided navigation system aims at improving surgeons to understand the spatial structure of the anatomy by integrating medical image and other source of information, such as tracked surgical instrument, and to reduce the risk of the surgery procedure. Spine surgery, especially for cervical and thoracic vertebra, is a high-risk surgery owing to important structures such as vessels, spinal cord and nerve system are contained in the small vertebral canal. Intra-operative spine navigation system based on 2D fluoroscopy X-ray or 3D cone beam X-ray is widely used [2] . While surgical navigation help surgeons to locate surgical target site more precisely, the target generally cannot be reached steady and precisely due to manual operation error, medical robotics can execute the surgical operation in a stable and precise mode and are being studied widely now [3] . In this paper a navigation system connected to a medical robot is developed based on Image-Guided Surgery Toolkit (IGSTK) [4] . IGSTK is a free open source C++ toolkit to provide a framework for rapid prototype of customized image-guided surgical application. The toolkit provides a set of components common to most navigation systems, such as interface to various tracking systems, DICOM image readers, landmark rigid body registration, visualization components, etc. OpenIGTLink protocol is used to transfer data between the navigation system and robot. The Open IGT Link protocol is a simple but extensible data format to transfer various types of data among software and devices used in image-guided therapy (IGT) [5] . In our navigation system, when pedicle screw is drilled into the vertebra by robot, the entry point and the target point should be transferred to the robot and these two points are all transformed into the robot coordinate system. The POSITION message in Open IGT Link protocol is used to transfer these two points. Tracking devices are an essential component of an image-guided surgery system. These devices are used to track the position of instruments relative to the patient anatomy. Optical tracking system is the most widely used device owing to its high accuracy and relatively large measurement volume. But a line-of-sight must be maintained between the tracking device and the tracked instrument. To improve this situation, a two-face tracked tool is developed. 2. MATERIALS AND METHODS 2.1. Tracking device and coordinate transformations Tracking system is the heart of a navigation system. It is also called position-sensing systems or localizer systems. In the work presented a NDI Polaris Vicra ® tracking system (www.ndigital.com) is used. A KUKA ® robot (www.kuka.com) acts as the tracked instrument for pedicle ___________________________________ 978-1-4244-8886-5/10/$26.00 ©2010 IEEE