3DSlicer module to perform registration: An intraoperative situation

Computer-assisted surgeries (CAS) had a great improvement in last decades. Nowadays, a lot of surgeries are performed with the aid of a tracking system and robotic devices. It is important to ensure the success of the intervention when it is performed with this kind of technologies. One of the most important steps in CAS is registration that allows the surgeon to track his instruments and to know what he is doing when the surgical field of view is limited. A 3DSlicer module is presented to perform the registration procedure quickly and intuitively, since this step must be made as fast as possible. This module allows the surgeon to collect points from the patient's anatomical structure that he is working on in order to perform a point-to-point registration followed by the surface registration based on iterative closest point algorithm. Thus, it is possible to match the coordinates system of the 3DSlicer model and the coordinates system of operating room so that the preoperative 3D model on the software and the tracking of the surgical instruments used during the surgery are synchronized. An example using a sheep skull and a tracking system is described and the results of the registration are shown. The registration procedure is evaluated calculating the mean distance from the landmarks from patient's anatomical structure and the surface of the 3DSlicer model. The value obtained was 0,29 mm RMS which indicates that the module could be a good option to perform the registration in a surgical room.