Jocelyne Troccaz

Semi-active guiding systems in surgery. A two-dof prototype of the passive arm with dynamic constraints (PADyC)

Abstract Guiding systems for surgical applications range from passive systems to active ones depending on the level of autonomy left to the surgeon. Passive systems provide the surgeon with suitable information to compare the executed strategy with a planned one whilst active systems autonomously perform a part of the surgical strategy. Depending on the selected technology, guiding systems may be more or less accurate, more or less safe, more or less user-friendly. Actuated robots are generally very accurate but raise safety and ergonomics issues; passive systems (optical localizers, motorless encoded arms, etc.) are well-suited to navigation but their use is difficult for executing complex surgical strategies. A new type of mechanical guiding system has been designed, based on the use of dynamic constraints; this passive arm is actuated by the surgeon who keeps, therefore, fully involved in the execution of the surgical strategy. At each instant, the motions proposed by the operator are “filtered” with respect to the task, before being transmitted to the arm. This system seems a good answer to the guided execution of potentially complex strategies in an accurate and ergonomical way. The principles of the PADyC arm are presented and experiments already done with a two-DOF prototype are described.

Targeted MRI-guided Prostate Biopsies for the Detection of Prostate Cancer: Initial Clinical Experience With Real-time 3-Dimensional Transrectal Ultrasound Guidance and Magnetic Resonance/Transrectal Ultrasound Image Fusion

OBJECTIVEnTo prove the feasibility and evaluate the initial clinical results of targeted prostate biopsies using the Urostation novel platform using magnetic resonance imaging (MRI)/transrectal ultrasound (TRUS) registration to help steer the biopsy needle to suspicious areas.nnnMETHODSnWe prospectively included 30 patients for suspicion of prostate cancer from November 2011 to August 2012. All patients were previously evaluated by a multiparametric MRI, interpreted by a single radiologist who attributed a Prostate Imaging-Reporting and Data System (PI-RADS) score to each lesion. A conventional 12-core randomized biopsy protocol was performed and 2 additional targeted biopsies were performed on suspicious area(s). The results of randomized and targeted biopsies were compared.nnnRESULTSnAmong the 30 patients, suspicious area(s) were found on MRI in 20 cases (67%). Median procedure time was 23 minutes. Targeting success rate (biopsy visualized inside the target) was 83%, with at least 1 biopsy reaching the target in all cases. Prostate cancer was detected in 14 cases (47%), including 11 cases with an abnormal MRI. Targeted biopsies detected cancer in all 11 cases and all but 1 were clinically significant. Randomized biopsies detected 10 of these 11 cases, and 3 more cases that MRI considered normal. Sensitivity to detect a significant cancer was 91% in both modalities.nnnCONCLUSIONnThis initial clinical study showed encouraging results for targeted MRI-guided prostate biopsies using MRI-TRUS fusion. Although further studies are needed to determine the role of prostate MRI before biopsy and the relevance of targeted biopsies, the Urostation is an MRI-TRUS fusion device that has good accuracy for targeting suspicious areas on MRI.

Assessing continuity and compatibility in augmented reality systems

Integrating computer-based information into the real world of the user is becoming a crucial challenge for the designers of interactive systems. The Augmented Reality (AR) paradigm illustrates this trend. Information is provided by an AR system to facilitate or to enrich the natural way in which the user interacts with the real environment. We focus on the output of such systems and, in particular, on the smooth integration of additional information in the real environment of the user. We characterize the integration of the computer-provided entities with the real ones using two new properties: compatibility and continuity. After defining the two properties, we provide factors and an analytical method needed for assessing them. We also empirically study the two properties to highlight their impact on interaction. The CASPER system, developed in our teams, is used to illustrate the discussion.

Development of a Novel Robot for Transperineal Needle Based Interventions: Focal Therapy, Brachytherapy and Prostate Biopsies

PURPOSEnWe report what is to our knowledge the initial experience with a new 3-dimensional ultrasound robotic system for prostate brachytherapy assistance, focal therapy and prostate biopsies. Its ability to track prostate motion intraoperatively allows it to manage motions and guide needles to predefined targets.nnnMATERIALS AND METHODSnA robotic system was created for transrectal ultrasound guided needle implantation combined with intraoperative prostate tracking. Experiments were done on 90 targets embedded in a total of 9 mobile, deformable, synthetic prostate phantoms. Experiments involved trying to insert glass beads as close as possible to targets in multimodal anthropomorphic imaging phantoms. Results were measured by segmenting the inserted beads in computerized tomography volumes of the phantoms.nnnRESULTSnThe robot reached the chosen targets in phantoms with a median accuracy of 2.73 mm and a median prostate motion of 5.46 mm. Accuracy was better at the apex than at the base (2.28 vs 3.83 mm, p <0.001), and similar for horizontal and angled needle inclinations (2.7 vs 2.82 mm, p = 0.18).nnnCONCLUSIONSnTo our knowledge this robot for prostate focal therapy, brachytherapy and targeted prostate biopsies is the first system to use intraoperative prostate motion tracking to guide needles into the prostate. Preliminary experiments show its ability to reach targets despite prostate motion.

Computer and Robot-Assisted Medical Intervention

Medical robotics includes assistive devices used by the physician in order to make his/her diagnostic or therapeutic practice easier and more efficient. This chapter focuses on such systems. It introduces the general field of computer-assisted medical interventions, its aims, and its different components, and describes the place of robots in this context. The evolution in terms of general design and control paradigms in the development of medical robots are presented and issues specific to that application domain are discussed. A view of existing systems, ongoing developments, and future trends is given. A case study is detailed. Other types of robotic help in the medical environment exist (such as for assisting a handicapped person, for rehabilitation of a patient or for replacement of some damaged/suppressed limbs or organs) but are outside the scope of this chapter.

Computer-augmented surgery

Abstract Computer-augmented surgery also called computer-assisted medical intervention (CAMI) aims to help the surgeon or physician in the definition and execution of an optimal strategy, through a quantitative use of multi-modal data. Perception, planning and action are the 3 stages of the related methodology. Planning corresponds to the determination of an optimal strategy. The evaluation of the selected strategy may require its simulation and the prediction of its effects. This cannot be done without a complex modelling of both the patient and the strategy. Complementary representations of the patient describing shape, behaviour and function of anatomical features and their evolution along time are needed. Since the surgeon is a key component of the ‘perception-planning-action’ loop, technological components that enable him to act on the patient with a visual and tactile feedback are also necessary. Our group, which has been working for 10 years in the field of CAMI, and has obtained clinical experience, is investigating this topic through different medical applications are described in this paper.

Safety Issues in Surgical Robotics

Abstract In (Latombe, 1991) one can read, “ One of the ultimate goals in Robotics is to create autonomous robots. Such robots will accept high-level descriptions of tasks and will execute them without further human intervention. The input descriptions will specify what the users wants rather than how to do it. The robots will be any kind of versatile mechanical device equipped with actuators and sensors under the control of a computing system ”. In the last two decades, a major part of the efforts of the research in robotics and automation has been devoted to the realization of such autonomous systems. Their application to medecine or surgery turns out to be very difficult since they have not been thought for such a drastically different use. In the medical field, the robot has, indeed, to cooperate with a man (a surgeon or a physician) to assist, rather than to replace, him in the execution of complex, precise and/or dangerous tasks. Since the surgeon is primarily working with his hands, the most suitable help for him is the one that makes it possible the physical guiding of these hands. The robot can be seen as a very well-suited man-machine interface that allows for a more quantitative use of medical images. Because it has to be used in a human environment, it cannot be “any kind of versatile mechanical device” as suggested before but it must be a safe, accurate and user-friendly system. Designing such a human-oriented system that would increase the human capabilities is still an open issue.

Education tools for surgery: a simulator for pelvic surgery

This poster presents a simulator dedicated to learning a computer-aided pelvic surgery procedure. Such a technique allows to position screws in the iliac bone minimally invasively (see [1]). The objective of the simulator is to make the clinical diffusion of such new techniques integrating intra-operative data acquisition for registration easier.