The DaVinci robot (Intuitive Surgical Device Inc., ): the master-slave system (left and middle); 

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Context 1

... to those motions and deformations in a discrete or continuous way. This raises very challenging robustness and safety issues. One important characteristic of those anatomic changes is their time scale with respect to the duration of the action to be performed. Consequently, different strategies may be selected: localization just before the action or tracking during the whole action. In the following sections, the way those questions have been solved in the case of urological targets will be analyzed. Historically, urology was one of the first clinical domains where a robot was used for patients. At the time V the late eighties V where most people dealt with neurosurgery or orthopaedics applications of robotics, the London Clinic and the Imperial College of London developed PROBOT [17]: a robot for the transurethral resection of the ad- enomatous prostate, i.e., the removal from the inside of the gland of extratissues compressing the urethra. The first test on a patient started in April 1991. After a feasibility study on five patients, a preclinical series with 40 patients was undertaken. Several versions of this system where developed; the first prototype was based on a PUMA 560 (from Unimation Inc.) connected to a passive frame. This frame is an elegant solution to safety issues since it constrains the tool movement inside a cone related to the task to be executed. The current system consists of a passive robot positioning a motorized frame with three degrees of freedom (DOF) V conical motion plus translation of the resectoscope. [42] reports the difficult task of automatically controlling this robot for resection monitor- ing from the real-time intraoperative ultrasound images. Indeed, because soft tissues move and deform, two types of strategies may be used in robot control. The ideal approach would be to continuously and automatically close the robot control loop using intraoperative information about the organ motion. To our knowledge, such a solution has not yet been developed for urology. However in radiotherapy, where the tool is outside the body and the planning is rather simple (beam orientation with respect to the patient and duration of radiation), organ tracking ability was introduced. In [15], the motions of intrabody implanted fiducials are correlated to the motions of infrared on-body markers for tracking breathing movements this process is however rather invasive. [41] proposes a noninvasive solution based on real-time image correlation for the detection of a predefined stage in the breathing cycle (full expiration for instance); this information is used for respiratory-gated radiotherapy treatment. The other and much simpler approach is to tele-operate robots: in that case the user closes the loop between robot motion and real-time image information. Such an approach is particularly interesting when opera- tive planning is too complex to be explicitly defined. Intermediate solutions consist in adding motion tracking abilities to tele-operated robots (see [22]) or to close the loop from imaging data in a more discrete way for simple tasks (see Section II-B). 1) Endoscope Holders: The first FDA approved medical robot, AESOP (from Computer Motion Inc.) [40] had a significant clinical and industrial success. Two thousand AESOP were sold to around five hundred hospitals between years 1994 and 2000. AESOP has a SCARA architecture with 4 active and 2 passive (pivot rotation) DOF; this tele-manipulator is voice controlled. Many other robotic endoscope holders have been developed in the academic and industrial tracks. One of them designed at TIMC [8] has the interesting property of being directly put on the patient abdomen skin (see Fig. 2). Because the robot is placed on the endoscope entry point, 3 DOF (2 rotations and 1 translation) are sufficient to handle the endoscope motions. As compared to AESOP and to most of the other systems which are positioned on the operating room (OR) table, floor or ceiling, this very compact system follows the patient motions and is very easy to install. It weights 625 g; it is voice controlled and completely sterilizable. Interest- ing evolutions of robotic endoscope holders deal with automatically control of robots from image information in order to track organs or instruments during the surgery (see [54] for instance). 2) Tele-Surgery Robots: Based on the robotic endoscope holders experience, instrument holders have naturally been designed resulting in the so-called tele-surgery robots. ZEUS, an evolution of the AESOP, is composed of 3 separated 4 DOF arms (one endoscope holder and two instrument holders). Another system, the DaVinci (from Intuitive Surgical Inc.), is composed of 3 or 4 arms mounted on a single basis. Articulated instruments provide extra intrabody DOF (see Fig. 3). Both systems are based on master-slave architectures; the arms are tele-operated 2 by the surgeon from endoscopic images. DaVinci proposes a B head-in [ stereoscopic display (see Fig. 3) while Zeus includes a B head-mounted [ stereoscopic display or a traditional screen. Intrabody DOF are a major advantage of the DaVinci, increasing the surgeon’s possibilities near open surgery conditions. Both systems are quite cumber- some and expensive; none of them include force feedback on the master workstation which may be a serious limitation for anastomoses for instance. The DaVinci has been extensively evaluated for urological applications. First robot-assisted laparoscopic radical prostatectomies were reported in [1], [9]. Very large series of patients have since been operated: the Vattikuti Institute in the Henry Ford Hospital of Detroit, USA, published in [34] a study concerning more than 1100 cases. In this center, laparoscopic prostatectomies started in October 2000 and the DaVinci assistance was introduced in March 2001. A study comparing conventional/laparoscopic/robot- assisted laparoscopic procedures showed clear advantages of the robotic series on many points including shorter hospital stays, reduced pain, reduced blood loss, better PSA control, reduced positive margins, better continence, and less impotence. Another advantage of robot assistance is a reduction of the learning curve for laparoscopic procedures; [2] reports an improvement factor of about 10. Laparoscopic radical prostatectomy is probably one of the domains were the robotic clinical added-value was so clearly demonstrated. Other applications of such robots to urology are reported in full details in [51]. Each time complex dissections, microsurgery or intracorporal sutur- ing are necessary, the robot may be a precious assistant. Several research projects in the world aim at develop- ing competitive smaller and/or cheaper solutions with articulated intrabody instruments and endoscopes and master station offering force feedback. Planning tools are also developed in order to optimize the entry ports positioning, enabling both target access and collision-free motion of the robots (see for instance [14]). Many gestures in urology are carried under interventional radiology: the diagnostic or therapeutic tool is moved under control of an imaging modality. Ultrasounds or fluoroscopy enable continuous control: the operator can see in real-time the tool position and the anatomy; CT or MRI allow asynchronous control: for instance, a needle is positioned, a control image is taken and the needle po- sition is corrected if necessary, and so on. This idea has been exploited to control from medical images robots performing simple tasks such as a linear tool insertion. 1) Prostate Biopsies and Brachytherapies: From a techni- cal viewpoint prostate biopsies and brachytherapies (see Fig. 4) are rather similar; they both consist in inserting needles in the prostate, either for tissue sampling or for radioactive seed placement, through transperineal or transrectal access, under imaging control V most often transrectal ultrasound imaging (TRUS). However, each biopsy makes use of a single ultrasonic (US) image in which the needle is visible while brachytherapy is based on a volume of images: often parallel axial US images acquired every 5 mm. Brachytherapy is based on a careful patient-specific dose planning while biopsies are generally performed following a predefined global scheme (for instance sextant or 11-core protocols). Needle insertion is slow and manual during brachytherapies while biopsies are very rapidly performed using a biospy gun. As demonstrated by [25] in a different medical context, increasing needle velocity results in minimizing the displacement and deformation of the tissue. Thus auto- mation may have a positive impact in terms of gesture accuracy. Moreover, prostate brachytherapy is based on the use of a template (a stereotactic grid) rigidly connected to the US probe. This restrains needle trajectories to lines parallel to the probe axis and results in potential collisions of the needles with the pelvic bone. Again, using a robot may enable various trajectory directions. [55] proposes to use a general purpose 6 DOF robot for needle positioning and insertion. [18] develops a special- purpose robot mimicking the conventional procedure (trajectories parallel to the US probe axis); a rotational DOF for the needle is added to reduce the needle flexion during tissue penetration. Those systems are still laboratory test beds. [38] describes a preclinical evaluation of a specific 9 DOF system (positioning platform plus biopsy robot) for transperineal prostate biopsies. A three- dimensional (3-D) prostate geometric model of the prostate is approximated from series of close parallel US images enabling planning of the biopsies. 2.5-mm accuracy is reported; those performances require very careful patient preparation and US probe handling. None of these systems really considers prostate motion and deformation during the procedure. Another approach consists in performing transrectal prostate biopsies or brachytherapies with ...

Context 2

... sensing (images, signals such as ECG); real-time re-planning may be necessary for the guiding system (for instance a robot) to adapt to these changes; finally robots should be synchronized to those motions and deformations in a discrete or continuous way. This raises very challenging robustness and safety issues. One important characteristic of those anatomic changes is their time scale with respect to the duration of the action to be performed. Consequently, different strategies may be selected: localization just before the action or tracking during the whole action. In the following sections, the way those questions have been solved in the case of urological targets will be analyzed. Historically, urology was one of the first clinical domains where a robot was used for patients. At the time V the late eighties V where most people dealt with neurosurgery or orthopaedics applications of robotics, the London Clinic and the Imperial College of London developed PROBOT [17]: a robot for the transurethral resection of the ad- enomatous prostate, i.e., the removal from the inside of the gland of extratissues compressing the urethra. The first test on a patient started in April 1991. After a feasibility study on five patients, a preclinical series with 40 patients was undertaken. Several versions of this system where developed; the first prototype was based on a PUMA 560 (from Unimation Inc.) connected to a passive frame. This frame is an elegant solution to safety issues since it constrains the tool movement inside a cone related to the task to be executed. The current system consists of a passive robot positioning a motorized frame with three degrees of freedom (DOF) V conical motion plus translation of the resectoscope. [42] reports the difficult task of automatically controlling this robot for resection monitor- ing from the real-time intraoperative ultrasound images. Indeed, because soft tissues move and deform, two types of strategies may be used in robot control. The ideal approach would be to continuously and automatically close the robot control loop using intraoperative information about the organ motion. To our knowledge, such a solution has not yet been developed for urology. However in radiotherapy, where the tool is outside the body and the planning is rather simple (beam orientation with respect to the patient and duration of radiation), organ tracking ability was introduced. In [15], the motions of intrabody implanted fiducials are correlated to the motions of infrared on-body markers for tracking breathing movements this process is however rather invasive. [41] proposes a noninvasive solution based on real-time image correlation for the detection of a predefined stage in the breathing cycle (full expiration for instance); this information is used for respiratory-gated radiotherapy treatment. The other and much simpler approach is to tele-operate robots: in that case the user closes the loop between robot motion and real-time image information. Such an approach is particularly interesting when opera- tive planning is too complex to be explicitly defined. Intermediate solutions consist in adding motion tracking abilities to tele-operated robots (see [22]) or to close the loop from imaging data in a more discrete way for simple tasks (see Section II-B). 1) Endoscope Holders: The first FDA approved medical robot, AESOP (from Computer Motion Inc.) [40] had a significant clinical and industrial success. Two thousand AESOP were sold to around five hundred hospitals between years 1994 and 2000. AESOP has a SCARA architecture with 4 active and 2 passive (pivot rotation) DOF; this tele-manipulator is voice controlled. Many other robotic endoscope holders have been developed in the academic and industrial tracks. One of them designed at TIMC [8] has the interesting property of being directly put on the patient abdomen skin (see Fig. 2). Because the robot is placed on the endoscope entry point, 3 DOF (2 rotations and 1 translation) are sufficient to handle the endoscope motions. As compared to AESOP and to most of the other systems which are positioned on the operating room (OR) table, floor or ceiling, this very compact system follows the patient motions and is very easy to install. It weights 625 g; it is voice controlled and completely sterilizable. Interest- ing evolutions of robotic endoscope holders deal with automatically control of robots from image information in order to track organs or instruments during the surgery (see [54] for instance). 2) Tele-Surgery Robots: Based on the robotic endoscope holders experience, instrument holders have naturally been designed resulting in the so-called tele-surgery robots. ZEUS, an evolution of the AESOP, is composed of 3 separated 4 DOF arms (one endoscope holder and two instrument holders). Another system, the DaVinci (from Intuitive Surgical Inc.), is composed of 3 or 4 arms mounted on a single basis. Articulated instruments provide extra intrabody DOF (see Fig. 3). Both systems are based on master-slave architectures; the arms are tele-operated 2 by the surgeon from endoscopic images. DaVinci proposes a B head-in [ stereoscopic display (see Fig. 3) while Zeus includes a B head-mounted [ stereoscopic display or a traditional screen. Intrabody DOF are a major advantage of the DaVinci, increasing the surgeon’s possibilities near open surgery conditions. Both systems are quite cumber- some and expensive; none of them include force feedback on the master workstation which may be a serious limitation for anastomoses for instance. The DaVinci has been extensively evaluated for urological applications. First robot-assisted laparoscopic radical prostatectomies were reported in [1], [9]. Very large series of patients have since been operated: the Vattikuti Institute in the Henry Ford Hospital of Detroit, USA, published in [34] a study concerning more than 1100 cases. In this center, laparoscopic prostatectomies started in October 2000 and the DaVinci assistance was introduced in March 2001. A study comparing conventional/laparoscopic/robot- assisted laparoscopic procedures showed clear advantages of the robotic series on many points including shorter hospital stays, reduced pain, reduced blood loss, better PSA control, reduced positive margins, better continence, and less impotence. Another advantage of robot assistance is a reduction of the learning curve for laparoscopic procedures; [2] reports an improvement factor of about 10. Laparoscopic radical prostatectomy is probably one of the domains were the robotic clinical added-value was so clearly demonstrated. Other applications of such robots to urology are reported in full details in [51]. Each time complex dissections, microsurgery or intracorporal sutur- ing are necessary, the robot may be a precious assistant. Several research projects in the world aim at develop- ing competitive smaller and/or cheaper solutions with articulated intrabody instruments and endoscopes and master station offering force feedback. Planning tools are also developed in order to optimize the entry ports positioning, enabling both target access and collision-free motion of the robots (see for instance [14]). Many gestures in urology are carried under interventional radiology: the diagnostic or therapeutic tool is moved under control of an imaging modality. Ultrasounds or fluoroscopy enable continuous control: the operator can see in real-time the tool position and the anatomy; CT or MRI allow asynchronous control: for instance, a needle is positioned, a control image is taken and the needle po- sition is corrected if necessary, and so on. This idea has been exploited to control from medical images robots performing simple tasks such as a linear tool insertion. 1) Prostate Biopsies and Brachytherapies: From a techni- cal viewpoint prostate biopsies and brachytherapies (see Fig. 4) are rather similar; they both consist in inserting needles in the prostate, either for tissue sampling or for radioactive seed placement, through transperineal or transrectal access, under imaging control V most often transrectal ultrasound imaging (TRUS). However, each biopsy makes use of a single ultrasonic (US) image in which the needle is visible while brachytherapy is based on a volume of images: often parallel axial US images acquired every 5 mm. Brachytherapy is based on a careful patient-specific dose planning while biopsies are generally performed following a predefined global scheme (for instance sextant or 11-core protocols). Needle insertion is slow and manual during brachytherapies while biopsies are very rapidly performed using a biospy gun. As demonstrated by [25] in a different medical context, increasing needle velocity results in minimizing the displacement and deformation of the tissue. Thus auto- mation may have a positive impact in terms of gesture accuracy. Moreover, prostate brachytherapy is based on the use of a template (a stereotactic grid) rigidly connected to the US probe. This restrains needle trajectories to lines parallel to the probe axis and results in potential collisions of the needles with the pelvic bone. Again, using a robot may enable various trajectory directions. [55] proposes to use a general purpose 6 DOF robot for needle positioning and insertion. [18] develops a special- purpose robot mimicking the conventional procedure (trajectories parallel to the US probe axis); a rotational DOF for the needle is added to reduce the needle flexion during tissue penetration. Those systems are still laboratory test beds. [38] describes a preclinical evaluation of a specific 9 DOF system (positioning platform plus biopsy robot) for transperineal prostate biopsies. A three- dimensional (3-D) prostate geometric model of the prostate is approximated from series of close parallel US images enabling planning of the biopsies. 2.5-mm accuracy is reported; those performances require very careful patient preparation and US probe handling. ...