Medical image computing and computer-aided medical interventions applied to soft tissues. Work in progress in urology

Until recently, Computer-Aided Medical Interventions (CAMI) and Medical Robotics have focused on rigid and non deformable anatomical structures. Nowadays, special attention is paid to soft tissues, raising complex issues due to their mobility and deformation. Mini-invasive digestive surgery was probably one of the first fields where soft tissues were handled through the development of simulators, tracking of anatomical structures and specific assistance robots. However, other clinical domains, for instance urology, are concerned. Indeed, laparoscopic surgery, new tumour destruction techniques (e.g. HIFU, radiofrequency, or cryoablation), increasingly early detection of cancer, and use of interventional and diagnostic imaging modalities, recently opened new challenges to the urologist and scientists involved in CAMI. This resulted in the last five years in a very significant increase of research and developments of computer-aided urology systems. In this paper, we propose a description of the main problems related to computer-aided diagnostic and therapy of soft tissues and give a survey of the different types of assistance offered to the urologist: robotization, image fusion, surgical navigation. Both research projects and operational industrial systems are discussed

Robot Autonomy for Surgery

Autonomous surgery involves having surgical tasks performed by a robot operating under its own will, with partial or no human involvement. There are several important advantages of automation in surgery, which include increasing precision of care due to sub-millimeter robot control, real-time utilization of biosignals for interventional care, improvements to surgical efficiency and execution, and computer-aided guidance under various medical imaging and sensing modalities. While these methods may displace some tasks of surgical teams and individual surgeons, they also present new capabilities in interventions that are too difficult or go beyond the skills of a human. In this chapter, we provide an overview of robot autonomy in commercial use and in research, and present some of the challenges faced in developing autonomous surgical robots

Automated pick-up of suturing needles for robotic surgical assistance

Robot-assisted laparoscopic prostatectomy (RALP) is a treatment for prostate cancer that involves complete or nerve sparing removal prostate tissue that contains cancer. After removal the bladder neck is successively sutured directly with the urethra. The procedure is called urethrovesical anastomosis and is one of the most dexterity demanding tasks during RALP. Two suturing instruments and a pair of needles are used in combination to perform a running stitch during urethrovesical anastomosis. While robotic instruments provide enhanced dexterity to perform the anastomosis, it is still highly challenging and difficult to learn. In this paper, we presents a vision-guided needle grasping method for automatically grasping the needle that has been inserted into the patient prior to anastomosis. We aim to automatically grasp the suturing needle in a position that avoids hand-offs and immediately enables the start of suturing. The full grasping process can be broken down into: a needle detection algorithm; an approach phase where the surgical tool moves closer to the needle based on visual feedback; and a grasping phase through path planning based on observed surgical practice. Our experimental results show examples of successful autonomous grasping that has the potential to simplify and decrease the operational time in RALP by assisting a small component of urethrovesical anastomosis

Positive surgical margins in nephron-sparing surgery; the great unknown

There is a currently a general trend towards organ-preserving surgery, and urology is no exception. Specifically, nephron-sparing surgery (NSS) has gained general acceptance for T1a renal cell carcinoma (guidelines recommendations). Moreover T1b, T2 and even T3 stage tumors have been included on the nephron sparing list at some centers. An unresolved issue is that of positive surgical margins (PSM), not only their detection but also the implications for follow up and treatment. This paper highlights data available on risk factors for PSM, their clinical relevance, and possible therapeutic consequences. From the surgeon’s viewpoint, NSS is a daring and risky surgical procedure. Urological guidelines stress the importance of NSS, and thus the trend is moving in that direction. Unresolved, however, is the problem of PSM. Trifecta, MIC, and pentafecta are applicable concepts which attempt to define the optimal endpoint of NSS, but further elaboration is necessary. Specifically, research needs to focus less on the concept of definitive margins and more on their identification and avoidance. Although some studies suggest that PSMs do not influence overall survival rate, the basic idea of preserving tissue that is not cancerous leads to further medical, social, and psychological considerations

Computer- and robot-assisted Medical Intervention

Medical robotics includes assistive devices used by the physician in order to make his/her diagnostic or therapeutic practices easier and more efficient. This chapter focuses on such systems. It introduces the general field of Computer-Assisted Medical Interventions, its aims, its different components and describes the place of robots in that context. The evolutions 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, on-going developments and future trends is given. A case-study is detailed. Other types of robotic help in the medical environment (such as for assisting a handicapped person, for rehabilitation of a patient or for replacement of some damaged/suppressed limbs or organs) are out of the scope of this chapter.Comment: Handbook of Automation, Shimon Nof (Ed.) (2009) 000-00

Autonomous Tissue Scanning under Free-Form Motion for Intraoperative Tissue Characterisation

In Minimally Invasive Surgery (MIS), tissue scanning with imaging probes is required for subsurface visualisation to characterise the state of the tissue. However, scanning of large tissue surfaces in the presence of deformation is a challenging task for the surgeon. Recently, robot-assisted local tissue scanning has been investigated for motion stabilisation of imaging probes to facilitate the capturing of good quality images and reduce the surgeon's cognitive load. Nonetheless, these approaches require the tissue surface to be static or deform with periodic motion. To eliminate these assumptions, we propose a visual servoing framework for autonomous tissue scanning, able to deal with free-form tissue deformation. The 3D structure of the surgical scene is recovered and a feature-based method is proposed to estimate the motion of the tissue in real-time. A desired scanning trajectory is manually defined on a reference frame and continuously updated using projective geometry to follow the tissue motion and control the movement of the robotic arm. The advantage of the proposed method is that it does not require the learning of the tissue motion prior to scanning and can deal with free-form deformation. We deployed this framework on the da Vinci surgical robot using the da Vinci Research Kit (dVRK) for Ultrasound tissue scanning. Since the framework does not rely on information from the Ultrasound data, it can be easily extended to other probe-based imaging modalities.Comment: 7 pages, 5 figures, ICRA 202

Robotic Partial Nephrectomy for a Peripheral Renal Tumor

Partial nephrectomy (PN) is the preferred surgical treatment for T1 renal tumors whenever technically feasible. When properly performed, it allows preservation of nephron mass without compromising oncologic outcomes. This reduces the postoperative risk of renal insufficiency, which translates into better overall survival for the patients. PN can be technically challenging, because it requires the surgeon to complete the tasks of tumor excision, hemostasis and renorrhaphy, all within an ischemic time of preferably below 30 minutes. The surgeon needs to avoid violating the tumor margins while leaving behind the maximal parenchymal volume at the same time. Variations such as zero ischemia, early unclamping, and selective clamping have been developed in an attempt to reduce the negative impact of renal ischemia, but inevitably add to the steep learning curves for any surgeon. Being able to appreciate the fine details of each surgical step in PN is the fundamental basis to the success of this surgery. The use of the robotic assistance allows a good combination of the minimally invasive nature of laparoscopic surgery and the surgical exposure and dexterity of open surgery. It also allows the use of adjuncts such as concurrent ultrasound assessment of the renal mass and intraoperative fluorescence to aid the identification of tumor margins, all with a simple hand switch at the console. Robot-assisted laparoscopic PN is now the most commonly performed type of PN in the United States and is gaining acceptance on the global scale. In this video, we illustrate the steps of robot-assisted laparoscopic PN and highlight the technical key points for success

Robotic total gastrectomy with intracorporeal robot-sewn anastomosis. A novel approach adopting the double-loop reconstruction method

Gastric cancer constitutes a major health problem. Robotic surgery has been progressively developed in this field. Although the feasibility of robotic procedures has been demonstrated, there are unresolved aspects being debated, including the reproducibility of intracorporeal in place of extracorporeal anastomosis. Difficulties of traditional laparoscopy have been described and there are well-known advantages of robotic systems, but few articles in literature describe a full robotic execution of the reconstructive phase while others do not give a thorough explanation how this phase was run. A new reconstructive approach, not yet described in literature, was recently adopted at our Center. Robotic total gastrectomy with D2 lymphadenectomy and a socalled ‘‘double-loop’’ reconstruction method with intracorporeal robotsewn anastomosis (Parisi’s technique) was performed in all reported cases. Preoperative, intraoperative, and postoperative data were collected and a technical note was documented. All tumors were located at the upper third of the stomach, and no conversions or intraoperative complications occurred. Histopathological analysis showed R0 resection obtained in all specimens. Hospital stay was regular in all patients and discharge was recommended starting from the 4th postoperative day. No major postoperative complications or reoperations occurred. Reconstruction of the digestive tract after total gastrectomy is one of the main areas of surgical research in the treatment of gastric cancer and in the field of minimally invasive surgery. The double-loop method is a valid simplification of the traditional technique of construction of the Roux-limb that could increase the feasibility and safety in performing a full hand-sewn intracorporeal reconstruction and it appears to fit the characteristics of the robotic system thus obtaining excellent postoperative clinical outcome