1204 Part F Field and Service Robotics eration or hands-on cooperative control interface.The positioning.or endoscope holding.One primary advan- primary value of these systems is that they can overcome tage of such systems is their potential to reduce the some of the perception and manipulation limitations of number of people required in the operating room,al- the surgeon.Examples include the ability to manipu- though that advantage can only be achieved if all the late surgical instruments with superhuman precision by tasks routinely performed by an assisting individual can eliminating hand tremor,the ability to perform highly be automated.Other advantages can include improved dexterous tasks inside the patient's body,or the abil-task performance (e.g.,a steadier endoscopic view), ity to perform surgery on a patient who is physically safety (e.g.,elimination of excessive retraction forces), remote from the surgeon.Although setup time is still or simply giving the surgeon a greater feeling of control a serious concern with most surgeon extender systems, over the procedure.One of the key challenges in these the greater ease of manipulation that such systems offer systems is providing the required assistance without pos- has the potential to reduce operative times.One widely ing an undue burden on the surgeon's attention.A variety deployed example of a surgeon extender is the daVinci of control interfaces are common,including joysticks, Part system [52.2](Intuitive Surgical Systems,Sunnyvale,head tracking,voice recognition systems,and visual CA)shown in Fig.52.2.Other examples include the tracking of the surgeon and surgical instruments,for ex- Sensei cathetersystem [52.6](Hansen Medical Systems,ample,the Aesop endoscope positioner[52.7]used both u Mountain View,CA.)and the experimental Johns Hop- a foot-actuated joystick and a very effective voice recog- kins University (JHU)Steady Hand microsurgery robot nition system.Again,further examples are discussed in shown in Fig.52.3.Further examples are discussed in Sect.52.3. Sect.52.3. It is important to realize that surgical CAD/CAM A second category,auxiliary surgical support and surgical assistance are complementary concepts. robots,generally work alongside the surgeon and per- They are not at all incompatible,and many systems have form such routine tasks as tissue retraction,limb aspects of both. 52.2 Technology 52.2.1 Mechanical Design Considerations designs.For example,laparoscopic surgery and percu- taneous needle placement procedures typically involve The mechanical design of a surgical robot depends cru- the passage or manipulation of instruments about a com- cially on its intended application.For example,robots mon entry point into the patient's body.There are two with high precision,stiffness and (possibly)limited basic design approaches.The first approach uses a pas- dexterity are often very suitable for orthopaedic bone sive wrist to allow the instrument to pivot about the shaping or stereotactic needle placement,and medical insertion point and has been used in the commercial robots for these applications [52.8-11]frequently have Aesop and Zeus robots [52.12,14]as well as several high gear ratios and consequently,low back-drivability, research systems.The second approach mechanically high stiffness,and low speed.On the other hand,robots constrains the motion of the surgical tool to rotate about for complex,minimally invasive surgery (MIS)on soft a remote center of motion (RCM)distal to the robot's tissues require compactness,dexterity,and responsive- structure.In surgery,the robot is positioned so that ness.These systems [52.2,12]frequently have relatively the RCM point coincides with the entry point into the high speed,low stiffness,and highly back-drivable patient's body.This approach has been used by the com- mechanisms. mercially developed daVinci robot [52.21,as well as by Many early medical robots [52.8,11,13]were es- numerous research groups,using a variety of kinematic sentially modified industrial robots.This approach has designs [52.15-171. many advantages,including low cost,high reliability, The emergence of minimally invasive surgery has and shortened development times.If suitable modifica-created a need for robotic systems that can provide tions are made to ensure safety and sterility,such systems high degrees of dexterity in very constrained spaces can be very successful clinically [52.9],and they can also inside the patient's body,and at smaller and smaller be invaluable for rapid prototyping and research use. scales.Figure 52.4 shows several typical examples of However,the specialized requirements of surgical current approaches.One common response has been to applications have tended to encourage more specialized develop cable-actuated wrists [52.2].However,a num-1204 Part F Field and Service Robotics eration or hands-on cooperative control interface. The primary value of these systems is that they can overcome some of the perception and manipulation limitations of the surgeon. Examples include the ability to manipu￾late surgical instruments with superhuman precision by eliminating hand tremor, the ability to perform highly dexterous tasks inside the patient’s body, or the abil￾ity to perform surgery on a patient who is physically remote from the surgeon. Although setup time is still a serious concern with most surgeon extender systems, the greater ease of manipulation that such systems offer has the potential to reduce operative times. One widely deployed example of a surgeon extender is the daVinci system [52.2] (Intuitive Surgical Systems, Sunnyvale, CA) shown in Fig. 52.2. Other examples include the Sensei catheter system [52.6] (Hansen Medical Systems, Mountain View, CA.) and the experimental Johns Hop￾kins University (JHU) Steady Hand microsurgery robot shown in Fig. 52.3. Further examples are discussed in Sect. 52.3. A second category, auxiliary surgical support robots, generally work alongside the surgeon and per￾form such routine tasks as tissue retraction, limb positioning, or endoscope holding. One primary advan￾tage of such systems is their potential to reduce the number of people required in the operating room, al￾though that advantage can only be achieved if all the tasks routinely performed by an assisting individual can be automated. Other advantages can include improved task performance (e.g., a steadier endoscopic view), safety (e.g., elimination of excessive retraction forces), or simply giving the surgeon a greater feeling of control over the procedure. One of the key challenges in these systems is providing the required assistance without pos￾ing an undue burden on the surgeon’s attention. A variety of control interfaces are common, including joysticks, head tracking, voice recognition systems, and visual tracking of the surgeon and surgical instruments, for ex￾ample, the Aesop endoscope positioner [52.7] used both a foot-actuated joystick and a very effective voice recog￾nition system. Again, further examples are discussed in Sect. 52.3. It is important to realize that surgical CAD/CAM and surgical assistance are complementary concepts. They are not at all incompatible, and many systems have aspects of both. 52.2 Technology 52.2.1 Mechanical Design Considerations The mechanical design of a surgical robot depends cru￾cially on its intended application. For example, robots with high precision, stiffness and (possibly) limited dexterity are often very suitable for orthopaedic bone shaping or stereotactic needle placement, and medical robots for these applications [52.8–11] frequently have high gear ratios and consequently, low back-drivability, high stiffness, and low speed. On the other hand, robots for complex, minimally invasive surgery (MIS) on soft tissues require compactness, dexterity, and responsive￾ness. These systems [52.2,12] frequently have relatively high speed, low stiffness, and highly back-drivable mechanisms. Many early medical robots [52.8, 11, 13] were es￾sentially modified industrial robots. This approach has many advantages, including low cost, high reliability, and shortened development times. If suitable modifica￾tions are made to ensure safety and sterility, such systems can be very successful clinically [52.9], and they can also be invaluable for rapid prototyping and research use. However, the specialized requirements of surgical applications have tended to encourage more specialized designs. For example, laparoscopic surgery and percu￾taneous needle placement procedures typically involve the passage or manipulation of instruments about a com￾mon entry point into the patient’s body. There are two basic design approaches. The first approach uses a pas￾sive wrist to allow the instrument to pivot about the insertion point and has been used in the commercial Aesop and Zeus robots [52.12, 14] as well as several research systems. The second approach mechanically constrains the motion of the surgical tool to rotate about a remote center of motion (RCM) distal to the robot’s structure. In surgery, the robot is positioned so that the RCM point coincides with the entry point into the patient’s body. This approach has been used by the com￾mercially developed daVinci robot [52.2], as well as by numerous research groups, using a variety of kinematic designs [52.15–17]. The emergence of minimally invasive surgery has created a need for robotic systems that can provide high degrees of dexterity in very constrained spaces inside the patient’s body, and at smaller and smaller scales. Figure 52.4 shows several typical examples of current approaches. One common response has been to develop cable-actuated wrists [52.2]. However, a num￾Part F 52.2