Presentation
The qualitative surgical robot: Types, training, and design direction
SessionRobotics Summit - Session 2
DescriptionRobotic surgery is rising globally, with increasing numbers and types in clinical use. This diversified robotic ecosystem defines needs for future training pathways, as well creating opportunities for robot manufacturers to improve design. There is an emerging need for a more qualitative analysis of the various robot types, with design architectures converging to perform similar operations. An understanding of their performance and limitations is key to safe and effective use, as well as for design impetus.
Robot architecture.
Surgical robots are the most complex medical devices that surgeons use. Three types are in clinical use in the UK (da Vinci, Versius, Hugo). Surgical motion is achieved by docking robotic arms to robotic instruments placed through ports in the body cavity. The operating surgeon sits remote from the patient at the surgeon console. Robot arms may radiate from a solitary boom (da Vinci), or be modularised (Versius, Hugo). The console may be of closed (da Vinci) or open layout (Versius, Hugo). Control inputs can be made through hand-controllers alone (Versius), or through both hand-controllers and foot pedals (da Vinci, Hugo). Only da Vinci currently has dual console. Robotic instrument dimensions vary across robot types, being shorter and narrower on Versius than the other platforms, and impacts port placement. Some instrument types are available in robot-specific form on all platforms: bipolar grasper, monopolar scissors, fenestrated grasper; others only on da Vinci Xi (advanced energy, stapling, clip application), so performed by the bedside assistant on other robot types. Table integrated motion also varies across types.
Degrees of freedom.
All robotic architecture converges on robotic instruments with up to 7 degrees of freedom (DOF) of intracorporeal motion. DOFs are actuated by movement of the robot arm and also by mechanisms within the robotic instrument. Robot arm joints are uniaxial and vary in number across platforms: 7 (Versius), 8 (da Vinci), and 9 (Hugo). Within the robotic instrument itself, three (Versius) or four cables (da Vinci, Hugo) generate 3-4 DOFs, through fin-cable (Versius) or cable-pulley (da Vinci, Hugo) mechanism. Hand-controller motion at the surgeon console maps directly to the robotic instrument DOF within the spatial envelope. Summing across all robotic arms, the console surgeon has 25 DOF, to visualise and manipulate anatomy.
Robotic function.
All robot types, with varied architecture, converge on the same DOF, target anatomy, and procedural steps. Similar technical challenges in function are therefore faced, with two specific problems to solve: an accurate abdominal wall fulcrum, and avoiding external clashing. An accurate fulcrum reduces traction at the port site, so reducing postoperative pain and port-site incisional hernia. Two engineering solutions to this are: (i) Remote Centre Motion (RCM; da Vinci, Hugo): the fulcrum is a point in space remote from the final joint and requires ‘direct docking’ of the robot arm with a robot-specific port as well as the instrument; or (ii) ‘Port training’ (Versius): the fulcrum is detected by the robot arm, which articulates with the instrument only and not with the port, also called ‘docking free design’. External clashing between robot arms disrupts workflow and prolongs operative time and workload. It can be reduced through port placement, endo-wrist use, and maintaining situational awareness of robotic arm states. All platforms work optimally on target anatomy range of 2 quadrants. Broader target anatomy requires re-docking.
Console surgeon.
The console surgeons sits remote from the patient bedside, so relies on telepresence and tele-operation.
Telepresence. Console vision is three-dimensional. However, there is no haptic feedback, which is therefore derived from visual information, termed pseudo-haptic feedback. This cross-modal perception is known to occur for natural phenomena, such as visual cues in lip movement modulating auditory perception (McGurk effect), but has not been formally studied in surgical robotics. In addition, bedside auditory cues and communication are more remote. Therefore, though visual perception is augmented, there is a decrement in auditory and haptic perception. Spatial orientation at the console also lacks the orientation cues available at the bedside (alignment of instruments with respect to the patient and each other, ‘embodied cognition’ of holding these instruments) so again gained purely from intracorporeal visual information and anatomical cues. Maintaining spatial orientation, including camera horizon, is key for this. Future robots could improve telepresence through haptic feedback and displaying bedside spatial cues at the console.
Tele-operation. Surgical motion is filtered, scalable, and applies to all four robotic arms, so exceeding laparoscopic capability. However, important limitations include a less obvious spatial envelope and lack of haptic feedback such that supra-physiological force can be inadvertently exerted on tissues.
Bleeding: cause and control. Bleeding can occur due to traction without haptic feedback. Even minor bleeding requires a controlled approach in robotic surgery. Anticipation of this pitfall should reduce the ‘startle response’. Awareness of the spatial envelope of instruments should be maintained, such that if bleeding were to occur, instruments can reach the site.
‘Performance envelope’. In aviation, the ‘flight envelope’ graphically depicts aircraft capability along parameters, with ‘envelope protection’ on modern airliners. In robotic surgery, there is in principle a maximum force for tissue traction. In addition, the spatial range, both linear and radial, is limited by robotic instrument length and robotic arm motion. These limitations form a ‘spatio-haptic envelope’. Currently, this is a tacit implicit concept for the console surgeon. Future surgical robots would benefit from this being made explicit at the console, and ultimately envelope protection could enhance safety.
Bedside assistance.
Bedside tasks vary according to robot type and surgeon preference. Tasks include traction, instrument change, tasks not available through robotic instruments, resolving external clashing, more general bedside situational awareness, and in the emergency setting performing protocol steps (e.g. major haemorrhage, emergency undocking). An important consider is ergonomic safety of the bedside assistant to facilitate precise surgical motion as well as reduce musculoskeletal risk.
Non-technical skills.
The human-machine interface given the complexity of the robot, and human-human interaction given the console surgeon situated remote from the bedside, creates non-technical challenges. Solutions include robot-specific checklists and guided setup through voice prompts, and other non-technical tools such as closed communication and standardised phraseology.
Robot architecture.
Surgical robots are the most complex medical devices that surgeons use. Three types are in clinical use in the UK (da Vinci, Versius, Hugo). Surgical motion is achieved by docking robotic arms to robotic instruments placed through ports in the body cavity. The operating surgeon sits remote from the patient at the surgeon console. Robot arms may radiate from a solitary boom (da Vinci), or be modularised (Versius, Hugo). The console may be of closed (da Vinci) or open layout (Versius, Hugo). Control inputs can be made through hand-controllers alone (Versius), or through both hand-controllers and foot pedals (da Vinci, Hugo). Only da Vinci currently has dual console. Robotic instrument dimensions vary across robot types, being shorter and narrower on Versius than the other platforms, and impacts port placement. Some instrument types are available in robot-specific form on all platforms: bipolar grasper, monopolar scissors, fenestrated grasper; others only on da Vinci Xi (advanced energy, stapling, clip application), so performed by the bedside assistant on other robot types. Table integrated motion also varies across types.
Degrees of freedom.
All robotic architecture converges on robotic instruments with up to 7 degrees of freedom (DOF) of intracorporeal motion. DOFs are actuated by movement of the robot arm and also by mechanisms within the robotic instrument. Robot arm joints are uniaxial and vary in number across platforms: 7 (Versius), 8 (da Vinci), and 9 (Hugo). Within the robotic instrument itself, three (Versius) or four cables (da Vinci, Hugo) generate 3-4 DOFs, through fin-cable (Versius) or cable-pulley (da Vinci, Hugo) mechanism. Hand-controller motion at the surgeon console maps directly to the robotic instrument DOF within the spatial envelope. Summing across all robotic arms, the console surgeon has 25 DOF, to visualise and manipulate anatomy.
Robotic function.
All robot types, with varied architecture, converge on the same DOF, target anatomy, and procedural steps. Similar technical challenges in function are therefore faced, with two specific problems to solve: an accurate abdominal wall fulcrum, and avoiding external clashing. An accurate fulcrum reduces traction at the port site, so reducing postoperative pain and port-site incisional hernia. Two engineering solutions to this are: (i) Remote Centre Motion (RCM; da Vinci, Hugo): the fulcrum is a point in space remote from the final joint and requires ‘direct docking’ of the robot arm with a robot-specific port as well as the instrument; or (ii) ‘Port training’ (Versius): the fulcrum is detected by the robot arm, which articulates with the instrument only and not with the port, also called ‘docking free design’. External clashing between robot arms disrupts workflow and prolongs operative time and workload. It can be reduced through port placement, endo-wrist use, and maintaining situational awareness of robotic arm states. All platforms work optimally on target anatomy range of 2 quadrants. Broader target anatomy requires re-docking.
Console surgeon.
The console surgeons sits remote from the patient bedside, so relies on telepresence and tele-operation.
Telepresence. Console vision is three-dimensional. However, there is no haptic feedback, which is therefore derived from visual information, termed pseudo-haptic feedback. This cross-modal perception is known to occur for natural phenomena, such as visual cues in lip movement modulating auditory perception (McGurk effect), but has not been formally studied in surgical robotics. In addition, bedside auditory cues and communication are more remote. Therefore, though visual perception is augmented, there is a decrement in auditory and haptic perception. Spatial orientation at the console also lacks the orientation cues available at the bedside (alignment of instruments with respect to the patient and each other, ‘embodied cognition’ of holding these instruments) so again gained purely from intracorporeal visual information and anatomical cues. Maintaining spatial orientation, including camera horizon, is key for this. Future robots could improve telepresence through haptic feedback and displaying bedside spatial cues at the console.
Tele-operation. Surgical motion is filtered, scalable, and applies to all four robotic arms, so exceeding laparoscopic capability. However, important limitations include a less obvious spatial envelope and lack of haptic feedback such that supra-physiological force can be inadvertently exerted on tissues.
Bleeding: cause and control. Bleeding can occur due to traction without haptic feedback. Even minor bleeding requires a controlled approach in robotic surgery. Anticipation of this pitfall should reduce the ‘startle response’. Awareness of the spatial envelope of instruments should be maintained, such that if bleeding were to occur, instruments can reach the site.
‘Performance envelope’. In aviation, the ‘flight envelope’ graphically depicts aircraft capability along parameters, with ‘envelope protection’ on modern airliners. In robotic surgery, there is in principle a maximum force for tissue traction. In addition, the spatial range, both linear and radial, is limited by robotic instrument length and robotic arm motion. These limitations form a ‘spatio-haptic envelope’. Currently, this is a tacit implicit concept for the console surgeon. Future surgical robots would benefit from this being made explicit at the console, and ultimately envelope protection could enhance safety.
Bedside assistance.
Bedside tasks vary according to robot type and surgeon preference. Tasks include traction, instrument change, tasks not available through robotic instruments, resolving external clashing, more general bedside situational awareness, and in the emergency setting performing protocol steps (e.g. major haemorrhage, emergency undocking). An important consider is ergonomic safety of the bedside assistant to facilitate precise surgical motion as well as reduce musculoskeletal risk.
Non-technical skills.
The human-machine interface given the complexity of the robot, and human-human interaction given the console surgeon situated remote from the bedside, creates non-technical challenges. Solutions include robot-specific checklists and guided setup through voice prompts, and other non-technical tools such as closed communication and standardised phraseology.
Author
Event Type
Robotics Workshop Submission
TimeSunday, March 3010:45am - 11:15am EDT
LocationHarbour A/B