Medical Robotics: An Overview

1. Medical Robotics: An Overview Jennifer Brooks for Comp 790-072, Robotics: An Introduction at University of North Carolina, Chapel Hill November 9, 2006

2. 3 Categories • Biorobotics • Rehabilitation Robotics • Robotics for Surgery • Autonomous Robots • Computer Assisted Surgery

3. Biorobotics • Modeling and simulating biological systems in order to provide a better understanding of human physiology • For example, haptics research to provide force-feedback in master-slave systems • May also lead to a number of practical applications for the substitution of organs and/or functions of humans • Examples: • bionic limb prosthesis • hearing aids and other aids targeted at neuromotor recovery • the possibility of inserting brain chips • implanting microscopic activators in the heart to pump blood • data and image acquisition microsystems for artificial sight • microchips to detect sound and to substitute the auditory nerve • May be used to aid in investigation of diseases or other health-related ailments • Examples • inch-worm robot developed in Singapore for colon exploration • intestinal bug developed in the Nanorobotics lab at CMU

4. Example Biorobotic System: DDX [Rovetta, 2001] • DDX is an experimental biorobotic system designed to acquire and provide data about human finger movement, applied in analysis of neural disturbances with quantitative evaluation of both response times and dynamic action of the patient. • The goal is to measure the response parameters of a person in front of a “soft touch”, made by his finger in front of a button. • It is now applied in daily clinical activity to diagnose the progression of the Parkinson pathology.

5. Disease Detector 3 (DD3) [Rovetta, 2001] • A fuzzy-based control system for detection of Parkinson disease • May be used remotely to monitor a patient’s health at his or her home • Patient pushes button on a joystick; system measures response time, speed, fingertip pressure, and tremor • Virtual Movement: on a display, the patient is asked to follow a virtual image relating to each moment of the test. Again, system measures response time, speed, fingertip pressure, and tremor from the press of a button and grip on a joystick.

6. Six-legged “Intestinal Bug” with swallowable camera to allow docs to see inside the intestine. Image from http://www.post-gazette.com, May 2005 Article in Health, Science, and Environment Other Biorobots Metin Sitti, director of CMU's Nanorobotics Lab A Retina-Like CMOS Sensor for vision Image from [Sadini et al, 2000] Above: Medical Telediagnostic System with Tactile Haptic Interfaces Image from [Methil-Sudhakaran et al, 2005] Biomechanics of Voice Production Goal is to address questions regarding the etiology and treatment of common voice pathologies. http://biorobotics.harvard.edu/research/heather.html

7. Other Biorobots (Cont’d) A scheme of a fingertip incorporating three different types of sensors which provide information on object geometry and material features comparable to those of the human fingertip. A close-up of one of the sensors (a 256-element array sensor), which imitates the space-variant distribution of tactile receptors in the fingertip skin. Image from [Dario et al, 1996]

8. Rehabilitation Robotics • Robotics systems for hospitals • HelpMates • MELKONG • Manipulators in rehabilitation • Wheelchair-mounted arms • MoVAR: the Mobile Vocational Assistant • URMAD: a mobile base that responds to a fixed workstation, mainly devised for residential applications • “Intelligent” wheelchairs • self-navigating wheelchairs with sensors enabling them to avoid obstacles • Daily life home assistance • MOVAID: a mobile base which fits into different activity workstations, built on URMAD technology • Advanced prosthesis and orthosis • Functional Electric Simulation (FES) • Computer-Aided Locomotion by Implanted Electro-Stimulation (CALIES) • Virtual environments for training and rehabilitative therapies

9. MoVAR (1983-1988) • Unique and patented 3-wheeled omni-directional base • Mounted PUMA-250 arm with camera to display robot’s activities and surroundings to user console • Desk-high and narrow enough to go through interior doorways. • Wireless digital link for receiving commands and sending position and status information. • Bumper-mounted touch sensor system for obstacle avoidance • Wrist-mounted force sensor and gripper-mounted proximity sensors to assist in manipulation • The robot console had three monitors: graphic robot motion planning, robot status, and camera view. It had keyboard, voice, and head-motion inputs for command and cursor control, and voice output. • Funding for it terminated in 1988. The hardware and software were transferred to the Intelligent Mechanisms Group at the NASA Ames Research Center (Mountain View, CA) for use in the development of real-time controllers and stereo-based user interfaces for semi-autonomous planetary rovers.

10. URMAD Image from [Dario, 1996]

11. Computer-Aided Locomotion by Implanted Electro-Stimulation (CALIES) • Probably the most important coordinated effort in the world for restoring autonomous locomotion in paralyzed persons [Dario, 1996] • Investigated the possibility of implanting electrodes into lower limb muscles, or nerves, which could be stimulated via an external computer to produce close to natural walking

12. Robotics for Surgery

13. A Definition • Robot - “A reprogrammable multifunctional manipulator, designed to move material, parts, tools or specialized devices through variable programmed motions for the performance of a variety of tasks” • Robot Institute of America • “A powered computer controlled manipulator with artificial sensing that can be reprogrammed to move and position tools to carry out a range of surgical tasks” • B Davies (2000) • “Robotic systems for surgery are computer-integrated surgery (CIS) systems first, and “medical robots” second. In other words, the robot itself is just one element of a larger system designed to assist a surgeon in carrying out a surgical procedure that may include preoperative planning, intraoperative registration to presurgical plans, use of a combination of robotic assist and manually controlled tools for carrying out the plan, and postoperative verification and follow-up.” • Taylor (2003)

14. Typical stages in robotic knee surgery [Davies, 1999] Robots: One Aspect of an Integrated System

15. Benefits from [Davies, 1999]: • The ability to move in a predefined and reprogrammable complex three-dimensional path, both accurately and predictably. • The ability to actively constrain tools to a particular path or location, even against externally imposed forces, thus preventing damage to vital regions. This can lead to safer procedures than those achieved using Computer Assisted Surgery (CAS). • The ability to make repetitive motions, for long periods, tirelessly. • The ability to move to a location and then hold tools there for long periods accurately, rigidly and without tremor. • The ability to perform in environments unsafe for humans, such as radioactive and fluoroscopic. • Precise micromotions with prespecified microforces. • Quick and automatic response to sensor signals or to changes in commands. • To be able to perform ‘keyhole’ minimal access surgery, without the aid of vision and without ‘forgetting’ the path or the location.

16. Timeline

17. Timeline (cont’d)

18. Timeline (cont’d)

19. Timeline (cont’d) * There are many more; these are just some highlights to give an idea about how medical robotics has evolved.

20. Robot Trivia The word "robot" was first used by Czech writer Karl Capek for his 1920 play, R.U.R.: Rossum's Universal Robots, in which artificial workers eventually overthrow their creators. But contrary to popular opinion, Karl Capek didn't invent the word "robot". He wanted to call the workers "labori" but his brother, cubist painter and writer Josef Capek, suggested they be called "robots". The Czech word "robota" means "forced work or labour".

21. Timeline • For another, more extensive timeline, see http://biomed.brown.edu/Courses/BI108/BI108_2005_Groups/04/timeline.html

22. “Robotic Surgery”: How it differs from “Computer-Assisted Surgery” (CAS)? • [Davies, 1999] differentiates between the two: • In CAS, the surgeon holds the tools and could ignore warnings to the contrary and cut into unsafe regions; whereas, a robot can be programmed to prevent motions into critical regions or only allow motions along a specified direction • computers might help in planning and positioning • In robotic surgery, robots will hold the tools, providing greater accuracy and precision • More recent developments, however, don’t fit easily into one of these categories based on the definitions offered by Davies (and later by [Bann et al, 2003]). • Consider telesurgery…

23. Benefits of “Computer-Assisted Surgery” • Some systems correct the surgeon’s tremor • Higher accuracy • Minimally Invasive Surgery • Reduction of radiation exposure for both patient and surgeon • Less time consuming interventions because of better planning and simulation[Schep et al, 2001]

24. Robotic Surgery: Current Applications TABLE 3. Current Applications of Robotic Surgery From:   Lanfranco: Ann Surg, Volume 239(1).January 2004.14-21

25. 2 Main Types of Robotics for Surgery • Those based on “image guidance” and • Those aimed at obtaining minimal “invasiveness” [Dario et al, 1996] • For example • Bone-mounted miniature robot • Some achieve both • For example • da Vinci Surgical System – a master-slave system • Zeus – a master-slave system

26. MARS: A Bone-Mounted Miniature Robot [Shoham et al, 2003] • Reasons given for slow uptake of Surgical Robots in the Operating Room: • Contemporary medical robots are voluminous. They occupy too much space and raise safety issues. • Commercial surgical robot systems are expensive ($300,000 to $1,000,000). Thus, their use is limited to the few large research hospitals that can afford them. • The patient anatomy needs to be immobilized by fixing it to the operating room table, or compensated for by tracking it in real time and adjusting the fixed robot position accordingly.

27. MARS: A Bone-Mounted Miniature Robot [Shoham et al, 2003] • MARS is a cylindrical 5x7 cm3, 200-g, six-degree-of-freedom parallel manipulator. • Authors were developing two clinical applications to demonstrate the concept: • surgical tools guiding for spinal pedicle screws placement; and • drill guiding for distal locking screws in intramedullary nailing. • In both cases, a tool guide attached to the robot is positioned at a planned location with a few intraoperative fluoroscopic X-ray images. • Preliminary in-vitro experiments demonstrated the feasibility of this concept.

28. MARS: A Bone-Mounted Miniature Robot [Shoham et al, 2003] • Design goals: • precise position and orientation of long, handheld surgical instruments, such as a drill or a needle, with respect to a surgical target; • small work volume enclosing a sphere whose radius is several centimeters; • rigid attachment to the bone; • lightweight and compact structure; • lockable structure at given configurations to provide rigid guidance; • capable of withstanding lateral forces resulting from instrument guidance of up to 10 N; • modular design to allow customization of the bone attachment and targeting guide for different surgical applications; • repeatedly sterilizable in its entirety or easily covered with a sterile sleeve; • quick and easy installation and removal from the bone.

29. MARS: A Bone-Mounted Miniature Robot The above is not from a MARS operation, but illustrates how a robot can perform more precisely than a human surgeon. Image from [Dario, 1996] Images from [Shoham et al, 2003]

30. Image-Guided CAS • Recall that the “robots” are one aspect of an integrated system that includes: • Pre-operative planning • Intra-operative Intervention • Post-operative assessment • In image-guided CAS: • Pre-operative planning involves processing of images such as CT- and MRI-scans. 3-D images are often computed at this stage. • The image data, including the validated pre-operative work-up are subsequently loaded on an OR workstation • During the operation, the position of the surgical instruments and implants are displayed on a computer screen in relation to the patient’s anatomy. For this purpose, position tracking and registration are required. [Schep et al, 2001]

31. Image-Guided CAS: Instrument and Position Tracking [Schep et al, 2003] • The system has been compared with a global positioning system (GPS) • car  surgical instrument • driver  surgeon • In surgical navigation, pre- or intra-operatively acquired digital radiographic images act as the roadmap. • Key element is the tracking sensor, which identifies the instruments in order to determine their position. • In a GPS, the tracking sensor is a satellite. • Surgical tracking systems use magnetic, acoustic or optical signals for locating a target within the operating room.

32. Image-Guided CAS: Instrument and Position Tracking (Cont’d) [Schep et al, 2003] • Most commonly used technique is tracking by (infrared) light emitting diodes (LEDs) or passive markers such as retro-reflective spheres or disks. • Shields with typically four or six LEDs/passive markers are attached to the instruments and the operated bone. • To allow freedom of movement during surgery, the position of the target bone is also tracked. Therefore, a frame with LEDs or passive markers is attached to the skeleton, the so-called dynamic reference frame (DRF).

33. Image-Guided CAS: Instrument and Position Tracking (Cont’d) [Schep et al, 2003] • The tracking sensor overlooking the surgical field receives the signals emitted by the LEDs/passive markers of both the DRF and the surgical instruments. • Subsequently, the position of the instruments is superimposed on the radiographic images of the operated bone.

34. Image-Guided CAS: Registration of Pre-Operatively Obtained Images [Schep et al, 2003] • Registration is required to establish a relationship between the anatomy in the operating field and the anatomy displayed in pre-operative images. • The procedure can be roughly divided in two different kinds of techniques. • External markers • Requires additional operation to implant the markers • Each marker on the patient is touched in a predefined order with a tracked instrument that registers it with a position on the pre-operative image • Anatomic landmarks • No operation needed to implant markers • Registration of the landmarks can be done a couple of ways: • Paired-point registration – a 3D localiser is used to touch well-defined anatomic landmarks on the bone surface. • Surface registration – a random cluster of points is used instead of specific landmarks. The computer uses trial and error technique to match the touched bone surface area with the corresponding 3-D image area

35. Image-Guided CAS Paired-point Registration Images from [Schep, 2003]

36. Image-Guided CAS: Registration (Cont’d) • [Schep, 2003] also mentions 2 newer types of registration which are non-invasive: • Ultrasound • Laser beams

37. the da Vinci System, picture from IntuitiveSurgical.com

38. the da Vinci System, picture from IntuitiveSurgical.com

39. Da Vinci System in Action • video-clip • Recording by students in Brown Medical School (http://biomed.brown.edu/Courses/BI108/BI108_2005_Groups/04/davinci.html)

40. Summary • Medical Robotics have a bright future. • Research and practice have shown that Robotic Surgery is safe, less invasive, and more accurate than surgery performed in the absence of robotics. • It is still in its infancy, however [Lanfranco et al, 2003] so there’s plenty of opportunity.

41. Some Current Opportunities in Medical Robotics Research • Robots with more autonomy to perform procedures • Haptics research that will provide force-feedback to the surgeon manipulating the tools in master-slave systems [Schep et al, 2003] • Though initial experiences have been promising, CAS is still complex and sensitive to failures due to pitfalls in registration, tracking and instability of software. • A more sophisticated solution is automated registration by intra-operative imaging. • Flouroscopy based CAS is evolving rapidly (i.e. navigation in 3D fluoroscopic images) • An additional inconvenience is limitation in tracking techniques. Optical tracking requires a straight line of sight between the LEDs and the camera, which could be obstructed by the surgeon. • More flexible tracking techniques with multi-angle detection of signals would allow a surgeon greater freedom of movement in OR.

42. References • Bann et al (2003) Bann et al, Robotics in Surgery • Boilot (2002) Classification of bacteria responsible for ENT and eye infections using the Cyranose system • Dario et al (1996) Robotics for Medical Applications • Davies (1999) A Review of Robotics in Surgery • Lanfranco (2004) Robotic Surgery: A Current Perspective • Marescaux et al (2002) Transcontinental Robot-Assisted Remote Telesurgery: Feasibility and Potential Applications • Methil-Sudhakaran et al (2005) Development of a Medical Telediagnostic System with Tactile Haptic Interfaces • Rovetta (2001) Biorobotics: An Instrument for an Improved Quality of Life. An Application for the Analysis of Neuromotor Diseases • Sandini (2000) A Retina-Like CMOS Sensor and Its Applications • Schep et al (2001) Computer assisted orthopaedic and trauma surgery: State of the art and future perspectives • Shoham et al (2003) Bone-Mounted Miniature Robot for Surgical Procedures: Concept and Clinical Applications • Sugano (2003) Computer-assisted orthopedic surgery • Taylor (2003) Medical Robotics in Computer-Integrated Surgery