Universita di Roma “La Sapienza”
Medical Robotics
Classification of surgical systems
Marilena Vendittelli
• potential benefits
– coupling (real-time/on-line) information to action
– accuracy
– access to hostile (e.g., X-rays) or space-constrained areas (inside of a patient orimaging system)
– smaller targets
– not replacement but extension/augmentation of the medical staff capabilities
⇒ human-robot cooperation is one of the the central topics in medical robotics
• w.r.t. industrial robots, medical robots require specific safety measures, kinematics,hardware and software since they have to
– cooperate with the medical staff and accomplish tasks in contact with the patient
– posses application-specific functionalities
– be easily movable, not bulky, manually controllable
– accomplish non-repetitive tasks in unstructured environments
– be sterilizable and compatible with imagine systems
⇒ technological challenges in sensing, actuation, interfaces, system design
• technical paradigms
– different by degree of autonomy, type of provided support, type of access
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 2
Classification 1(J. Troccaz, 2001)
• passive systems
provide information to the surgeon
• active systems: perform the procedure under human supervision
• interactive systems: mechanical guides
semi-active devices
synergistic devices
• teleoperated systems
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 3
passive system example
Viewing Wand(ISG Technologies)
• articulated arm with manually guidedprobe
• the probe position w.r.t. to the skull isused for– registration
– navigation
characteristics
• “tracking” of the object of interest
• stability of positioning if the arm is equipped with brakes
drawbacks
• tracking of only one object• cumbersome• constraints the surgeon motion• limited to navigation
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 4
active systems
• tasks with a complex geometry
– ROBODOC, CASPAR
• carry/hold heavy tools
– Cyberknife
• force controlled actions
– Hippocrate, SCALPP
• intra-body tasks
– EMIL
• moving targets
– Cyberknife + real-time patient tracking
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 5
ROBODOC
• SCARA maniplator with a 2dof wrist• 6D force/torque sensor• Orthodoc: planning system
example: hip surgery
1. planning with Orthodoc
2. pre-op to intra-op registration using implanted titanium pins
3. intra-operative bone milling procedure using ROBODOC
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 6
radiosurgery
traditional linear accelerator set-up
• complex trajectories for improved tumor destruction
• 6 dof required
• very heavy tools
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 7
Cyberknife
• 6MeV accelerator (1 eV= amount of kinetic energy gained by a single unbound electron when itaccelerates through an electrostatic potential difference of one volt)
• frameless neurosurgery
• small patient motion compensation
• large workspace
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 8
interactive systems
• principle: the robot constrains the surgeon’s action
• possible approaches
– semi-active: a mechanical constraint
– synergistic: a programmable mechanical constraint
• advantages
– man/machine cooperation (safety, psychological acceptance)
– rather direct interpretation of haptic data
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 9
semi-active systems
NeuroMate
• pre-positioning: robot
• surgical action: surgeon
• simple tasks– linear motions (e.g., needle insertion)
– planar motions (e.g., osteotomy)
– conical motions (e.g., laparoscopy)
• specific architecture
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 10
synergistic systems
• generalization of semi-active systems
• programmable mechanical guides
• different technologies
– programmable brakes (Taylor, P-TER, IMCAS)
– “nonholonomic coupling” of dofs (Cobot)
– windows of admissible velocities (PADyC)
– active Constraint ROBOT (Acrobot)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 11
PADyC (Passive Arm with Dynamic Constraints)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 12
freewheels
• one joint: two freewheels mounted in the opposite direction and actuated by twoindependent motors
F1: ω−i = 0 ∧ ω+i 6= 0 only ω+
user
F2: ω−i 6= 0 ∧ ω+i = 0 only ω−user
F3: ω−i 6= 0 ∧ ω+i 6= 0 both directions
F4: ω−i = 0 ∧ ω+i = 0 none
• ω−i and ω+i controlled by the computer, ωuser controlled by the user
• motion authorized for ω−i ≤ ωi ≤ ω+i
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 13
task constraints
• free mode: no constraint, the system computes and memorizes the position of thesurgical tool
• position mode: PADyC helps the user to move the tool towards a predefined positionand orientation (e.g., bone fragment or a prosthesis component)
• region mode: the tool is free to move in a given region of space, but cannot escapefrom that region (e.g., tumor resection or cavity preparation for prosthesis placement,avoidance of critical areas)
– keep inside
– keep outside
• trajectory mode: constrains the motion to follow a predefined trajectory with a givenaccuracy (e.g., biopsy trajectory)
• specialized modes
– linear motions
– planar motions
– conical motions
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 14
window of admissible configurations
regione
autorizzata
WAC(t)
Q(t)
q1(t)
q2(t)
q1(t)+!1+"t q1(t)-!1
-"t
q2(t)-!2-"t
q2(t)+!2+"t
example: 2R manipulator, region mode
given the robot configuration Q(t), the velocity constraints must be such that the configu-ration Q(t + ∆t) is contained in the admissible region
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 15
problem: mapping the task constraints to configuration constraints in real time
⇒ computation of WACj(t) for k control points on the surgical tool
WAC(t) = ∩kj=1WACj(t)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 16
teleoperated systems
• daVinci
• Zeus
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 17
Classification vs function
domain of use
function
control modality
(strictly related to the degree of autonomy)
kinematicarchitecture
sensors and actuators
orthopedicsmachining
of rigid surface
cooperative or “hands-on”
MISconstrainedmanipulation
neurosurgery, intervantional radiology,
radiotherapy
constrainedtargeting
microsurgery micromanipulationshared/cooperative
control
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 18
Classification 2(Russel H. Taylor, 2003)
Computer Integrated Surgery (CIS)
surgical robotic systems are first part of CIS and then medical robots ⇒ they can beclassified according to their role in CIS systems
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 19
- patient modeling- planning- registration- execution- follow-up
advantages
- optimal planning- consistent and accurate execution- safety- validation- information management
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 20
examples
• robot assisted execution
– orthopedic prosthesis implant (ROBODOC)
– percutaneous therapy (NeuroMate)
• execution assisted by navigation systems
– therapy delivery with the aid of multi-modal images (Cyberknife)
– augmented reality (images overlay)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 21
surgical extenders
– improve or extend surgeon’s abilities in manipulating surgical tools (e.g., tremorcancellation)
auxiliary surgical supports
– work side-by-side with the surgeon (e.g., endoscope holding or retraction)
advantages
- perform otherwise not possible procedures (e.g., beating heart surgery)- mortality and errors reduction- reduction of operating time- increased efficiency
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 22
examples
surgical extenders
– teleoperated systems (Zeus, daVinci)
– microsurgical systems (teleoperated or not, possibly without “manipulators”)
– cooperative systems
auxiliary surgical supports
– endoscopes, ecographic probes, . . ., controlled by the surgeon through variousinterfaces (AESOP)
– systems for intraluminal appilcations (active catheters, capsules)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 23
Classification 3(L. Joskowicz, 2005)
computer assisted surgery support systems
• passive mechanisms
– adjustable frame/arm/support
– individual templates
• intraoperative imaging
• navigation
• robotics
– floor/bed mounted
– patient mounted
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 24
floor or bed-mounted
advantages
– integrated planning/execution
– intraoperative modifications
– rigid and accurate
drawbacks
– immobilization or tracking
– bulk, cost (EU 30 –500K)
– safety risk due to the large workspace and inertia
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 25
patient-mounted robot
advantages
– small size/footprint —minimal obstruction
– close proximity to surgical site
– no patient/anatomy immobilization, no tracking/real-time repositioning
– small workspace –fine positioning device
– potentially higher accuracy
– intrinsic safety due to small size/low power
drawbacks
– patient mount
– require manual coarse positioning
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 26
examples
spine surgery: pedicle screw insertion
recommended use
vertebra fracture
degenerative diseas
spine tumor
scoliosis
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 27
• individual template
advantages∗ inexpensive∗ rigid mechanical support∗ customized
drawbacks∗ requires manufacturing∗ no intraoperative changes∗ limited use: anatomy-dependent
• patient-mounted robots
MARS –Mazor Surgical Technologies, Israel
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 28
Classification 4(P. Dario, 2004)
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification 29
Bibliography
O. Snider, J. Troccaz, “A six-degree-of-freedom Passive Arm with Dynamic Constraints(PADyC) for cardiac surgery application: Preliminary experiments,” Computer AidedSurgery, vol. 6, pp. 340–351, 2001.
P. Kazanzides, G. Fichtinger, G.D. Hager, A.M. Okamura, L.L. Whitcomb, R.H. Taylor,“Surgical and Interventional Robotics - Core Concepts, Technology, and Design,” IEEERobotics & Automation Magazine, vol. 15, no. 2, pp. 122–130, 2008.
R.H.Taylor, D. Stoianovici, “Medical robotics in computer-integrated surgery,” IEEETransactions on Robotics and Automation, vol. 19, no. 5, pp. 122–130, 2003.
M. Shoham, M. Burman, E. Zehavi, L. Joskowicz, E. Batkilin, Y. Kunicher “Bone-Mounted Miniature Robot for Surgical Procedures: Concept and Clinical Application-sy,” IEEE Transactions on Robotics and Automation, vol. 19, no. 5, pp. 893–901,2003.
M. Vendittelli Medical Robotics (Universita di Roma “La Sapienza”) – Classification: Bibliography 30