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Overview. IntroductionChallengesComputer-integrated surgery (CIS)Telesurgical systems (e.g. da Vinci
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1. Medical Robotics:Current Research Trends
3. Introduction Potential benefits of medical robotics include:
Coupling of information to action in the OR
Increase in accuracy of task performance
Operation in tightly constrained environments
Tool support in between phases of operation
Hyperspectral sensing (X-ray, IR, magnetic, etc)
Tremor mitigation
Remote surgery (meters to 1000’s kilometers)
Navigational planning through tracking
4. Robots & Humans
5. Challenges (I) Manipulation
Safety in shared workspace with humans
Sterile environments
High dexterity in small spaces
Possible interference from outside sources (magnetic)
6. Challenges (II) Registration
Determination of geometric transformation matrices
Required high accuracy of sensed-to-model match
Nonrigid nature of deformable tissues
Implicit dependence on quality of sensing
7. Computer-Integrated Surgery (CIS)
8. CIS Information Flow Minimally invasive surgery (MIS) serves as model
9. Frame Transformations
10. Telesurgical Systems (I) Da Vinci ® (Intuitive Surgical, Inc.)
11. Telesurgical Systems (II) System components such intent recognition and virtual fixtures for enhanced surgical assistance are currently in the research phase
12. Hidden Markov Model Intent Recognition Key component is the representation and learning of the sequential and temporal characteristics in activity sequences
There is also an inherent hierarchical organization of activities and their typical duration
13. Precision Path Systems (I) Early systems such as CyberKnife (Accuray Incorporated) for stereotactic radiosurgery were used to stabilize the patient with respect to an instrument
Closed loop control of the instrument was based on tracking of patient movement
14. Precision Path Systems (II) Path planning can be used for optimal insertion point and sequence of forces and torques (or velocities) to guide needle to target with minimal damage to surrounding tissue
Real time image based control used for motion planning
15. Precision Positioning Systems (I) 6 Degree-of-Freedom (DoF) robot for needle placement while under guidance using CT or fluoroscopy
Decoupled translational, orientational, and insertion movements
Guided using joystick or touch screen
16. Precision Positioning Systems (II) Fiducial registration systems used for precision needle placement
17. Imaging, Modeling, & Analysis
18. Computer Vision Assisted Surgery (I) Method mitigates need for external tracking system
Accuracy is well suited for tightly constrained environments such as transnasal zones
Directly matches endoscopic video to 3D structure
Mean closest distance error of 0.227mm
Currently limited to offline processing
19. Computer Vision Assisted Surgery (II) Accurate matching to preoperative volumetric imagery hampered by need to extract motion of endoscopic camera from image derived feature points and rejection of outlier matched points (potentially up to 50%)
ASKC (Adaptive Scale Kernel Consensus) estimator simultaneously estimates model parameters & scale of inliers
Camera motion parameters estimated between video images using SIFT (Scale Invariant Feature Transform) feature point extraction coupled with SVD (Singular Value Decomposition) matching
Model parameter estimate using a variable bandwidth
kernel density estimate with residuals r is:
20. Modeling for Surgical Training Mockups used for training fixture
Tracking of instruments same as that used in OR
Graphical User Interface (GUI) gives feedback during mock operaion
21. Modeling for Planning & Results Analysis Previously used extensively in facial reconstructive surgery combining CT imagery and finite elements computer graphics
Metrics have been defined for matching of results to plan for hard surfaces such as bone
Differencing software for pre- and post-operative tumor removal procedures based on transformations of non-rigid structures is in common use
22. Interface Technologies
23. Haptic Feedback Systems Robotic telesurgery suffers from loss of sense of touch
Two types are force and tactile
Suturing task requires dexterity as well as tactile feedback
Force feedback alone can’t be used to replicate accuracy of hand ties
Still an open research area
24. Tremor Cancellation (I) Physiological tremor, drift, and nontremulous motion (e.g. myoclonic jerk) are three major components of inaccuracy in manipulation
Telerobotic, “steady-hand” and handheld micromanipulator with active tremor cancellation are among methods to improve accuracy
88 neurosurgeons with varying experience participated in study to determine magnitude of tremor and drift related inaccuracies
25. Tremor Cancellation (II) Lower frequency components are order of magnitude larger than 10 Hz peak
Handheld micromanipulator “Micron” with active tremor cancellation decreased power spectrum density by close to two orders of magnitude in 8-12 Hz range
Surgeon must still support instrument during the operation
26. Augmented Reality Overlays Registration of model to live sensor feed is main constraint
Overlay or laser guidance without obscuration of surgeon’s view is another constraint
27. Summary Sensor-based methods from ground and space robotics are useful in the medical robotics application areas
Constraints on accuracy, speed, and size are driving factors that differentiate medical from industrial robotics
Certification processes are in place but will need to evolve with increases in autonomy
Operation such as that seen yesterday is beyond the capabilities of the current robotic systems
28. Backup Slides