Computer Assisted Surgical Intervention

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A presentation on computer-assisted surgical intervention. Includes a case study on needle insertion.

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Computer Assisted Surgical Intervention

  1. 1. Shah Hrishi Shivaswamy Anirudh
  2. 2. Introduction <ul><li>“Computer-assisted intervention” is defined as the use of automated systems in surgery </li></ul><ul><li>Two different approaches : </li></ul><ul><ul><li>As a tool (assisting the surgeon) </li></ul></ul><ul><ul><li>An autonomous system (replacing the surgeon) </li></ul></ul><ul><li>Several assistive systems are available, but the autonomous systems are still in the development stages </li></ul>
  3. 3. History <ul><li>First robot-assisted surgery performed in 1985, for treating brain lesions </li></ul><ul><li>First robot-assisted orthopedic surgery was performed in 1991 </li></ul><ul><li>In 1991, the first patient was treated with Probot, for prostate cancer. </li></ul>Newer version of Probot 
  4. 4. Classification of surgical systems <ul><li>Surgical Robots </li></ul><ul><li>Service Robots </li></ul><ul><li>Prostheses </li></ul><ul><li>Simulators </li></ul><ul><li>Robots for diagnosis </li></ul><ul><li>Passive manipulators </li></ul><ul><li>Assistive Robots </li></ul>
  5. 5. Surgical Robots <ul><li>Surgical robots can be tele-manipulators or preprogrammed robots </li></ul><ul><li>Tele-manipulators are handled by the surgeon during surgery (intraoperative images used) </li></ul><ul><li>Preprogrammed robots are guided by a fixed plan (preoperative images used) </li></ul>
  6. 6. Workflow of tele-manipulators
  7. 7. Typical Workflow of surgical robots
  8. 8. Service Robots. <ul><li>These are used for rehabilitation </li></ul><ul><li>They have some pre-programmed movements which help the patient regain lost functionality </li></ul><ul><li>A vision system may be present to support interaction </li></ul>
  9. 9. Simulators <ul><li>Simulators help in training/ assessment of surgeons </li></ul><ul><li>Able to simulate a wide variety of situations </li></ul><ul><li>Not subject to the constraints of practicing on humans/animals </li></ul>Simulator for Orthopaedic operation 
  10. 10. Applications <ul><li>Orthopaedics </li></ul><ul><li>Urology </li></ul><ul><li>Radiosurgery </li></ul><ul><li>Biopsies / interventional radiotherapy </li></ul><ul><li>Endoscopy/Colonoscopy/Endoscopy </li></ul><ul><li>Cardiac Surgery </li></ul><ul><li>Neurosurgery </li></ul><ul><li>ENT Surgery </li></ul><ul><li>Oral/Cranio-maxillofacial surgery </li></ul>
  11. 11. Orthopaedics. <ul><li>The operation procedure consists of four main steps: </li></ul><ul><ul><li>Image acquisition </li></ul></ul><ul><ul><li>Planning with Orthodoc </li></ul></ul><ul><ul><li>Registration in the operating theatre </li></ul></ul><ul><ul><li>Milling the cavity by the robot </li></ul></ul><ul><li>Examples are RoboDoc, Acrobot, CRIGOS </li></ul>Parallel Link Robot CRIGOS 
  12. 12. Urology. <ul><li>Probot used for transurethral resection of the prostate </li></ul><ul><li>Both imaging and cutting done in the operating theatre - no pre-operative planning required </li></ul><ul><li>Main steps: </li></ul><ul><ul><li>Measuring gland size with ultrasound </li></ul></ul><ul><ul><li>Imaging and cavity design </li></ul></ul><ul><ul><li>Cutting </li></ul></ul>
  13. 13. Radiosurgery. <ul><li>Main steps: </li></ul><ul><ul><li>Image acquisition of CT/MR scans </li></ul></ul><ul><ul><li>Segmentation and modeling of tumor </li></ul></ul><ul><ul><li>Planning of radiation procedure </li></ul></ul><ul><ul><li>Execution of intervention </li></ul></ul><ul><li>Dose distribution and various directions of dose delivery help to protect vital organs from radiation. </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Accuray Cyberknife </li></ul></ul><ul><ul><li>Hitesys NOVAC7 </li></ul></ul>Accuray Cyberknife 
  14. 14. Endoscopy/Colonoscopy/Laparoscopy <ul><li>Surgeon can’t handle instruments and camera at the same time </li></ul><ul><li>Other manual control leads to errors so robot control is preferred </li></ul><ul><li>Robot may be controlled by surgeon’s head movement. </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Endoassist </li></ul></ul><ul><ul><li>Aesop </li></ul></ul>Endoassist in operation 
  15. 15. Cardiac Surgery. <ul><li>Generally system consists of a master console and a slave manipulator that executes the commands in the thorax. </li></ul><ul><li>Instruments and endoscope inserted through small incisions. </li></ul><ul><li>Examples: Zeus, DaVinci. </li></ul>DaVinci robot in operation 
  16. 16. Case study – Needle Insertion… Introduction <ul><li>Main aim is to avoid obstacles and reach target with minimum invasion </li></ul><ul><li>Flexible needle modeled as beam with virtual springs and approximated as a 7 degree polynomial </li></ul><ul><li>Initial path planning done </li></ul><ul><li>Real time correction </li></ul><ul><li>Experimental verification </li></ul>Overall setup of system 
  17. 17. Case study – Needle Insertion… Virtual Spring Model <ul><li>Tissue forces are non-linear with strain – so modeled as combination of tangential friction force and lateral springs. </li></ul><ul><li>Needle broken up into a number of segments at the spring attachment points </li></ul>Tissue interaction modeled as springs Linear system model
  18. 18. Case study – Needle Insertion… Forward / Inverse Kinematics <ul><li>Generally, forward kinematics required to ascertain position of needle end-point from known needle base parameters. </li></ul><ul><li>In this scenario, inverse kinematics is done for each point on the planned path to ascertain needle base parameters for this position. </li></ul>
  19. 19. Case study – Needle Insertion… Path Planning / Optimization <ul><li>Relates to finding a path that connects the target to the needle insertion point while maintaining minimum needle curvature. </li></ul><ul><li>Orientation of needle tip unimportant- infinite paths possible. </li></ul><ul><li>Minimize sum of squares of virtual spring displacements and slopes. </li></ul>Multiple solutions for path with same endpoint 
  20. 20. Case study – Needle Insertion… Control Loop. <ul><li>Input is desired needle target excluding its orientation (optimized by controller). </li></ul><ul><li>Controller does inverse kinematics and optimization to minimize needle deflections. </li></ul>Control Loop Diagram
  21. 21. Case study – Needle Insertion Needle Detection. <ul><li>Needle end-point detected by comparison with reference image and rest of needle tracked using low-gradient area. </li></ul><ul><li>Full image comparison done only once </li></ul><ul><li>Needle length also checked </li></ul><ul><li>Needle fitted using 7 degree polynomial </li></ul>Actual Needle profile from Fluoroscopy Interpolated needle profile
  22. 22. Current Trends… <ul><li>MRI-compatible materials / mechatronics / actuators </li></ul><ul><li>Safety studies </li></ul><ul><li>Incorporating haptic feedback into surgical systems </li></ul>
  23. 23. Challenges/Future Scope <ul><li>Robotic systems are not usable for routine treatment </li></ul><ul><li>Unlike industrial robots, medical robots need to operate in conjunction with the operator </li></ul><ul><li>Ease of training and assessment </li></ul><ul><li>Minimally invasive surgery </li></ul>
  24. 24. References <ul><li>Various product websites ( Prosurgic, Intuitive etc.) </li></ul><ul><li>“ Robots in the operating theatre—chances and challenges” - Korb, Marmulla et. al. , Int. J. Oral Maxillofac. Surg. 2004(33) </li></ul><ul><li>“ Image-Guided Robotic Flexible Needle Steering” – Shoham, Glozman, IEEE Trans. Robotics Vol.23 No.3 </li></ul><ul><li>Encyclopedia Britannica </li></ul>

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