Biomechanics Biorobotics in Minimally Invasive Surgery

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					Minimally Invasive Surgery Task Decomposition -

Etymology of Endoscopic Suturing




                            Jacob Rosen* Ph.D.,
             Lily Chang** MD, Jeff Brown ***, Andy Isch** MD
   Blake Hannaford* Ph.D., Mika Sinanan** MD Ph.D., Richard Satava** MD

                  * Department of Electrical Engineering
                          ** Department of Surgery
                     *** Department of Bioengineering
                          University of Washington
                             Seattle, Washington
 Surgery - The Big Picture
   Human - Machine Interface
                                              Reality


                                       Tool               Tissue




Surgeon                Robot
                      (master-slave)




                                              Virtual Reality

                     Haptic
                                       Tool               Tissue
                     Device
Evaluation of Surgical Skill
 Surgery - The Hidden Language Metaphor


Operator                               Surgeon

             Resident



            Language
HMI                                    Language

Tool                    Robot / Tool



Target                    Patient
Surgery - The Hidden Language Elements
Research Aim


    Create new quantitative knowledge of the forces
     and torques (F/T) applied by surgeons to their
     instruments and the positions and orientations
     (P/O) of the endoscopic tools during minimally
     invasive surgery

    Develop and evaluate an objective surgical skill
     scale based multi finite state models (Markov
     Model) incorporating information regarding the
     kinematics and the dynamics of the endoscopic
     tools
Instrumented Endoscopic Grasper
Blue DRAGON
Blue DRAGON
Blue DRAGON - Graphical User Interface
Experimental System


                                                        VCR
                           Mixer                     (PIP Mode)




            PC (A/D) GUI

     Data                                    Video

   Blue DRAGON    Blue DRAGON
                                       Endoscope
        Left          Right



                           13 (Channels) * 2 (Dragons) = 26 Channels
Experimental Protocol

   Surgical Tasks:

   Task 1: Running the bowel, 10x3” (right to left)
   Task 2: Running the bowel, 10x3” (left to right)
   Task 3: Dissecting Mesenteric Vessels, 4x
   Task 4: Passing a Suture, 5x
   Task 5: Tying a Knot, 4x
   Task 6: Suturing the Bowel and Tying a Knot
   Task 7: Passing Stomach Fundus behind the Esophagus, 1x


   Subjects: 5x (R1, R2, R3, R4, R5, E) - 30 Subjects
Normalized Completion Time
Learning Curve of Surgical Residents
Position (Path) - Raw Data


                             Novice




                             Expert
Normalized Trajectory Length
Learning Curve of Surgical Residents
Forces - Raw Data


                    Novice




                    Expert
Torques - Raw Data


                     Novice




                     Expert
Tool/Tissue-Object Interactions - Taxonomy
F/T Clusters (GR-PS-SW)
Generalized Markov Model of MIS Surgery -
One Tool
Generalized Markov Model of MIS Surgery -
Two Tools
 Left Tool                             Right Tool
Laparoscopic Cholecystectomy
Exposure of Cystic Duct




                               Surgeon
                               Non - Surgeon
Learning Curve - Markov Model Statistical Distance


         R1                    R2




                                    R3
                     E
                R5



                          R4
Normalized Statistical Distance
Learning Curve of Surgical Residents
Subjective Score (Video Analysis) - Criteria
Suturing the Bowel and Tying a Knot


   Overall performance [1-5]
   Economy of movement [1-5]
   Tissue handling [1-5]
   Numbers of errors [No.]
     – Drop needle
     – Drop suture
     – Lose suture loop
     – Break suture
     – Needle injury to adjacent tissue
     – Inability to puncture bowel with needle
Normalized Subjective Score (Video Analysis)
Learning Curve of Surgical Residents
Correlation Between Subjective and Objective
Assessment of Surgical Skill
Conclusions / Application
   Analyzing Minimally Invasive Surgery requires a synthesis between visual and
    haptic information.

   Differences between expert and novice surgeons can be defined in terms of:
     – Force / Torque / Velocity signatures
     – State transitions / combinations
     – Time spent in each state
     – Trajectory (tool tip) length


   Good correlation (R2=0.86) between objective (Markov Model) and subjective
    (video analysis scoring) assessment of surgical skill

   The objective methodology for surgical skill evaluation is a modality
    independent. It can be applied to:
      – In-vivo surgical conditions
      – Telerobotic systems
     –   VR haptics simulators
10Q

				
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posted:6/17/2011
language:English
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