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SøRen Toksvig Larsen. The Role Of Cas (Computer Assisted Surgery). Slide 1 39
 

SøRen Toksvig Larsen. The Role Of Cas (Computer Assisted Surgery). Slide 1 39

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    SøRen Toksvig Larsen. The Role Of Cas (Computer Assisted Surgery). Slide 1 39 SøRen Toksvig Larsen. The Role Of Cas (Computer Assisted Surgery). Slide 1 39 Presentation Transcript

    • Søren Toksvig-Larsen Dept Orthopedics Hässleholm Hospital Lund University Sweden The role of computer assisted surgery (CAS)
    • WHAT’S WRONG WITH THIS SCENARIO 2007?
      • Orthopaedic Surgeon:
      • Mallet and a Goniometer
    • WHAT’S WRONG WITH THIS SCENARIO 2007?
    • introduction The purpose of modern technique:
      • improve the duration of implants
      • reduce the human error
      • simplification of the surgical technique
    • Not necessarily make every case better
      • prevent the outliers
      • explore the possibilities of enhanced
      • ROM, stability, and alignment
        • knowing the functional Kinematics
    • My background Istituti Ortopedici Rizzoli EU projects
    • CAOS Computer Assisted Orthopaedic Surgery
    • Robot surgery ” active”
    • Formula 1 Robot surgery
    • 3-D op technique
    • Problem Too troublesome Feed back systems Safety systems
    •  
    • Why continue using modern technique??
    • Who is a non-responder My problem Non responders
    • Satisfaction - TKA
      • 18 % were dissatisfied or uncertain
          • O. Robertsson et al. 2000
    • Possible Malalignment Rotational malalignment Translational malalignment
      • Varus
      • Valgus
      • Flexion
      • Extension
      • Internal rotation
      • External rotation
      • Medial
      • Lateral
      • Proximal
      • Distal
      • Anterior
      • Posterior
      CAOS 12 º freedom for each component
    • Navigation “ passive” Surgical set up
    • Navigation gives information during surgery to position the instruments and implants according the “anatomy”
    • Knee Navigation workflow HIP center
    • Knee Navigation workflow
    •  
    • NAV as other computers ” shit in, shit out”
    • Record Alignment
    • More sophisticated instruments
    • Tibia cut
    • Gap balancing/tension ?????????????
    • Navigation
      • Positioning of TKA with and without navigation
            • Sparmann et al. JBJS-Br 2003
            • improved mechanical, frontal and sagital femoral axis and frontal tibial axis
            • 240 patients (120 CAOS, 120 conventional)
      Fewer outliers
    • Navigation
      • 60 cases TKA
      • superior results for the CAOS group compared to the conventional group
      • however
      • no statistically difference for
          • the mechanical axis
          • the tibial axis, the femural axis
          • a tendency for valgus positioning the femural component in the CAOS group
            • Miehlke et al. Z. Orthop 2001
    • TKA navigation
      • A prospective randomised study
        • 50 TKA knees, Genesis knee
        • Conclusion
        • CAOS excellent, but not better than conventional
              • J. Victor D. Hoste (Efort 2003)
    • TKA navigation
      • A prospective randomised study
        • 50 knees, Genesis knee
        • Accuracy CAOS – excellent
          • Outcome Conventional CAOS
          • Torniquet time 56 min 72 min p 0.002
          • Operative time 70 min 93 min p<0.001
          • Blood loss 3.3 g/dl 4 g/dl ns
          • Patellar alignment no tilt>5 º no tilt>5 º
          • Patellar alignment no subluxation no subluxation
          • Tibial slope 3.5 º 3 º
              • J. Victor D. Hoste (Efort 2003)
    • ???Does it matter???
      • Sample-sizes needed in prospective randomised trials
      • Detect a difference in outcome of 2.5% (i.e., 92.5 vs. 95 %) after 10 years with 80 % power at a 5 % level of significanse.
      • 2000 patients are required!!!
    • OVERALL SYSTEM ERROR  2 mm the average difference between point distance in the virtual scene and the corresponding point distance in the real world, is given by: ACQUISITION ERROR:  1 mm errors in surface position produced by the segmentation algorithm SIMPLIFICATION ERROR: 0.4 mm ACCURACY OF THE TRACKING SYSTEM:  0.5 mm REGISTRATION ERROR:  1 mm ACCURACY OF THE POSITION SENSOR: 1.0 mm defined as the standard deviation of a set of measures with respect to the “real” value, obtained by means of a calibration instrument.
    • Intraoperative cutting errors Some of my experience using navigation Pinning the cutting block can change the position of the block 1 - 2 degree The cutting process can change the surface additional 1 - 2 degree Can partly be corrected using navigation
    • Evaluation
      • Methods with a lower accuracy than the CAOS systems
    • z Alignment – outliers (2-D) Femural component too extended valgus positioning the femural component Less bloodloss Individuality Tibial rotation
    • So far NOT ACHIEVED But it will The purpose of modern technique:
      • improve the duration of implants
      • reduce the human error
      • simplification of the surgical technique
    • The CAOS technique The cost-effective problems
      • Longer operation time
      • Additional surgical intervention
      • Complications?
    • The CAOS technique The cost-effective problems
      • Big investment/costs to run the equipment
      • Troublesome technique
      saved costs for revisions
    • New technique
      • A new technique becames viable if it makes a process or service deliveries either
        • easier
        • faster
        • cheaper
        • better
        • 2 of these benefits would make a technology more popular
        • For arthroplasty all 4 are required??!!