Test-setup to quantify haptic interaction in CTO interventions to identify potentials for medical training
Dr.-Ing. Christian Hatzfeld Nataliya Stefanova Dr.-Ing. Thomas Opitz Jochen Genzel Prof. Dr.-Ing. Roland Werthschützky Prof. Dr. mont. Mario Kupnik Prof. Dr. med. Wolfram Voelker
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 1
Motivation Chronic Total Occlusions (CTO) Long-time closure of coronary arteries Strong and stiff deposits of various materials
Challenging Procedure Risk of puncture due to stiff guide wires Antrograde and retrograde re-channeling techniques
Goal: Training system for CTO-interventions
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 2
Agenda
CTO intervention
• Procedure • What to train?
System Overview
• • • • •
Force sensing guide wire Guide wire position Interaction force measurement Occlusion model X-Ray simulation
CTO Training System
• Experimental Design • Conclusion
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 3
CTO Procedure 1. Placement of „thick“ guide wire at the coronary vessels 2. Placement of guide catheter over first guide wire 3. Removal of first guide wire, insertion of thin guide wire in guide catheter Standard diameter 0.014“ (360 µm) Different tip loads (0.5 … 20 grams)
4. Penetrating and rechanneling of deposit with thin guide wire 5. Eventually using different guide wires with increasing tip load 6. Widening of the vessel with balloon catheter and stent [SA Budelmann]
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 4
What to train? State of the Art Longest time is used to penetrate and re-channel the deposit with thin guide wire Tip movement of guide wire corresponds with expert-assessed skill
Risk Assessment Wires with high tip load can puncture vessel Exposure to X-ray (cardiologist) and contrast agent (patient)
Placement and penetration phase Focus on mechanical interaction Tip force and movement of guide wire Commanding forces
Comparison of experts and novices Find trainable skills of experts Hypothesis: Less tip forces on adjacent structures, less re-positioning Smoother movement
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 5
Guide Wire Tip Force Measurement
force tungsten sensor spring packaging R1
stainless steel core
wires
hydrophilic coating
R4
R3
Force (N)
R2
contact pad 200 µm µm
Displacement (mm)
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 6
connector
Guide Wire Movement Measurement
Optical Encoders Translational measurement with a pulley system fixed at the port polyurethane coating (Shore A80) maximum force ± 1N resolution 78,24 µm uncertainty 2,3 % Rotatory measurement combined with electrical contacts for tip force sensor Linear bearing with 20 cm movement range 31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 7
Interaction Force Measurement
Torquer Force Sensor
Unidirectional force sensing Resistive full-bridge circuit Nominal force 10N Combined uncertainty 3,9% Bandwidth DC … 160 Hz (0.5dB)
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 8
Occlusion model (I)
Viscoelastic, multi-component model Only little data about mechanical behaviour of deposits available Wacker Silgel 612 for simulation of varying hardness (penetration forces of 20 to 60 mN) Polymer foils to simulate fibrous caps (penetration forces of about 200 mN) Integration in a standard silicone heart model 31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 9
Occlusion model (II) (BBraun Navitas (9 gr tip load) with inspekt table5) Force displacement curve depending on silicone mixture (A:B, 15 samples)
Penetration force of polymer foils (3 samples) 0,3
0,12
12 : 10
0,25
Axial Force (N)
0,1
Axial Force ( N)
0,08
0,06
11 : 10
0,04
0,02
0,2
0,15
0,1
0,05
10 : 10
0
0
0
2
4
6
Position (mm)
8
10
0
5
Wire travel (mm)
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 10
10
X-Ray simulation
Simulation of a C-arc X-ray Two full-HD cameras on goosenecks Manual repositioning Backlit vessel model with occlusion component Video processing by NI LabVIEW Recording and contrast agent simulation by foot pedal 31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 11
Next steps: Experimental design
Experimental Design Comparison of CTO interventions conducted by experts and novices Measurement of guide wire tip force and movement, interaction forces, contrast agent usage and x-Ray dose for different occlusion models Determination of differences between experts and novices Identification of potential training scenarios
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 12
Conclusion Development of a measurement setup to quantify haptic interaction in CTO interventions System will be used to assess cardiologist skills and identify training potential Development of training instructions and scenarios Similar approach can be used for other interventions Catheter usage in neurosurgery Cochlea implantation Pericadium puncture
31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 13
Thank you for your attention!
Special thanks to Marco Degünther for preparing the occlusion model in his bachelor thesis!
Dr.-Ing Christian Hatzfeld
[email protected] www.institut-emk.de 31. Oktober 2016 | Institut EMK | Fachgebiet Mess- und Sensortechnik | Dr.-Ing. Christian Hatzfeld | 14
