More Related Content
Viewers also liked (13)
Similar to End of Term Presentation_EDITED (20)
End of Term Presentation_EDITED
- 1. CUSA P-Series September 2015 - May 2016 Findings Team BarraCUSA Benjamin Yorkey Keegan Manion Faye Titchenal Scott Schloss Zack Jones Paul Silva
- 2. Overview Background Objective/Criteria Design Progression Final Design Testing Results Recommendations
- 3. Background Cavitational Ultrasonic Surgical Aspirator (CUSA) market debut 1977 o Tissue breakdown and aspiration o Tissue Selectivity Device effective for surgeries involving delicate tissue and need for tissue selectivity Limited in practical applications due to cost, cutting speed and operation time
- 4. Our Objective Explore feasibility of Sonicision transducer integration with CUSA technology o Proven by fulfilling design criteria Successful incorporation can yield: o Cost reduction o Increased handpiece efficiency o No need for internal cooling water/cooling water pump
- 5. Design Criteria Criteria for gauging system efficacy: o 55.5 kHz Resonant Frequency o Minimal Electro-Mechanical Impedance o Peak Tip Velocity ~20 m/s (~787 in/s) o Minimal Power Consumption o Stresses below 37.5 ksi (Factor of Safety ~ 2)
- 6. Design Progression November 2015 December 2015 April 2016 October 2015
- 7. CUSA P-Series Features o Aspirated slurry evacuated through waveguide and nipple in intermediate extender component o Utilizes classic CUSA components Silicone Flue and Nose Cone Functional Assembly o Sonicision Transducer o Titanium Extender and Waveguide o 3D Printed Case o CUSA Flue/Nose Cone o Power Supply/Tubing/Pumps
- 9. Transducer Sonicision Transducer: o Lead Zirconate Titanate (PZT) for piezoelectric actuation o Resonant frequency of 55.5 kHz Reasons for Use: o Existing transducer and experimental generator use o Piezoelectric transduction more efficient than magnetostrictive transduction o Lower manufacturing cost than original CUSA transducer
- 10. Extender Purpose: connects waveguide to transducer in a way that facilitates aspiration exit o Enables use of original CUSA nose cone o Allows waveguide nipple to sit closer to a node Minimizes impedance from tubing Anti-Node to Node: 他 了 long
- 11. Waveguide Propagates mechanical wave in uniaxial direction o Minimizes energy loss Makes contact with and effectively breaks down tissue Pertinent Features o Gaussian Profile o Pre-Aspiration Holes o Nipple Node to Anti-Node: 他 了 long Nipple
- 12. Case Objectives: o Minimize Impedance Single connection at transducer flange o Attain adequate ergonomics o Mate with Nose Cone
- 13. Flue & Nose Cone Flue: o Consolidates saline fluid and directs flow towards tip of waveguide and pre-aspiration holes o Protective barrier for surrounding tissue Nose Cone: o Prevents saline leakage o Uses existing aspiration tubing Create a proper mate to the waveguide nipple
- 14. Test Plan 1. Resonance and Impedance o Using impedance analyzer - important for proper wave propagation 2. Tip Velocity o Using doppler laser vibrometer - important for tissue selectivity 3. Power Consumption o Using generator sensors and Mongoose display - important for understanding heat generation & efficiency of system 4. Tissue Testing o Prove that device is capable of cutting tissue effectively
- 15. Impedance & Resonant Frequency Results:
- 17. Results: Generator Non-Calibrated Generator Calibrated Generator Peak Tip Velocity (High amplitude) 14.1 m/s (~555 in/s) 19.9 m/s (~783 in/s) Power Consumption (High amplitude) ~10 W standalone ~10-20 W during operation ~17 W standalone ~17-27 W during operation Tissue Testing Device cut slowly and errored out when attempting to cut deep Device cut much faster/deeper and no erroring out
- 19. Recommendations Should Medtronic choose to move forward with the CUSA P-Series, we recommend pursuing the following: o Find Source of Wobble in device o Higher Voltage & Tissue Selective Generator o Cord/Tube Consolidation o New Transducer Design Avoid need for extender Reduce case size o Multifunctionality Add Grasping, Vessel Sealing, etc.
- 20. Thank You We would like to thank the following people/parties for being an integral part of the project: Tony Ross, Ken Taylor, Bob Stoddard, Dave Van Toll, Dan Friedrichs, Daria Kotys-Schwartz, Medtronic Staff, Jim Evens, Design Center CU Staff, University of Colorado Boulder
Editor's Notes
- #2: Ben Introduce each member and state each team member's project role
- #3: Ben Make look better
- #4: Ben Debut by valleylab Oscillates back and forth and the mechanical contact breaks the tissue apart Tissue Selectivity based on amplitude, irrigation, aspiration rates Delicate tissue extraction (brain, prostate, liver) Mention downfalls of CUSA(Magnetorestrictive transducer inefficiency, cooling water necessity, power/water cord size)
- #5: Ben Cost Reduction (Manufacturing Costs, All available manufacturing processes available with Medtronic, No specialized engineers necessary to construct transducer)
- #6: Scott Goals that we were shooting for Tip Velocity: Proven number for effective tissue selectivity Power Consumption: Not heating up too much
- #7: Scott KISS: Keep It Short & Simple October: Pretotype, Concept understanding of the components November: Casing designed around Sonicision spinner, NUSA waveguide , too bulky December: Added existing CUSA nosecone and flue, used new waveguide,
- #8: Scott Aspirated slurry evacuates through waveguide and exits through an intermediate extender at a 45 degree angle Tubes: Saline irrigation and aspirated slurry
- #9: Keegan Highlight Important Features: Expand when you explain specific parts
- #10: Keegan Horn: Maximal mechanical gain with minimum stress concentration Mention no cooling water necessity
- #11: Keegan
- #12: Keegan - 他 wavelength long from flange to tip (does not include hex and thread profile) Pre aspiration holes: 90-95% of irrigation (maybe dont say evacuate saline into waveguide, but some word similar to inlet)
- #13: Paul Ergonomics( Channels, functional representation of pencil grip to ease of use)
- #14: Paul Flue brings saline to the tip of the device to aid in wetting the tissue for slurry evacuation, Protective against waveguide touching delicate tissue and damaging the tissue
- #15: Faye
- #16: Faye
- #17: Faye
- #18: Zack So then, once we knew the device was operating at an acceptable resonance frequency with reasonably low resistance, we began testing our device at its operating capacity. At first, we were using a generator calibrated to handle the needs of the sonicision, achieving a 14.1 m/s tip velocity and consuming between 10-20 W of energy which began slightly heating up the waveguide. With the knowledge that this tip velocity was a bit low to cut tissue, we thought we would give it a shot, and found that though the device was able to cut tissue, it was slow and could not go much deeper than the surface of the tissue without erroring out. We then talked about reasons for this shortcoming, and found that we had a very high mechanical, and needed a higher electrical gain (biking uphill in high gear). To mitigate the issue of not operating at the necessary voltage to achieve our max calculated displacement, we were supplied a generator calibrated and given a bigger power source, and with the increased power we achieved our necessary tip velocity of 20m/s. The power consumption naturally increased as well, but was maintained within a manageable range. During tissue testing this time around, we found that the device cut much faster/deeper and did not error out.
- #19: Zack Here is a video of our successful tissue testing session running with the calibrated generator with the partial assembly
- #20: Zack As we finish up our part of this design, we hope to see the project move forward with these recommendations in mind. First, we did a paper clip test where we placed a paper clip onto the waveguide to find the node locations, but we were unable to assess them due to wobble in the waveguide. We believe center of mass inconsistencies near the aspiration channel may be to blame, but would need to be investigated further. Secondly, Design a higher voltage & tissue selective generator. To do this, a larger power source must be built into the generator, and it must also have the capacity to have an adjustable duty cycle to achieve the tissue selectivity. Third, create effective cord consolidation at the back of the handpiece to ensure more ease of use for the surgeon. Fourth, design a new transducer that is slimmer for the purpose of ergonomics of the grip, as well as design to eliminate the need for an extender by having the transducer end at a node for the aspiration exit. Avoiding the need for an extender will reduce setup errors before surgeries. Finally, redesign to incorporate multifunctionality of the instrument, such as grasping, vessel sealing, etc.
- #21: Zack Tony Ross- our client for this project Ken Taylor - our senior design director Bob Stoddard and Dave Van Toll for helping us with the design and testing of our device Dan Friedrichs Jim Evans Daria Kotys-Schwartz- senior design professor Medtronic Staff Design Center CU Staff University of Colorado Boulder Thank you all for coming, and taking time out of your busy days to come to this presentation We would like to open up the floor to any further questions