ADAPTABLE RETRACTOR FOR TOTAL HIP REPLACEMENT SURGERY Trey DeLong Lacey Gorochow Brian Rappa Adam Vandergriff Sandra Wadeer Advisor: Dave Martinez VP of Sales at Zimmer, Inc. Surgical Consult: Dr. Michael Christie, M.D. Southern Joint Replacement Institute
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Adaptable Retractor for Total Hip Replacement Surgery
Trey DeLong Lacey Gorochow Brian Rappa Adam Vandergriff Sandra Wadeer Advisor: Dave Martinez VP of Sales at Zimmer, Inc. Surgical Consult: Dr. Michael Christie, M.D. Southern Joint Replacement Institute. Adaptable Retractor for Total Hip Replacement Surgery. Problem Statement. - PowerPoint PPT Presentation
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ADAPTABLE RETRACTOR FOR
TOTAL HIP REPLACEMENT
SURGERYTrey DeLong
Lacey GorochowBrian Rappa
Adam VandergriffSandra Wadeer
Advisor: Dave MartinezVP of Sales at Zimmer, Inc.
Surgical Consult: Dr. Michael Christie, M.D.
Southern Joint Replacement Institute
Problem Statement Current tissue retractors are narrow, multiple
retractors are required especially in obese patientsNY times reports 34% adults are obese+Surgical Techs($20.00/hr*2-4hr/surgery*200k
surgeries/year)Time of surgery increases as well
Previous team designed an adjustable retractor Complex and impractical for industrial productionPrototype could not be used in surgery
Mechanism & Consequences Mechanism causing the problem
Physical properties of adipose tissue allow it to wrap around narrow retractors
Consequences of unresolved problem
Poor surgical field of visionIncrease cost for additional materials and personnel
Surgery Experience
Fat tissue getting in the way
4-5 in (6 in in bigger patient)
3 in wide
Depth can range from 1-6 inches depending (Patient Size)
Dr. Christie’s Perspective Functions of retractor:
Orient the incisionKeep tissue from falling into
surgical window Disposabile vs. Non
Not “green”Strength concerns
Ideal Device:Robust Simple Movable window
Design Requirements & Objectives Keep back adipose tissue Fit multiple patient sizes and provide a clear view
of the surgical site Must be cost efficient
Simple manufacturingcheap material
Ready for use in surgeryEasily attachedEasily sterilized
Strong enough to hold back fat tissue
Design
• Lofted feature-rounded to keep back tissue• Curvature based on angle of known
measurements in surgery video
Material of Attachment Piece 17-4 Precipitation Hardening Stainless
SteelComposition: 15.5% Chromium, 4.5%
Nickel, 3.5%CopperUltimate Tensile Strength: 1000-1340 MpaHigh strength maintained up to 600°FCorrosion resistance superior Readily welded-preheating not usually
required
Stainless Steel Model Weld rods onto existing retractor
to provide rails
Attachment made in machine shop using CAD design
Goals Reduce total hip replacement surgery
costLess personnel in the operating roomLess retractors needed for surgery
Increase vision and work room for the surgeonIncrease efficiency of the surgeryReduce surgery time
Performance Metrics Retractor system work on 95% of
patientsDifferent size attachments for non-
disposable. Costs
Keep production costs minimal○ Mass production○ Readily machined
Predicted to be ~$300 for retractor and attachments (non-disposable)
System and Environment Role in surgery
Increase view of region and allows access Why its beneficial to the surgeon
Reduce people near patientReduce number of retractorsMake surgery easier
Testing Methods Verification and Validation
Hardware Testing
Stress Testing
Sterilization Testing
Verification and Validation Verification: ensuring that all of the
parts of the device work togetherObtained a model made of ABS plastic
made from an FDM process
Validation: making sure that the device satisfies specified requirementTaking the actual prototype into surgery for
Dr. Christie to use
Hardware Testing Protocol Use of mechanical equipment to test strength of
deviceTake retractor with similar properties to testing labs Apply a load using a compression/ tensile machine to the
deviceHold the load over the device for several minutesObserve the deformation of the device over time
Mechanically test ability of steel to get the properties
Stress Testing Protocol Computer Modeling
Use PDE Toolbox (MATLAB) to analyze tissue
Obtain force load on the retractor from tissue data
Model stress on the retractor using force loads
Analyze model during normal use
Sterilization Testing Use in surgery Run through Autoclave to test resilience
and observe any remaining tissue Run through multiple cycles and
observe the number of cycles until completely clean.
Next Steps… Obtain a completed prototype to be
shown in the final presentation Conduct testing methods