pptx - Research

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Transcript pptx - Research

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
Problem Statement
Current tissue retractors are narrow, multiple
retractors are required especially in obese
 NY times reports 34% adults are obese
 +Surgical Techs($20.00/hr*2-4hr/surgery*200k
 Time of surgery increases as well
Previous team designed an adjustable
 Complex and impractical for industrial
 Prototype could not be used in
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 vision
Increase cost for additional materials and personnel
Surgery Experience
4-5 in (6 in in bigger patient)
3 in
Depth can range from
1-6 inches depending
(Patient Size)
Fat tissue getting in the way
Dr. Christie’s Perspective
Functions of retractor:
 Orient the incision
 Keep tissue from falling into
surgical window
Disposabile vs. Non
 Not “green”
 Strength concerns
Ideal Device:
 Robust
 Simple
 Movable window
Design Requirements &
Keep back adipose tissue
 Fit multiple patient sizes and provide a clear view
of the surgical site
 Must be cost efficient
 Simple manufacturing
 cheap material
Ready for use in surgery
 Easily attached
 Easily sterilized
Strong enough to hold back fat tissue
• 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
 Composition: 15.5% Chromium, 4.5%
Nickel, 3.5%Copper
Ultimate Tensile Strength: 1000-1340 Mpa
High strength maintained up to 600°F
Corrosion resistance superior
Readily welded-preheating not usually
Stainless Steel Model
Weld rods onto existing retractor
to provide rails
Attachment made in machine
shop using CAD design
Reduce total hip replacement surgery
 Less personnel in the operating room
 Less retractors needed for surgery
Increase vision and work room for the
 Increase efficiency of the surgery
 Reduce surgery time
Performance Metrics
Retractor system work on 95% of
 Different size attachments for non-
 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 patient
 Reduce number of retractors
 Make 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 together
 Obtained a model made of ABS plastic
made from an FDM process
Validation: making sure that the device
satisfies specified requirement
 Taking the actual prototype into surgery for
Dr. Christie to use
Hardware Testing Protocol
Use of mechanical equipment to test strength
of device
 Take retractor with similar properties to testing labs
 Apply a load using a compression/ tensile machine
to the device
 Hold the load over the device for several minutes
 Observe the deformation of the device over time
Mechanically test ability of steel to get the
Stress Testing Protocol
Computer Modeling
 Use PDE Toolbox
(MATLAB) to analyze
 Obtain force load on
the retractor from
tissue data
 Model stress on the
retractor using force
 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
 Verification
 Validation
 Hardware Testing
 Stress Testing
 Sterilization Testing
Present our final project