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. Adaptable Retractor for Total Hip Replacement Surgery

Problem Statement • Current tissue retractors are narrow, multiple retractors are required especially in obese patients • NY 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 production • Prototype 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 vision Increase cost for additional materials and personnel

Surgery Experience 4-5 in (6 in in bigger patient) 3 in wide Fat tissue getting in the way

Dr. Christie’s Perspective • Functions of retractor: • Pull on incision • Keep tissue from falling into surgical window • Disposability • Not “green” • 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 manufacturing • cheap material • Ready for use in surgery • Easily attached • Easily sterilized • Strong enough to hold back fat tissue

Preliminary Design • Similar to cheek retractor • Plastic material • Disposable • Hands-free • Does not allow for mobile window • No relaxation on one side (non-movable window)

Preliminary Design #1 Flap(similar to cheek retractor) 4 in Guide Rails 1 in sliding room

Preliminary Design #2 3 guide rails inside this part

Preliminary Design #3 Rails Guides Attaching Part Retractor

Preliminary Design #3

Goals • Reduce total hip replacement surgery cost • Less personnel in the operating room • Less retractors needed for surgery • Increase vision and work room for the surgeon • Increase efficiency of the surgery • Reduce surgery time

Performance Metrics • Retractor system work on 95% of patients • Different size attachments for non-disposable and disposable design • Costs • Keep production costs minimal • Mass production • Readily machined • Predicted to be ~$300 for retractor and attachments (non-disposable) • Disposable: $1-$10 per device

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 • Ensuring all parts of the device function together properly • Detect errors at all stages of development • Validation • Determine whether device is easily sterilized • Hardware Testing • Use of mechanical equipment to test strength of device • Stress Testing • Pro/E Mechanical Analysis • Safety Testing • Take into surgery and access ability to use device

Next Steps…

References • http://www.bls.gov/bls/blswage.htm • http://www.innomed.net/hip_rets_mis.htm#Anchor-APC-49575 • http://www.nytimes.com/2010/01/14/health/14obese.html • http://www.orthosupersite.com/view.aspx?rid=1889 • http://www.zimmer.com/z/ctl/op/global/action/1/id/8140/template/PC/navid/10427

Adaptable Retractor for Total Hip Replacement Surgery