Retractor for Breast Surgery Clients: Dr. Piasecki ~ Plastic Surgery UW Hospital Dr. Gutowski ~ Plastic Surgery UW Hospital Advisor: Prof. Murphy ~ Biomedical Engineering Department UW-Madison Christopher Westphal – Leader Sarajane Stevens – Communicator Arinne Lyman – BSAC Eric Bader – BWIG

Overview Problem Statement Design Constraints Background Designs Procedure Current Device Light/Suction Designs Future Work

Problem Statement Our goal is to develop a breast retractor that will allow the doctor to create a cavity in the breast through a small inframammary incision. The retractor must be self-standing, contain a light source that emits light in all directions, and create suction in various places of the breast cavity.

Design Constraints Self-standing Proper light and suction distribution Fit through a 3-4 cm incision Sustain a maximum force of 60 lb Non-porous material Withstand autoclaving temps (121°C)

Background – Procedure 3 cm incision Retractor holds tissue up Form cavity with electrocautery tool Implant placed above or below pectoralis Closed with dissolvable sutures http://rejuven8u.com/plasticsurgery/breast_augmentation_surgery_info.html

Current Device ASSI® Breast Retractors Neon Breast Retractor Fiber optic light source Suction source “C” or “L” shape Neon Breast Retractor Light reflective polymers Distributed light Lightweight Insulated One-time use http://www.accuratesurgical.com/accuratesurgical/Docs/breast_instrumentation/retractors/stanger.asp http://www.sheffmed.com/neonret.htm

Background – Light/Suction Light Sources Fiber optics Light reflective polymers LightMat™ Suction Sources Standard hospital wall mount 20-120 mmHg http://www.lumitex.com/medical.html http://www.buyemp.com/product/1012001.html

Design 1 – The Raisin’ Squeeze handle Actuates ratchet mechanism Quick release

Design 1 – The Raisin’ Pros Cons Wide base Easily adjusted Minimally obstructed field of view Cons No pivot Bulky handle Difficult to clean

Design 2 – The Spreader Twist knob Pivot point at base Large angle spread

Design 2 – The Spreader Pros Cons Dog-legged for minimal obstruction Light-weight Pivot creates taller cavity Cons Hard to adjust May exert pressure on patient Non-discrete step increments

Design 3 – The Jack Pull top bar back Lift up Slide forward

Design 3 – The Jack Pros Cons Used with various procedures Simple design Easy to manufacture/clean Cons Instability No pivot point Obstructs field of view

Design Matrix Criteria Raisin’ Spreader Jack 14 9 8 5 11 13 2 3 10 6 7 Self-Standing [15] 14 9 Pivot [10] 8 5 Clear Field of View [15] 11 13 2 Force [10] 3 Ease of Use [15] 10 Cost [10] 6 7 Safety [10] 4 Manufacturing [15] Total [100] 62 61 48

Future Work Determine method of construction Create prototype Test for sufficient force, light, and suction distribution Revise design if needed

References http://medevoice.co.uk/sheffmed/January05.php http://www.accuratesurgical.com/accuratesurgical/Docs/breast_instrumentation/retractors/stanger.asp http://rejuven8u.com/plasticsurgery/breast_augmentation_surgery_info.html http://www.lumitex.com/medical.html http://www.buyemp.com/product/1012001.html

Questions