E N D
Abstract Current breast augmentation surgeries require a surgeon to constantly pull on the breast tissue which results in surgeon fatigue. A device is proposed that will be self-standing, allowing the retractor to support the tissue instead of the surgeon in addition to evenly distributing light and suction throughout the entire cavity. The Raisin’ combines a familiar motion of a bar clamp, specifically the IRWIN® Quick-Grip®, which allows a simple squeeze to actuate a vertical movement. It is self-standing on any horizontal surface and has vertical increments 8.636mm. Modifications of the first prototype included decreasing the blade length, widening the base, thickening the lower blade, and adding a rib support, all of which served to strengthen the prototype and increase the applied force of the moment. The second prototype was able to sustain a force of 22.6kg under a point load at the tip of the blade. Maximum displacement of the top blade was 2.5cm. Fiber optics were beyond our budget limits, thus testing of intensity could not take place. Suction ports will be tested upon use by the client to determine if specifications were met.
Project Motivation • Client’s objectives • Decrease load on surgeon’s arm • Reduce required personnel • Shortcomings • Minimal light and suction • Not self-standing http://www.accuratesurgical.com/
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
http://www.accuratesurgical.com/ http://www.sheffmed.com/neonret.htm Background - Current Device • ASSI® Breast Retractors • Fiber optic light source • Suction source • “C” or “L” shape • Neon Breast Retractor • Light reflective polymers • Distributed light • Lightweight • Insulated • One-time use
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 Background – Light/Suction
Design Constraints • Self-standing • Proper light and suction distribution • Fit through a 3-4 cm incision • Sustain a maximum force of 22.73 kg • Non-porous material • Must not exceed stress of 68.58 kPa • Withstand autoclaving temps (121°C)
Design: The Raisin’ • Insert into incision • Rests on chest wall • Squeeze handle • Quick release
C-blades Plasma cut Handle Two halves Milled out Welded together Tubes Fittings Welded/Brazed Components Slide bar Brake lever Brake spring Driving lever Driving spring Squeeze handle Manufacturing
Important Constraints • Rib Stress • σmax = 68.58 kPa • ≥10% of AC-blade contacts chest wall • Pmax = 2.26 kg • Increment • Full pull =0.5932 cm • Std Dev = 0.0875 cm
Future Work • Construct out of medical grade materials • Titanium • Surgical steel • Glass fiber optics • Ergonomically correct handle
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
A Special Thanks • Professor Murphy • Dr. Karol Gutowski • Larry and Dave from the Tool Crib • Justin Lyman • Lee Kruschke
Client: Karol Gutowski, M.D. UW Hospital – Plastic Advisor: Professor WilliamSurgery Murphy
UW-Madison BiomedicalEngineering Dept.Christopher Westphal ~ Leader Communicator