The design of an in-vivo rotator cuff measuring tool PROJECT UPDATE Kathleen Bieryla, Katie Fronczak, Martha Loehr, Eric Rainis University of Pittsburgh Senior Design - BioE1161

Overview- Problem Surgical methods dependent upon ratio of a/b Currently there is no tool available to measure these dimensions Humeru s Scapula a)Length of torn tendon edge b)Size of avulsed humeral insertion c)Retraction of tendon

Overview- Proposed Solution The Arthromeasure is a one-handed tool for surgeons to use during arthroscopic surgery in order to measure the extent of rotator cuff tears Provides accuracy as specified by the user Allows for correct classification of size of tear, which aids in surgical treatment

Description Initial Design Shaft Length: 15 cm (13 cm exposed) OD: 4 mm ID: 0.51 mm (0.020 in) Handle 18 cm x 4 cm x 4 cm Current Design Alterations: Dimensions Propulsion System Wire Ejection Location Measurement System

Gear Mechanism

Features & Benefits Convenient moving mechanism on the handle Provides desired accuracy a: +/- 1 cm b: +/- 5 mm Gives surgeon an easy way to determine the best method of repair

Competitive Analysis Currently, no tool is available 3mm hook - surgery String and digital caliper – cadaveric research Strengths More accurate Easy to use Weaknesses Inaccuracy comes from surgeon

Team/Resources MSRC Patrick McMahon M.D. Richard Debski Ph.D Lab and equipment Swanson Center Rapid prototyping process Bioengineering Department Funding Limitations Money Size of handle

Schedule February—Initial prototype Choose final wire material Purchase gears and assemble Testing – accuracy and repeatability March—Cadaveric testing April—Final product and grant proposal

Team Responsibilites Katie B Determine materials for measuring device Testing of wire and shaft materials Help with SolidWorks model Katie F Keep quality controlled documents up to date Final design history file Write protocols for cadaveric testing of reliability/accuracy Martha Design handle of measuring device Complete SolidWorks design Structural testing in SolidWorks Eric Design gear system for measuring device Scheduling and external relations Physical cadaveric testing

Road Blocks Meeting with advisor Redesign of gear system Changed based on surgeon’s input Lack of knowledge

Current Status and Milestones Solidifying final design Gear system Sample materials for shaft and wire Viewed surgery – ask us what it’s like to be med students! Updated responsibilities and working plan First draft of SBIR phase I proposal

Acknowledgements Dr. Patrick McMahon Dr. Richard Debski MSRC Department of Bioengineering, University of Pittsburgh