The design of an in-vivo rotator cuff measuring tool

PROJECT UPDATE

Kathleen Bieryla, Katie Fronczak, Martha Loehr, Eric Rainis

University of PittsburghSenior Design - BioE1161

Overview- Problem

• Surgical methods dependent upon ratio of a/b

• Currently there is no tool available to measure these dimensions Humer

us

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