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ENGINEERING

SULUNA

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January - April 2015
Award for Best Overall Presentation, PEO Engineering Student Paper Night
4th-year project, Bio-Instrumentation (MCG 4150)
Jonathan Bédard Schami, Christopher Morgan
Dr. Fraser Rubens for initial project inspiration and organizing the device demonstration.
John Perrins for manufacturing aluminum parts.
uOttawa Makerspace staff for 3D printing support.

uOttawa Skills and Simulation Centre for hosting the device demonstration.

The Suluna device was designed to assist surgeons, during heart valve replacement surgery, in selecting the appropriate size of artificial heart valve to be implanted. Given that every patient’s heart anatomy is unique, correctly sizing and fitting the artificial valve to the patient is crucial to the procedure’s long-term success. Current valve sizing methods utilize large kits of incrementally sized gauges to determine the appropriate artificial valve size through trial and error. The Suluna device, on the other hand, allows surgeons to perform the sizing using a single instrument. Initial inspiration for the project was provided by Dr. Fraser Rubens, cardiac surgeon at the Ottawa Heart Institute.

The Suluna device was designed with usability in mind. The surgeon begins by inserting the device’s four tines into the heart valve’s annulus. Upon actuating the device, the tines expand while continuously measuring the forces exerted on the tines by the walls of the annulus. Once a preset force threshold is met, the device retracts the tines and displays the corresponding annulus diameter for the surgeon.

The operation of the device relies primarily on the chuck mechanism. When the scroll gear is turned by the motor, the chuck jaws are pushed radially along grooves in the frame causing the tines to expand or retract.

The team decided to take the course project to the next level by prototyping the device. Most of the device’s mechanical components were produced using 3D printers provided by the uOttawa Makerspace. Algorithms were generated to translate the device’s force readings into usable outputs displayed on the LCD for the user.

After completing the prototype, Dr. Rubens invited the team to demonstrate the Suluna device on a pig heart at the uOttawa Skills and Simulation Centre.

Sizing kits, such as the one pictured above, are currently used to size artificial heart valves.

Heart valves regulate the flow of blood in the heart. A defective valve can be removed during heart valve replacement surgery and substituted with an artificial valve like the one pictured.

Dr. Rubens began the demonstration by excising the pig heart’s natural aortic heart valve.

Dr. Rubens provided an explanation of the heart’s anatomy and located the heart valve annulus.

To establish a point of comparison, Dr. Rubens inserted a few different sizers from the kit into the heart valve annulus and used his experience to judge the fitting. He gauged that a 19mm artificial valve would be appropriate for implant.

Following the conventional heart valve sizing, the Suluna device was used. With a simple press of a button, it was successful in repeatedly outputting an artificial valve size corresponding to Dr. Rubens’ evaluation.

The Suluna team (left to right): Christopher Morgan, Jonathan Bédard Schami, and Matthieu Lemay.

© Matthieu Lemay 2015