Date of Award

Spring 1-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Mark Rentschler

Second Advisor

Virginia Ferguson

Third Advisor

Max Mitchell

Abstract

Current detection of Ventricular Septal Defects (VSD) in pediatric patients can be difficult for hard to reach anatomy, such as apical defects, or for multiple VSDs. Existing technology such as Magnetic Resonance Imaging (MRI), catheterization, and echocardiography can be expensive, dangerous, or simply does not provide adequate images of these holes in the septal wall. Similarly, state of the art treatment practices have definitive limits in capability. Cardiac Transcatheterization and subsequent implantation of an occlusion device may not succeed as the occluder may be too close to heart valves or in relation to each other in the case of multiple or―swiss-cheese‖ defects.

Oftentimes, the best course of action is open heart surgery, the gold standard of pediatric VSD patient care. However, even in this type of surgery visualizing and repairing VSDs can be difficult. Delineating the borders of a VSD from the right ventricle can be stifled by the complex geometry of the heart wall. Conversely, opening the smooth-walled left ventricle may result in nervous conduction path disturbances or blockages as the surgeon dissects the heart tissue.

This thesis describes the design, fabrication, and testing of a small, integrated camera system for visualizing and aiding in the repair of Ventricular Septal Defects (VSDs) in open surgery. Currently, a device to view VSDs from the left ventricle does not exist, though it is ideal for clearly viewing these congenital heart defects. This device will help solve some of the major problems associated with current imaging and surgical closure of VSDs in children by allowing the surgeon to view VSDs from the left ventricle. Furthermore, this device would include a tool capable of deploying through the VSD and grasping a suture to better demarcate its location.

First, current detection and treatment practices and limitations will be discussed, including state of the art echocardiographic techniques, transcatheterization, and open surgery. Next, the investigational device will be described from concept through development, including the formulation of customer requirements into engineering requirements. The application of Quality Functional Deployment, Design Failure Modes and Effects Analysis, and Voice of Customer methods to this project will be conveyed. Similarly, the design process for initial development of the device will be reviewed, including creation of each prototype build. Lastly, preliminary test methods and results will be discussed, concluding with an overall device analysis and description of future work.

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