Hydraulically controlled magnetic bougienage for correction of long-gap esophageal atresia

Abstract

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 133-135).About one in 4000 babies in the United States is born with their esophageal disconnected and separated by a gap, which is called esophageal atresia. Esophageal atresia with a relatively short gap can be directly corrected with surgery, whereas babies with a relatively long gap requires a treatment over several weeks to stretch the esophageal pouches. In this thesis, we have designed and developed a hydraulically controlled bougienage system as a case study for correction of long-gap esophageal atresia. We insert two magnetic bougies into the esophageal pouches and applying stretching force. The key idea is to employ the magnetic force between the two bougies. The bougie is designed based on a piston mechanism, which consists of a barrel and a magnetic plunger. The plunger has a through hole in the center, so that we can push water into the piston to extend the barrel. A catheter is connected to the bougie to transfer the water. Also, the catheter is driven using a friction drive placed near the mouth, which adjusts the neutral gap size between the two magnets. A syringe pump pushes water through the catheter to extend the tip of the bougie. Therefore, the system can stretch the esophageal pouch without changing the gap size between the two magnets, which helps to apply the stretching force in a controllable manner. The piston mechanism also enables measurement of the stretching force while the bougienage is being performed. A prototype bougienage system is built and integrated on a test bench, in which surgical rubber tubing is used as a mock-up of the esophagus. We have experimentally demonstrated that the prototype bougienage system can stretch the mock-up by a desired amount of force. Also, we have shown that the bougie can reliably measure the stretching force when the O-ring friction is compensated with dither. This bench level experiment shows promising results and forms the basis for further efforts towards utilization in patients.by Minkyun Noh.S.M