Dr. Evans: There have been other efforts to use magnetic force to treat esophageal atresia, but we knew from a series of research studies we’d done a few years ago that the difference between achieving a good outcome for patients and a not-so-good outcome would come down to the architecture of the device components. In particular, we knew that it would be essential to engineer devices that mate with one another where the mating surface creates a little bit of what the engineers would call radial shear in the interposed tissue. The radial shear spurs central necrosis and simultaneous peripheral healing, and the combination of those two is what sets the patient up for a favorable outcome, with low likelihood of stricture or leak.
Dr. Harrison: It was through a joint effort between our group and Dr. Muensterer that we were able to design and carry out a set of very important studies that are what we call preclinical studies, which are incredibly important in our gaining an understanding of how new types of devices could be used to repair esophageal atresia.
Dr. Evans: At the same time, we started to delve into the practical issues of engineering device components—we call them anchors—that incorporate powerful magnetic elements while being absolutely safe for the patient. Magnets have been used in surgery for quite a long time and have found very important applications in some specialized areas, but there are many challenges with magnets. For instance, many materials that have favorable properties from the standpoint of magnetic force are toxic to the human body. So the magnets have to be encapsulated in something that is going to withstand the corrosive environment within the human gastrointestinal tract. These devices need to be engineered to withstand all of the different types of environments that can be encountered in the gastrointestinal tract.
Dr. Harrison: So that’s where the partnership with ProPlate became so important. Here, the anatomy we’re working in requires very small devices—only a few millimeters in size. With the neodymium material, we knew we’d need to use the right amount for magnetic force, while addressing the material toxicity issues and the fragility of neodymium.
Ross Peterson: The manufacturing process for making NdFeB magnets involves a sintering process that results in a highly porous surface. The electroplating challenge was to provide a corrosion resistant surface, increased mechanical strength to the fragile sintered magnet, and perfectly pore-free coverage to the highly porous magnet surface.
Dr. Evans: We were thrilled that ProPlate was able to engineer a multilayer plating process that confers really amazing mechanical and chemical integrity to these tiny devices, where they can tolerate any combination of forces and impacts they might possibly encounter during placement.
Dr. Harrison: With all the experience and research gained with these new devices, there is endless opportunity for growth in the medical field. With this device, it has already been thought of using it for similar malformations; we see atresias in other parts of the bowel, like duodenal atresia, and we can build from what we have done here with esophageal atresia to be able to treat those atresias further down in the GI tract.
Dr. Harrison: With all this knowledge of how magnets can be safely incorporated into medical devices, the future for this field is boundless.