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February 1, 2023
5 Min Read
GI Windows President and CEO Brian Tinkham Image courtesy of GI Windows
A variation of an innovative surgical anastomosis technology that relies on magnetic compression is advancing to a pivotal clinical trial after promising results in early studies. The technology, developed by Westwood, MA-based GI Windows Surgical, uses self-forming magnets (SFM) that are delivered by endoscope or similar devices to the site where they need to be positioned as a segmented string. They then form into the ringlike formation needed to create the anastomosis.
The magnets in a magnetic anastomosis compress toward each other to cause necrosis in the tissue between them. As the tissue between the magnets dies, the tissue around them fuses between the two pieces of the organ in which they are placed.
In the most recent study, published in Surgery, the GI Windows self-forming magnets were shown to be superior to stapled anastomosis technology in early seal creation, with less trauma, and lower bacterial infiltration, leading to earlier healing of an anastomosis in porcine models.
The company said the study was the third recent longitudinal pre-clinical comparison of SFM, staplers, and sutured anastomoses, and that SFM has been demonstrated to be superior at six weeks in burst testing, reduction in fibrosis, and adhesions to conventional methods of anastomoses creation.
The technology, which was granted Breakthrough Device status by FDA in 2020, is now being evaluated in a pivotal trial called SEAM (Sutureless End-end Anastomosis by Magnetic compression) for patients undergoing an ileostomy reversal. SEAM is a multi-center, single-arm study that will evaluate outcomes in a minimum of 100 subjects undergoing ileostomy reversal using the GI Windows magnets. They will be compared to a historical control cohort of 300 or more patients who underwent ileostomy reversal using conventional closure techniques of stapling or suturing. The study is estimated to be complete by the end of 2023. GI Windows President and CEO Brian Tinkham said the first three patients had already been operated on, and 30 had been enrolled thus far.
Latest Chapter of Innovation
Magnetic anastomoses are not new; the first clinical results were published in the 1990s, with some reports crediting them back to the 1970s. However, the standard of care remains either hand-sewn or stapled anastomoses; in terms of safety, according to the authors of a 2022 study of the comparative strength of the three anastomosis techniques, both hand-sewn and surgical stapling procedures involve penetrating tissue, thus invoking inflammation and damage to the surrounding tissue, which can cause leaks at the anastomosis site and other adverse events. “Neither technique has yet been proved to be superior to the other, inasmuch as a meta-analysis found no difference in mortality, clinical leak rates, or cancer recurrence rates,” the authors wrote.
But even with predominantly favorable results in studies, magnetic anastomoses have yet to take off at scale. Michael Harrison, M.D., a pediatric surgeon at the University of California, San Francisco, who is considered the father of fetal surgery, is also a pioneer in creating magnetic anatomical devices, including the Magnamosis, now being developed by Myka Labs, also in San Francisco (for which Harrison is the chief scientific officer). Harrison had a simple take on why magnets have not replaced staples or sutures in anastomoses yet.
“Frankly, I think it’s just reluctance from most surgeons to do something new,” he said. “There has been really nothing unfavorable to stop the progress and it will happen, it’s just happening very slowly. It’s just surgical conservatism.”
Tinkham, however, also ascribes part of the slow take-up of the technology to the size of solid magnets that must be placed.
“To make a large anastomosis with rigid magnets you need large magnets,” he said. “And to get a big object into someone’s stomach, intestine, or even mouth, you need a huge hole.”
That, he said, flies completely counter to the prevailing trend in surgery to be as non-invasive as possible: “No one wants to make bigger holes to make their anastomosis.”
This is where he sees opportunity for the GI Windows SFM technology to prevail.
Not for Intestinal Healing Only
But the magnetic anastomosis technology can also be used for conditions other than intestinal diseases or bowel surgical repair. In 2021, a team at Monroe Carell Jr. Children’s Hospital at Vanderbilt University Medical Center used a Magnamosis device to reconstruct the esophagus of a child suffering from a rare form of esophageal atresia. The novel approach required compassionate use approval from FDA, and the surgical team also held a live Zoom conference with Harrison and Oliver Muensterer, M.D., from Germany, who had been the only other surgeon in the world to ever use the device prior to the Vanderbilt procedure. Irving J. Zamora, the procedure’s lead surgeon, said in a Vanderbilt news service story that the magnetic devices turned a “potentially daylong, high-risk, open-chest and abdominal surgery” into a 38-minute endoscopic procedure.
Harrison said Myka will concentrate first on getting the technology approved for esophageal atresia, and is preparing to start a full-scale trial in Europe.
Tinkham said, like Harrison, that the principles of magnetic anastomoses are compelling, and GI Windows magnets have received positive reactions from surgical reviewers. Tinkham, whose previous foray into medical device development was as co-founder of Beacon Endoscopic, which was purchased by Covidien in 2013, said patience and financial resources will be vital to those companies that emerge as leaders. Thus far, GI Windows has raised $43 million from sources including Johnson & Johnson Innovation, Sonder Capital, GT Healthcare, JC Investco, and one additional strategic investor.
“We just got a paper back on a study on connecting the esophagus to the small bowel and reviewer comments from surgical oncologists were very positive, like lavish praise,” Tinkham said, “but working with the FDA is hard and they are not doing anything wrong. What they are asking for is fair and reasonable, and showing that this is safe and effective takes time and money.
“And if you can’t raise the money, it doesn’t matter how much time you have.”
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