Dr. Joao Rezende-Neto
Dr. Joao Rezende-Neto recalls how his trauma patients came to St. Michael’s Hospital bleeding out from liver injuries. He lost track of the surgical sponges—10, maybe more—he packed against every shattered liver. The pressure of the sponges often stopped the hemorrhaging, but Dr. Rezende-Neto always knew what would happen in 48 hours.
“The moment those sponges came out, the crucial blood clots would tear away with them,” he says. “In this way, we would introduce re-bleeding, and sometimes that can be fatal.”
A second problem was equally troubling: surgeons never knew how much pressure they were applying to the liver.
“Too little pressure, and the bleeding won’t stop,” Dr. Rezende-Neto says. “Too much, and we risk cutting off blood supply to an already injured organ.”
Dr. Rezende-Neto had stood in the operating room countless times, frustrated because his patients deserved the latest in care. He recalls comments such as, “It’s what we have.”
“It wasn’t good enough,” Dr. Rezende-Neto says. But with no existing solution available, he decided to invent one.
First, he obtained CT scans of patients and studied them. Next, he created a soft silicone model of the liver with the same consistency as human tissue. He began developing his invention: the liver airbag—an inflatable medical device that would compress the liver to reduce bleeding without excessive pressure on the organ and while also protecting newly formed clots from being dislodged.
Finally, he took the liver airbag to Angels Den at Koerner Hall in 2019—and won the Keenan Biomedical Innovation Award.
The Angels Den experience
Winning Angels Den was a turning point for both the liver airbag and Dr. Rezende-Neto’s approach to medical innovation. The competition provided $50,000 in initial funding, which he used to further develop the liver airbag.
The original design of the liver airbag was a simple prototype—a single piece of plastic that surrounded the entire liver. But as Dr. Rezende-Neto continued his research after winning Angels Den, he discovered a flaw.
“The liver is tightly attached to the diaphragm muscle,” Dr. Rezende-Neto says, adding that wrapping a single piece around it required detaching the liver from that muscle—a time-consuming process that could cause more bleeding when every second matters.
His solution was simple: divide the liver airbag into three smaller pieces that could be applied individually to different areas of the liver. He also improved the design with small air channels that eliminated the need to tie it around the organ and replaced the brittle plastic with a softer, medical-grade material suitable for real clinical applications.
The problem within the problem
However, as Dr. Rezende-Neto worked with liver trauma patients who needed the airbag, he saw another problem: after placing the device—or the surgical sponges—the abdomen needed to be left open from 48 hours up to 20 days. After such a lengthy period surgical teams often couldn't close the patients up.
“When we bring the patient back to do the last operation and take the liver airbag or even the sponges out and attempt to close, we’re not able to because the gap is so wide and the abdominal wall doesn’t come together,” he explains.
For patients who couldn't be closed, the outcomes were grim: skin grafts or mesh placement requiring additional surgeries for definitive repair three years later—something that can have lasting consequences for patients’ mobility, function, and quality of life.
“Again, our existing solutions were not good enough,” he says. Again, Dr. Rezende-Neto set out to solve it. This time, he developed an abdominal closure device—called AbClo®—that runs across the abdomen and gradually brings the separated tissue back together. The device, applied at the bedside, features rotating knobs connected by strings that gradually and gently pull on the abdominal wall, preventing the gap from widening too much and giving doctors the ability to close the abdomen with greater efficiency.
A clinical trial at St. Michael’s revealed the AbClo® device’s effectiveness. Without the AbClo®, only 55 percent of open abdomens could be successfully closed. The trial showed that with the initial prototype, the abdominal closure rate jumped to 85 percent.
As Dr. Rezende-Neto refined the design, the results of the improved version were extraordinary: a 94 percent abdominal closure rate, regardless of whether it was a trauma or an emergency general surgery case.
Impact of Angels Den and early-stage investment
This early-stage clinical validation process is a pivotal part of translating new ideas into patient care, says Dr. Ori Rotstein, Vice-President of Research and Innovation at Unity Health Toronto.
“Early-stage research and innovation is often the most difficult phase of the process to support,” he says. “That’s why Angels Den plays a vital role in advancing research at St. Michael’s. It provides this early support that gives health teams not just the funding, but the confidence to take an idea and transform it into a life-saving solution for patients around the world.”
Dr. Rezende-Neto and AbClo® are a prime example of the impact of Angels Den. Since AbClo® obtained FDA and Health Canada approval, Dr. Rezende-Neto created a startup to commercialize the technology. In Canada, St. Michael’s is the highest-volume user, he says, adding that his colleagues are employing AbClo® almost every week—sometimes on two or three patients at once. The device is also being used in a multicenter trial in Vancouver and Halifax hospitals.
AbClo® is also being used in 45 major hospitals across the United States and annual sales are increasing. The device was recently used in Japan and at Harvard’s Massachusetts General Hospital.
Dr. Rezende-Neto credits the Angels Den competition with making his success possible. First, the financial support allowed him to develop both the liver airbag and, eventually, AbClo®. As well, winning Angels Den elevated his credibility as an entrepreneur and innovator.
“It was Angels Den that helped to break the misconception that a surgeon or a physician cannot also be an entrepreneur and inventor,” Dr. Rezende-Neto says. “It is possible as a physician to be a successful inventor. My experience is proof of that.”
“For our patients, research like this can be life-changing,” says Dr. Rotstein. “These discoveries influence so much—recovery, long-term function, and quality of life. That’s the profound impact of what Angels Den makes possible.”
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