Support structure: This latex tube has been treated with heated polaxamer to make it rigid. Doctors could use the gel during surgery to mend vessels with glue rather than sutures.
Credit: Nature
Credit: Nature
BIOMEDICINE
The new technique could make some delicate surgical procedures quicker and safer.
A synthetic, temperature-sensitive gel could help surgeons reconnect blood vessels more quickly, safely, and easily. The new gel, successfully tested in rats, could also enable more complex robotic surgery as well as minimally invasive surgery.
There have been few advances in the art of reconnecting blood vessels since French surgeon Alexis Carrel received the Nobel Prize in 1912 for his method of sewing them together. About a decade ago, surgeon Geoffrey Gurtner found himself longing for a substance that could be poured into the tiny blood vessels he was struggling to reconnect in order to prop them open while he sewed them together. "A lot of surgeries require reconnecting vessels," he says. "For two-thirds of operations, this would be helpful."
When Gurtner took a post at Stanford University, he partnered with a group of Stanford chemical engineers and biomaterials experts who adapted a substance called Poloxymer 407, which is already approved by the U.S. Food and Drug Administration for internal use, to do the job.
The trick was to tweak the properties of the substance so that it changes from a liquid to a solid state a few degrees above body temperature. The group used a halogen lamp to heat up the area around a severed blood vessel in rats, added the poloxymer, and then sealed the two ends with surgical glue.
"The liquid turns into a solid, and then instead of a bunch of collapsible floppy pieces of linguini, you have something like pixie sticks," Gurtner says. After connecting them, "you're left with a scarless joint between the two blood vessels."
The group tested the technique in the aorta, as well as tiny, hard-to-reach, and oddly angled blood vessels, of rats. Not only was it five times faster than hand-sewing, the animals also had less scarring and inflammation up to two years later. The technique is described in a study published online in Nature Medicine.
Gurtner isn't the first to attempt such an approach. Roger Khouri, a plastic surgeon and microvascular surgeon based in Miami, patented a similar idea almost 20 years ago.
Khouri used a lipid-based substance that could be cooled to a solid state using cold water, and then dissolved at body temperature. But there were no glues available at the time that could be used in the body, so his team employed surgical staples. "I used the technique on patients, but it never really took off because those staples never held very well," he says.
Gurtner says he hopes to begin testing the technique in patients next year, but would like to improve the glue that his team used. "Having that glue be perfect is really going to make this a no-brainer for doctors," he says.
But Bruce Klitzman, a biomedical engineer and microvascular physiologist at Duke University, cautions that even if it works as well in humans as the developers hope, it might not be fully embraced by vascular surgeons. "It may save them five or 10 minutes, and if so, they might do it, but then again, you may have flexibility with suture that you may not have with this approach," he says.
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