SPRAY-ON "sticking plasters" can now help heal the wounds inside the body made during delicate keyhole surgery. The bright blue plasters, sprayed directly onto organs in the form of a gel, promise to prevent post-surgical complications that usually mean another operation.
"It's like an internal wound dressing," says Amarpreet Sawhney, founder of Confluent Surgical of Waltham, Massachusetts, the company developing the gel. Sawhney described the gel last week at BioPartnering, a London biotechnology conference
Although similar dressings are already available as biodegradable sheets (New Scientist, 10 May 1995, p 23), he says surgeons can only apply these during standard, open surgery-and they sometimes don't stay in place. But you can spray on the gel during keyhole surgery, and it will stay put.
The dressings protect the surfaces of organs and wounds, preventing them from sticking to neighbouring organs and tissues to form post-surgical adhesions. These painful scars happen after routine gynaecological, heart, gut, brain and general surgery. Corrective operations cost an estimated $3 billion worldwide each year, says Sawhney.
The gel starts off as two separate liquids. When they're sprayed together onto an organ, they congeal into a bright blue gel which sticks to the surface of the wound. It degrades harmlessly about a week later once the tissue underneath has healed.
The liquids are two variants of a polymer called polyethylene glycol. A double-barrelled dispenser turns solutions of both polymers into a fine mist which surgeons spray onto wounds. The liquids solidify into a gel within 2 seconds of contact with the wound.
"It's blue so the surgeon can see where it goes," says Sawhney. "It's really hard for them to screw up." The gel is undergoing clinical tests at hospitals in France, Germany and the US. "We've done 60 patients so far with no problems," Sawhney told New Scientist.
The gel can be tweaked chemically- so that it dissolves faster or slower, for example. The company is also testing the gel to see if it can suffocate tumours and fibroids by blocking their blood supply. Sawhney and his colleagues have special dispensers which plug up blood vessels with the gel. Tumours will wither and die if their blood supply is cut off, a process called anti-angiogenesis.
"We're talking about mechanical anti-angiogenesis," says Sawhney. "We can shut off every street or alley supplying the tumour," he says.
The same device is being tested experimentally as a way of treating aneurysms, the cardiovascular equivalents of tyre blowouts.
Martin Cortvriend of Genzyme, the company in Boston which makes existing films for preventing post-surgical adhesions, heard Sawhney's talk in London and agrees that the new system could be very useful in keyhole surgery.
Author: Andy Coghlan
New Scientist issue: 28th October 2000
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