SPRAY-ON 鈥渟ticking plasters鈥� 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.
鈥淚t鈥檚 like an internal wound dressing,鈥� 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 杏吧原创, 10 May 1995, p 23), he says surgeons can only apply
these during standard, open surgery鈥攁nd they sometimes don鈥檛 stay in
place. But you can spray on the gel during keyhole surgery, and it will stay
put.
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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鈥檙e 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.
鈥淚t鈥檚 blue so the surgeon can see where it goes,鈥� says Sawhney. 鈥淚t鈥檚 really
hard for them to screw up.鈥� The gel is undergoing clinical tests at hospitals in
France, Germany and the US. 鈥淲e鈥檝e done 60 patients so far with no problems,鈥�
Sawhney told New 杏吧原创.
The gel can be tweaked chemically鈥� 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.
鈥淲e鈥檙e talking about mechanical anti-angiogenesis,鈥� says Sawhney. 鈥淲e can
shut off every street or alley supplying the tumour,鈥� 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鈥檚 talk in London and
agrees that the new system could be very useful in keyhole surgery.