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Monday, September 12, 2011

Sutureless blood vessel repair

Geoffrey Gurtner and his colleagues from Stanford University have tested a new way to reattach severed blood vessels.  Rather than relying on needle and thread, they used thermoreversible poloxamer and a bioadhesive. The former holds the vessels open while the latter glues the ends together.

Although sutures still work very well in many applications, they do have drawbacks.  For one thing, there is a lower size limit for a stitchable repair area.  For another, the suturing itself can cause localized trauma which can lead to obstructed blood flow at that point.  And finally, using discrete stitches of any kind allows for the possibility of leakage around the stitches.  Using adhesives can eliminate all these shortcomings.  However, you need something to keep the blood vessels fully dilated both during and after sticking the ends together, which is where the poloxamer comes in.

A poloxamer is a type of polymer gel composed of units with hydrophobic centers and hydrophilic ends. The scientists used the thermoreversible Poloxamer 407, which is solid above body temperature but liquifies at body temperature.  Using a halogen lamp to heat and solidify the poloxamer, the researchers successfully propped rat blood vessels open with the gel long enough for an adhesive to seal the vessels.  At that point, the gel was allowed to cool and dissolve away into the blood stream.

Both the sealant (Dermabond) and the poloxamer are already FDA approved for other uses.  Nevertheless, more animal studies most be done before the researchers can progress to human trials. 

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