May 24, 2011

New Device Reduces Surgical Scarring

(Ivanhoe Broadcast News) -- When skin or organs are damaged, the body naturally wants to heal itself.  Since the body cannot re-create healthy skin or tissue, it puts together new fibers that are not as functional as the original tissue, but that serve as a protective, useful barrier. Researchers at Stanford University have developed a special wound dressing that they report was able to considerably reduce scar tissue caused by incisions.

Results of animal tests and of an initial clinical trial of the dressing were "stunning," which Michael Longaker, MD, MBA, the Deane P. and Louise Mitchell Professor at the School of Medicine and senior author of a study that details the findings, was quoted as saying.  "It was a surprisingly effective treatment."

As soon as sutures are removed, the edges of a healing incision are pulled in different directions by the taut, surrounding skin, causing scar tissue to thicken and spread.  The new dressing, which the authors refer to as a "stress-shielding device," eliminates this tension and therefore a substantial amount of scarring.

Lead author Geoffrey Gurtner, MD, professor and associate chair of surgery, and his colleagues created the dressing in his lab.  It is made of a thin and stretchy silicone plastic that is stretched across the incision once sutures have been fully removed.  The dressing sticks to the skin with the aid of an epoxy resin.  As it contracts, it provides a consistent firmness across the wound.

Scar tissue, which is less elastic than normal skin, can cause functional problems, such as restricting motion.  Hair does not grow in a scar, and it doesn't have sweat glands.  Furthermore, scars do not appear like that of regular skin: They are frequently raised and have a pinkish hue.  Many people believe them to be unappealing.  Yet they are an inescapable side effect of surgery.  Every year in the United States, more than 50 million incisions are created during operations.  In the meantime, hundreds of millions of people already have scars that they would like to eliminate.  Existing scar-removal techniques, including surgical excision, steroid injections and laser therapy, are usually expensive, excruciating or basically not very efficient.

In pigs, which have skin comparable to that of humans, the area of scars caused by approximately 1-inch incisions were reduced six-fold by the stress-shielding device, in comparison to pigs in a control group with identical sized incisions.  The stress-shielded wounds "demonstrated nearly scarless closure" eight weeks following sutures had been removed.

Researchers furthermore tested the device on roughly 1-by-1.5-inch excisions "” a wound that mimics the type caused by scar removal "” and established that "stress shielding dramatically decreased scar area" in comparison to unprotected wounds of the same size.
"The device seemed to promote regenerative-like repair rather than scar formation," the authors wrote.

Subsequently, the researchers tested the device on nine female patients who had undergone abdominoplasties (tummy tucks).  Longaker added that he and his colleagues intentionally chose to test the dressing on incisions closed with high tension: If the dressing could decrease scarring in such cases, it would certainly work on any other type of incision.

One side of the abdomen-wide incision on every patient was treated with the stress-shielding dressing; the other half ultimately was not.  A panel of three plastic surgeons unaffiliated with the research, in addition to a panel of three people not in the medical profession, acted as judges.  On a 100-point scale, the lay panel scored the appearance of stress-shielded wounds an average of 13.2 points higher than the control wounds.  The specialist panel scored the scar appearance of the treated incisions 39.2 points higher.  In both of these analyses, the variation between the treated side and the control side were exceedingly significant.

In any case, the researchers cautioned that this was merely groundwork in the clinical study, which was designed simply to illustrate "proof of principle in humans."

"Larger clinical trials are being planned to include greater ethnic diversity within the patient population and to determine the optimal range of stress-shielding forces for anatomic region- and dimension-specific wounds," the authors conclude.

SOURCE: Annals of Surgery,  May 23, 2011