PALM BEACH, FLA. Certain widely held beliefs among dermatologic surgeons are revealed as myths when subjected to scientific scrutiny, according to Dr. James M. Spencer.

"In surgery we do a lot of things just because a respected professor once told us to," said Dr. Spencer of Mount Sinai School of Medicine, New York.

An example Dr. Spencer cited is the dictum that one should never use epinephrine with lidocaine on the fingers, because the epinephrine is so vasoconstrictive that hypoxia and necrosis would result. This prohibition is included as dogma in textbooksyet a literature review identified only 50 reported cases of digital gangrene following local anesthesia. All of these were early 20th century cases and multiple medications were involved, including cocaine and procaine, with nonstandardized techniques and methods of mixing, he said.

These early cases also included the inappropriate use of tourniquets and postoperative hot soaks (J. Am. Acad. Dermatol. 2004;51:7559). There have been no reports of necrosis of the finger since commercial lidocaine with epinephrine was introduced in 1948, Dr. Spencer said at the annual meeting of the Florida Society of Dermatologic Surgeons.

Another myth is that dog-ears must be completely removed at the time of surgery or they will be permanent. "I was taught 'thou shalt not leave dog-ears,' but this is clearly untrue," he said.

"When I had my first job at the University of Miami, the chairman of the department of plastic surgery would do primary repairs leaving patients with dog-ears. I wondered why no one had ever told him not to leave dog-ears, but then I thought, what are the chances of me being right and the chairman of plastic surgery being wrong? Zero," he said.

When this was studied prospectively, in 43 postexcision dog-ears in 26 patients, some degree of regression was seen in all 43. The dog-ears were measured immediately postoperatively and followed for up to 180 days. Complete regression was seen in 19 of the 43, over a mean of 132 days, and the probability of complete regression was greater in dog-ears of 8 mm in height or less (Dermatol. Surg. 2008;34:10706).

"I can tell you from experience that dog-ears on hands regress completely, those on arms and legs do pretty well, but those on the forehead not at all," he said.

"We also were all taught that nonabsorbable sutures are always preferred as outer, cuticular sutures because absorbable sutures are too inflammatory, they favor infection, and give an inferior cosmetic result," he said.

Patients, however, would prefer not to have to return for suture removal, so a group of emergency physicians performed a study in which they randomized pediatric patients with lacerations to treatment with absorbable plain gut sutures or nonabsorbable nylon sutures and evaluated them at 10 days and at 45 months.

At 10-day follow-up, there were no differences in wound outcome, including infection and dehiscence rates, and 45 months later, evaluation by a blinded plastic surgeon showed no difference in cosmetic outcome (Acad. Emerg. Med. 2004;11:7305). "In fact, the plain gut sutures appeared to give a slightly better cosmetic result," said Dr. Spencer, who also is in private practice in St. Petersburg, Fla.

Another myth that has been perpetuated by dermatologists is that patients receive 80% of their lifetime sun exposure by age 18.

The 80% number was an extrapolation from a calculation in 1986 that sunscreen use by young people would reduce their lifetime risk of skin cancer by 78%. In fact, the original publication stated that the incidence of nonmelanoma skin cancer was related to the square of the ultraviolet dosethe actual dose was not calculated (Arch. Derm. 1986;122:53745).

A more recent analysis determined that Americans actually receive less than 25% of their total exposure by age 18 (Photochem. Photobiol. 2003;77:4537). "This, of course, means that sun protection is equally important in older and younger patients," he said.

Finally, it has been accepted that laser resurfacing is contraindicated while a patient is on isotretinoin, but there is very little evidence to support this, with only nine cases of keloid scarring having been reported. Six were from Dr. Henry Roenigk in Chicago, who has done thousands of cases of dermabrasion on patients with acne scars who were on isotretinoin or had only recently discontinued it (J. Am. Acad. Dermatol. 1986;15:2805). The remaining three were patients from Great Britain who developed scarring after dermabrasion or argon laser while taking isotretinoin (Br. J. Dermatol. 1988;118:7036).

"That's it. Nine patients in the world literature have become a medicolegal fact. Textbooks don't even reference it, they just state it like it's the 11th commandment."

Dr. Spencer disclosed having no conflicts of interest relevant to his presenation.

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'I was taught "thou shalt not leave dog-ears," but this is clearly untrue.' DR. SPENCER

Common Dermatologic Surgery Beliefs Dispelled by Expert