RHODES, GREECE A new intralesional cryosurgery technique for targeting dermal skin lesions is safe and effective for the treatment of keloids and hypertrophic scars, Dr. Christos Zouboulis reported at the 15th Congress of the European Academy of Dermatology and Venereology.

The technique is a modified version of one first reported in 1993 and is performed using a novel intralesional cryoprobe (Etgar Group International Ltd., Israel) invented by Dr. Yaron Har-Shai of Berlin, Germany, and his associates. The probe, which is approved by the U.S. Food and Drug Administration, has an elongated, double-lumen, uninsulated needle with a safety cryogen vent and a sharp-cutting, sealed, distal tip designed to easily penetrate hard and dense dermal lesions such as keloids and hypertrophic scars.

In a pilot study of nine patients with recalcitrant auricular keloids, the proximal end of the probe was attached to an adaptor, which was connected to a standard "cryogun" cryogen source. The cryogun was filled with liquid nitrogen about 15 minutes before the procedure to allow adequate pressure to build up.

The patients were placed in the supine position, and the keloid surface was cleaned, disinfected, and draped. The area to be penetrated with the cryoprobe was intralesionally anesthetized with 1% lidocaine, and the sterile cryoprobe was forced into the long axis of the scar, with the sharp tip of the needle penetrating the distal edge of the scar.

Upon activation of the cryogun, the cryogen froze the keloids within 530 minutes, depending on scar volume, as iceballs appeared at each penetrating point of the cryoneedle and gradually spread toward one another. When the iceballs met, indicating complete freezing of the keloid, the cryogun was disengaged, and the cryoprobe was allowed to defrost for 12 minutes before being carefully withdrawn.

Treatment resulted in an average 67% reduction in scar volume at 6 months, which was maintained for up to 18 months after a single treatment. The average pretreatment scar volume was 2.89 cm

Patients also had significant reductions in scar hardness, scar elevation, and redness (average pre- and posttreatment scores of 2.9 vs. 0.50, 3.0 vs. 1.0, and 2.9 vs. 0.8, respectively). Subjective complaints were also reduced following treatment, with reductions seen in itching, pain, and tenderness (average pre- and posttreatment scores of 2.5 vs. 1.19, 2.0 vs. 0.3, and 2.3 vs. 0.4, respectively). There were no scar recurrences at 18 months' follow-up.

The treatment was generally well tolerated, Dr. Zouboulis said.

Any mild pain or discomfort that occurred during or after the procedure was easily managed. No active bleeding, infection, or adverse reactions such as hypopigmentation occurred, he noted.

The patients, seven women and two men aged 1855 years, had a total of 10 keloids of 6 months' to 6 years' duration. The keloids, which resulted from piercings in 9 of 10 cases, and from a laceration in 1 case, had failed to respond to excision, laser surgery, surface cryosurgery, intralesional corticosteroid injections, and/or silicone ointment. The findings were reported earlier this year by Dr. Har-Shai, Dr. Zouboulis, and their associates (Wound Rep. Regen. 2006;14:1827).

Histologic evaluation and studies of swine tissue following ex vivo intralesional cryosurgeryconducted as part of the same study in an effort to explain the mechanism of action of the cryoprobeshowed that the technique destroys the core of the scar with only small effects on surface cells, including melanocytes. The cryodamage caused by the technique is self-limited, and complete cell death is identified in the central cryolesions immediately following treatment; this suggests that direct cryothermic injury is the primary mechanism of action, the investigators explained.

The lack of hypopigmentation in this studywhich might be explained by the minimal histologic changes in superficial adjacent areas of the central cryolesion, revealing a limited, demarcated, irreversible cell injurysuggests this technique might be particularly useful in patients with black or pigmented skin, who have a high prevalence of keloids, Dr. Zouboulis noted, adding that this technique and technology can be applied to scars of various shapes and contours at the ear helix and lobule, as well as in other areas of the body, as demonstrated in this and other studies.

In fact, the technology was developed for and will be studied for other indications involving deep skin lesions; keloids served as a "nondangerous proving principle" for efficacy, he explained.

"The major advantage of the intralesional cryoprobe to destroy the deeply localized target tissue with minimal effect on the superficial skin layers may have a significant importance in the future in the clinical application of cryosurgery not only in the treatment of keloids but also of other deeply localized skin lesions and tumors," he concluded.

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Auricular keloids are shown at baseline (left) and after the intralesional cryosurgery technique. Photos courtesy Dr. Yaron Har-Shai

Intralesional Cryosurgery Good for Deep Lesions : Procedure reduced scar hardness, elevation, and redness; no recurrences were reported at 18 months.