David J. Barnette

Nonablative skin remodeling: selective dermal heating with a mid-infrared laser and contact cooling combination.

Many of the microscopic changes associated with photodamage reside in the dermis. It follows that subsurface heating of the skin might allow for cosmetic enhancement without loss of the epidermis. Accordingly, we investigated the clinical and microscopic changes produced by a mid‐infrared laser coupled with a contact cooling device.

Comparison of carbon dioxide laser, erbium:YAG laser, dermabrasion, and dermatome: A study of thermal damage, wound contraction, and wound healing in a live pig model: Implications for skin resurfacing

BACKGROUND Advances in laser technology allow for precise tissue removal and minimal thermal damage. However, mechanisms for cosmetic improvement have not been determined. Investigators have suggested that ablation, collagen shrinkage, and new collagen deposition all contribute to the clinical outcome. OBJECTIVE In a live farm pig, we examined gross and microscopic effects of thermal and mechanical ablation devices to characterize immediate and long-term mechanisms in skin rejuvenation. METHODS Two CO(2) lasers, an erbium:YAG laser, a dermabrader, and a dermatome were used to treat flank skin in a farm pig. There were 14 different treatment groups based on device type and working parameters. One to five sites were treated for each group. Wound surface areas were measured before treatment, immediately after treatment, and 7, 17, 23, 30, and 60 days thereafter. Biopsies were performed immediately after irradiation and 2, 7, 17, and 60 days after treatment. RESULTS For the CO(2) laser-induced wounds, surface area measurements showed that immediate and final wound contraction tended to increase with initial residual thermal damage (RTD) for a range of values, above which immediate contraction remained relatively constant. Although there was no immediate wound contraction with mechanical ablation devices, long-term wound contraction in the dermatome and dermabrasion sites increased with depth of ablation. The erbium:YAG laser sites healed in a manner similar to that of mechanically induced wounds. Wound contraction profiles over time were dependent on depth of RTD and depth of ablation. Sixty days postoperatively, histologic examination showed varying degrees of fibroplasia. Overall, there was greater compaction and horizontal orientation of collagen fibers in those wounds with more than 70 microm of dermal RTD. Grossly, all wounds were similar after 60 days, with the exception of the deep dermabrasion sites, at which clinical scarring was observed. CONCLUSION Our results show that CO(2) laser resurfacing produces short- and long-term wound contraction that is greater than that induced by purely ablative methods for the same total depth of injury. The erbium laser produced wound contraction profiles similar to those produced by mechanical wounding. The data suggest that initial collagen contraction and thermal damage modulate wound healing.

Effects of overlap and pass number in CO2 laser skin resurfacing: a study of residual thermal damage, cell death, and wound healing.

Newer CO2 laser systems incorporating short pulse and scanning technology have been used effectively to resurface the skin. As the number of resurfacing cases has increased, hypertrophic scarring has been reported more commonly. Previous dermabrasion and continuous wave CO2 studies have suggested that depth of injury and thermal damage are important predictors of scarring for a given anatomic region. To determine whether rapid overlapping of laser pulses/scans significantly altered wound healing, we examined residual thermal damage, cell death, and histologic and clinical wound healing in a farm pig.

Subsurface skin renewal by treatment with a 1450-nm laser in combination with dynamic cooling

A new nonablative laser device, Smoothbeam, has been under evaluation for nonablative wrinkle reduction in skin with minimal side effects. This device incorporates a laser at 1450-nm wavelength to heat the dermis and cryogen spray cooling to prevent epidermal damage. The thermal injury created is internal and imperceptible. The wound-healing response to this internal injury causes improvement in the appearance of skin wrinkles. Biopsies taken immediately after treatment showed mild residual thermal damage (RTD) at a depth range of 150 to 400 microm, which is the dermal zone where most solar elastosis resides. Biopsies from two months after treatment showed fibroplasia extending over a range of depths similar to the acute RTD zones. An improvement in wrinkle severity was noted on the treated side compared with the control side.

Embryonal rhabdomyosarcoma presenting in an adult: A case report and discussion of immunohistochemical staining

&NA; Embryonal rhabdomyosarcoma is the most common soft tissue sarcoma of childhood but is rarely seen in adults. We report an embryonal rhabdomyosarcoma of the cheek in a 21‐year‐old Filipino man presenting as a rapidly enlarging mass. An incisional biopsy was consistent with embryonal rhabdomyosarcoma. The patient failed to respond to one cycle of chemotherapy after initial diagnosis and workup for metastatic disease. Wide local excision of the tumor was then completed with the use of the Mohs technique to clear the glabrous cutaneous margins during surgery. A Mohs surgeon and dermatopathologist were involved in interpretation of the Mohs sections. Subsequent immunohistochemical staining revealed a poorly differentiated spindled and epithelioid cell tumor, which stained diffusely positive for vimentin, S‐100, and MyoD1. Rare rhabdomyoblasts were present and stained positively for desmin, musclespecific actin, and phosphotungstic acid hematoxylin. The patient subsequently underwent radiation therapy for a total of 6,000 cGy, followed by two cycles of chemotherapy. The patient continues to be disease‐free at 22 months after his wide local excision.