Laser Excision and Vaporization

Published on 09/03/2015 by admin

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CHAPTER 69

Laser Excision and Vaporization

Michael S. Baggish

Although carbon dioxide (CO2) laser vaporization of vulvar intraepithelial neoplasia is an effective, quick, and cost-efficient method of treatment, it does present a significant disadvantage: No tissue specimen is available for histologic examination when tissue is ablated; therefore, no information relative to margins or the severity of the disease can be obtained. For obtaining a tissue specimen, laser excision is preferable to ablative techniques.

Laser Excision by Thin Section

The laser “thin section” has three advantages: It (1) requires neither closure nor grafting, (2) heals rapidly without gross scar formation, and (3) provides a specimen for pathologic examination.

The lesion should be mapped preoperatively. The patient is positioned and prepared as for a knife resection (Fig. 69–1). A superpulsed (UltraPulse) CO2 laser coupled to a micromanipulator is the instrument of choice. The area for resection is outlined with laser spots (Fig. 69–2). The laser power is set at 8 to 12 W, and a tracer cut is made around the lesion. Next, a 1 : 100 vasopressin solution is injected subdermally, completely circumscribing the lesion and infiltrating beneath the skin (Fig. 69–3). Next, laser power is increased to 15 to 20 W, and, with a tightly focused beam, a plane is created parallel to the surface of the skin. The cut is made beneath the papillary dermis into the reticular dermis (Fig. 69–4). Maintenance of the plane and the excision is facilitated by keeping constant tension on the skin that is to be excised (Fig. 69–5). Small bleeding vessels are directly sutured with 4-0 or 5-0 Vicryl (Fig. 69–6). Application of clamps is avoided to diminish trauma to the tissue.

The excised specimen is placed in fixative and sent to pathology (Figs. 69–7 and 69–8A, B). Postoperatively, the patient is instructed to take tub baths in salt water (Instant Ocean) twice daily and to apply silver sulfadiazine (Silvadene) cream to the wound site 3 times per day. Alternatively, a urethane dressing (OpSite) is applied to the wound (Fig. 69–9A, B). Healing is complete at 4 to 6 weeks (Fig. 69–10A, B).

Laser Vaporization

CO2 laser vaporization is performed by using specifications identical to those used for excision (i.e., vaporization in hair-bearing areas, perineum, and perianal skin to a depth of 2.3 mm with a 3-mm peripheral margin) (Figs. 69–11 through 69–16). For the labia minora, periclitoral lesion vaporization is carried to a depth no greater than 1 mm; again, wide peripheral margins are recommended to diminish the chance of recurrence (Figs. 69–17 and 69–18). Preoperative mapping with extensive preoperative tissue sampling is a requirement before any laser vaporization to (1) determine that the disease is not invasive carcinoma, and (2) predict the extent of the disease and the peripheral margins for vaporization. The medial and lateral margins of the neoplasia are outlined after the patient has been anesthetized, prepared, and draped (Figs. 69–19 and 69–20). Power is set at 20 W, and the beam is defocused to permit a 2-mm-diameter spot (Figs. 69–21 and 69–22). The laser places multiple impact spots, much in the manner of marking the lesion with a pen. The spots are then connected, producing a clear outline of the area to be vaporized (Figs. 69–23 and 69–24

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