Basic dermatological surgery

Published on 04/03/2015 by admin

Last modified 04/03/2015

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Basic dermatological surgery

The demand for the removal of benign and malignant skin lesions has increased considerably, such that skin surgery is now practised by many general practitioners as well as by dermatologists. Knowledge of basic surgical techniques is mandatory for all those who treat skin disease.

Instruments and methods

No-one should attempt a procedure if unsure about it. Those with limited experience should remove only benign lesions. All procedures are ideally performed in an operating theatre with trained nurses and adequate lighting. Sterile instruments, an aseptic technique and sterile gloves are essential. The operator plans the procedure, explains it to the patient, discusses the scar and obtains written consent. The direction of crease marks is assessed: any excision is usually made parallel to these lines.

The basic instruments (Fig. 1) include a #3 scalpel handle and #15 blade, a toothed Adson’s forceps, a small smooth-jawed needle holder, a pair of fine scissors, artery forceps and a Gillies skin hook. Curettes and skin punches come in various sizes. A solution of 1% lidocaine (Xylocaine) with 1/200 000 adrenaline (epinephrine) is usually satisfactory as the local anaesthetic, but plain lidocaine must be used on the fingers, toes and penis. The maximum safe dose for an 80-kg person using 1% lidocaine and adrenaline (1/200 000) is 40–50 mL. This volume is significantly reduced if higher concentrations of lidocaine or no adrenaline are used. The skin is prepared (but not sterilized) using, for example, 0.05% aqueous chlorhexidine (Unisept). Alcohol-based preparations are avoided as, if cautery is used, the solution may ignite. Sterile towels, placed around the operation site, reduce the chance of infection.

Fig. 1 A typical surgical set for skin surgery.

A curette is included.

Absorbable subcutaneous sutures (e.g. polyglactin; Vicryl) are used for excisions where the wound may be deep or under tension. For cuticular stitches, monofilament nylon (e.g. Ethilon) and polypropylene (e.g. Prolene) are reccomended. Use 5/0 or 6/0 sutures on the face, 3/0 on the back and legs, and 4/0 elsewhere. Stitches are preferably removed at 5–7 days on the face, 10–14 days on the legs or trunk and 7–8 days at other sites. Steristrips give extra support to a wound either in addition to sutures or when applied after their removal. An adherent tape or dressing (e.g. Micropore or Mepore) is used in most cases. For scalp biopsies, spray adhesive (e.g. Opsite spray) is useful.

Every biopsied lesion is sent for histology. If more than one specimen is taken from a patient, separate pots are used and each labelled before the biopsy is placed in it. The usual fixative is 10% formalin.

Basic surgical techniques

Excisional biopsy

An excisional biopsy is planned after considering the local anatomy. The excision’s axis depends on the skin creases (Fig. 2) and its margin on the nature of the lesion. The ellipse to be excised is drawn on the skin using a marker pen. An ellipse has an apical angle of about 30° and is usually three times as long as it is wide. If any shorter, ‘dog-ears’ appear at either end, although these can easily be corrected. After cleaning, local anaesthetic is infiltrated using a fine needle into the area of the lesion. Once numbed, the skin is incised vertically down to fat with the scalpel, in a smooth continuous manner to complete both arcs of the ellipse. The ellipse is freed from surrounding skin, secured at one end with a skin hook and removed from the underlying fat, usually using the scalpel blade (Fig. 3). In most cases, the wound can now be repaired, although any bleeding vessels will need to be stemmed with cautery, hyfrecation or suturing.

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