White : Diseases of the Skin - Physical Therapies and Skin Surgery

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Gary M. White & Neil H. Cox

Diseases of the Skin

5	Physical Therapies and Skin Surgery

SURGICAL TREATMENTS

A detailed discussion of surgical treatments is beyond the scope of this book, but a brief outline is provided.

Materials

It is essential when performing skin surgery to have adequate facilities, lighting, biopsy equipment, cautery, resuscitation facilities, etc. It is assumed that the reader will be familiar with these issues. This section on biopsy materials will therefore be limited to a brief discussion of local anesthesia and suture materials.

Fig. 5.1 Cryotherapy of warts. Cryotherapy using the liquid nitrogen (LN2) spray technique. For warts or actinic keratoses, it is usual to perform a single period of freezing (one freeze–thaw cycle, FTC), whereas for malignancies two FTCs are usual, to increase the degree of damage. It is usual to record the cryogen, and the number and duration of treatment cycles, for example LN2, 2* 20 s FTC.

Fig. 5.2 Hemorrhagic blisters following cryotherapy.

Fig.5.3 Injection of local anesthetic. Using a fine needle, local anesthetic (LA) is first infiltrated along one edge of the planned ellipse. Typically, the needle would be advanced from its insertion point A to point B, then LA injected as the needle is slowly withdrawn but without fully removing it from the skin (thus avoiding the discomfort of a second needleprick at point A). This is repeated from point A to C to give a V- or wedge-shaped area of anesthesia. After waiting a couple of minutes the LA is infiltrated from B to D and then from C to D, areas B and C at this point being anesthetized and therefore avoiding needleprick discomfort. Although the LA itself may sting, this method involves a single perceived needleprick, and avoids distorting the lesion itself with injected fluid. Note that the lesion shown is a simple seborrheic keratosis that required no intervention, and no needleprick was involved in this demonstration photograph.

Local anesthetic

For some superficial procedures, such as destroying molluscum contagiosum lesions, topical local anesthesia may suffice. Agents that are used include amethocaine and a mixture of lidocaine and prilocaine.

For most procedures, injectable local anesthetics are used. These include agents such as lidocaine, bupivacaine, ropivacaine, and prilocaine (note that the latter is an ester and does not cross-react with amide anesthetics such as lidocaine, a point that is useful in rare patients with true local anesthetic allergy). These may be combined with vasoconstricting agents for use
at most parts of the body, for example lidocaine with adrenaline (epinephrine) or prilocaine with octapressin. Vasoconstrictors not only reduce surgical bleeding but also slow absorption of the anesthetic so that less is required, anesthesia lasts longer, and the drug is less likely to cause toxicity by systemic absorption.

Many local anesthetics sting when injected. This can be reduced by using lower concentrations, by warming the solution, by slow injection using a fine 27-G needle (Fig. 5.3), and by using nerve blocks for tender areas such as nose or digits.

For the technique of liposuction, large volumes of very dilute local anesthetic are used (tumescent anesthesia).

Fig. 5.4 Suture placement. Each picture shows initial needle entry with planned pathway (in red), position of stitch before knotting, and final position of knotted suture. (a) Placement of simple non-absorbable suture: note the slightly flask-shaped placement, which causes some eversion of the wound edge during healing. (b) Subcutaneous suture: note the placement of the knot at the deeper aspect of the tied suture.

Suture materials

While simple skin surface sutures are adequate for small wounds without tension, many dermatologic procedures benefit from additional use of subcutaneous sutures to improve wound strength (Fig.5.4). For either surface or deeper sutures, a huge array of different brands and materials are available. These vary in terms of absorption (fast, slow, or non-absorbable), filament type (monofilament or braided, coated or uncoated), diameter, and color. They also vary in their physical properties, for example in ease and strength of knotting.

Absorbable sutures include polyglycolic acid (Dexon), polyglactin 910 (Vicryl), polydioxanone (PDS), polyglyconate (Maxon), and poliglecaprone 25 (Monocryl). Commonly used non-absorbable suture types include nylon (e.g. Ethilon), polyester (e.g. Ethibond), polybutester (Novafil), and polypropylene (e.g. Prolene).

More recently, tissue glues such as cyanoacrylate have increased in popularity, both for simple wound closures and to adhere skin grafts to recipient sites.

Types of procedure

Dermatologists may perform a wide range of diagnostic or therapeutic procedures, including the following.

•	Incisional biopsies for diagnosis—ellipse and punch biopsy.
•	Curettage—a technique for scraping off superficial lesions; generally combined with cautery for hemostasis, occasionally with chemical hemostatics such as aluminum chloride
•	Shave biopsy—a superficial form of biopsy particularly suited to benign lesions such as ordinary nevi, but also used for diagnosis or treatment of small neoplasms, such as basal cell carcinoma, and as a treatment for broader areas of abnormal skin, such as rhinophyma.
•	Cautery without tissue removal, for example to small angiomas.
•	Excisional biopsy—the main method for removing skin neoplasia; includes specialized excisional procedures such as Mohs micrographic surgery, in which the tumor extent is mapped by special histologic processing (discussed and illustrated later in this chapter).

Fig. 5.5 Healing by second intention. In this case, a basal cell carcinoma at the edge of the concha of the ear (a) has been excised as a disk down to cartilage. Making 3-mm punch biopsy holes through the cartilage, known as fenestration (b), allows granulation tissue to extend from the posterior skin of the ear to provide a base for epithelialization. Individual holes in this fashion preserve the rigidity of the cartilage (like a colander), and healing (c) is excellent, without distortion of the shape of the ear.

Fig. 5.6 Rotation flap closure. (a) Basal cell carcinoma on the tip of the nose (the lesion in the nasolabial fold is a simple dermal nevus). (b) The edge of the tumor and the proposed flap design have been marked: the line of the proposed wound is along a ridge that separates nasal subunits. (c) The tumor has been excised with a margin of normal skin, and the flap is being prepared; note that the small wedge at the upper end of the wound (known as a Burow triangle) has been excised and discarded, a process that prevents puckering of the wound tip. (d) The flap is undermined to create mobility. (e) Flap sutured into place.(f) Final result.

The choice of technique, and indeed consideration of alternatives such as cryotherapy or radiotherapy, takes into account many factors, including the following.

•	Patient factors—age, general health and medications, body site affected (this may influence healing or scarring), ability to attend for treatment, ability to care for a wound, etc.
•	Lesion factors—clinical or incisional biopsy diagnosis, subtype (e.g. morpheic basal cell carcinoma has higher local recurrence risk than in other types), size and rate of growth (may influence what is technically achievable or perceived aggression of the lesion).
•	Other factors—availability of treatment and skills of the clinician.

Repair of excised wounds may involve a number of techniques.

Elliptic wounds can generally be repaired by side-to-side closure, but other commonly used techniques include the following.

•	Healing by second intention—a useful technique but slow to heal, and may produce contracture of the skin. Particularly useful on the ears where it may be combined with fenestration of the cartilage to improve granulation (Fig. 5.5)
•	Skin grafting—split thickness or full thickness; the latter is especially used on the face to match the donor skin and recipient grafted site. Grafting is also used in treatment of leg ulcers, vitiligo, and other disorders.
•	Various flap repairs—advancement, rotation, transposition, island pedicle, etc. (Fig. 5.6) and(Fig. 5.7). In some instances, if the wound is large and the area is tight, additional preliminary techniques such as tissue expansion may be applied.

Fig. 5.7 Flap on the rim of the pinna. (a) Basal cell carcinoma of the pinna. (b) Planned excision, with a sliding wedge repair (the aim of this, rather than a simple wedge resembling a slice of cake, is that it avoids a linear wound along which the cartilage can fold).
(c) Tumor excised; note that both the lesion excision and the Burow triangle involve the full thickness of the ear.
(d) Flap sutured into place; the ﬁnal result is a slightly smaller but essentially normally shaped ear.

Pitfalls

It is pertinent to briefly consider some potential pitfalls of surgery for the less experienced practitioner.

These include the following.

•	Unnecessary operation—for example of a lesion erroneously thought to be malignant or of a rash that could be clinically diagnosed.
•	Wrong operation or technique—for example shave excision of a melanoma.
•	Poor healing or infection—may be unavoidable but can be predicted if operating on infected lesions.
•	Damage to other structures—especially nerve transection.
•	Issues of scarring—stretched scars (Fig. 5.8), keloid scars, and effects of scar contracture (e.g. ectropion).
•	Histology issues—lack of histology on some samples, surprise results, and interpretation of reports.
•	Inadequate excision—for example incomplete removal of a malignant neoplasm.
•	Inadequate records—a major cause of problems.

Fig. 5.8 Complications of surgery include a stretched scar (a); note the stretched freckles), suture marks and hypertrophic scar (both shown in b), and keloid formation, which particularly occurs on the head and upper trunk, and is shown here following an otoplasty operation (c). (Panel a from Lawrence CM, Cox NH. Physical Signs in Dermatology, 2nd edn. London: Mosby, 2002.)

Fig. 5.9 Methods used to take histopathologic sections of an excised localized lesion. An ellipse of skin containing a tumor is cut across the middle of the tumor nodule in the middle of the ellipse. At least in theory, this samples the tumor at the site of its closest lateral margin (compare distances marked ‘a’ and ‘b’). Further slices may be taken parallel to this one (‘bread loaf’ technique) or from each end of the specimen at right angles to the section drawn. Compare with biopsy of a rash (Fig. 2.26). Explaining to the laboratory workers what has been sampled helps them to make the correct decision about tissue processing.
(After an original drawing by Dr. N. H. Cox.)

Fig. 5.10 Limitations of histology reporting. Even with multiple sections from a tumor, it may be impossible to comment with complete accuracy on the excision. In this example, the visible tumor nodule is in dark blue and the clinically invisible extent is pale blue, with a solid border representing clinically unapparent tumor that will fall within the planned ellipse and a dotted border where tumor lies in skin outside the ellipse (asterisks) or below the skin surface (arrow). All three sections taken appear to have a margin of normal skin around the tumor, but three areas (asterisks) have not been excised. This is the rationale for micrographic surgery (Figs 5.11 and 5.12) in poorly defined lesions. (After an original drawing by Dr. N. H. Cox.)

Fig. 5.11 Mohs micrographic surgery. (a) Tumor nodule, with clinically visible portion in dark blue and clinically invisible portion in pale blue; the latter lies partly outside the planned circular excision. (b) The central nodule is debulked (this helps to determine the extent and creates a thinner skin specimen) and an excision line is created; nicks are made in the specimen and in the adjacent skin, so that the sample can be oriented and the tumor mapped histologically. (c) The specimen of skin is freed; in this diagram, a further, clinically unapparent extension of the tumor is shown (arrow) on the undersurface of the specimen. (d) The specimen is divided according to the premarked nicks at its edges, and the samples numbered to correspond to an identiﬁable quadrant of the surgical site. (e) Each quadrant is placed flat, so that the whole of the undersurface and the most peripheral margin will be sampled in a tissue section from this deep aspect (dotted line). (f) The location of tumor at the margin or deep surface of each specimen is documented and drawn on to a diagram.
(g) Further surgery can then take place at the sites where there is residual tumor, sparing areas where a clear margin has been identiﬁed. (After an original drawing by Dr. N. H. Cox.)

Fig. 5.12 Micrographic (Mohs) surgery to a nasal basal cell carcinoma. (a) Initial poorly deﬁned basal cell carcinoma. (b) Stage 1 excision. (c) Stage 2 excision.
(d) Stage 3 excision. (e) Stage 4 excision. (f) After repair. (Courtesy of Dr. C. M. Lawrence.)

Many of the above are technical issues that can be avoided by appropriate training, and by attention to the local anatomy and to surgical options
for operating at specific body sites. It is of importance to have some understanding ofi laboratory issues: adequate information for the pathologist is crucial, correct samples are required (e.g. frozen tissue for direct immunofluorescence), and reports must be read in the context of what has been performed. For example, a report indicating complete excision of a lesion that has been routinely ‘bread loaf'–processed will just be an assessment of the adequacy of excision in the section(s) that have been examined (Fig. 5.9 and Fig. 5.10). This problem is avoided by the micrographic surgical method, in which the whole of the deep and lateral margin of each specimen is examined and any residual tumor can be mapped; however, this technique is time consuming for both operator and pathologist, and is therefore usually reserved for large or indistinct tumors, recurrent lesions, tumors associated with scar tissue, or tumors at sites where maximum preservation of non-lesional skin is important Fig. 5.11 and Fig. 5.12).

Practice points

•	Cryotherapy is painful and may cause edema or blistering; always consider whether it is appropriate for the lesion and site.
•	Always consider whether an operation is necessary, and whether the choice of procedure is the correct one.
•	Stretched scars and effects of scar contracture (e.g. ectropion) can usually be avoided by consideration of tension lines and use of subcuticular sutures.
•	Inadequate records are a major cause of medicolegal problems.