Abstract
Certain anogenital conditions require surgical intervention and although the specialty training curriculum for genitourinary (GU) medicine mentions skin biopsy as the only surgical skill required for training, most practitioners could usefully provide a more extensive surgical or ‘minor ops’ service. The purpose of this paper is to provide guidance for practitioners considering starting a minor surgery service, outlines the equipment required and describes commonly used techniques such as skin biopsy, cryotherapy, excision, electrosurgery and laser ablation.
INTRODUCTION
Certain anogenital conditions require surgical intervention, either to aid diagnosis or as a method of treatment. There are a number of different surgical approaches and the experienced practitioner will opt for the technique best suited to the presenting condition or management need. Commonly used surgical methods of treatment include cryosurgery (also known as cryotherapy), electrosurgery, excision and laser ablation. Skin biopsy is a surgical technique used for diagnostic purposes. Although surgery is often considered as a late stage management option for genital warts, lesions that may respond slowly to self-applied podophyllotoxin or imiquimod, such as solitary keratinized warts and multiple lesions of moderate size, are ideal for excision.
The purpose of this paper is to provide an overview of how to set up a minor surgery service in the genitourinary (GU) medicine/sexual health setting and the surgical techniques required, bearing in mind that patients with more extensive disease would usually be referred to surgical colleagues or, ideally, to a multidisciplinary team comprising dermatology, surgery/gynaecology/urology and GU medicine/sexual health.
The information provided in this paper was obtained by performing a literature search with PubMed using ‘electrosurgery’, ‘cryotherapy’ and ‘skin biopsy’ as keywords, and from dermatological textbooks, two of which are listed at the end of this paper as suggested further reading, discussion with dermatology colleagues and from personal experience.
LOCAL ANAESTHESIA
Local anaesthesia is required prior to surgery, with the exception of cryotherapy (see below). There are a number of types of local anaesthetic but lidocaine is readily available, cheap and a good first-choice agent. The addition of adrenaline causes vasoconstriction, which results in a longer duration of anaesthesia and, possibly more importantly for minor anogenital surgery, reduced bleeding. About 1% lidocaine with 1:200,000 adrenaline provides optimal vasoconstriction and good duration of action. Lidocaine with adrenaline is a little more painful to inject than plain lidocaine owing to the addition of sodium metabisulphite, which prevents the oxidation of adrenaline. Large volumes of lidocaine can be tolerated by healthy individuals. The maximum safe dose is considered to be 200 mg, which is equivalent to 2 × 10 mL ampoules of 1% lidocaine. Lidocaine is safe to use in pregnancy, even with the addition of adrenaline, although deferring surgery until after the first trimester is prudent in non-urgent cases. There is no contraindication to its use in breast-feeding mothers.
The maximum safe dose of adrenaline is considered to be 500 μg (2 × 10 mL ampoules of 1% lidocaine with 1:200,000 adrenaline contains 200 μg of adrenaline). Although some practitioners advise against the use of adrenaline in penile anaesthesia, small amounts (e.g. 0.5–1.0 mL, and possibly more) can be used safely. Lidocaine without adrenaline should be used for a penile nerve block.
A number of drugs may change lidocaine blood levels and for this reason the maximum dosage is probably best reduced in patients taking β-blockers, amiodarone, disopyramide and cimetidine. There is also a risk of ventricular arrhythmias in patients taking saquinavir and fosamprenavir.
Prilocaine with felypressin, acting as a vasoconstrictor, is used by some practitioners as an alternative to lidocaine. As with a variety of the lidocaine injections with adrenaline, this is available in cartridges for use with a dental syringe, which can be fitted with a 27-gauge (G) needle. Long 27G and short 30G needles are also available for use with non-dental syringes, and are to be preferred to the standard orange 25G needle.
Topical anaesthesia with a mixture of prilocaine and lidocaine as a cream (EMLA®, AstraZeneca UK Ltd, Luton, UK) can be used in place of injected anaesthetic and should be applied under polythene occlusion for 1–2 hours. Using EMLA for a shorter duration (e.g. 30 minutes) prior to injecting lidocaine or prilocaine, in an attempt to make the procedure virtually painless, is good practice. Some patients become particularly anxious at the thought of a genital or anal injection, and prefer this ‘preinjection numbing’ approach, although the extra time required needs to be factored into the clinic appointment schedule.
In addition to using a 27/30G needle and prior use of EMLA, other techniques to help reduce the discomfort of injection include injecting very slowly, injecting subcutaneously rather than into the dermis and, when anaesthetizing larger areas, re-introducing the needle through already anaesthetized skin.
SKIN BIOPSY
A skin biopsy should be considered as an initial investigation to diagnose dysplasia or malignancy. Although patients with anogenital squamous cell carcinoma present uncommonly to departments of GU medicine/sexual health, dysplastic lesions are not uncommon and biopsy in these cases is essential to confirm the diagnosis. The need for biopsy to diagnose a dermatosis or non-neoplastic lesion is determined to some degree by the clinical experience of the practitioner, in particularly with respect to the practitioner's genital dermatology experience. 1
Punch biopsies are quick and easy to perform and a disposable 3 or 4 mm size punch is usually adequate. This provides a full thickness biopsy down to the fat layer which is ideal for suspicious pigmented naevi and dysplastic lesions. Multiple biopsies may be required from dysplastic lesions to reduce the chances of missing invasion. Following a twisting action with gentle pressure, remove the punch and gently grip and pull the tissue with forceps, allowing the base to be snipped through with fine scissors or a scalpel blade. As toothed forceps may damage the biopsied tissue, untoothed forceps or skin hooks (e.g. Gillies) are preferred by some practitioners. The biopsy site may be left open and haemostasis provided by the application of Monsel's solution. This is a reddish-brown solution of ferric subsulphate prepared from ferrous sulphate and nitric acid. Although available as a solution, it can be turned into an easily applied paste if left open to the air and stirred daily for 1–2 weeks. Silver nitrate sticks are effective but burn and are not recommended on external genital sites. Chemical haemostasis should be avoided if a suture is to be used as the dead tissue within the wound may predispose to infection.
A punch biopsy is unnecessarily deep if the pathology is likely to be restricted to the epidermis or high dermis, as is the case for dermatoses, benign naevi and benign lumps. In these cases, a shave biopsy using a scalpel blade would be preferred. A superficial scissor excision may be used but tends to produce a crushing effect which may interfere with the histological assessment. Similarly, the use of toothed forceps can damage tissue, so use with care or opt for non-toothed forceps when lifting the skin for biopsy. Shave and scissor biopsies do require a degree of experience to ensure reaching the correct depth.
Incisional biopsy is particularly suited to moderately sized pigmented lesions, too large for total excision. A strip of tissue is obtained by making a narrow incision through the lesion. This provides the histologist with a potentially more representative biopsy than would be obtained from a single punch. Any pigmented lesion raising a suspicion of melanoma should be referred urgently to dermatology colleagues.
A couple of practical points regarding penile biopsy: consider biopsying the prepuce in men with a balanoposthitis as the preputial skin is often easier to biopsy than the glans and the biopsy site tends to ‘gape’ less. Also, consider leaving the biopsy site open to heal by granulation as sutures are strained and may not remain intact with penile erection.
SUTURES
Although there are a variety of suture materials available, both non-absorbable and absorbable, becoming familiar with one or two types is probably sufficient for GU medicine practice. Vicryl is an absorbable suture which is easy to use and knot. ‘Coated’ Vicryl eases passage through tissue and Vicryl Rapide is a quick absorbing suture (7–10 days) and very good for the mucosa.
Needle thickness and length are determined by the size of the suture material. The needle is passed through the skin at 90° to the surface and should be of a length that can be easily grasped by forceps without damaging the needle tip. Curved needles are ideal for skin surgery and should be used with a ‘rotating wrist’ action, following the curve of the needle, when passing the needle through the skin. A reverse-cutting needle has a cutting edge on the outer side of the needle which therefore points away from the wound and the direction of pull. This means that it is less likely to cause the suture to tear through the wound edge compared with a needle with the cutting edge on the inner curve. Small-sized needles, such as 4-0 or 5-0, are usually adequate for the anogenital skin and mucosa. Although suturing technique is beyond the scope of this article, it is important to remember that needles should be grasped in the middle third and not at the tip or at the weak end by the suture (shank end).
PREOPERATIVE ASSESSMENT AND ADVICE TO THE PATIENT
Before embarking on surgery the patient should be asked whether there have been previous problems associated with local anaesthesia, such as at the dentist. Enquire about allergic reactions, conditions that may affect haemostasis and whether they are taking medications that could interact with lidocaine or adrenaline. Possible complications should be discussed prior to obtaining written consent for the procedure. These are uncommon but include bleeding, bruising, infection and scarring or keloid formation. Bleeding can cause alarm, so warning the patient that this is usually easily controlled by firm pressure is reassuring. Bathing with a weak salt solution is anecdotally helpful and the use of a topical lidocaine gel appreciated by many. Advising against sexual activity until a degree of healing has occurred is wise but often not heeded.
SURGICAL METHODS
Cryotherapy
This method of ablative therapy is commonly used in the field of dermatology for treating a range of common skin conditions, 2 and in GU medicine/sexual health mostly for treating anogenital warts and molluscum contagiosum. It can also be used for treating dysplastic lesions, such as vulval intraepithelial neoplasia (VIN), penile intraepithelial neoplasia and anal intraepithelial neoplasia, although excision or laser ablation are probably more effective once imiquimod has been used or considered inappropriate. Some practitioners consider cryotherapy to be less useful for treating dysplastic lesions in immunosuppressed patients. Cryotherapy is an effective method of treating symptomatic cervical ectopy 3 and penile papules, 4,5 although most men with this common finding do not warrant treatment. 6
Cryotherapy damages tissue by intracellular ice formation, cell disruption secondary to osmotic changes during thawing, cold injury to small blood vessels causing ischaemic damage and immunological stimulation following the release of antigens from damaged tissue. The degree of tissue damage is determined by the rate of freezing, the coldest temperature reached, the freeze time and the rate of thawing. Rapid freezing followed by a slow thaw is most destructive. A temperature of −30°C is sufficient to cause cell death. Liquid nitrogen is a cheap and highly effective cryogen that can be used via a probe or spray. The boiling point of liquid nitrogen is −196°C, which allows temperatures of −25°C to −50°C to be achieved within 30 seconds of use. Fine spray attachments can be used for treating small lesions without damaging the surrounding skin. The required duration of freeze or ‘freeze time’ is determined by the site, type and size of lesion. The freeze time is taken from the point when the lesion is completely frozen with a surrounding white halo (so-called point of ‘ice ball’ formation). Lesions of molluscum contagiosum are very sensitive to cryotherapy and often require only a few seconds of freezing. Small warts usually respond to a 10-second freeze while larger lesions may require 30–45 seconds. Anecdotally, anal canal warts may require a longer freeze time. Although most patients tolerate cryotherapy, the use of topical EMLA for just 10 minutes prior to freezing has been shown to reduce the discomfort. 7 Some practitioners treat large anogenital warts with much longer freeze times than generally used. In these cases, the potential for patient discomfort should be appreciated and may be obviated by the use of pre-treatment oral non-steroidal anti-inflammatories and post-treatment topical anaesthesia. A double freeze-thaw cycle produces more tissue damage but is usually unnecessary for benign lesions, such as warts.
Electrosurgery
Electrosurgery is known by a few names and includes surgical diathermy, cold electrocautery and hyfrecation. This approach is ideally suited for cutting, desiccation and haemostasis. Electrosurgical equipment produces high frequency alternating current which is converted into heat energy as it passes through a high-resistance medium such as the skin. The equipment uses either unipolar or bipolar electrodes. Unipolar or monoterminal electrodes produce current from a point source that dissipates through the patient. Although this has the potential to cause electrical burns caused by sparks passing between the patient and operator, this is rarely a problem with the low energies used for anogenital electrosurgery. Bipolar electrodes produce and collect current via a pair of electrodes. Monoterminal electrosurgery is adequate for most anogenital lesions and is particularly useful for removing warts and keratoses. Holding the electrode against the skin results in electrodissection whereas holding the electrode a short distance away from the skin causes a spark to jump between the electrode tip and the skin and is called fulgarization. Electrodissection produces less tissue damage but otherwise the type of damage produced is the same. The electrode should be applied to the lesion to produce tissue softening without charring and slowly dragged to remove tissue. The area can then be wiped using a gauze swab to leave an uncharred underlying surface.
Thin wire loop excision, as used for treating cervical intraepithelial neoplasia, is a method of electrocautery that can be used to remove warts at all genital sites, including the cervix and vagina. The wire is moved slowly through the base of the lesion which is lifted away from the skin by non-conducting (plastic) forceps.
Electrocautery or ‘heat cautery’ involves heating a ‘wire tip’, as for cold electrocautery described above, but without the passage of electrical current. The power should be set to ‘below glowing’ which involves increasing the power until the wire tip just starts to become red and then reducing power slightly so that there is no longer a glow. The wire can be sterilized after use by simply increasing the power until the tip glows red hot. This burns off any tissue debris remaining on the wire.
On a practical note, it is wise to avoid alcohol-based skin cleansing agents when using electrosurgery because of the risk of fire. Also worth noting is that electrosurgery in the anogenital area will not affect pacemaker function; this is more of a concern for procedures performed on chest lesions located close to the pacemaker.
Laser
Laser is an acronym for Light Amplification by the Stimulated Emission of Radiation. The laser works by focusing an immense amount of monochromatic light energy onto a small area. The carbon dioxide laser is the type most frequently used for treating anogenital lesions. This emits light in the invisible electromagnetic spectrum at 10,600 nm, either as a continuous or pulsed beam. This degree of energy heats intracellular and extracellular water to boiling point resulting in evaporation of the cell. The beam can be directed with precision using a hand piece which may be connected to a colposcope to enable the accurate removal of small lesions. One of the major advantages of laser ablation is the minimal damage to surrounding tissue, which can be a problem with electrosurgery. Minimal heat conductivity results in a layer of necrosis of only a few tenths of a millimetre. The depth of tissue destruction is controlled by adjusting the power setting, regulating the diameter of the light beam and varying the speed of beam motion. A focused beam can be used for cutting whereas a defocused beam (about 2 mm diameter) causes vaporization of superficial cell layers. The major disadvantages to using a laser are the cost and the health and safety issues.
Laser ablation can be used to treat anogenital warts and intraepithelial neoplasia, although recurrence with VIN is well reported, in part related to disease extending into hair follicles.
Excision
Excision can be performed by scissor, scalpel, razor blade and curettage. Scissor or snip excision is an excellent method for removing skin tags, fibroepithelial polyps and anogenital warts, particularly large lesions and those with a narrow base. Large areas of warts can be removed following the infiltration of anaesthesia which elevates and separates the lesions (Thomson's method). By lifting the warts, individual lesions can be easily removed without damaging unaffected surrounding skin. A curved iris scissor is ideally suited for this technique.
Epidermoid cysts (e.g. vulval or scrotal sebaceous cysts) may require excision if they become repeatedly infected or for cosmetic reasons. Inflammation of a cyst is not always indicative of infection. If the cyst wall ruptures, for example after being squeezed, keratin is released and causes a foreign body reaction in the surrounding tissue. The cyst will be tender but with little erythema. Injecting triamcinolone into the cyst should relieve the discomfort and may lead to resolution. If removal is considered necessary, the technique involves extirpating or shelling out the cyst by blunt scissor or scalpel dissection. The correct tissue plane for dissection is next to the cyst wall and although removal is usually easy, puncturing the cyst can occur. This may leave fragments behind that can lead to recurrence. An alternative method to dissection involves deliberately puncturing the cyst, expressing the contents and then grasping the furthest inner cyst wall and pulling the cyst inside-out through the skin wound and removing.
Shave excision by scalpel is a useful method for removing anogenital warts, keratoses and benign naevi. The scalpel blade is moved through the base of the lesion horizontally and can be used mounted on a scalpel handle or held in the fingers. Some practitioners prefer to use a one-sided razor blade, bent at the middle, as this may provide greater control over the depth of excision.
Curettage is less commonly used by GU medicine practitioners but is a good method for removing lesions where there is a natural cleavage plain between the lesion and the surrounding tissue, such as seborrhoeic keratoses and warts. The skin must be held tense in order to find the plain of cleavage and this can often prove difficult at genital sites and result in skin tearing. There are various types of curette available but a 3–4 and 7 mm cutting edge would provide adequate choice. Disposable instruments are particularly useful.
PROVIDING A SURGICAL SERVICE WITHIN GU MEDICINE
Although skin biopsy is the only surgical skill required for training in GU medicine, as detailed in the specialty training curriculum for GU medicine, 8 most practitioners should be able to provide a rather more extensive surgical or ‘minor ops’ service. Surgical technique workshops organized through the British Association of Sexual Health and HIV are now running in the UK and are to be recommended for trainees and experienced practitioners wishing to improve their surgical know-how. In addition, although not featuring in the curriculum, I would strongly advise attending dermatology minor surgery sessions.
Appendix A lists what I would consider to be the minimum requirements for providing a surgical service within the GU medicine/sexual health clinic setting. Colleagues already performing minor surgery will have their own preferences and those just starting a service will identify particular needs over time.
Remember that appointment times should be appropriately spaced to allow for consent, the procedure, discussion and the possibility of the patient feeling unwell postsurgery. As mentioned earlier, the application of EMLA cream under occlusion for 30–40 minutes prior to injecting local anaesthetic can make the procedure virtually painless and is appreciated by patients.
DISCUSSION
The skills required to provide a minor surgery service within the GU medicine/sexual health clinic setting are easily learnt and some doctors in training may consider it beneficial to learn surgical techniques beyond that of cryotherapy and skin biopsy. Surgically managing anogenital disease in the clinic rather than referring onto our colleagues in dermatology, gynaecology and urology may be beneficial to patients, is often clinically rewarding for the practitioner and is seen to be providing a more comprehensive service. More extensive anogenital disease and suspected malignancy should optimally be referred but the surgical management of ‘minor’ disease should fall within the clinical expertise of GU medicine/sexual health.