Risks and complications of skin surgery

Introduction

Skin surgery includes removal of skin lesions or sampling them (biopsy) to confirm a diagnosis. The sample will be sent to a pathologist who will examine the skin under a microscope.

The initial healing process occurs over 2-3 weeks. Remodelling and strengthening of the wound continues for 6 to 12 months following skin surgery. Complications such as bleeding and infection may delay the healing process, increase pain and discomfort and result in a larger scar.

This topic covers:

• Immediate complications of skin surgery
• Delayed complications of skin surgery
• Late complications of skin surgery
• Unnecessary or inappropriate skin surgery

Immediate complications of skin surgery

Complications quite commonly arise during or shortly after surgery, including:

• Bleeding
• Damage to important structures
• Adverse reactions to medications.
• Difficulty in closing the wound

There may also be difficulty in wound closure.

Bleeding during skin surgery

Risk factors for excessive bleeding include:

• Blood clotting abnormalities: low platelet count, low clotting factors (as occurs in liver failure), haemophilia, von Willebrand disease
• Medications: aspirin, clopidogrel, warfarin, dipyridamole, heparin, dabigatran
• Over-the-counter preparations: fish oil, garlic, ginko, ginseng, vitamin E, Dong quai, feverfew, resveratrol
• Surgical site: forehead, scalp and eyelids often bruise more than other sites.

A small amount of bleeding and bruising can be expected. Your surgeon will try to minimise this as much as possible during the procedure by either clotting small vessels using electrosurgery (cautery) or tying off bleeding vessels with a stitch / suture.

Excessive bleeding:

• Increases the risk of bacterial wound infection
• Causes swelling and discomfort
• Delays wound healing
• May cause light headedness, shortness of breath, chest discomfort or syncope (a faint).

If bleeding occurs, rest with the affected area elevated above the level of your heart, and apply firm, constant pressure on the wound for 20 minutes without removing the original dressing. If bleeding continues, urgent medical advice should be sought.

Damage to important structures during skin surgery

Skin surgery inevitably results in an injury to some components of the skin i.e. the epidermis (outer layer), dermis (structural layer) and subcutaneous tissue (fat layer).

However, important structures may also be damaged, particularly if the skin lesion for removal has grown deep into underlying structures or the lesion is in a site where important structures such as nerves or salivary glands lie close to the skin surface.

Adverse reactions to drugs during skin surgery

Medications used immediately before or during surgery include local anaesthetic and analgesics to reduce the pain of the procedure.

Local anaesthetics

Local anaesthetics work by blocking sodium channels on nerve cell membranes. This results in blockage of pain impulses along the nerve. Adrenaline-containing local anaesthetic is administered in an acidic substance. This is essential to maintain the anaesthetic in a soluble form. It is also responsible for a stinging sensation on injection. There are two main types of local anaesthetic: esters and amides.

Local anaesthetics are generally safe. Adverse reactions may occur if a large volume is injected or if the anaesthetic is inadvertently injected into a blood vessel.

• Mild reactions are relatively common. They include: tingling of mouth, metallic taste and dizziness.
• Severe reactions are rare. They include slurred speech, double vision, confusion, muscle twitching, seizures, coma and cardiovascular toxicity such as arrhythmia (irregular heart beat) and cardiac arrest.
• True allergy to local anaesthetic is very uncommon. It is occasionally seen with the ester type, due a metabolite (para-aminobenzoic acid or PABA). Amide local anaesthetics have a very low risk of allergic reaction as the particles are mostly too small to provoke an immune response.

Local anaesthetics are often injected together with adrenaline (also called epinephrine). Adrenaline causes vasoconstriction resulting in less bleeding and less systemic absorption of the anaesthetic agent. Large volumes of adrenaline may result in:

• headache
• tremor
• tachycardia (fast heart rate leading to palpitations)
• chest pain
• high blood pressure.

Analgesics (pain relief medications)

Paracetamol (also called acetominophen) is available over the counter in pharmacies and supermarkets in New Zealand and elsewhere without the need for prescription.

• Paracetamol is generally safe and well tolerated.
• Paracetamol is metabolised by the liver and may cause toxicity or liver failure if taken above the recommended dose. People with liver impairment should consult with their doctor before taking paracetamol as lower doses or complete avoidance may be required.
• Rare side effects of paracetamol include gastrointestinal upset, pancreatitis, blood count abnormalities and, with prolonged use, renal toxicity.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a class of drugs which include ibuprofen, diclofenac, naproxen, meloxicam and indomethicin. These are marketed under a number of trade names in New Zealand and some are available without prescription.

• Common side effects of NSAIDs: gastrointestinal upset, heartburn, rash, headache, dizziness, elevated liver function tests.
• Rare side effects of NSAIDs: gastrointestinal bleeding, allergic reaction, leg swelling, urticaria, drowsiness and asthma.
• Very rare side effects of NSAIDs: pancreatitis, seizures, depression or psychosis, high blood pressure, photosensitivity, cardiac failure, renal failure.
• NSAIDs should be avoided in asthmatics and people with renal impairment.

Opioids include codeine, tramadol, morphine and oxycodone. Codeine is available without prescription in a combined form with paracetamol in pharmacies. Other opioid analgesics require a doctor's prescription.

• Common side effects: drowsiness, nausea, vomiting, itch, dry mouth, constipation.
• Rare side effects: respiratory suppression, confusion, hallucinations, urticaria, heart rate or rhythm disturbance, dizziness, headache, urinary retention.
• Tolerance and addiction can develop especially if opioids are used at high doses for long periods of time.
• Dose adjustment may be required in renal or liver impairment.

Delayed complications of skin surgery

Complications may arise hours, days or weeks after a surgical procedure, including:

• Wound infection
• Wound breakdown
• Suture reactions
• Incomplete excision
• Delayed healing
• Persistent swelling

Wound infection after skin surgery

Wound infection occurs in approximately 1% of skin surgeries, although this figure varies with the type of procedure, type and location of tumour, and patient factors. Signs of skin infection usually appear several days after surgery and include increasing redness, swelling, and pain around the wound +/- pus or discharge from the wound. If you develop these symptoms you should see your surgeon promptly and you may be prescribed a course of antibiotics.

Severe wound infection is rare after skin surgery and may lead to fever and severe illness due to spread of bacteria via the bloodstream (bacteraemia). Left untreated, severe infection could be fatal.

The type of bacteria causing infection differs depending on body site:

• Glabrous skin (non hair bearing skin): Staphylococcus aureus, Streptococcus pyogenes
• Mucosal surface e.g. eyes, mouth: Streptococcus viridans, Peptostreptococcus species
• Perineum, groin: Staphylococcus aureus, Enterococcus species, Escherichia coli

Factors that increase the risk of infection include:

• Ulcerated or crusted skin lesion
• Increased skin tension at the wound site
• Poor blood supply to the area
• Smoking
• Immune deficiency (ability to fight infection is diminished such as in HIV infection, certain malignancies and inherited syndromes)
• Poorly controlled diabetes mellitus
• Malnutrition
• Certain drugs, e.g. systemic corticosteroids, chemotherapy agents
• Surgery on lower legs or in skin folds such as groin and armpits
• Old age
• Longer duration of surgery
• Soaking the wound soon after surgery; it is recommended to keep the wound dry for 48 hours/

If one or more of these risk factors are present, oral antibiotics may be prescribed for 7-10 days to prevent infection. It is important that the prescribed course is completed. Common antibiotic choices for skin infection include:

• a penicillin such as flucloxacillin
• a macrolide such as erythromycin
• a tetracycline such as doxycycline
• a cephalosporin such as cefaclor.

Wound breakdown after skin surgery

After stitches are removed the wound may reopen (dehisce), for example:

• If there is excessive tension at the site.
• If the wound develops infection

A clean reopened wound can be re-stitched but an infected wound is usually left to heal by secondary intention.

Surgical wound dehiscence

Surgical wound dehiscence

Suture reactions

Wounds are usually closed with sutures made of synthetic (e.g. nylon) or natural materials (e.g. cotton, catgut, silk). Some sutures are absorbable and others will need to be removed once sufficient wound healing has occurred.

Suture material may elicit redness and swelling at the wound site, as they are foreign to the body. This is an expected reaction and does not represent allergy or infection. Factors associated with increased reaction include larger caliber sutures, delayed suture removal, natural materials and braided sutures.

Absorbable subcutaneous sutures may also occasionally extrude through the skin as they dissolve; this can occur weeks or months after the procedure.

True allergy to suture material is rare but has been reported with catgut, silk and nylon sutures.

Incomplete excision of a skin cancer

A margin of healthy appearing skin is excised around a skin cancer to improve the chances of its complete removal. Once excised, the removed skin is sent to a pathologist for examination under a microscope. This gives a more reliable indication of whether the whole lesion has been removed. Skin cancers can occasionally recur even after careful surgery and when the pathologist has reported clear margins.

If a skin cancer is not completely excised, further surgical treatment may be required or a course of radiotherapy may be recommended.

Non-cancerous skin lesions may also recur. For example, epidermal cysts that have been drained or excised may reappear, requiring further surgery.

Delayed healing after skin surgery

Factors that delay healing after skin surgery include:

• Wound infection
• Poor blood supply
• Unsutured, open, wounds
• Diabetes mellitus
• Chronic disease, e.g. congestive heart failure, renal failure, malignancy
• Smoking
• Old age
• Malnutrition
• Marked swelling of the wound site
• Radiotherapy.

Wounds on the legs that are left to heal by secondary intention are particularly at risk of delayed healing due to poor blood supply.

If a wound remains unhealed after several weeks it should be reviewed by your dermatologist or surgeon. Underlying factors contributing to delayed healing should be optimised or treated where possible. Special dressings may be used to assist wound healing.

Persistent swelling

Surgery may damage lymphatic channels and cause swelling that takes weeks or months to resolve. Common sites for persistent swelling after skin surgery are the Lower eyelid and lower Legs

Lymphatic damage may also cause increased risk of infection and ultimately delayed healing.

Late complications after skin surgery

Late complications after skin surgery may include:

• Unsightly cosmetic result
• Recurrent tumours.

Unsightly cosmetic result

The appearance of the healed surgical site varies, depending on the type of surgery and its site. Some scar tissue always forms during surgery because the dermis (deep skin layer) is damaged.

Atrophic scar

Hypertrophic scar

Recurrent tumours

Tumour may recur at the excision site or a new tumour may develop. This usually requires repeated surgery to excise the new lesion. Depending on the tumour type, radiotherapy may be recommended as well or instead of further surgery.

Recurring melanocytic naevus

Recurring basisquamous cancer

Recurring lentigo maligna

Unnecessary or inappropriate skin surgery

Sometimes a skin lesion suspected of being cancerous is benign when examined under the microscope. Therefore, surgical excision (and the associated risks) was undertaken unnecessarily.

It may be difficult to make a definitive diagnosis based on the lesion's clinical appearance. The potential risk of missing a skin cancer must be weighed against the risk associated with potentially unnecessary surgery. Assessment of the lesion by a specialist dermatologist prior to surgery will help reduce the number of unnecessary procedures. In many cases, a skin biopsy may be undertaken prior to a major skin surgical procedure. Of course skin surgery may be chosen to remove non-cancerous growths for functional or cosmetic reasons.

Other examples of inappropriate surgery include:

• Wrong lesion excised (it is good practice to confirm and mark the exact site of surgery with the patient on the day of the procedure)
• Wrong technique eg, excising a lesion such as a wart which could have been treated with cryotherapy.