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Skin lesions

Surgery key points test

Which of the following statements are true? #! An elderly person is less likely to have a prominent scar than a child # A dark skinned person is less likely to have a prominent scar than a fair skinned person #! Scarring is greater if the direction of the scar is perpendicular to the natural lines than if it is parallel to these lines #! Haematoma, infection and wound dehiscence increase scarring Explanation: Elderly skin appears more forgiving because there is less vigorous collagen formation after skin injury and scars can often be hidden within wrinkles and skin furrows. Scars in dark skinned individuals are often more noticeable because of hypopigmentation, hyperpigmentation and hypertrophy or keloid formation. Scars are least obvious if the excision is at right angles to the direction of the resultant pull of the muscles or parallel to natural skin creases. They may be more severe if there is haematoma, infection or wound dehiscence. Regarding local anaesthetic agents: # The onset of action of Emla is one to two minutes # The onset of action of lignocaine with adrenaline is faster than of plain lignocaine #! The addition of adrenaline to lignocaine reduces its toxicity # The maximum safe volume of 1% plain lignocaine in an adult on a single occasion is about 5ml Explanation: The onset of action of Emla is slow, so it needs to be applied one to two hours prior to the planned procedure. The addition of adrenaline to lignocaine prolongs its duration, reduces toxicity and controls bleeding but has no effect on the time of the onset of its action. The maximum safe volume of 1% plain lignocaine in an adult on a single occasion is about 20ml. Select the appropriate time after surgery to remove sutures from a small skin wound #! 6 days on the face # 12 days on the nose #! 14 days on the lower leg # 6 days on the upper back Explanation: Sutures should be removed 4 to 7 days after the procedure from the face and 7 to 14 days elsewhere (neck and arms < trunk < legs). If available, Mohs micrographic surgery should be considered for which tumours: # 6 mm nodular squamous cell carcinoma on the forearm #! 20 mm morphoeic basal carcinoma on the nasolabial fold #! Indistinct multiply recurrent superficial basal cell carcinoma on the forehead # 12 mm superficial spreading melanoma on the upper back Explanation: Mohs micrographic surgery is used for primary and recurrent non-melanoma skin cancer in high-risk areas such as the midface. Haemostasis can be obtained using: #! Aluminium chloride solution # Calcium chloride solution # Electrosection # A ligature applied to a capillary Explanation: Haemostasis can be obtained by localised pressure, using chemical haemostatic agents such as aluminium chloride or ferric subsulphate, electrosurgery or ligature of the bleeding vessel. Capillaries are too tiny to ligate! Electrosurgery may be used for which of the following procedures? #! Gentle electrodessication prior to curettage of a viral wart #! After curettage of a basal cell carcinoma #! To obtain haemostasis during an excision biopsy #! To eradicate a facial spider telangiectasis Explanation: Electrosurgery may be used for all described indications.