Skin Wound Closure OSCE — Suturing Technique, Staples, Tissue Glue, and Aftercare

Why This Station Is Tested

Skin wound closure is a core practical skill tested in surgical, procedural, and emergency medicine OSCE stations. It assesses sterile technique, suture material selection, knot-tying, wound edge apposition, and patient communication. Most medical schools test this on a suture pad or synthetic skin model.

Wound Assessment Before Closure

Before closing any wound, assess:

Wound Preparation

1. 1Irrigate thoroughly with normal saline (10–20 ml/cm wound length under pressure)
2. 2Debride devitalised tissue
3. 3Achieve haemostasis (pressure, diathermy if available)
4. 4Anaesthesia: lidocaine 1% (max 3 mg/kg without adrenaline; 7 mg/kg with adrenaline) — inject into wound edges, not the wound

Choosing the Closure Method

Interrupted Suture Technique

Suture selection: nylon (non-absorbable) or polypropylene for skin; vicryl (absorbable) for deeper layers.

Size by site: Face 5-0 or 6-0; scalp 3-0; trunk/limb 3-0 or 4-0; hand 4-0 or 5-0.

Steps:

1. 1Load needle holder (needle in jaws at right angle, 2/3 from tip)
2. 2Enter skin perpendicular to surface, 3–5 mm from wound edge
3. 3Travel through dermis in a curved motion, emerging on the opposite side equidistant from edge
4. 4Pull thread through — leave a 2–3 cm tail
5. 5Tie instrument knot: three throws (square knot — first throw reversed)
6. 6Cut suture tails 3–5 mm from knot
7. 7Place sutures 5–8 mm apart; wound edges should evert slightly (not invert)

Suture Removal Times

Signs of Wound Infection

Counsel the patient to look for: PRICE — Pain (increasing after 48 hours), Redness, Increasing swelling, Colour change (pus/discharge), Elevated temperature (fever).

Frequently Asked Questions

"What is the correct suture technique for a simple interrupted skin suture?"

The interrupted suture technique requires: loading the needle at 90° to the needle holder jaws, approximately two-thirds from the tip of the needle. Enter the skin perpendicular to the surface (not at an angle) approximately 3–5 mm from the wound edge. Curve the needle through the dermis following its natural arc, emerging on the opposite side equidistant from the edge. Pull the suture through leaving a 2–3 cm tail. Tie a square (reef) knot using three instrument throws — the first throw should be doubled for security, with the second and third throws in the opposite direction. The knot should lie to one side of the wound, not over it. Cut tails to 3–5 mm. Everted wound edges (slightly raised) indicate correct tension — this prevents an unsightly depressed scar.

"How do you select the correct suture size and material?"

Suture size is expressed as a number — the larger the number, the finer the suture (e.g., 6-0 is finer than 3-0). For skin sutures, non-absorbable monofilament (nylon, prolene) is preferred because it causes minimal tissue reaction and is easy to remove. Size by site: face 5-0 or 6-0 (cosmesis important), scalp and trunk 3-0 or 4-0, limbs 3-0, hand 4-0. For deeper layers, use absorbable sutures (vicryl 2-0 or 3-0) to close subcutaneous fat and reduce dead space — this also reduces tension on the skin sutures. In an OSCE, stating your suture choice with a rationale ("I'll use 4-0 nylon for this hand laceration as it minimises tissue reaction and can be removed at 10–14 days") demonstrates clinical thinking.

"When should you not close a wound primarily?"

Wounds that should not be closed primarily include: bite wounds (human or animal — high bacterial load including Pasteurella, Eikenella, anaerobes); wounds contaminated with soil, faeces, or organic material; wounds presenting more than 6 hours after injury (risk of bacterial colonisation — particularly on the lower limb where blood supply is poorer); and wounds with significant devitalisation or tissue loss. These should be irrigated, debrided, and either managed with delayed primary closure (at 48–72 hours if no signs of infection) or allowed to heal by secondary intention. An exception is facial wounds, which due to rich blood supply can often be closed at 12–24 hours with close monitoring.

"What is the maximum dose of lidocaine and how do you calculate it?"

The maximum dose of plain lidocaine (without adrenaline) is 3 mg/kg. With adrenaline (1:200,000 or 1:100,000), the maximum dose is 7 mg/kg, as adrenaline causes local vasoconstriction, slowing systemic absorption. Lidocaine 1% = 10 mg/ml. For a 70 kg patient: plain lidocaine maximum = 210 mg = 21 ml of 1%; with adrenaline = 490 mg = 49 ml of 1%. Signs of lidocaine toxicity: perioral tingling, metallic taste, tinnitus, visual disturbance, confusion, convulsions, cardiovascular collapse. Never use adrenaline-containing local anaesthetic in end-arterial sites: digits, tip of nose, ear pinna, and penis — the vasoconstriction can cause ischaemia and necrosis.

"How do you give aftercare instructions to a patient after wound closure?"

Aftercare instructions must cover: keep the wound dry for the first 24–48 hours; after this, gentle cleaning with soap and water is allowed — avoid soaking (baths, swimming). Watch for infection signs — PRICE (Pain increasing after 48 hours, Redness spreading, Increasing swelling, Colour change/pus, Elevated temperature/fever) — and return to A&E or GP if these develop. Return at the appropriate time for suture removal (site-dependent: face 3–5 days, trunk/limbs 10–14 days). Advise on sun protection to the healing wound for 6–12 months to prevent hyperpigmentation. Check and update tetanus status if indicated. In an OSCE, clear, structured aftercare instructions delivered in plain language score marks in both communication and safety-netting domains.

"What are the advantages and disadvantages of tissue glue vs sutures?"

Tissue glue (e.g., Dermabond — 2-octyl cyanoacrylate) advantages: no needles required (preferred in children and needle-phobic patients), faster application, no suture removal needed, acts as a bacterial barrier, comparable cosmetic outcome to sutures for appropriate wounds, and lower risk of needlestick injury. Disadvantages: only suitable for superficial lacerations under low tension; breaks down if wet (instruct patients to keep dry); contraindicated in bite wounds, infected wounds, joints (constant movement breaks the bond), mucous membranes, and wounds under significant tension. It should not be placed inside the wound — only on the apposed edges. Sutures remain superior for deep wounds, high-tension areas, irregular edges, and areas requiring precise edge apposition.

Related guides: Wound Care and Suturing OSCE · Skin Lesion Examination OSCE · Venepuncture and Cannulation OSCE · Scrub Technique and Sterile Field OSCE · Post-Operative Review OSCE