The simple interrupted stitch

What it is

The simple interrupted stitch is the basic skin closure and the one most OSCE suturing stations ask for. Each stitch is an independent loop: the needle enters the skin on one side, passes through the dermis, crosses the wound at the same depth and exits on the other side at the same distance from the edge, and the stitch is tied with an instrument knot and cut before the next one is placed. Because every stitch stands alone, the tension can be adjusted along an irregular wound, and a single stitch can be removed to drain a collection without opening the whole wound. The aim is edges that meet exactly and are slightly everted (turned up), because flat or inverted edges heal into a depressed scar. It is slower than a running closure and leaves more knots, but it is the most forgiving technique and the safest default for a traumatic laceration.

Indications

• Clean, recent lacerations through the full thickness of the skin that can be closed without tension.
• Irregular or curved wounds, where the tension and alignment need adjusting stitch by stitch.
• Wounds with some risk of infection, where removing one or two stitches to drain is an advantage.
• Placing the first key stitches (at a corner, a skin crease or the vermilion border) before closing the rest by any method.

Contraindications and precautions

• Do not close infected wounds, abscesses or wounds with a retained foreign body that has not been removed.
• Wounds seen late, heavily contaminated wounds and high-risk bites may be better left open or closed later: decide with the wound assessment.
• Deep injury to tendon, nerve, vessel, joint or duct, and complex facial wounds (eyelid margin, lip border, ear cartilage), go to a senior or specialist.
• Ask about allergies to local anaesthetic or materials, anticoagulants, diabetes, smoking and steroids, which affect bleeding and healing.
• Wounds under tension need deep dermal stitches first; skin stitches alone pulled tight cut through and leave marks.

Equipment

• Sterile gloves, drape, antiseptic solution and good light.
• Local anaesthetic, syringe and fine needles; irrigation fluid and a syringe for pressure irrigation.
• Needle holder, toothed fine forceps and suture scissors.
• Non-absorbable monofilament skin suture (nylon or polypropylene) on a reverse-cutting needle, sized for the body site.
• Gauze, a sterile dressing and a sharps container.

Step by step (and why)

1. Introduce yourself, confirm identity, consent and allergies — the station marks communication and safety first.
2. Assess, anaesthetise and irrigate the wound and check it for foreign bodies — closing over dirt or glass causes infection.
3. Load the needle two-thirds back from the tip in the needle holder tips — this grip is stable and does not blunt the point.
4. Evert the edge gently with toothed forceps and enter at 90° to the skin — a perpendicular entry gives a wide deep bite and everted edges.
5. Follow the curve of the needle with a rotating wrist — pushing straight bends the needle and tears the skin.
6. Take a bite as wide as it is deep, the same on both sides and level — symmetry stops the edges overlapping or stepping.
7. Tie an instrument knot, lay it to one side of the wound and cut the tails short but graspable — a knot on the wound line irritates it.
8. Snug the stitch so the edges just meet — tissue swells, and a tight stitch causes ischaemia and track marks.
9. Space stitches about as far apart as the bite width, halving the wound if needed — even spacing gives even tension.
10. Dispose of sharps yourself, dress the wound and explain care and removal — needlestick prevention and aftercare are marked.

Typical choices; tension, age, healing and local practice change them.

Complications

• Wound infection: redness, warmth, swelling, pain and discharge; remove one or more stitches to drain and review.
• Dehiscence: the wound opens, often from tension, infection or removing stitches too early.
• Suture marks across the scar from stitches tied too tight or left in too long.
• Inverted or stepped edges from shallow, uneven or angled bites, healing into a poor scar.
• Skin necrosis at the edges from excessive tension; hypertrophic scar or keloid in prone patients.
• Needlestick injury to the operator.

Next step

• Dress the wound and advise keeping it clean and dry at first, with gentle washing after a day or two.
• Explain the warning signs (spreading redness, pus, fever, increasing pain) and to return if they appear.
• Arrange stitch removal at the right time for the body site (face early, limbs and joints later).
• Check tetanus status and give prophylaxis by the local scheme.
• Call a senior for deep structure injury, complex facial wounds, or a wound you cannot close without tension.

Test yourself

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Elsewhere in DurgiPedia

• Removing sutures and staples
• Healing of skin wounds: first and second intention

Connections

← All clinical skills

Educational content; it does not replace supervised hands-on training, your institution's protocols or a prescriber's order. A procedure is learnt with a teacher and done only once you are trained to do it.

Sources: Wound Closure Techniques (StatPearls (NCBI Bookshelf), 2023); Sutures and Needles (StatPearls (NCBI Bookshelf), 2023).

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Representative model, for educational purposes only.