Principles

Z-plasty: a transposition of two adjacent triangular flaps that share a common limb (the central limb of the "Z"). It achieves:
- Lengthening of the central limb (theoretically by 25% / 50% / 75% / 100% for 30° / 45° / 60° / 75° flap angles; 60° is standard with ~75% gain).
- Reorientation of the central limb by twice the angle (60° angle → reorient by 90°).
W-plasty: a series of small interdigitating triangles replacing a straight scar with a zig-zag. It achieves no lengthening but visually breaks up the scar and aligns sub-segments with relaxed skin tension lines (RSTLs).

Indications

Z-plasty:
- Linear contracture across a joint (axillary, antecubital, popliteal, web spaces).
- Scar perpendicular to RSTL.
- Webbing along nasolabial, oral commissure, or paranasal regions.
- Misaligned vermilion border.
W-plasty:
- Long straight scar crossing aesthetic boundaries (e.g. forehead, nasolabial, perioral).
- Post-skin-cancer linear scar visible at a distance.
- Avoid in highly mobile or contracture-prone areas — geometric break-up does not lengthen.

Z-plasty:
1. Mark the central limb along the existing scar.
2. Mark two limbs of equal length to the central limb, at 60° each (other angles for specific lengthening / reorientation).
3. Excise the original scar within the central limb.
4. Raise the two triangular flaps in the subdermal / deep-fascial plane respecting underlying neurovascular structures.
5. Transpose flaps so that tip of A goes to base of B, and vice versa.
6. Inset carefully in layers, avoiding tip tension and preserving flap vascularity.
W-plasty:
1. Plan a series of triangles 3-5 mm at base along the scar.
2. Match each triangle to a precisely opposing triangle on the contralateral side.
3. Excise the scar within the triangles; close interdigitating triangles primarily.
4. Each segment ideally aligns with local RSTL.

Inadequate undermining → flap tension and tip necrosis (commonest pitfall).
Tip-angle <30° → unreliable distal flap survival.
Tip-angle >75° → limited transposition / suboptimal lengthening.
Disregarding underlying anatomy (facial nerve in cheek Z-plasty).
W-plasty across mobile / joint-crossing scars provides no functional lengthening.
Pin-cushioning of small triangles in elderly or sun-damaged skin.

For long contracture scars, multiple serial Z-plasties may be more reliable than one large Z (less tip necrosis risk).
Four-flap Z-plasty (90°-90°) — increased lengthening (~120%); useful for first-web-space contracture.
Five-flap (jumping-man) — combination Y-V advancement with two Z-plasties; useful in dorsal hand-web release.
Consider intralesional / topical silicone gel post-revision (≥3 months) to optimise long-term scar appearance.
Counsel patients that scar revision exchanges one scar pattern for another — better, not invisible.