# Local Flap Design and Execution
## Overview
Local flaps are tissue rearrangements that move adjacent skin and subcutaneous tissue into a defect while maintaining a vascular pedicle. They are the workhorses of reconstructive surgery, particularly for head and neck defects where they provide excellent color and texture match. Mastery of geometric planning principles is essential for optimal outcomes.
## Fundamental Concepts
### Advantages of Local Flaps Over Grafts
Better color and texture match (like-with-like tissue replacement). Superior cosmetic result with less contraction. Durable coverage with full-thickness tissue including subcutaneous fat. Maintain sensation (innervated tissue). No donor site morbidity from a distant region.
### Key Biomechanical Principles
**Tension and laxity** -- flaps redistribute tension; always assess tissue laxity with pinch test. **Pivot point** -- the fixed point around which a flap rotates; effective length decreases with rotation. **Effective length** -- the farther a flap must rotate, the shorter its effective reach. **Blood supply** -- local flaps are generally random pattern (subdermal plexus); length-to-width ratio 2:1 body, 3-4:1 face.
**Relaxed skin tension lines (RSTLs)** -- place incisions parallel to RSTLs when possible for optimal scars. **Aesthetic subunits** -- place incisions along subunit borders to hide scars (especially on the face).
## Z-Plasty
### Principles
Transposition of two triangular flaps to redirect a scar, lengthen a contracture, or reorient tissue. Central limb is placed along the existing scar or contracture. Two lateral limbs of equal length are drawn at equal angles from each end of the central limb, on opposite sides.
### Geometry and Gain in Length
| Angle | Theoretical Gain in Length | Transposition Angle |
|-------|---------------------------|---------------------|
| 30 degrees | 25% | 60 degrees |
| 45 degrees | 50% | 90 degrees |
| 60 degrees | 75% | 120 degrees |
| 75 degrees | 100% | 150 degrees | | 90 degrees | 120% | 180 degrees |
The **60-degree Z-plasty** is the most commonly used -- good balance between length gain (75%) and ease of transposition. All three limbs should be of equal length.
### Applications
Release of linear scar contractures (e.g., across joints, neck, axilla). Reorientation of scars to align with RSTLs. Lengthening of webbed spaces (syndactyly, first web space). Correction of trapdoor deformity.
**Multiple Z-plasties** (running Z-plasty) -- several small Z-plasties in series; distributes changes over a longer scar with less distortion.
## W-Plasty (Running W-Plasty)
### Principles
Irregular excision of a scar in a zigzag pattern (interdigitating triangles). Does NOT lengthen or redirect the scar, only breaks up linearity. Best for long, conspicuous scars that cross RSTLs and cannot be redirected.
### Technique
Design interdigitating triangles along both sides of the scar. Triangles are typically 5-7 mm per side at 60-degree angles. Excise and close with precise alignment of the zigzag pattern.
## V-Y Advancement
### Principles
V-shaped incision is advanced and closed as a Y. The triangular flap advances on its deep pedicle (subcutaneous blood supply). Lengthens tissue in one direction. No tissue discarded.
### Applications
Fingertip reconstruction (Atasoy V-Y for dorsal tip loss; Kutler bilateral V-Y for lateral tip loss). Lengthening of columella in cleft lip. Release of scar contractures. Correction of whistle deformity after cleft lip repair. Island V-Y advancement for larger defects.
### Y-V Advancement
Reverse of V-Y: Y-shaped incision closed as a V. Shortens tissue in the direction of advancement. Used to correct displaced structures (e.g., elevated hairline).
## Rotation Flaps
### Design Principles
Semicircular flap that pivots about a point to close a triangular defect. The arc length should be 4-8 times the width of the defect base for adequate rotation. The larger the flap, the less tension at the closure point. Tension is maximal at the pivot point and the point farthest from the pivot.
### Technical Considerations
**Back-cut** -- incision toward the pivot point to increase mobility; shortens the effective pedicle (use cautiously). **Burow triangle** -- excision of standing cutaneous deformity at the base of the flap to facilitate closure. Can be designed as a single rotation or bilateral rotation (Yin-Yang / O-to-Z).
### Applications
Scalp defects (large rotation flaps, multiple flaps -- Orticochea). Cheek defects (cervicofacial rotation flap). Sacral pressure injuries.
## Advancement Flaps
### Single Advancement Flap
Rectangular flap advanced directly forward into the defect. Burow triangles excised at the base to allow linear advancement. Random pattern blood supply.
### Bilateral Advancement (H-Plasty)
Two advancement flaps from opposite sides of a defect. Creates an H-shaped incision pattern. Each flap bears half the tension. Useful for midline defects (forehead, scalp).
### Island Advancement Flap
Skin island isolated on a subcutaneous pedicle. Advanced on the pedicle into the defect. Greater mobility than standard advancement. V-Y is a form of island advancement.
## Transposition Flaps
### General Principles
Flap is lifted and transposed over intervening intact skin into the defect. Creates a secondary defect at the donor site (closed primarily or grafted). The flap's effective length decreases as the arc of rotation increases.
### Rhomboid (Limberg) Flap
Defect is designed or converted to a rhombus with 60-degree and 120-degree angles. Flap is created as a parallelogram adjacent to one side of the rhombus. Four possible flap orientations for each rhomboid -- choose the one that: Places maximum tension in the direction of greatest tissue laxity.
Places scars along RSTLs or aesthetic unit borders. Short diagonal of the rhombus indicates the direction of maximum tension at closure.
### Dufourmentel Flap (Modified Rhomboid)
Allows use of flap angles other than 60/120 degrees. More versatile than classic Limberg for defects that are not perfect rhomboids. The transposition angle equals half the sum of the defect angles.
### Bilobed Flap (Zitelli Modification)
Two-flap transposition technique using two lobes based on a common pedicle. Total arc of rotation: 90-100 degrees (Zitelli modification; original described 180 degrees). First lobe: closes the primary defect (slightly smaller than defect). Second lobe: closes the secondary defect from the first lobe (smaller still).
Tertiary defect: closed primarily. Classic application: nasal tip and alar defects. Standing cone deformity (dog ear) at the pivot point must be excised.
### Banner Flap and Note Flap
Small transposition flaps for periorbital and perinasal defects. Based on named or random pedicle.
## Interpolation Flaps
### Principles
Flap pedicle passes over or under intervening skin to reach the defect. Always a staged procedure: second stage for pedicle division (typically 2-3 weeks). Allow reconstruction with tissue from non-adjacent areas while maintaining pedicle blood supply.
### Paramedian Forehead Flap
Axial pattern flap based on the supratrochlear artery. Gold standard for nasal reconstruction (covered in detail in Seminar 67). Typically three-stage procedure: transfer, intermediate thinning, pedicle division.
### Abbe Flap (Lip Switch Flap)
Cross-lip interpolation flap based on the labial artery. Transfers full-thickness lip tissue from one lip to the other. Used for central upper lip defects (philtral reconstruction). Pedicle divided at 2-3 weeks.
### Retroauricular Interpolation Flap
Used for anterior ear and conchal defects. Based on postauricular skin with its rich blood supply.
Geometric illustration of Z-plasty technique showing: (A) initial scar with central limb and two lateral limbs drawn at 60 degrees on opposite sides, (B) the two triangular flaps elevated, (C) the flaps transposed with the central limb now reoriented 90 degrees, (D) final closure showing lengthened and redirected scar. Measurements and angles clearly labeled. The theoretical 75% gain in length is indicated. Clean surgical planning diagram style.
Surgical planning diagram showing four possible rhomboid (Limberg) flap orientations around a rhomboid defect with 60-degree and 120-degree angles. The short diagonal and long diagonal of the rhombus are marked. Each flap option is shown with an arrow indicating the direction of maximum tension at closure. The preferred flap is highlighted based on tissue laxity and RSTL orientation. Top-down view in medical illustration style.
Step-by-step illustration of the Zitelli bilobed flap technique for a nasal tip defect: (A) circular defect on nasal tip with the two lobes designed at approximately 45 degrees apart with a total arc of 90-100 degrees, first lobe slightly smaller than the defect, second lobe smaller than first, (B) both lobes elevated with common pedicle, (C) first lobe transposed into defect, second lobe into first lobe donor site, tertiary defect closed primarily, (D) standing cone deformity at pivot point excised, (E) final closure. Surgical planning view from above with clean medical illustration style.
## Key Clinical Pearls
Always assess tissue laxity (pinch test) before designing any local flap -- insufficient laxity leads to excessive tension and flap necrosis or distortion. The 60-degree Z-plasty provides 75% theoretical lengthening and is the most commonly used angle in clinical practice. For rhomboid flaps, choose the orientation that places maximum tension along the line of greatest laxity and places scars along RSTLs. The Zitelli modification of the bilobed flap (90-100 degree total arc) dramatically reduces the standing cone deformity compared to the original 180-degree design.
V-Y advancement flaps are versatile for fingertip, lip, and contracture reconstruction because they advance on a deep subcutaneous pedicle without external tension. Effective flap length decreases with greater arcs of rotation -- always design flaps larger than you think necessary. When designing local flaps on the face, respect aesthetic subunit boundaries and place incisions at junctions between subunits. A flap that is too tight is worse than a skin graft -- never force a local flap if there is inadequate tissue laxity.
## References
- Zitelli JA. The bilobed flap for nasal reconstruction. *Arch Dermatol*. 1989;125(7):957-959.
- Borges AF. Elective incisions and scar revision. *Little, Brown and Company*; 1973.
- Limberg AA. *The Planning of Local Plastic Operations on the Body Surface: Theory and Practice*. Collamore Press; 1984.
- McGregor IA. The theoretical basis of the Z-plasty. *Br J Plast Surg*. 1957;9:256-259.
- Baker SR. *Local Flaps in Facial Reconstruction*. 3rd ed. Elsevier; 2014.