KEY NOTES CHAPTER 1: GENERAL PRINCIPLES (D) Geometry of local flaps. Flashcards
What is the best orientation for a surgical incision?
Parallel to RSTL / rhytid.
Perpendicular to LMEs.
Parallel to direction of hair growth.
Pinch test.
What are Langer’s lines and what did Borges describe?
Langer (19th century) made circular awl wounds in cadavers which resulted in elliptical defects due to skin tension.
Borges termed:
RSTL - parallel to rhytids, perpendicular to underlying muscle fibres.
LME - parallel to underlying muscle fibres, perpendicular to RSTLs.
What is a z-plasty?
Transposition of 2 adjacent triangular flaps. Purpose: 1. increase length of scar. 2. break up straight line scar. 3. realign scar.
How much does a z-plasty elongate a scar by?
30 deg - 25% 45 deg - 50% 60 deg - 75% 75 deg - 100% 90 deg - 125% Angles of flaps need not be equal but length of limbs do.
How do you design a z-plasty?
- Draw desired orientation of resultant scar (dotted).
- Draw line of original scar (bold).
- Draw 2 possible z plasty flaps, use ones with acute angle at apex of flap (not obtuse).
Draw a 4 flap plasty.
CADB
Draw a 5 flap plasty.
BACED
When is a W-plasty used?
To break up linear scar to improve aesthetics, does not lengthen scar.
What different types of local flaps are there?
- Advancement
- Simple e.g. Moberg
- VY e.g. Atasoy, Venkataswamy / Evans step advancement (blood supply comes from deep tissue through a subset pedicle
- Keystone - trapezoidal flaps used to close elliptical defects, blunt dissection maintains perforators, lateral deep fascial margin is incised to increase mobilisation, 2 ends of donor site are closed as VY advancements.
- bipedicled (e.g. von Langenbeck mucoperiosteal flap, posterior auricular bipedicle flap)
- Burrow’s triangle excision / Z plasty - Pivot flaps with SSG of donor site
- Transposition flaps with direct closure of donor site e.g. rhomboid, Dufourmentel
- Interpolation flaps - flap raised from local bridge and pedicle is passed under / over skin bridge
- Rotation
Design a keystone flap
.
Design a Limberg (rhomboid) flap
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Design a rotation flap
- flap circumference should be 5-8x diameter of defect
- can design back cut, donor site closes directly by tissue redistribution
Design a MacGregor flap
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Design a bilobed flap
Esser (1918) - 2 flaps designed 90 degrees to each other
Zitelli - 45 degrees