KEY NOTES CHAPTER 1: GENERAL PRINCIPLES - Geometry of local flaps

Question 0

What is the best orientation for a surgical incision?

Answer 0

Parallel to RSTL / rhytid.
Perpendicular to LMEs.
Parallel to direction of hair growth.
Pinch test.

Question 1

What are Langer’s lines and what did Borges describe?

Answer 1

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.

Question 2

What is a z-plasty?

Answer 2

Transposition of 2 adjacent triangular flaps.
Purpose:
1. increase length of scar.
2. break up straight line scar.
3. realign scar.

Question 3

How much does a z-plasty elongate a scar by?

Answer 3

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.

Question 4

How do you design a z-plasty?

Answer 4

1. Draw desired orientation of resultant scar (dotted).
2. Draw line of original scar (bold).
3. Draw 2 possible z plasty flaps, use ones with acute angle at apex of flap (not obtuse).

Question 5

Draw a 4 flap plasty.

Answer 5

CADB

Question 6

Draw a 5 flap plasty.

Answer 6

BACED

Question 7

When is a W-plasty used?

Answer 7

To break up linear scar to improve aesthetics, does not lengthen scar.

Question 8

What different types of local flaps are there?

Answer 8

1. 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
2. Pivot flaps with SSG of donor site
3. Transposition flaps with direct closure of donor site e.g. rhomboid, Dufourmentel
4. Interpolation flaps - flap raised from local bridge and pedicle is passed under / over skin bridge
5. Rotation

Question 9

Design a keystone flap

Answer 9

• Trapezoidal flaps used to close elliptical defects.
• 2 V-Y flaps end-to-side.
• Designed to straddle longitudinal structures, e.g. superficial nerves and veins, which are incorporated into flap.
• Blunt dissection to deep fascia preserves perforators and subcutaneous veins.
• Lateral deep fascial margin can be incised for increased mobilisation.
• Extremes of donor site are closed as V-Y advancements, which produces transverse laxity in the flap.

Question 10

Design a Limberg (rhomboid) flap

Answer 10

Draw RSTLs.
Draw LMEs.
Draw the 2 designs of parallelogram, parallel to LMEs.
Draw the flaps (2 out of 4 possible designs will close along RSTLs).

Question 11

Design a rotation flap

Answer 11

• Flap circumference should be 5-8x diameter of defect.

- Can design back cut, and donor site closes directly by tissue redistribution.

Question 12

Design a MacGregor flap.

Answer 12

Ian McGregor BJPS 1973.

• For eyelid recon 1/3 - 2/3.
• Lateral canthotomy incision is extended laterally from outer canthus following natural curve of lower lid margin as far as pre-auricular hairline.
• Construction of Z-plasty.
• Mobilisation of flap: lateral to orbicularis, skin flap is raised at facelift level. Orbicularis is raised with lower lid skin.
• Lateral canthotomy.
• Conjunctiva advanced (no resistance as lateral fornix has abundant laxity).
• Suture tarsus, knots placed externally (conjunctiva is closely adherent to tarsus so no need to suture).
• Match grey line on lid margin, suture skin.
• Transpose z-plasty flaps.

Question 13

Design a bilobed flap

Answer 13

Esser (1918) - 2 transposition flaps designed 90 degrees to each other
Zitelli - 45 degrees