Chapter 25

Flaps and Microsurgery

Flap Definitions

1. Axial flap: Tissue that is based on the vascular territories of named vascular pedicles with an axial alignment

2. Random flap: Tissue that is based off of an unnamed vascular supply, whereby the primary vascularity is provided through the subdermal plexus

3. Delayed flap: A flap that is incised and minimally or partially elevated and then immediately placed back in its in situ position to enhance flap circulation through the dilation of choke vessels

4. Perforator flap: A flap that is designed and elevated based on a perforating vessel within a known vascular territory, whereby the perforator is dissected down to a known source pedicle of sufficient length and diameter

5. Freestyle flap: A type of perforator flap that is designed randomly off of an identified perforating vessel within a specific region, whereby the perforator is dissected down to a pedicle of sufficient length and diameter

6. Prelaminated flap: An axial flap that is modified with grafts (e.g., mucosa, cartilage, or bone) to create composite tissue structure at the donor site before flap transfer

7. Prefabricated flap (see Figure 25.1): A flap that is created by introducing a vascular pedicle to a desired donor site that on its own does not possess an axial blood supply. This induces vascularization of the donor site from the pedicle before transfer.

Figure 25.1 1-4, Flap prefabrication technique. TE, Tissue expansion. (Reprinted from Wei, F.C., Mardini, S. [Eds.], 2009. Flaps and Reconstructive Surgery. Elsevier, 103–116.)

8. Tubed flap: A flap that is rolled on itself to serve as a conduit

9. Reverse flow flap: A flap that is supplied through retrograde flow

• Venous flow is possible through communicating vein branches along the comitantes that allow reverse shunting of flow to bypass valves.

10. Venous flap (see Figure 25.2): A flap of skin, subcutaneous, tissue, and a venous plexus, whereby the inflow and outflow of the flap is through veins.

• Considered for small dorsal or palmar defects, fingers, or hand requiring simultaneous reconstruction of venous outflow or arterial inflow

• Arterialized venous flaps: An arteriovenous fistula is created by anastomosing the inflow vein to a recipient artery and the outflow vein to a vein

• Arterialized venous “flow-through” flap: The proximal and distal veins are anastomosed to a proximal and distal artery to create a flow-through flap.

Figure 25.2 Classification of venous flaps. A, Type I. B, Type II. C, Type III. (Reprinted from Neligan, P.C., Gurtner, G.C. [Eds.], 2013. Principles in Plastic Surgery, vol. 1, 3rd ed. Elsevier, 512–572.)

Flap Classification

1. Mathes-Nahai classification

• Type 1: Flap vascular supply via one major pedicle

• Type 2: Via one major and one minor pedicle

• Type 3: Via two major pedicles

• Type 4: Via segmental pedicles

• Type 5: Via one major and segmental pedicles (see Figure 25.3 and Box 25.1–25.5)

Figure 25.3 Mathes-Nahai classification of muscle and musculocutaneous flaps. (Reprinted from Neligan, P.C., Gurtner, G.C. [Eds.], 2013. Principles in Plastic Surgery, vol. 1, 3rd ed. Elsevier, 512–572.)

Box 25.5

Type-V Vascular Pattern Muscles

Reprinted from Neligan, P.C., Gurtner, G.C. (Eds.), 2013. Principles in Plastic Surgery, vol. 1, 3rd ed. Elsevier, 512–572.

Common Local Flaps

1. Z plasty: Useful for increasing length along a central limb

• Degree of angles dictates the amount gained in length

▪ 30 degree angle leads to a 25% gain

▪ 45 degree: angle leads to a 50% gain

▪ 60 degree angle leads to a 75% gain

▪ 75 degree angle leads to a 100% gain

▪ 90 degree angle leads to a 120% gain (see Figure 25.4)

Figure 25.4 Z-plasty technique. A, Central limb designed along the scar. Both limbs are equal in length, and angles A and B are 60 degrees. B, The flaps are transposed and sutured. Note that the original central limb has been lengthened and the scar is reoriented. (Reprinted from McCarthy, J.G., Galiano, R.D., Boutros, S.G. [Eds.], 2006. Current Therapy in Plastic Surgery. Elsevier, 3–10.)

2. W plasty: Useful for scars that cross the relaxed skin tension lines

• Requires undermining and removal of “healthy” surrounding tissue for closure (see Figure 25.5)

Figure 25.5 W plasty. A,B, W plasty for repair of a straight scar. Triangles become smaller at the end of the scar. A W plasty, however, results in excision of nonscarred skin. (Reprinted from McCarthy, J.G., Galiano, R.D., Boutros, S.G. [Eds.], 2006. Current Therapy in Plastic Surgery. Elsevier, 3–10.)

3. Rhomboid flaps: A rotation flap based on a rhomboid skin design that allows closure of the donor site primarily (see Figure 25.6)

Figure 25.6 Rhomboid flap. (Reprinted from McCarthy, J.G., Galiano, R.D., Boutros, S.G. [Eds.], 2006. Current Therapy in Plastic Surgery. Elsevier, 11–21.)

4. Bilobed flaps (see Figure 25.7): A double transposition flap that allows for movement of skin over a longer distance than possible with a single transposition flap

• Useful for reconstruction of defects within the face and nose

Common Flaps of the Head and Neck

1. Scalp flaps: Highly redundant blood supply allows for multiflap variations based off of a vascular pedicle.

• Vascular supply (see Figure 25.8): Supratrochlear a. and supraorbital a. (anterior scalp); superficial temporal a. (temporal scalp); posterior auricular a. (parietal scalp); occipital a. (occipital scalp)