Flaps

Flaps are defined as the tongue of the tissue containing skin and subcutaneous tissue which carries its own blood supply and remains attached to the body all the time for its nourishment

Angiosome: three-dimensional composites of skin, subcutaneous tissues, muscle, and bones, supplied by a single source of vessels and its branches

Classifications

Relation of the donor to the recipient site

1. Local (eg. one leg to the same leg)
2. Regional (eg. one leg to same foot)
3. Distant: ( eg. one leg to next leg pedicle remains intact)
4. Distant-free flap: (eg. one leg to next leg with microvascular anastomosis of nutrient vessels with next leg)

Types of movement

1. Advancement: Linear configuration and stretched in defect
2. Transposition
3. Rotational
4. Rotational and advancement combined flaps

Vascular Sources

Random flap: It receives blood supply from the perforated myocutaneous vessels terminating in dermal, subdermal plexus which nourishes the skin

Axial flaps: It receives blood supply from direct cutaneous vessels and its accompany venous drainage in such a way that vessels run parallel to the long axis of flap

Groin flap is usually based on the superficial circumflex iliac artery

Composition of tissue type

1. Skin and subcutaneous tissue
2. Skin and subcutaneous tissue + deep fascia (fascio-cutaneous flap)
3. Skin and subcutaneous tissue + deep fascia+ muscle (myo-cutaneous / musculocutaneous flap)
4. Skin and subcutaneous tissue + deep fascia+ muscle (myo-cutaneous / musculocutaneous flap)+ bone (Osseo-cutaneous flap)
5. Muscle only (Muscular flap)
6. Bone only ( free fibular graft)
7. Skin and subcutaneous tissue+ Nerve (neurocutaneous flap)
8. Omentum or a part of the small bowel, when used to reconstruct with microsurgical techniques
9. Composite: More than one tissue (osseo-myo-fascia0-cutaneous flaps)

Microvascular free flap

Distant free flap along with its vascular pedicle completely divided from the donor site and anastomosis of vessels at recipient site using the microvascular technique

When a free flap is failing due to venous or arterial thrombosis it is necessary to attempt to remove entire propagated clot

Island flap

Perforator flap

Propeller flap: An island flap that reaches the recipient site through an axial rotation of more than 90°

The flap which is part of the subscapular vascular axis

1. Serratus anterior flap
2. Latissimus dorsi flap
3. Parascapular flap
4. Thoracodorsal flap

Uses of Flaps

1. Closure of the wound where the graft will not take
2. Closure of wound open, exposed wound of bones, tendons
3. Closure of wound above joints
4. Management of chronic osteomyelitis
5. Reconstruction of sole defects
6. Reconstruction of bony defects
7. Provision of padding in fingertip injury and pressure sore
8. Thump reconstruction
9. To restore circulation to distal extremity in case of damage to vascular structures
10. Functional muscle transfer

Mathes and Nahai Classification of Muscle flap

The Mathes and Nahai Classification (1981) describes muscle flaps based on the number of pedicles available

Types	Major Pedicle	Minor Pedicle	Examples
Type I	1	0	Gastrocnemius, Tensor fascia lata
Type II	1	>1	Gracialis, Trapezius
Type III	2	0	Gluteus Maximus, Rectus abdominis, Pectoralis minor
Type IV	0	Segmental	Sartorius, Flexor hallucis
Type V	1	Segmental	Latissmus dorsi, pectoralis major

Taylor classified flaps according to their nerve supply.

Mathes and Nahai Classification of Septocutaneous flap

Type	Pedicle	Examples
Type A	Direct cutaneous pedicle	Groin flap, Foucher flap
Type B	Septocutaneous pedicle	Scapular flap, PIA flap
Type C	Musculocutaneous pedicle	ALT flap, Deltopectoral flap

Ischemia

Primary flap ischemia is a mandatory event for free tissue transfer however secondary, tertiary, quaternary and so on flap ischemia occurs when the flap experiences another episode of ischemia following revascularization.

Tissue/organ ischemia causes complex pathophysiological processes depending on the duration and extent of the ischemia. During reperfusion in the microcirculation bed, a ‘no-flow’ phenomenon can be caused by :

• Swelling of endothelial cells
• Endothelial blebs
• Increase capillary permeability
• Interstitial Edema
• Microthrombi
• Plugged red blood cell aggregates
• Adhesion and plugging of neutrophil leukocytes
• Local acidosis and swollen myocytes around compressing vessels

Pseudointima

Pseudointima usually lines the anastomosis by postoperative day five.

At the site of microvascular anastomosis the following sequences occurs in order:

Platelet aggregation —> Fibrin formation —> Pseudointima —> Endothelium

Summary of Soft tissue coverage of the tibia

See also: Chronic Osteomyelitis

See also: Pollicization

See also: Cartilage Injury