Plastic Surgery in the Foot and Ankle
Ted Fitzpatrick, MS4
Allow soft tissue defect to heal by secondary intention Primary wound closure Apply split- or full-thickness skin graft Rotating or advancing a local random flap Transfer a pedicled flap Transplanting an autogenous microvascular free flap
Goal is to create least amount of morbidity and trauma to soft tissues as possible.
Angiosomes- A specific block of tissue supplied by a given source artery. Venosome- A territory drained by a named vein. Angiotome- The territory encompassed by the overlapping angiosome and venosome. Allows surgeon to design safe incisions, avoid complications and determine which will flaps will work the best when covering as defect.
Angiosomes (Mathes and Nahai)
Type 1- Muscle has a single dominant vascular pedicle. Type 2- Muscle has a dominant vascular pedicle and several minor pedicles. Type 3- Muscle has two dominant pedicles. Type 4- Muscle has segmental vascular pedicles. Type 5- Muscle has dominant pedicle and secondary segmental vascular pedicles.
Types 1,2,3,and 5 are the easiest to rotate as pedicled or free flaps because dominant pedicle supplies sufficient blood flow. Type 4 are the least mobile due to minor pedicles and no dominant pedicle. All muscles of lower leg in the anterior, lateral and deep posterior compartments are type 4.
The pattern of blood supply dictates the usefulness and mobility that a given flap has.
Split-thickness skin graft- Epidermis and part of the dermis is harvested. Full-thickness skin graft- Incorporates the epidermis and all of the dermis.
Split-thickness Skin Grafts
Thinner grafts have higher chances of successful take due to higher number of blood vessels in graft. Thinner vessels will shrink as they heal. Thinner grafts have higher chance for hyperpigmentation. Thinner grafts are more susceptible to trauma due to absence of anchoring rete pegs.
STSG Donor Sites
Thighs Calves Dorsum of Foot Medial plantar area
Full-thickness Skin Grafts
There is minimal if any shrinkage that occurs at the wound site. FTSG stay lubricated for life due to presence of sebaceous glands (less friction and trauma). Disadvantage is that thickness makes graft less likely to be successful giving a greater chance of slough.
FTSG Donor Sites
Side pulp of the large toe Sinus Tarsi Popliteal Fossa Inguinal Fold
Keys to Successful Skin Graft
Adequate preparation of the recipient bed. Bacterial count <100,000/g of tissue Wound edges show signs of nonepithelialization, should be soft, wrinkled and without any erythema. Recipient site should have healthy red granulation tissue (should be removed prior to grafting).
Keys to Successful Skin Graft
Wound pH at 7.4 TcO2 pressure greater than 40 mmHg
Strict elevation for 5-7 days Gradual dangling regimen (5 min/h on day 7, 10 min/h on day 8, 15 min/h on day 9, etc.) to prevent undue swelling and potential slough. Application of Unna boot to promote good adherence of graft to wound and prevent swelling.
10 days for thin graft (8-12 mm) Up to 20 days for intermediate graft (1318mm) Up to 2 months for thick graft (19-25 mm)
Skin Graft Complications
Partial or total loss of a skin graft due to seroma, hematoma, shearing, infection or inadequate recipient bed. Infection by beta-hemolytic strep can lead to quick loss of graft while P. aeruginosa is somewhat less virulent. (Topical silver sulfadiazine and serial debridements to prevent).
0.5 mm of fluid delays revascularization by 12 hours. 5.0 mm of fluid delays revascularization by 5 days. Prevention by meticulous hemostasis, use of topical thrombin and meshing of the graft to allow fluid to escape.
Involve the skin and underlying subcutaneous tissue. Length-to-width ratio determines if flap survives---WRONG! Milton showed survival depends on the quality of blood supply at the base of the flap. Skin blood supply 1) direct cutaneous artery 2) perforators from underlying muscle 3) via fasciocutaneous perforators.
Useful in the heel, midfoot and forefoot. Rotate laterally from a pivot point at the base of the flap to cover a defect. Are large semicircular flaps that fill triangular or lenticular defects.
Useful for defects over the Achillies tendon, medial and lateral malleoli and dorsum of the foot. Rectangular piece of skin and underlying fat designed to fill triangular or lenticular defect. Line of greatest tension-pivot point to the furthest point of defect.
Useful in small circular defects under the metatarsal heads or over the proximal and distal interphalangeal joints of the digits. Allows excellent exposure of the underlying bone. Donor site can be closed without using a skin graft.
Advancement Flaps: V-Y
Useful anywhere on the sole of the foot and dorsum of the foot at the base of a hyperextended toe. Is a triangular flap that fills a small lenticular or round defect. Amount flap can be advanced is limited (only 1.5-2 cm). Base should be equal to diameter of the defect.
Advancement Flaps: ZPlasty
Used to gain length in the direction of the central limb. Gain in length depends on the angle between the side arms and central limb (60 degrees has been found to give max. result). Good for releasing toes that are dorsiflexed, burns on the dorsum of foot that have led to contracture and lengthening soft tissue over Achillies tendon.
Movable blocks of tissue with an anatomically identifiable blood supply that are dissected free from the surrounding tissue while the vascular pedicle is left intact. Dorsalis Pedis flap Filet of Toe Flap and the Toe Island Flap Lateral Calcaneal Flap Medial Plantar Flap
Filet of Toe Flap
Useful in diabetics with large ulcers over the metatarsal and osteomyelitis of the MPJ’s.
Leave minimal donor defects, are easy to dissect out, rotate easily and bring immediate increased blood supply.
Soleus Muscle FDL Peroneus Brevis EDL and Peroneus tertius EHL Abductor Digiti Minimi
Abductor Hallucis Brevis Flexor Digitorum Brevis Flexor Digiti Minimi and Opponens Digiti Minimi Extensor Digitorum Brevis
Flaps whose blood supply arises from perforators that travel along intermuscular and/or intercompartmental fascial septa to the superficial fascia and skin. Alternative to muscle flaps. Distally based Peroneal flap. Lateral Supramalleolar Flap. Distally based Sural Artery Flap.