I. Overview
A. General principles
1. Considerations regarding the defect
a. Location of the defect
b. Tissue at the base of the defect
c. Whether coverage is needed
2. Considerations regarding tissue coverage
a. Availability of local tissue
b. Availability of distant tissue if no local tissue is available
B. Reconstructive ladder
1. The "reconstructive ladder" describes wound management as a ladder consisting of rungs (procedures) of increasing complexity.
[
Table 1. The Reconstructive Ladder]
*Martin I. Boyer, MD, MSc, FRCSC, or the department with which he is affiliated holds stock or stock options in OrthoHelix, Inc, and is a consultant for or an employee of MiMedx, Inc.
2. One version of the reconstructive ladder is outlined in Table 1.
II. Types of coverage
A. Primary closure
B. Healing by secondary intention
C. Split-thickness skin graft (STSG)
1. Supplies required—Dermatome and blade, mineral oil, tongue depressor, towel clip, towel, scarlet red, medicated gauze, 4 × 4 gauze pad, cling wrap, elastic bandage.
2. Characteristics of STSGs
a. STSGs can be of variable thickness. Thicker grafts contain greater depths of dermis, which contain hair follicles and sweat glands; thicker grafts contract less because of their greater proportion of dermis. Subcutaneous fat is not included in the graft. STSGs are classified as follows:
i. Thin (0.005-0.012 in)
ii. Intermediate (0.012-0.018 in)
iii. Thick (0.018-0.030 in)
b. STSGs obtain their nutrition by diffusion from the healthy bed on which they are placed.
c. They contain keratinocytes.
d. STSGs are vulnerable to hematoma or seroma collection, rendering them nonviable.
3. STSGs should be applied over well-perfused beds, where wound contraction will not lead to decreased joint mobility or scar contracture.
4. Revascularization begins 2 to 3 days after grafting.
D. Full-thickness skin graft (FTSG)
1. Characteristics of FTSGs
a. They contain no underlying adherent subcutaneous fat.
b. Nutrition is by diffusion from a well-vascularized bed.
c. They contain full thickness of both dermis and epidermis, containing hair follicles and sweat glands.
d. Hematoma and seroma collection cause failure in FTSGs, as in STSGs.
e. FTSGs have better reinnervation, and therefore sensation, than STSGs.
f. FTSGs are more durable and wear-resistant, and they produce less scar contraction than STSGs.
g. Subcutaneous fat is not included in the graft.
2. Procedure
a. FTSGs should be applied over well-perfused beds.
b. The graft is inset under tension and applied directly to a vascularized bed.
c. Multiple tie-over sutures are used to keep shear forces to a minimum.
d. Dress with medicated gauze and moist cotton; leave in situ for 5 to 7 days.
3. Revascularization begins 2 to 3 days after grafting.
E. Random pattern local flap
1. Characteristics
a. A random pattern local flap is a pedicled skin flap that does not contain an axial cutaneous vessel. By definition, a flap contains its own blood supply. "Random pattern" implies that a named vessel is not found within the flap boundaries (compare axial pattern flap, island flap).
b. The length-width ratio should be no greater than 2:1.
2. Random pattern local flaps are used when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, and cannot support an STSG or FTSG.
3. The donor site usually can be closed primarily, but STSG also can be done.
4. Geometric patterns
a. Mitten (bilobed) flap
b. Limberg (rhomboid) flap
c. Semicircular rotation
d. Bipeninsular
e. Simple unipeninsular advancement
5. Mobile skin, such as on the dorsum of the metacarpus, is required.
F. Axial pattern local flap
1. Characteristics
a. "Axial pattern" implies the presence of a direct cutaneous vessel (and its venae comitantes) within the flap boundaries (compare random pattern flap, island flap) oriented along the long axis of the flap.
b. The length-width ratio can be substantially greater than 2:1.
2. Procedure
a. The donor site usually can be closed primarily, but STSG also can be done.
b. Axial pattern local flaps are used when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, and cannot support STSG or FTSG.
c. Muscle flaps can be used, over which an STSG can be placed.
d. An anconeus flap is used for elbow/olecranon/radiocapitellar coverage.
e. The pedicle is posterior and superior to the descending branch of the profunda brachii.
f. The maximum area of an axial pattern local flap is 7 cm2 (thenar, hypothenar).
G. Island pattern local flap
1. "Island pattern" implies an area of skin that is detached from all of its host attachments except for the artery that is perfusing it, and the venae comitantes that are draining it (compare random pattern flap, axial flap).
2. A length-width ratio is not applicable.
3. The donor site can sometimes be closed primarily, but STSG also can be done.
4. An island pattern local flap is used when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, and cannot support STSG or FTSG.
5. This flap is useful for coverage of dorsum of the hand proximal to the metacarpophalangeal (MCP) joints.
6. Island pattern local flaps commonly used for the hand:
a. Posterior interosseous artery (PIA) flap. The PIA lies between the extensor digiti quinti (EDQ) and extensor carpi ulnaris (ECU). The main perforators proximally are approximately one third of the way between the lateral epicondyle and the distal radioulnar joint (DRUJ). The proximal extent of the PIA is deep to the anconeus muscle belly along the proximal ulna.
b. Reverse pedicle radial forearm flap (radial artery, between flexor carpi radialis [FCR] and brachoradialis [BR])
c. Radial forearm fascial flap (radial artery, between the FCR and BR)
d. Radial forearm fascial perforator flap (uses perforators from radial artery [RA] to forearm fascia between radial styloid and 7 cm proximal to styloid)
e. Ulnar artery flap (ulnar artery, deep to [ie, radial to] ulnar nerve)
H. Distant random pattern flap
1. The distant random pattern flap contains its own random blood supply through the base of the flap. Examples are the chest flap and abdominal flap.
2. "Random pattern" implies there is no named direct cutaneous vessel within the flap boundaries (compare axial pattern flap, island flap).
3. The length-width ratio should be no greater than 2:1.
4. The donor site usually can be closed primarily, but STSG also can be done.
5. Use this flap when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, cannot support STSG or FTSG, and when local tissue of sufficient amount or quality is unavailable.
I. Distant axial pattern flap
1. The length-width ratio can be substantially greater than 2:1.
2. The donor site usually can be closed primarily, but STSG also can be done.
3. This flap is indicated when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, cannot support STSG or FTSG, and when local tissue of sufficient amount or quality is unavailable.
4. Groin flaps—The groin flap is supplied by the superficial circumflex iliac artery (SCIA). The origin of the SCIA is 2 cm below the inguinal ligament on the lateral aspect of the common femoral artery. The SCIA runs parallel to the inguinal ligament and emerges into superficial subcutaneous tissue lateral to the sartorius.
5. Hypogastric artery flap (Shaw flap; based on the superficial inferior epigastric artery [SIEA])
a. The SIEA arises either from a common trunk with the SCIA from the femoral artery or from the femoral artery directly.
b. The flap may be raised either transversely oriented or proximodistally.
J. Free tissue transfer
1. Definition—In a free tissue transfer, an axial or island pattern flap that is supplied by a recognizable artery and is drained by recognizable veins is surgically removed from one site (the donor site) and is transferred and revascularized in another site (the recipient site) within the same individual. In other words, the flap is transferred heterotopically, in a procedure in which the blood supply is first divided and then re-established by microsurgical anastomosis of its arterial supply and draining vein(s).
2. A length-width ratio is not applicable.
3. The donor site usually can be closed primarily, but STSG also can be done.
4. Free tissue transfer is used when the defect cannot or should not be closed primarily, should not be allowed to heal secondarily, cannot support STSG or FTSG, and when local or distant tissue of sufficient amount or quality is unavailable for random, axial, or island flap transfer.
5. A free tissue transfer flap can be cutaneous, fasciocutaneous, musculocutaneous, muscular, osseous, or composite.
III. Coverage for Common Defect Sites
A. Fingertip
1. Atasoy (volar V-Y advancement)—Useful for transverse or dorsal oblique tip amputations.
2. Kutler (side digital V-Y advancement flaps)—Provides bilateral midlateral fingertip tissue, especially for revisions.
3. Iselin (flag) flap—Useful for stump coverage.
4. Thenar flap—Useful for tip coverage of index and middle fingers in young patients.
5. Thenar H flap—Modification of the thenar flap; same indications as for the thenar flap.
6. Full-thickness skin grafts
7. Healing by secondary intention (if no exposed bone, or in preadolescent patient)
B. Finger
1. Side finger flap
a. This flap is useful for coverage of volar MCP defects following contracture release.
b. The side finger flap has a random blood supply.
2. Lateral finger rotation flap
a. This flap is useful for coverage of the dorsal aspect of the proximal interphalangeal (PIP) joint.
b. The lateral finger rotation flap has a random blood supply.
3. Iselin (axial flag) flap
a. The skin of the proximal phalanx dorsum is supplied by the anastomosis between the dorsal metacarpal artery and the proper digital artery.
b. This flap is useful for coverage of the volar or dorsal aspect of the adjacent digit, or the volar aspect of the same digit.
4. Arterialized side finger flap
a. This flap is useful for coverage of defects over the dorsal aspect of the PIP joint.
b. The blood supply is provided by the digital artery. (The digital nerve is left in situ.)
5. Cross finger flap
a. The cross finger flap is a random pattern flap consisting of the dorsal skin and subcutaneous tissue of a digit used to cover the volar aspect of the adjacent digit.
b. The flap can be laterally or distally based.
c. The defect is full-thickness skin grafted over the intact extensor tendon epitenon.
d. The flap can be made sensate using the dorsal branch of the proper digital nerve, divided at 2 to 3 weeks, and revascularized from the healing wound edges.
6. Reverse cross finger flap
a. The reverse cross finger flap uses dorsal adipofascial tissue, over which STSG or FTSG can be placed to cover the dorsum of an adjacent digit.
b. The flap is raised after elevation of the dorsal dermis and epidermis only, leaving the adipofascial tissue to cover the extensor tendon.
7. Homodigital reverse adipofascial turndown flap
a. This flap is useful for dorsal oblique amputations.
b. The axial pattern flap can be used when the base is >5 mm proximal to the proximal extent of the germinal matrix.
c. STSG or FTSG is required to cover.
8. FTSG—May be used when a suitable soft-tissue bed (extensor epitenon, digital sheath) is present.
C. Thumb tip
1. Moberg flap
a. The Moberg flap is an axial pattern advancement flap comprising volar thumb skin containing both digital arteries and digital nerves.
b. This flap is possible only because of the robust dorsal vascular supply of the thumb.
c. IP or MCP contracture is a common complication of the Moberg flap procedure.
2. Volar cross finger flap
a. This cross finger flap (see above, III.B.5) is taken from the index finger.
b. Index MCP stiffness is a complication of the volar cross finger flap procedure.
3. Digital neurovascular flap from radial aspect of ring finger
a. Popularized by Littler
b. Donor site complications
i. Poor circulation to donor and ulnar adjacent digits
ii. Cold intolerance
iii. Poor 2-point discrimination
iv. Cortical reorientation, where the thumb will feel as if the ring finger is being touched, is uncommon.
4. Full-thickness skin graft
5. Wound healing by secondary intention (if no exposed bone, or in preadolescent patient)
D. Dorsal aspect of thumb
1. Kite flap
a. Supplied by the first dorsal metacarpal artery
b. Lies subfascially on the first dorsal interosseous muscle on its radial aspect
c. Usually reaches only to the thumb IP joint
d. The donor site is full-thickness skin grafted.
2. FTSG—Useful if suitable extensor epitenon coverage of the first and third dorsal compartment tendons is present.
E. Forearm and dorsal aspect of the hand
1. Muscle flaps do not provide a gliding surface beneath which extensor tendon function can be preserved, and they are therefore not good choices for reconstruction of dorsal hand defects.
2. STSG may be used if there is suitable extensor epitenon coverage.
3. Random pattern local flaps (see II.E above)
4. Island flaps from the forearm (reverse pedicle radial forearm flap, reverse pedicle radial forearm fascial flap, radial forearm perforator fascial flap, PIA flap)
5. Axial pattern distant flaps (hypogastric, groin), divided at 2 to 3 weeks after insetting
6. Free tissue transfer
a. Lateral arm flap
i. This flap is supplied by the posterior radial collateral artery (PRCA). The profunda brachii divides into the middle collateral and the radial collateral arteries after piercing the lateral intermuscular septum. The PRCA runs in the intermuscular septum between the BR and the triceps.
ii. The flap can be extended 6 cm distal to the elbow.
b. Radial forearm flap
i. This flap is supplied by the radial artery, which runs between the BR and the FCR.
ii. The flap may include a portion of the radius <30% of the diameter of the diaphysis, the forearm fascia, the BR, and the palmaris longus.
c. These flaps are based on the circumflex scapular artery. The axillary artery deep to the teres major gives off the subscapular artery, which then gives off the thoracodorsal artery to the latissimus dorsi and the circumflex scapular artery to the cutaneous flap.
d. Lateral thigh flap
i. The lateral thigh flap is based on the third branch of the profunda femoris artery, a septocutaneous artery.
ii. This flap can be made sensory if the lateral cutaneous femoral nerve is harvested.
e. Anterolateral thigh flap
i. The anterolateral thigh flap is supplied by muscular perforators derived from the descending branch of the lateral femoral circumflex artery.
ii. This branch of the lateral femoral circumflex artery travels between the vastus lateralis and the rectus femoris.
F. Thumb-index finger web space reconstruction
1. 2- or 4-flap Z-plasty
a. 2-flap for greater depth, 4-flap for greater contour
b. 45° angles lengthen 50%; 60° angles lengthen 75%.
2. Dorsal rectangular rotation flap
a. Random pattern from dorsum of metacarpus
b. Defect may need FTSG or STSG.
3. Arterialized palmar flap—Defect can be closed primarily.
4. Brand flap
a. Random full-thickness dermoepidermal flap harvested from the radial aspect of the index finger
b. The donor site usually can be closed primarily.
5. Dorsal thumb flap
6. Axial or island pattern local or distant flaps
G. Digital reconstruction
1. Toe-to-hand transfers
a. Great toe
i. Great toe-to-hand transfer—The great toe is supplied by the dorsalis pedis and first dorsal metatarsal artery that runs either upon or within the dorsal interosseous muscle.
ii. Wraparound—Morrison flap; advantages are conserved hallux length at the donor site and preservation of some element of cosmesis.
b. Second toe—This transfer can be based on any of the following arteries:
i. Dorsalis pedis and first dorsal metatarsal artery OR
ii. Second dorsal metatarsal artery OR
iii. First or second plantar metatarsal artery with dorsalis pedis.
c. Second and third toe—Same as second toe.
2. On-top plasty (index tip to thumb tip transposition)
3. Osteoplastic reconstruction of thumb—An insensate radial forearm flap (reverse pedicle) is transferred to cover an iliac crest autograft to restore thumb length. This is followed by a neurovascular island pedicle transfer from the radial aspect of the fourth ray.
4. All microsurgical thumb reconstructions require a carpometacarpal (CMC) joint that is both present and motored. In the absence of a normal CMC joint, pollicization of the index ray is performed.
IV. Muscle Flap Coverage of Lower Extremity Soft-Tissue Defects
A. Medial soft-tissue defects following open fractures of the proximal third of the tibia
1. Use a medial gastrocnemius rotational flap (axial pattern flap supplied by the medial branch of the sural artery, a branch of the popliteal artery).
2. Use STSG onto the transposed flap and closure of the donor incision.
B. Lateral soft-tissue defects following open fractures of the proximal third of the tibia
1. Use a lateral gastrocnemius rotational flap (axial pattern flap supplied by the lateral branch of the sural artery, a branch of the popliteal artery).
2. Use STSG onto the transposed flap and closure of the donor incision.
3. Note that the muscle belly is much smaller on the lateral side, extending down the leg to a much lesser extent.
C. Soft-tissue defects following open fractures of the middle third of the tibia
1. Use a soleus flap, proximally based as well. This flap is perfused by perforating branches from both the posterior tibial and the peroneal arteries (vascular supply has main branches proximally, another large pedicle intermediately, and distal variable pedicles).
2. The flap is not detached proximally during harvest.
D. Soft-tissue defects following open fractures of the distal third of the tibia
1. Fasciocutaneous perforator flaps (from the posterior tibial or the anterior tibial arteries, distally based rotational flaps) may be used.
2. Alternatively, free muscle flaps may be used. The most common are:
a. Gracilis (arterial supply from medial femoral circumflex artery)
b. Latissimus dorsi (thoracodorsal artery arising from subscapular artery)
c. Rectus abdominis (inferior epigastric artery, branch of the external iliac artery).
E. Serratus anterior flap
1. This flap can be used for small defects where bulky flaps may not be desirable.
2. Use the caudad 3 to 4 slips only to prevent scapular winging.
3. This flap is supplied by the subscapular or thoracodorsal artery branch.
4. The serratus anterior flap is also useful for functional reconstruction of the thenars using the long thoracic nerve.
V. Bone Flaps
A. Fibula flap
1. The fibula flap is a free tissue transfer based upon the peroneal artery, which travels in its own sheath medial to the fibula and just posterior to the interosseous membrane.
2. Division of the soleus perforators is necessary during harvest. The peroneal artery arises from the tibioperoneal trunk, which in turn originates from the popliteal artery following takeoff of the anterior tibial artery.
3. Complications
a. Ankle instability
b. Cold intolerance
c. Wound breakdown
d. Extensor hallucis longus contracture
e. Knee instability and drop foot (if the proximal fibula is harvested on the anterior tibial artery pedicle)
4. Leave 6 cm of bone cephalad to the mortise to minimize the risk of ankle instability.
5. The fibula flap can be harvested with the flexor hallucis longus (FHL) and a skin paddle.
B. Iliac crest flap
1. The iliac crest flap is a free tissue transfer based upon the deep circumflex iliac artery.
2. It is possible to harvest the accompanying muscle, but there is no reliable skin paddle.
C. Pronator flap
1. This flap is based on the anterior interosseous artery.
2. A fragment of the distal radius can be harvested with it.
VI. Tissue expansion
A. Tissue expansion results in decreased dermal thickness.
B. The epidermal thickness increases initially but then returns to baseline.
C. Collagen bundles in the expanded tissue are longitudinally oriented, orderly, and parallel.
Top Testing Facts
1. The posterior interosseous artery is located between the EDQ and the ECU.
2. The groin flap is supplied by the superficial circumflex iliac artery.
3. The kite flap (for thumb dorsum reconstruction) is supplied by the first dorsal metacarpal artery.
4. The lateral arm flap is supplied by the posterior radial collateral artery.
5. Flaps used for open tibia fractures: proximal third, medial gastrocnemius rotational flap; middle third, soleus flap; distal third, fasciocutaneous perforator flaps or free tissue transfer.
Bibliography
Galumbeck M, Colen LB: Soft tissue reconstruction: Coverage of lower leg. Rotational flap. Orthop Clin North Am 1993;24:473-480.
Germann G, Sherman R, Levin LS: Decision-Making in Reconstructive Surgery: Upper Extremity. Berlin, Springer-Verlag, 2000.
Levin LS, Erdmann D: Primary and secondary microvascular reconstruction of the upper extremity. Hand Clin 2001;17: 447-455.
Neumeister MW, Brown RE: Mutilating hand injuries: Principles and management. Hand Clin 2003;19:1-15.