(A) 25%
(B) 50%
(C) 75%
(D) 100%

The correct response is Option D.

The Z-plasty is a technique in which pairs of triangular transposition flaps are created adjacent to a scar and then transposed across the scar, increasing the length of the central limb and changing the orientation of the scar. This technique can be used in patients undergoing burn reconstruction to lengthen linear scar contractures, disperse linear scars, and realign scars within the lines of minimal tension. The theoretic gain in length correlates directly with the angle and length of the flap limbs. The actual gain in the length of the central axis will be decreased by 30% to 50% because of the contractile properties of skin.

The theoretic gain achieved with each angle is illustrated in the table below.

A 60-degree Z-plasty is performed most commonly because it produces a significant gain in length while minimizing the tension of closure.

References
1. Peacock EE Jr, Cohen IK. Wound healing. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;1:161-185.
2. Place MJ, Herber SC, Hardesty RA. Basic techniques and principles in plastic surgery. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:13-26.
3. Rohrich RJ, Zbar RI. A simplified algorithm for the use of Z-plasty. Plast Reconstr Surg. 1999;103:1513-1517.

According to the Mathes/Nahai classification of muscle and musculocutaneous flaps, which of the following is a type III flap?

(A) Gastrocnemius
(B) Gluteus maximus
(C) Latissimus dorsi
(D) Pectoralis major
(E) Vastus lateralis

The correct response is Option B.

The gluteus maximus and rectus abdominis muscle flaps have a type III vascular pattern consisting of dual dominant pedicles.

Type I muscle flaps have one dominant pedicle; examples include the gastrocnemius, tensor fascia lata, and vastus lateralis flaps. In type II muscle flaps, such as the gracilis and trapezius, there is one dominant pedicle and multiple secondary pedicles. The external oblique and sartorius muscle flaps have a type IV vascular pattern, which is characterized by a segmented blood supply. Type V muscle flaps, such as the latissimus dorsi and pectoralis major, have one dominant pedicle and multiple secondary segmental pedicles.

References
1. Mathes SJ. Muscle flaps and their blood supply. In: Aston SJ, Beasley RW, Thorne CH, eds. Grabb & Smith’s Plastic Surgery. 5th ed. Philadelphia, Pa: Lippincott-Raven; 1997:61-72.
2. Mathes SJ, Nahai F. Reconstructive Surgery: Principles, Anatomy, and Technique. New York, NY: Churchill Livingstone, Inc; 1997:29-31.

A 20-year-old woman is undergoing evaluation eight months after sustaining a severe degloving injury, including multiple injuries to skin and tendons, to the dorsal aspect of the left hand. At the time of injury, extensive wound care was followed by full-thickness skin grafting from the left side of the groin. On current physical examination, the patient has severe contractures and clawing of the metacarpophalangeal joints. The photograph above shows an outline of the flap that is to be used to resurface the dorsal aspect of the hand.

This flap derives its axial blood supply from which of the following arteries?

(A) Deep inferior epigastric artery
(B) Medial femoral circumflex artery
(C) Superficial circumflex iliac artery
(D) Superficial external pudendal artery
(E) Superficial inferior epigastric artery

The correct response is Option E.

The flap depicted in the photograph is the superficial inferior epigastric artery (SIEA) flap, also known as the Shaw flap. This flap derives its axial blood supply from the superficial inferior epigastric (SIE) artery, one of three cutaneous arteries supplied by the common femoral artery. The SIE artery arises from the intersection of the inguinal ligament and the femoral artery, then courses superiorly and laterally toward the anterior axillary line.

The SIEA flap is typically transferred as a pedicled flap, but fasciocutaneous free tissue transfer has also been described. This flap is recommended for coverage of wounds of the hand and forearm because it lies in a relatively higher position on the torso than the groin flap; this allows for improved mobility of the shoulder while placing the elbow in a comfortable, flexed position while the flap matures. To confirm the pedicle pattern, Doppler ultrasonography can be performed prior to elevation of the flap. A photograph of the inset of the flap is shown above.

The superficial circumflex iliac artery provides the axial blood supply to the groin flap. This artery also originates from the femoral artery and travels parallel to the inguinal ligament, approximately 1 cm deep to the ligament.

Although the deep inferior epigastric artery supplies the rectus muscle on its deep surface, it does not supply the skin of the abdomen directly; instead, perforators emerge from the deep inferior epigastric artery and course through the rectus muscle to supply blood to the skin of the abdomen. This vascularity allows the skin and muscle to be harvested for free flap transfer.

The superficial external pudendal artery provides vascularity to the pubic region.

References
1. Barfred T. The hypogastric (Shaw) skin flap. In: Strauch B, Vasconez LO, eds. Grabb’s Encyclopedia of Flaps. Boston, Mass: Little, Brown & Co; 1990;2:1101-1104.
2. Mathes SJ, Nahai F. Superficial inferior epigastric artery (SIEA) flap. In: Reconstructive Surgery. New York, NY: Churchill Livingstone, Inc; 1997;2:1095-1103.
3. Schlenker JD, Atasoy E. The abdominohypogastric skin flap for hand and forearm coverage. In: Strauch B, Vasconez LO, eds. Grabb’s Encyclopedia of Flaps. Boston, Mass: Little, Brown & Co; 1990;2:1158-1160.

Immediately after undergoing reconstruction of a wound of the dorsal aspect of the hand using a reverse radial forearm flap, a patient has marked venous congestion of the flap. There is no hematoma visible under the flap. Which of the following is the most appropriate management?

(A) Increasing the temperature of the hand
(B) Elevation of the hand
(C) Intravenous infusion of heparin
(D) Application of leeches to the flap
(E) Anastomosis of an outflow vein

The correct response is Option E.

When harvesting a reverse island flap such as the reverse radial forearm flap, the surgeon should always attempt to preserve an outflow vein, which will be necessary for drainage of the flap if the reverse flow venous system does not function adequately. Most patients exhibit only mild venous congestion, and leeches can be applied to drain the flap sufficiently and thus preserve it. However, any patient who has immediate onset of marked venous congestion in which the cause is not obvious (ie, kinking of the pedicle or hematoma under the flap) should undergo immediate anastomosis of an outflow vein to decompress the flap.

Conservative measures such as increasing the temperature of the hand, elevating the extremity, or infusing heparin intravenously will ultimately fail in a patient with marked venous congestion requiring immediate operative treatment.

Reference
1. Jones NF, Lister GD. Free skin and composite flaps. In: Green DP, Hotchkiss RN, Pederson WC, eds. Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone, Inc; 1999;1:1159-1200.