(A) 5%
(B) 10%
(C) 25%
(D) 55%

The correct response is Option D.

This 16-year-old boy has a keloid on the left shoulder. Unlike hypertrophic scars (which remain within their original boundaries), keloids are abnormal scars that extend beyond the confines of the healing wound and do not regress. Recurrence rates following surgical excision alone have been shown to be at least 55% and as high as 100%, according to the results of some studies. Therefore, excision alone is not recommended; it should instead be combined with postoperative injection of corticosteroids and/or application of gel sheeting or compression garments to minimize recurrence.

In patients with more severe keloids, a short postoperative course of radiation therapy is recommended following excision to decrease recurrence rates to an acceptable level.

References
1. Alster TS, West TB. Treatment of scars: a review. Ann Plast Surg. 1997;39:418-432.
2. Ogawa R, Mitsuhashi K, Hyakusoku H, et al. Postoperative electron-beam irradiation therapy for keloids and hypertrophic scars: retrospective study of 147 cases followed for more than 18 months. Plast Reconstr Surg. 2003;111:547-555.
3. Rockwell WB, Cohen IK, Ehrlich HP. Keloids and hypertrophic scars: a comprehensive review. Plast Reconstr Surg. 1989;84:827-837.

Which of the following is the predominant cell type involved in wound contracture?

(A) Eosinophil
(B) Erythrocyte
(C) Fibroblast
(D) Monocyte
(E) Neutrophil

The correct response is Option C.

Fibroblasts, specifically myofibroblasts, are the predominant cell type involved in wound contracture. These cells first appear approximately three days after injury and are typically located at the periphery of the wound, but contain actin-rich filaments that act throughout the area of injury to initiate contracture and alter the shape of the open wound. Wound contracture is a cell-mediated process that typically begins four to five days after the initial injury and continues until at least 21 days after injury. It can be influenced by many factors, including the degree, area, and shape of the injury and the length of time that the wound remains open. Transforming growth factor-beta and possibly other cytokines may also contribute to wound contracture.

Although erythrocytes, monocytes, and neutrophils are important cell mediators in the wound healing process, they are not primarily involved in wound contracture. Eosinophils are typically involved in hypersensitivity and allergic reactions.

References
1. Lawrence WT. Physiology of the acute wound. Clin Plast Surg. 1998;25:321-340.
2. Monaco JL, Lawrence WT. Acute wound healing an overview. Clin Plast Surg. 2003;30:1.

Which of the following is the most likely mechanism of action of silicone sheeting/gel pads in enhancing scar maturation?

(A) Decreasing wound tension
(B) Deregulating cellular integrins
(C) Enhancing epidermal contact inhibition
(D) Increasing the static electronegative field
(E) Maintaining regulated wound temperature

The correct response is Option D.

Silicone sheeting and silicone gel pads are used to treat hypertrophic or immature scars and keloids. Although their exact mechanism of action is unknown, some surgeons postulate that their positive effect is associated with the generation of an increased static electronegative field by the silicone. This mechanism of action results in favorable wound effects. Other theories propose that the wound-healing mechanism is related to the decreased oxygenation, sustained pressure, or hydrating effects of silicone oil resulting from the use of these products.

Silicone sheeting/gel pads have not been shown to decrease wound tension, affect epidermal contact inhibition, or regulate intracellular integrins or wound temperature.

References
1. Berman B, Flores F. The treatment of hypertrophic scars and keloids. Eur J Dermatol. 1998;8:591-595.
2. Hirshowitz B, Lindenbaum E, Har-Shai Y, et al. Static-electric field induction by a silicone cushion for the treatment of hypertrophic scars. Plast Reconstr Surg. 1998;101:1173-1183.

Which of the following is an absolute contraindication to performing vacuum-assisted closure (VAC) therapy for wound management?

(A) Bacterial colonization of the wound
(B) Open fracture of a long bone
(C) Presence of an enteric fistula
(D) Presence of exposed blood vessels
(E) Presence of osteomyelitis

The correct response is Option D.

Vacuum-assisted closure (VAC) is an effective technique for management of open wounds. Advantages include promoting the ingrowth of healthy granulation tissue, decreasing the duration of the wound healing process, simplifying dressing changes, and increasing the intervals between dressing changes. However, the presence of exposed arteries or veins is an absolute contraindication to VAC therapy because the vessel may burst and subsequently hemorrhage into the VAC device; this can be potentially fatal.

Although VAC therapy is not contraindicated in open wounds, which by their nature are colonized by bacteria, the presence of gross bacterial infection precludes the use of the VAC device.

VAC therapy is an option for management of open fractures until definitive flap reconstruction can be performed.
The presence of an enteric fistula within the wound is no longer an absolute contraindication to VAC therapy.

The presence of osteomyelitis in the wound bed is not a contraindication to VAC therapy.

References
1. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method for wound control and treatment: clinical experience. Ann Plast Surg. 1997;38:563-577.
2. Morykwas MJ, Argenta LC, Shelton-Brown EI, et al. Vacuum-assisted closure: a new method for wound control and treatment: animal studies and basic foundation. Ann Plast Surg. 1997;38:553-562.