Wound Healing, Hypertrophic scars and Keloids Flashcards
A 23-year-old woman comes to the office because of a hypertrophic scar after undergoing abdominoplasty 3 months ago. A multimodal approach to improving the appearance of the scar is planned. Which of the following therapies is supported by the highest quality evidence in this patient?
A) Allium cepa extract
B) Fat injection
C) Microneedling
D) Silicone gel
E) Vitamin E
The correct response is Option D.
Silicone gel has demonstrated efficacy in improving hypertrophic scars in a number of studies and is supported by level I evidence. Vitamin E, fat injection, allium cepa extract and microneedling are supported by lesser quality studies in a recent comprehensive review of the literature.
A 30-year-old man presents with a large open wound to the right thigh. The proposed treatment plan after debridement and establishing a clean wound is to use negative pressure wound therapy (NPWT). Which of the following is the main direct mechanism for wound healing by this method?
A) Improvement in tissue auto-debridement
B) Increase in collagen synthesis
C) Reduction in wound bacterial load
D) Removal of interstitial fluid leading to increased blood flow
The correct response is Option D.
Based on the original studies by Moryk, it was hypothesized that the beneficial wound-healing effects of negative pressure wound therapy (NPWT) was a combination of a fluid-based mechanism and a mechanical stress mechanism. The fluid-based mechanism involves the removal of excess interstitial fluid from the wound bed by the vacuum, which results in the interstitial pressure decreasing below the capillary filling pressures, thus allowing “re-opening” of these wound bed capillaries. This leads to improved blood flow within the wound, allowing for granulation tissue formation. The mechanical strain mechanism is created by micro-strain forces created by the vacuum on the cells within the wound. Cellular deformation leads to numerous molecular changes, including activation of the vascular endothelial cell growth factor (VEGF) pathway, which enhance angiogenesis.
Collagen synthesis is not directly affected by NPWT. There is equivocal evidence for whether there is a positive or negative effect of NPWT on wound bacterial loads.
NPWT does not auto-debride wounds. It is important when using NPWT to ensure adequate mechanical debridement of nonviable tissues from the wound bed prior to initiating NPWT.
During the inflammatory phase of wound healing, which of the following cellular components is most likely to appear first?
(A) Fibroblasts
(B) Lymphocytes
(C) Macrophages
(D) Myofibroblasts
(E) Neutrophils
The correct response is Option E.
Wound healing begins at the moment that tissue integrity is traumatically disrupted. Platelets are the first cells to enter the wound and provide the first burst of soluble molecules that modulate and mediate an initial hemostatic phase of wound healing. As hemostasis ensues secondary to vasoconstriction, platelet activation, and activation of the clotting cascade, various substances are present in the wound site that subsequently result in secondary vasodilation, increased capillary permeability, and chemoattraction and activation of leukocytes.
Neutrophils are the first leukocytes to enter the wound and thereby establish acute inflammation, peaking at approximately 24 hours post-wounding, followed shortly thereafter by the appearance of macrophages and lymphocytes.
The appearance of fibroblasts, epithelial cells, and endothelial cells characterize the subsequent proliferative phase of wound healing.
Which of the following is the most likely mechanism of action of silicone sheeting/silicone 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) Maintaning 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 and gel pads have not been shown to decrease wound tension, affect epidermal contact inhibition, or regulate intracellular integrins or wound temperature.
A 58-year-old woman develops full-thickness dermal necrosis in a 4 × 4 × 2-cm area of her lower breast following reduction mammaplasty. After debridement to healthy tissue, she starts daily wound packing with a calcium alginate fiber dressing. The main advantage of calcium alginate versus saline gauze dressings is a decrease in which of the following?
A) Dressing change frequency
B) Healing time
C) Keloid scarring
D) Treatment cost
E) Wound infection rate
The correct response is Option A.
An effective dressing should aid in surface debridement, absorb wound exudate, and maintain a moist healing environment. Normal saline wet-to-dry gauze dressings have been a mainstay of wound management for generations because they are easy to perform, widely available, and inexpensive. They are best changed 2 to 3 times daily to remove exudative material because they can quickly become saturated. Some of the wound healing byproducts, such as metalloproteinases and elastase, can slow down wound healing and result in chronic wounds. By wicking away these potentially harmful agents, more absorptive wound dressings can help simplify care. Alternatives to conventional saline wet-to-dry gauze dressing materials include hydrogels, hydrocolloids, foams, alginates, and negative pressure dressings. They are more expensive than traditional saline-gauze dressings but are typically far more absorptive, allowing for less frequent dressing changes. Daily dressing changes versus two to three times a day are far more convenient for patients and may ultimately save total treatment costs by allowing for fewer nursing visits or allowing for outpatient care. Many studies show no difference in healing times, though some studies suggest a mild benefit in diabetic foot ulcers. Current recommendations call for additional studies, as evidence of faster healing times is lacking. No studies show lower infection or scarring.
Calcium alginates are fibers made of brown seaweed fibers, and they can hold more than ten times their weight in fluid. Some manufacturers claim that they are able to deactivate metalloproteinases and stimulate healing, although in vitro data are lacking. They are a comfortable and effective alternative to saline wet-to-dry dressings, albeit at a higher product cost.
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.
A 55-year-old woman is admitted to the hospital for treatment of chronic pancreatitis. She has a 10-year history of severe rheumatoid arthritis managed with corticosteroids. Physical examination performed on admission shows an ulcer of the right ischium with purulent drainage. Results of culture show a polymicrobial infection. Serum albumin level is 1.8 g/dl. Necrotic soft tissue is debrided, resulting in a 6 x 4-cm defect and exposure of the underlying ischium. Which of the following is the most appropriate next step in management?
(A) Enzymatic debridement
(B) Vacuum-assisted closure (VAC) therapy
(C) Skin graft
(D) Gluteus fasciocutaneous flap
(E) V-Y hamstring advancement flap
The correct response is Option B.
The patient described has a full-thickness wound with exposed bone and will be a good candidate for flap closure once her infection is resolved and her nutrition optimized. Immediate reconstruction in a malnourished patient increases the risk of wound dehiscence and infection. During the interim, a vacuum-assisted closure (VAC) device is the most appropriate coverage for the wound. The VAC device promotes wound healing by facilitating the removal of excess interstitial fluid due to an increased pressure gradient and causes mechanical deformation of the wound resulting in enhanced granulation tissue formation, even over bone.
Enzymatic debridement may be appropriate in some patients with pressure sores but is not required in this patient because she has already undergone surgical debridement. A skin graft will not take to bone and provides insufficient soft-tissue coverage.
A 10-year-old boy underwent removal of a pigmented nevus from his scalp 2 weeks ago with suture closure. The tensile strength of the incision line today is most likely which of the following percentages of its final strength?
A) 10%
B) 20%
C) 40%
D) 60%
E) 80%
The correct response is Option A.
The tensile strength of a skin incision 2 weeks following repair is approximately 10%. Classic studies by Madden and Peacock showed that a cutaneous wound achieves 5% of its ultimate strength after 1 week, 10% after 2 weeks, 20% after 3 weeks, 40% after 4 weeks, and 80% after 6 weeks. The scar has its full strength 12 weeks after repair.
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.
A 42-year-old woman is scheduled to undergo autologous breast reconstruction. Which of the following is the most likely effect of steroid use in this patient?
A) Long-term corticosteroid use is associated with increased risk of free flap failure
B) Single perioperative corticosteroid dose is associated with transient hyperglycemia
C) Single perioperative corticosteroid dose negatively affects wound healing
D) The use of vitamin E counteracts the negative effects of corticosteroids on wound healing
The correct response is Option B.
The effects of corticosteroids on wound healing have been extensively studied. A single perioperative dose has not been associated with wound healing problems or complications. There is, however, a mild increase in glycemia, even in patients without diabetes.
The long-term use of corticosteroids has been associated with increased wound complications in susceptible individuals. It depends on the dose and duration of corticosteroid treatment.
The use of vitamin A, not E, has been shown to counteract the negative effects of corticosteroids on wound healing.
A 26-year-old man comes to the emergency department because he has a laceration of the anterior aspect of the right lower leg. Physical examination shows a superficial 2-cm full-thickness skin laceration. Sutures are placed. If the wound heals normally, which of the following is the earliest time that the epidermis is likely to be restored?
(A) 12 Hours
(B) 24 Hours
(C) 2 to 3 Days
(D) 4 to 5 Days
(E) 6 to 7 Days
The correct response is Option B.
If the basement membrane has been destroyed, epithelial cells and keratinocytes located on wound edges proliferate and send out projections to reestablish a protective barrier against fluid loss and bacterial invasion. The stimuli for epithelial proliferation and chemotaxis are epidermal growth factor and transforming growth factor (TGF) €‘α produced by activated platelets and macrophages. Fibroblasts do not synthesize TGF €‘α.
After closing a surgical incision, epithelialization usually occurs within 24 hours, at which point it is no longer necessary to keep the wound dry. Washing to remove dried blood can reduce bacterial proliferation and improve wound healing. This process may take longer in patients in whom wound healing may be compromised, such as elderly patients or patients with diabetes.
Epithelialization occurs early in wound healing. If the basement membrane remains intact, epithelial cells migrate upward in the normal manner. The epithelial progenitor cells remain intact below the wound in skin appendages, and the normal layers of the epidermis are restored in two to three days.
An 11-year-old girl has full-thickness dermal necrosis in the infusion zone of an antebrachial intravenous catheter which was used for treatment of a metastatic lower extremity sarcoma. Localized swelling was noted five days earlier after approximately 100 mL of the medication extravasated into the subcutaneous tissues. Total parenteral nutrition and intravenous doxorubicin had been administered as well as intravenous cefazolin and vancomycin. CT of the leg with intravenous contrast medium had also been performed in the past week. Which of the following is the most likely causative agent of the dermal necrosis from extravasation injury?
A ) Cefazolin
B ) Doxorubicin hydrochloride
C ) Radiographic contrast medium
D ) Total parenteral nutrition
E ) Vancomycin
The correct response is Option B.
Extravasation injuries are potentially dangerous occurrences that necessitate careful clinical follow-up and early treatment to avoid late catastrophic sequelae. Cytotoxic and hyperosmolar agents may result in local tissue necrosis, and high-volume injuries may cause compartment syndrome and limb ischemia. Though such injuries can occur in any patient, higher risk groups include children and the elderly, intensive care and chronically ill patients.
While any of the agents listed could be harmful in sufficient volume, doxorubicin hydrochloride (Adriamycin) is the one agent that should raise particular alarm. Adriamycin is associated with severe soft-tissue necrosis and warrants close follow-up for early surgical debridement, if needed. Dilution of the agent with saline or hyaluronidase may be helpful. Other early interventions, which are standard to all extravasation injuries, include splinting, elevation, local dressings, and close serial examination.
A 55-year-old woman who is wheelchair-bound has a stage IV ischial pressure ulcer. She has a history of systemic lupus erythematosus and multiple sclerosis. Medications include prednisone and gabapentin. BMI is 21 kg/m2 and has been stable for the past year. White blood cell count is 10.5 × 109/L, hematocrit is 30%, and serum albumin concentration is 3.6 mg/dL. After debridement of nonviable tissue, wound care is instituted. Supplementation with which of the following is most likely to promote wound healing?
A) Echinacea
B) Ferrous gluconate
C) Glutamine
D) Lipid emulsion
E) Vitamin A
The correct response is Option E.
Vitamin A is essential because it promotes epithelialization in collagen synthesis for wound healing, and supplementation is advocated in patients on chronic corticosteroid immunosuppressive medications such as prednisone. A 20,000-IU daily dosage can be useful for wound healing in immunosuppressed or irradiated patients and appears to reverse the wound healing–suppressive effects of the medication.
Patients with chronic wounds frequently have some form of malnutrition that can impede the wound-healing process. In this case, the patient has a serum albumin concentration within the reference ranges, and a stable BMI, signifying adequate protein. In protein-deprived patients, supplementing amino acids that serve as the building blocks of protein synthesis is vital. L-arginine, in particular, has been shown to augment wound healing and collagen production. One study in elderly human subjects found that daily supplementation of 30 g of arginine aspartate for 14 days resulted in markedly enhanced collagen production and total protein.
Ferrous gluconate is a useful supplement in iron deficiency anemia. This patient has borderline anemia, though not of a severity likely to be the central impediment to wound healing. Echinacea is a common herbal supplement used as an immunostimulant but has also been shown to have immunosuppressive effects. Lipid emulsion would be useful in a severely malnourished patient, though in this case, the patient’s BMI is stable in the normal range. Of note, omega-3 fatty acids appear to inhibit the quality of collagen strength, and avoiding this common supplement during healing may be advisable.
Which of the following types of collagen is most abundant in a healed scar?
(A) I
(B) II
(C) III
(D) IV
(E) V
The correct response is Option A.
The most abundant type of collagen in a healed scar is Type I. This type is the most abundant collagen in the body, including the skin. Type II collagen is found predominantly in cartilage and vitreous. Type III collagen is the second most abundant collagen in a healed scar. It also exists in elastic tissues, such as blood vessels. Type IV collagen is located mainly in the basement membranes. Type V collagen is widespread.
The use of routine systemic antibiotic prophylaxis is indicated in which of the following procedures?
A) Abdominoplasty
B) Carpal tunnel release
C) Excision of squamous cell carcinoma of the skin
D) Reduction mammaplasty
E) Rhytidectomy
The correct response is Option D.
Systemic antibiotic prophylaxis is recommended in clean breast surgery. Studies have shown that the use of antibiotic prophylaxis in patients undergoing breast surgery (with or without implant) significantly reduces the risk of surgical site infections. The benefit from routine antibiotic prophylaxis is greater in individuals receiving tissue expanders or breast implants for reconstruction, but patients undergoing breast augmentation or reduction mammaplasty also benefit from antibiotic prophylaxis. With the exception of cosmetic breast surgery, clean operations have not been shown to benefit from routine antibiotic prophylaxis. Therefore, the use of routine antibiotic prophylaxis is not indicated in clean surgical cases of the hand (carpal tunnel release), skin (squamous cell carcinoma of the skin), head and neck, or abdominoplasty. It is indicated in contaminated surgery of the hand or face.
Which of the following processes of healing provides maximal tensile strength of a wound?
(A) Accumulation of collagen
(B) Addition of sugar moieties
(C) Hydroxylation of lysine
(D) Hydroxylation of proline
(E) Molecular cross-linking
The correct response is Option E.
Intramolecular and intermolecular cross-linking between collagen fibers accounts for the maximal tensile strength of a wound. Maximal strength occurs during the remodeling phase of wound healing. Peak increase in tensile strength occurs three to six weeks after injury but approaches maximal after about three months when it achieves up to 80% of the normal skin strength.
Collagen synthesis peaks at about three weeks, and collagen accumulates to its maximum at six weeks; however, intramolecular and intermolecular cross-linking between collagen fibers provides the tensile strength of the wound.
The addition of sugar moieties occurs just before cleavage of amino and carboxy terminal ends. After this, the molecules are termed collagen, which then develops further intermolecular and intramolecular bonds for strength.
The hydroxylation of lysine and proline in the endoplasmic reticulum of the fibroblasts is a crucial step in collagen production and is important in future intermolecular cross-linking. However, this step occurs much earlier in wound healing, primarily during the proliferative phase.
Which of the following substances has been shown to occur in higher levels in keloids and red hypertrophic scars than in pink or white hypertrophic scars?
(A) Adenosine triphosphate
(B) Creatine kinase
(C) Fibronectin
(D) Guanosine triphosphate
The correct response is Option A.
When compared with more mature pink and white scars, keloids and red hypertrophic scars have been shown to have higher levels of adenosine triphosphate. In addition, greater quantities of fibroblasts have also been found in keloid scars when compared with more mature scars. Both keloids and hypertrophic scars actively synthesize collagen fibers and have been shown to have increased activity of glycolytic enzymes in vivo.
Creatine kinase, fibronectin, and guanosine triphosphate have not been shown to be present at higher levels in keloids or red hypertrophic scars.
Which of the following is the primary role of adipose-derived stem cells (ADSC) in wound healing?
A) Assist in chemotaxis of platelets and granulocytes
B) Differentiate directly into fibroblasts and keratinocytes
C) Induce development of hair and sweat follicles
D) Provide a scaffold for deposition of granulation tissues
E) Register and organize pro-collagen fibrils
The correct response is Option B.
Adipose-derived stems cells (ADSC) have had extensive study in vitro and in vivo because there are ready sources of them from adult patients, which bypasses many ethical and regulatory issues of embryonic stem cells.
ADSC have both direct structural and paracrine roles in wound healing. They can directly differentiate into keratinocytes, endothelial cells, and dermal fibroblasts. ADSCs, through paracrine phenomena, are modulators of the inflammatory environment of the wound healing milieu but are not involved in the immediate chemotaxis during the inflammatory period nor do they function as a scaffold during the proliferative phase. Lysyl oxidase is the extracellular enzyme responsible for final alignment of collagen fibrils.
Presence of skin adnexa such as hair follicles and sweat glands are hallmarks of scarless, fetal healing. Hair follicle formation typically only occurs during embryonic development and involves interaction of ectodermal and mesenchymal cells influenced by signaling pathways including Wnt/b-catenin and BMPl but not ADSCs.
A 24-year-old woman who works as a radiology technologist presents to the emergency room 1 hour after her right hand was exposed to an estimated 5 Gy of radiation. Examination shows no abnormalities. Which of the following is the most likely clinical outcome?
A) Delayed dermal necrosis
B) Extensive blistering of the entire hand
C) Increased susceptibility to soft-tissue infections
D) Transient erythema, pruritus, and hair loss
E) No sequelae
The correct response is Option D.
The upper extremity is commonly affected in workplace and industrial fluoroscopy accidents.
Mild, or low, energy exposures (less than 10 Gy) are generally associated with a transient erythema, itching, and loss of hair. Moderate exposures (10 to 20 Gy) can have more immediate erythema that will resolve but then reoccur 1 to 2 weeks following injury. Higher exposures (greater than 20 Gy) are associated with more immediate symptoms of erythema and pain and can lead to complete tissue necrosis. Pseudomonas infection has been reported in these injuries but is more commonly involved in more severe cases that necessitate amputation.
A 42-year-old man develops a dehiscence of the abdominal incision six weeks after undergoing a lower body lift. Medical history includes a 100-lb (45-kg) weight loss during the past three years. Which of the following is the most likely cause of the wound-healing problem?
A ) Hematoma
B ) Patient movement
C ) Seroma
D ) Skin necrosis
E ) Wound infection
The correct response is Option C.
Body lift procedures after massive weight loss have a complication rate of approximately 50%. The most common complication is wound dehiscence, which occurs in greater than 30% of patients. Wound dehiscence can be characterized as either early (in the immediate postoperative period) or late. Early wound dehiscence may be caused by patient movement, while late wound dehiscence is often due to underlying seroma. Although infection and skin necrosis can occur in the postoperative period and result in wound dehiscence, seroma is much more common.
Which of the following is the predominant type of collagen found in basement membrane?
(A) Type I
(B) Type II
(C) Type III
(D) Type IV
(E) Type V
The correct response is Option D.
Type IV collagen is the predominant collagen in basement membrane. In contrast, type I collagen is most often found in normal, mature skin, as well as in tendon and bone. Type II collagen is present in hyaline cartilage and the tissues of the eye. Type III collagen is located in the papillary dermis, arteries, intestinal walls, and uterus. In addition, hypertrophic and immature scars can contain as much as 30% type III collagen. Type V collagen is also found within the basement membrane in lesser amounts than type IV collagen.
A 41-year-old man undergoes an elective transplantation of the right hand 2 years after traumatic amputation in a machine accident. Postoperatively, the patient takes immunosuppressive medications to minimize the chance of rejection. To monitor for cellular rejection, observation and biopsy of which of the following tissue types in the postoperative period is most appropriate?
A ) Blood vessel
B ) Bone
C ) Muscle
D ) Skin
E ) Tendon
The correct response is Option D.
Composite tissue allotransplantation (CTA) has been performed on a host of tissues, though more recently in plastic surgery; this has largely been in the field of hand or upper extremity and facial transplantation. This requires immunosuppressive regimens which have had varying degrees of success, as well as issues with patient compliance, especially as these medications are expensive and, at least at this time, necessary for the rest of the patient’s life. Skin is thought to be the most antigenic and immunoreactive tissue in CTA. Experience from China in hand transplantation demonstrated that cellular rejection in these patients was largely limited to the skin, with relative sparing of the underlying blood vessels, bone, muscle, nerve, and tendon. However, as the skin is an easily monitored tissue (versus solid organs), it is the most sensitive indicator of acute rejection in that it is clearly visible and can be easily evaluated by both patient and physician. Therefore, this tissue type is most appropriate to be monitored and biopsied.
A 26-year-old man sustains circumferential abrasions and lacerations to the right arm in a roll-over motor vehicle collision. On examination, the arm is covered in dirt and debris. In addition to irrigation of the wound site, which of the following is the most appropriate initial management?
(A) Immediate closure
(B) Operative closure
(C) Immediate split-thickness skin grafting
(D) Daily whirlpool hydrotherapy
(E) Mechanical debridement
The correct response is Option E.
The most appropriate management of this patient is irrigation and mechanical debridement of the wound site. Patients with soft-tissue lacerations covered with debris often have foreign particles embedded within the dermis or subcutaneous tissue. If this material is not removed promptly, a traumatic tattoo will ultimately develop; treatment of this complication is difficult and frequently unsuccessful. Therefore, mechanical devices, such as scrub brushes or pulse irrigation devices, should be used with physical retrieval to ensure that all debris is removed.
Coverage of the extremity with any type of dressing will not address the embedded particulate matter. Hydrotherapy may be useful in removing surface debris but not subcutaneous debris.
A 63-year-old man comes for evaluation of a dehisced surgical incision 3 weeks after undergoing open reduction of the right ankle. He has a history of coronary artery disease, hypertension, hypercholesterolemia, and poorly controlled type 2 diabetes mellitus. He had a myocardial infarction 2 years ago. Physical examination shows a dehisced surgical incision with exposed tibialis anterior tendon without paratenon. A photograph is shown. The patient refuses free tissue transfer. Which of the following is the most appropriate skin substitute for the wound?
A) Biodegradable bilaminate neodermal matrix (Integra)
B) Biosynthetic wound dressing (Biobrane)
C) Cryopreserved neonatal fibroblast-derived dermal substitute (Dermagraft)
D) Human fibroblast-derived composite skin substitute (TransCyte)
E) Living bilayered skin substitute (Apligraf)

The correct response is Option A.
Integra is a bilaminate neodermal replacement product that is composed of a biodegradable bovine collagen-glycosaminoglycan (collagen-GAG) matrix underlayer with a silicone outer layer. Although its ?on-label? indication is for burn reconstruction, it also has utility in reconstruction of wounds of exposed bone without periosteum, exposed cartilage without perichondrium, and exposed tendon without paratenon, such as in the scenario described. The collagen-GAG matrix serves as scaffolding for the ingrowth of cells and neovascularization. After regeneration, which takes between 2 to 4 weeks, the silicone outer later is removed and a thin split-thickness skin graft completes the reconstruction by providing epithelial cells over the neovascularized dermal replacement.
Biobrane is a temporary, rather than permanent, bilaminar skin substitute that is constructed of an inner layer, composed of nylon and collagen, which is covered by an outer silicone film. Biobrane serves as a temporary wound dressing, usually in burn patients, where it helps prevent evaporative loss (due to the silicone outer layer) and subsequent wound desiccation. It decreases wound pain and provides a barrier to bacterial infection. Biobrane is removed either before permanent grafting or after epithelialization of the wound has occurred. Dermagraft is a dermal substitute composed of neonatal foreskin fibroblasts cultured on a polyglactin mesh, and it is generally used in the treatment of diabetic foot ulcers, where it often is combined with meshed skin grafts.
TransCyte is also a temporary wound dressing. It is similar to Biobrane but has an added biologic layer derived from neonatal fibroblasts that are seeded onto the nylon matrix to produce type I collagen, fibronectin, and glycosaminoglycans. TransCyte is removed either before skin grafting or after epithelialization of the wound. It has been shown to significantly decrease pain and time to epithelialization.
Apligraf, another permanent replacement product, is constructed of type I bovine collagen and cultured neonatal human fibroblasts and keratinocytes. After construction of the dermal matrix equivalent, cultured keratinocytes are applied. It is generally used in the treatment of venous ulcers and diabetic foot ulcers (may take more than one application). Its long-term durability, however, makes it an inappropriate choice in situations with a full-thickness defect with exposed vital structures.
A follow-up photograph of the ankle is shown.










