Wound Healing Flashcards
Use of negative pressure wound therapy with a sponge dressing is likely to result in an adverse outcome in which of the following clinical scenarios?
A) A hand wound with exposed tendons
B) A lower extremity wound with exposed femoral vessels
C) A Stage IV sacral pressure sore
D) As a bolster over a split thickness skin graft on the arm
E) Over a closed surgical incision after hernia repair
The correct response is Option B.
Negative pressure wound therapy (NPWT) has dramatically improved our ability to manage complicated and complex wounds. Advantages of NPWT include decreased healing time, simplified wound care with less frequent dressing changes, and promotion of healthy granulation tissue. However, there are several contraindications to the use of NPWT. The presence of exposed vessels is an absolute contraindication to its use; arterial rupture has been reported with multiple fatalities. In addition to placement over exposed vessels, significant bleeding has also been noted with use of NPWT in groin and sternal wounds, in patients on blood-thinning medications, and during removal of well-integrated foam pieces. Other complications include infections due to retained pieces of foam.
In addition to exposed vessels, NPWT should not be used in the setting of active, uncontrolled infection, malignant wounds, wounds with unexplored and/or nonenteric fistulas, and poorly debrided wounds.
Although NPWT may not be the definitive wound management in the other scenarios listed, there is no contraindication for its use.
2018
Which of the following technical factors has the greatest favorable impact on the final appearance of a surgical scar?
A) Closing the wound in a single layer B) Use of an absorbable suture C) Use of topical cyanoacrylate D) Retention suture E) Wound-edge eversion
The correct response is Option E.
The two technical factors that increase the likelihood of a “good” scar are placement of sutures that will not leave permanent suture marks and wound-edge eversion. In wounds where the skin is brought precisely together, there is a tendency for the scar to widen. In wounds where the edges are everted or hypereverted in an exaggerated fashion, this tendency is minimized possibly by reducing the tension on the closure. While the most common method of closing a wound is with sutures, there is nothing necessarily superior about sutures or a specific type of suture. Staples, skin tapes, or wound adhesives are also useful in certain situations. Regardless of the method of closure or type of suture used, precise approximation of skin edges without tension is essential to ensure healing with minimal scarring. Simple interrupted suture is the gold standard for suturing wounds closed and everting the skin edges. Retention sutures tend to leave the most obvious and unsightly cross-hatching if they are not removed early. Wounds deeper than the skin are closed in layers. The key is to eliminate the dead space and provide a strong closure to prevent dehiscence and reduce tension. However, not all layers necessarily require separate closure.
2018
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.
2018
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.
2018
A 77-year-old man undergoes wide local excision of a melanoma on the posterior shoulder. Concomitant sentinel lymph node biopsy is positive for metastasis. Completion axillary lymph node dissection and adjuvant radiation therapy to the axilla are performed. Metastatic workup shows no abnormalities. Postoperatively, the patient develops chronically draining seroma and open wound to the axilla. He is referred for management of the radiation wound after it fails to improve with conservative local wound care. Physical examination shows a 2-cm open wound to the axilla, which tunnels 5 cm into the apex and is surrounded by extensive fibrosis and erythema. Which of the following interventions is most likely to result in a definitive closure?
A) Administration of 30 hyperbaric oxygen treatments at 2.4 ATA
B) Application of negative pressure wound therapy
C) Excision of the wound cavity and full-thickness skin graft reconstruction
D) Excision of the wound edges and application of acellular dermal matrix
E) Wide excision of the irradiated soft-tissues and repair with a thoracodorsal artery perforator flap
The correct response is Option E.
Radiation damage produces a hypoxic, hypovascular, and hypocellular environment that can lead to delayed healing and even ulcer formation. Principles of management once a chronic radiation wound has developed include aggressive surgical removal of the entire zone of injury, which is sometimes larger than initially anticipated, and repair with well-vascularized tissue. A thoracodorsal artery perforator flap will provide sufficient healthy and supple soft tissue to cover the entire axilla. The thoracodorsal pedicle should be intact as it is not regularly divided during axillary lymph node dissection.
Negative pressure wound therapy would be contraindicated in this wound because of the potential for exposure of blood vessels in the axilla as well as for sponge retention in the tunneled wound and is, therefore, incorrect.
Excision of the wound edges only may be inadequate treatment of the zone of injury, and it is not the best choice. Furthermore, acellular dermal allograft plays no role, aside from possibly a temporizing measure, in the treatment of radiation ulcers.
Hyperbaric oxygen therapy is indicated for soft tissue radionecrosis. This delivers increased levels of oxygen to the hypoxic, irradiated wound and establishes a steeper oxygen gradient between the wound and surrounding tissues. The cellular response to this gradient stimulates neovascularization and can improve or even heal some wounds. However, with this large, cavitary wound, hyperbaric oxygen therapy, as a single-line treatment, would be unlikely to heal the wound completely.
Excision of the wound cavity and full-thickness skin graft reconstruction is not the best option for two reasons. First, the excision may lead to exposure of neurovascular structures that should not be covered with a skin graft. Second, risk of partial or total loss of a full-thickness skin graft may be unacceptably high in an irradiated wound bed.
2018
During which of the following phases of wound healing is collagen deposition the greatest?
A) Collagen deposition occurs equally during all phases of wound healing
B) Collagen deposition does not occur during wound healing
C) Inflammatory
D) Proliferative
E) Remodeling
The correct response is Option D.
The proliferative phase of wound healing occurs in two phases. Fibrin and fibronectin are formed during the initial proliferative period. Around day 3 of wound healing, fibroblasts appear and begin production of collagen. The proliferative phase ends between 2 to 4 weeks of wound healing when collagen accumulation reaches a maximum and collagen remodeling begins, marking the beginning of the remodeling phase of wound healing.
Inflammatory phase is dominated by white blood cells. There is an influx of polymorphonuclear leukocytes (PMNs), macrophages, and lymphocytes. PMNs are not essential to wound healing, but macrophages are essential. Sterile incisions normally heal without PMNs.
Type III collagen is converted to type I in the remodeling phase. In this phase there are increased collagen cross-linking and increased tensile strength.
Collagen deposition does not occur during wound healing is incorrect. It occurs during all phases of wound healing.
Collagen deposition occurs equally during all phases of wounding healing is incorrect because collagen deposition is heaviest during the proliferative phase. Fibroblasts differentiate from resting mesenchymal cells in connective tissue. They are chemoattracted to the site, divide and produce components of ECM and their primary function is to synthesize collagen during that phase.
2018
A 40-year-old man with a history of seizure disorder presents with jaw pain and malocclusion 12 hours after he was punched in the face during a brawl. X-ray studies show a displaced left angle fracture and right parasymphyseal fracture. He smokes one pack of cigarettes daily. Open reduction and internal fixation of the fractures is planned. Which of the following factors in this patient’s clinical presentation places him at greatest risk for postoperative wound infection?
A) History of seizures B) History of tobacco use C) Patient age D) Patient gender E) Surgery delayed until 5 days after injury
The correct response is Option B.
Although early treatment of mandible fractures would help relieve pain, delay of treatment in multiple series has not been directly correlated with an increased wound infection rate. In a recent review, tobacco use has been associated with a sixfold increase in wound infection compared with nonsmokers. Although the incidence of complications after mandible fractures is lower in children, in the adult population, patient age and gender do correlate with an increased complication rate. Factors that have correlated with a higher complication rate include the number of mandible fractures present and incision location, intraoral and combined intraoral, and combined intraoral and extraoral incisions were associated with higher infection rates than only extraoral incisions.
2018
A 45-year-old woman undergoes breast reconstruction with a transverse rectus abdominis musculocutaneous (TRAM) flap. During donor site closure, a size-0 absorbable suture that maintains the greatest strength over time is desired for closure of Scarpa fascia. Which of the following sutures is most appropriate?
A) Chromic gut B) Poliglecaprone (Monocryl) C) Polydioxanone (PDS) D) Polyglactin (Vicryl) E) Polypropylene (Prolene)
The correct response is Option C.
Chromic gut is an absorbable natural monofilament suture whose strength decreases to 50% in approximately 14 days, with near complete loss of strength at approximately 3 weeks.
Polyglactin (Vicryl) is an absorbable synthetic polyfilament suture whose strength decreases to 50% in approximately 2 to 3 weeks, with near complete loss of strength at approximately 1 month.
Poliglecaprone (Monocryl) is an absorbable synthetic monofilament suture whose strength decreases to 50% in approximately 7 to 10 days, with near complete loss of strength at approximately 3 weeks.
Polydioxanone (PDS) is an absorbable synthetic monofilament suture whose strength decreases to 50% in approximately 4 weeks, with near complete loss of strength at approximately 6 weeks.
Polypropylene is a a nonabsorbable synthetic monofilament suture.
2017
A patient presents with an 8-cm linear laceration to the forearm from a bicycle accident. Compared with typical suturing techniques, which of the following outcomes is more likely with a cyanoacrylate glue–only closure?
A) Dehiscence B) Hyperpigmentation C) Infection D) Keloid scarring E) Pain
The correct response is Option A.
While cyanoacrylate glue closures such as Dermabond and Indermil offer the advantages of speed, ease-of-use, and comfort in the closure process, some studies show that the outcomes are unpredictable, especially for longer lacerations. One pediatric groin hernia incision closure showed a 24% dehiscence rate, while a porcine study of 10-cm lacerations showed a 15% dehiscence rate. Glue closures do have a role in smaller, tension-free lacerations, particularly in children or others who may not easily tolerate traditional closure. This simplicity of closure does come with the cost of a higher dehiscence rate, so glue closures may be inappropriate for longer, more complex wounds. When used as an adjunct to a comprehensive subdermal interrupted closure, it appears that the dehiscence rate normalizes. Data are less convincing on long-term scar results, but it does not appear likely that glue closures improve or worsen scarring to any appreciable extent for wounds that achieve primary healing without disruption.
2017
A 24-year-old man comes to the office because of a 1-year history of a lesion of the left earlobe following an attempt to pierce his ear at home. A photograph is shown. The patient reports that the lesion is enlarging gradually in size and mildly itchy. Which of the following features most likely characterize this lesion?
Photo: giant keloid on earlobe
A) It is a hypertrophic scar because it extends beyond the margin of the initial scar
B) It is a hypertrophic scar with distinct bundles of collagen oriented parallel to the skin surface
C) It is a keloid and has an increased ratio of type I to type III collagen compared with normal scars
D) It is a keloid and has increased levels of transforming growth factor beta (TGF-B) and type III collagen
E) It is a keloid with distinct bundles of collagen oriented parallel to the skin surface
The correct response is Option D.
All wounds leave scars. Wound healing is mediated by fibroblasts and is divided into three phases: the inflammatory phase (3 to 10 days), fibroblastic (10 to 14 days), and maturation (14 days to one year). During the proliferative phase, immature collagen fibrils are cross-linked and form mature collagen. The amount of collagen in a healing wound reaches a peak in three weeks, but remodeling continues months to years after the initial injury.
The difference between a keloid and a hypertrophic scar is often made clinically. A hypertrophic scar does not transgress the margins of the original wound; a keloid invades the adjacent normal skin. From the history of an ear piercing and the appearance of the lesion, the lesion is clearly a keloid.
Normal skin contains distinct collagen bundles that run parallel to the epithelial surface. The collagen structure in disordered scars such as hypertrophic scars and keloids is present in randomly oriented dense sheets.
Keloid scars contain excess amounts of type III collagen. In normal skin and scars the ratio of type I collagen to type III collagen is 4:1. In keloids the ratio is decreased due to excess type III collagen deposited by fibroblasts.
2017
Negative pressure wound therapy with a sponge dressing is CONTRAINDICATED in which of the following clinical scenarios?
A) An abdominal wound with an enteric fistula
B) A dorsal hand wound with an exposed tendon
C) A lower extremity wound with acute osteomyelitis
D) Over a closed surgical incision
E) A radiated scalp wound with exposed bone
The correct response is Option C.
The use of negative pressure therapy (NPT) is contraindicated in wounds with active infection including osteomyelitis. Negative pressure dressings in these wounds convert an open, draining wound into a closed wound, which could potentially lead to abscess formation and/or sepsis. NPT has become an integral part of wound management over the past decade and a half. It is a commonly used wound dressing and/or chronic wound management tool. It is instrumental in acute wounds as well (e.g., lower extremity trauma, abdominal wall trauma), and as a skin graft bolster dressing. The major contraindications for its use include wounds with active infection such as untreated osteomyelitis, malignant wounds, wounds with exposed major vessels and/or organs, and wounds with unexplored and/or nonenteric fistulas.
Apart from the infected wound, all the wounds mentioned in the option set may benefit from the use of NPT. It may not be the definitive management for those wounds, but it could be used as a temporary measure prior to the definitive treatment. Recently, studies have shown that the use of NPT over closed incisions may reduce the risk for dehiscence and infections.
2016
A 63-year-old man underwent resection of a chest wall sarcoma that was covered with an anterolateral thigh flap. He now undergoes external beam radiation therapy, and there is erythema, edema, and dry desquamation of the surgical sites. Which of the following is the most appropriate treatment?
A) Diphenhydramine B) Hyaluronic acid C) Hydrocortisone D) Salicylate E) Vitamin E
The correct response is Option C.
Radiation dermatitis is one of the most common side effects of radiotherapy for cancer and can occur any time, from hours to weeks after radiation exposure.
Acute radiation-induced skin changes depend on the radiation dose and include erythema, edema, pigment changes, epilation, and dry or moist desquamation. They can also be accompanied by pain and pruritis.
For the lower grade changes described for this patient, topical corticosteroids with low to medium potency, such as hydrocortisone 1% cream, are recommended. This is in addition to a skin-washing protocol to keep skin clean and dry before treatments.
All of the other topical agents listed – antihistamines, salicylate analgesics, vitamin E, and hyaluronic acid – have all been previously studied and shown to have no added benefit.
More severe skin changes such as moist desquamation, skin necrosis, or intractable pain may require radiation to be stopped, resulting in inadequate disease treatment.
2016
A 38-year-old unconscious and intoxicated woman is brought to the emergency department after being struck by a motor vehicle. She sustained multiple injuries, including a wound on the right thigh, which measures 12 × 18 cm with areas of exposed fat and muscle. There is dirt and gravel in the wound. Which of the following is the most appropriate next step in management?
A) Broad-spectrum antibiotic therapy B) Injection of tetanus toxoid C) Negative pressure wound therapy D) Split-thickness skin grafting E) Wound irrigation and debridement
The correct response is Option B.
In a patient with a grossly dirty wound, it is appropriate to administer a tetanus shot. Tetanus (also known as lockjaw) is characterized by a prolonged contraction of skeletal muscle fibers. The primary symptoms are caused by tetanospasmin, a neurotoxin produced by Clostridium tetani, a gram-positive, rod-shaped, obligate anaerobe. Infection generally occurs through wound contamination and often involves a cut or deep puncture wound.
In the acute period before definitive wound closure can be achieved, it is critical to debride all devitalized tissue such that there is a healthy, viable wound bed. The administration of broad-spectrum intravenous antibiotics has not been shown to decrease the risk of wound infection, and may, in fact, lead to the development of selecting out for resistant pathogens. The mainstay of treatment is performing repeat surgical debridement as often as necessary until the wound is clean. Debridement and cleansing of the wound are ideally performed in the operating room under controlled conditions; however, depending upon the condition of the patient, concomitant injuries, and the ability of the patient to tolerate the procedure, it may be necessary to perform a limited, conservative wound washout at the bedside or in the emergency department. Over the course of the initial hospital stay, debridement should continue until healthy tissue is encountered, which can be identified by visual inspection and the presence of punctate bleeding.
The surgeon must consider several things when deciding between closure with a flap or a graft. The defect in this patient is too large to achieve primary closure. The use of negative pressure wound therapy for such a large wound may be helpful as a temporary measure, but, as a method of definitive wound closure, would result in healing by secondary intention, scarring, and prolonged wound care. If there were exposed bone, tendon, nerves, blood vessels, or significant dead space, this would make a stronger argument for a flap-over-skin graft. Although not provided as an option in this question, the use of biosynthetic materials or dermal matrix tissues has been reported in the literature as an intermediate step to skin grafting, but it is important to consider the necessity of these materials in effecting outcomes in light of the significant cost of using them.
Split-thickness skin grafts can provide wound coverage over a large area. A mechanical dermatome is often used. Typical thicknesses may range from 8/1000th of an inch to 14/1000th of an inch. The graft can be meshed in various ratios such as 1:1.5, 1:2, and 1:3 to allow for a larger area of coverage per unit of harvested skin. It is important that the underlying wound bed be viable and free of necrotic tissue or infection to allow for healing of the skin graft (“skin graft take”). Adequate immobilization of a skin graft is important for “take” of the graft, and can be achieved with negative pressure wound therapy, or tie-over bolster dressing. The thigh has an abundant amount of soft tissue and muscle, which is why skin grafts are often sufficient for wound coverage rather than flaps.
2016
An 82-year-old man is referred for reconstruction of the scalp after Mohs micrographic surgery for an aggressive squamous cell carcinoma. He is scheduled to undergo radiation therapy as soon as possible after reconstruction. The patient has pulmonary fibrosis and is receiving oxygen via nasal cannula. Physical examination shows a vertex scalp defect of 4 × 4 cm with calvarium exposed throughout. Which of the following is the most appropriate management?
A) Bilaminate neodermis B) Delayed reconstruction C) Local tissue rearrangement D) Radial forearm free flap E) Split-thickness skin graft
The correct response is Option C.
In any reconstruction, many factors (local, regional, and systemic) have to be considered before deciding on a proper treatment option. Indeed, there may very well be multiple options. The patient described is an elderly man who is an extremely poor candidate for anesthesia (example of systemic consideration). Additionally, he will need radiation therapy to the scalp as soon as possible. Therefore, the reconstruction option needs to have excellent blood supply to heal in the first place, heal quickly, and withstand the effects of radiation. Additionally, coverage of the exposed calvarium is necessary, as periosteum has been removed by the Mohs surgeon. Out of the options given, local scalp flap coverage best accomplishes this goal.
Delay of treatment is not recommended because it only creates a greater problem after radiation therapy, because all local options as well as the calvarium will be irradiated, which severely hampers the surgeon’s ability to provide a low-morbidity procedure and avoid a substantial operation.
Dermal matrices (any form) are not appropriate options here for many reasons. They are not the definitive treatment option in a patient who is about to undergo radiation. Once the matrices become incorporated, they will usually need a skin graft to complete reconstruction or they will need a prolonged period of dressing changes, neither of which is optimal in this patient (a second surgery or a prolonged healing phase). Also, they need to be placed on a well-vascularized bed in order for them to “take” and heal more effectively. An exposed calvarium (without additional burring of bone) is not an optimal bed for a dermal matrix.
Skin grafts (of any variety) lack blood supply after harvest. They also need to be placed on a well-vascularized bed in order for them to “take” and heal more effectively. An exposed calvarium (without additional burring of bone) is not an optimal bed for a skin graft. Also, a thin skin graft may not be the best form of reconstruction in a patient who is about to undergo radiation therapy, if other options exist.
Radial forearm free flap is too complex an operation for this patient with many comorbidities and a relatively small defect.
2016
An otherwise healthy 25-year-old woman is scheduled to undergo resection of a 3 × 5-cm atypical nevus of the right thigh. Medical history includes systemic lupus erythematosus. She has been receiving oral corticosteroid therapy for more than 5 years. She is well nourished. Perioperatively, administration of which of the following vitamins is most likely to improve this patient’s wound healing?
A) A B) B complex C) C D) D E) E
The correct response is Option A.
Perioperative administration of vitamin A is most likely to improve wound healing in this well-nourished patient receiving chronic corticosteroid therapy.
Corticosteroids have been shown to negatively affect all major steps of the wound healing process. Several mechanisms have been proposed, including a stabilizing effect in the lysosomal membrane of cells. Vitamin A was known to cause the opposite (destabilizing) effect in lysosomal membranes in vivo, which led to the first studies on the interaction between these two classes of drugs in wound healing in the 1960s. Since then, supplementation of vitamin A in patients receiving corticosteroids has been shown to counteract most of the deleterious effects of corticosteroids in wound healing, with the exception of wound contraction and infection.
There is no consensus in dose and duration of treatment. Most proposed regimens include oral administration of 10,000 to 25,000 international units (IU) per day for 5 to 14 days. Various topical regimens have also been proposed, with doses around 200,000 IU every 8 hours.
Administration of vitamins B, C, D, or E has not been shown to significantly improve wound healing in well-nourished patients. Vitamin C deficiency impairs collagen synthesis, which may lead to poor wound healing and scurvy.
2016
A 30-year-old man is evaluated one year after undergoing vascularized allograft transplantation at the midforearm level. Surveillance angiogram and duplex ultrasound show 60% closure of the ulnar artery and complete occlusion of the radial artery. The patient is adherent to the prescribed immunosuppressive therapy. Clinical evidence of chronic ischemia is suspected. Which of the following underlying processes is most likely in this patient?
A) Deposition of preformed immune complex and complement activation
B) IgA-mediated response
C) IgM and IgG antigen–mediated response
D) T-cell–modulated immune response
The correct response is Option D.
Hypersensitivity reactions are divided into four different responses.
Type 1 (allergy) refers to immediate release of IgE, mediated release of histamine, and other vasoactive mediators resulting in manifestation within minutes. Examples include asthma or anaphylaxis.
Type 2 (cytotoxic-antibody dependent) refers to binding of IgM or IgG to the target cell, which in this case is a host cell. This results in the membrane attack complex (MAC) destruction of the targeted cell. Examples include thrombocytopenia, Goodpasture, and membranous nephropathy.
Type 3 (immune complex–mediated reaction) refers to IgG binding to circulating antigen resulting in formation of an immune complex. These complexes can end up collecting in the vasculature, joints, and kidneys resulting in local destruction. Examples include rheumatoid arthritis, systemic lupus erythematosus, and serum sickness.
Type 4 (delayed type hypersensitivity) refers to the activation of TH1 helper T cells by an antigen-presenting cell. This establishes an immune response memory and when activated again, the TH1 cells activate a macrophage-mediated response resulting in cellular damage. Examples include chronic transplant rejection, contact dermatitis, and multiple sclerosis.
Transplant patients require immunosuppression to avoid a type 4 hypersensitivity. Although an overwhelming majority of the recent upper extremity transplants have done well, there have been several cases of vascular compromise attributed to chronic rejection. Close monitoring of vascular status is part of the vascularized composite transplant protocol.
2016
A 32-year-old man with a history of self-inflicted gunshot wound is evaluated because of significant facial deformity despite multiple complex reconstructive procedures. Composite tissue allotransplantation is performed. One episode of rejection is successfully treated 4 weeks postoperatively. Three months postoperatively, the patient develops recurrent swelling and hyperemia of the facial skin. Which of the following is the most likely cause of this condition?
A) ABO incompatibility B) Acute rejection C) Antibody incompatibility D) Chronic rejection E) Hyperacute rejection
The correct response is Option B.
The most likely diagnosis is acute rejection, because this patient is still in the early postoperative period when acute rejection is most likely to occur (0 to 3 months). ABO incompatibility and antibody incompatibility would result in hyperacute rejection, which is mediated by the humoral immune system and occurs within minutes of transplantation. Chronic rejection occurs after years and is characterized by vasculopathy and fibrosis.
2015
A 36-year-old man with traumatic injuries, who is intubated and sedated in the intensive care unit, is noted to have extravasation of concentrated calcium solution from a peripheral access intravenous line. The consult is made immediately after extravasation. Which of the following is the most appropriate management of this injury?
A) Intravenous administration of dexrazoxane
B) Local injection of hyaluronidase
C) Phentolamine infiltration
D) Topical application of dimethyl sulfoxide
E) Topical application of heat
The correct response is Option B.
Hyaluronidase is an enzyme that breaks down hyaluronic acid, a mucopolysaccharide that is a normal component of the interstitial fluid barrier. It has been shown to increase the rate of absorption of an injected substance by facilitating diffusion of the substance over a large area. When injected locally within 1 hour of extravasation, it breaks down hyaluronic acid and decreases the viscosity of the extracellular matrix, and facilitates absorption and dispersal of the extravasated chemical.
The ischemic effects of extravasated vasoconstrictive agents such as norepinephrine and dopamine may be reversed with local infiltration of phentolamine, which is an alpha-blocking agent. Topical heat application has been recommended in vinca alkaloid extravasation to promote local circulation and speed up clearance of the extravasated agent. Topical cooling in animal models has been demonstrated to increase ulcer formation.
Dexrazoxane has been shown to antagonize the effects of several topoisomerase II poisons such as anthracycline agents, including doxorubicin. Recent clinical trials in Europe have demonstrated its efficacy in minimizing tissue damage from anthracycline extravasation if administered intravenously within 6 hours of extravasation. It is now the recommended initial treatment of anthracycline extravasation, especially in light of its FDA approval in 2007.
Dimethyl sulfoxide (DMSO) is a free radical scavenger and an effective solvent. It may also have antibacterial, anti-inflammatory, and vasodilatory properties. Its topical application is effective in preventing ulcerations caused by doxorubicin extravasation.
2015
A 30-year-old woman who underwent uneventful abdominoplasty is evaluated 2 weeks postoperatively because of midline wound dehiscence with tissue necrosis. She reports that she did not stop smoking before surgery as instructed. A photograph is shown. Which of the following mechanisms is the most likely cause of the delayed wound healing?
A) Decreased catecholamine production B) Decreased hemoglobin concentration C) Decreased leukocyte function D) Increased fibrinogen production E) Increased microvascular vasoconstriction
The correct response is Option E.
Cigarette smoking is a leading cause of preventable death and disability in the United States. Over the past 20 years, several studies have demonstrated an increased risk of postoperative complications following plastic surgical procedures, including rhytidectomy, breast reconstruction, digital replantation, muscle flaps, and body-contouring procedures. Tobacco smoke is a complex mix of particulate matter, volatile acids, and gases. There are over 4000 different compounds in cigarette smoke, many of which are toxic, mutagenic, and carcinogenic. Tobacco-induced vasoconstriction is mediated directly and indirectly by nicotine, a colorless, odorless, and poisonous alkaloid.
Increased cellular levels of nicotine cause direct microvascular vasoconstriction. Indirect pathways of vasoconstriction include the enhancement of thromboxane A2 and stimulation of catecholamine release. Random skin flaps such as abdominoplasty, rhytidectomy, and mastectomy flaps are predominantly supplied by the subdermal plexus, which is very sensitive to sympathomimetic agonists such as catecholamines.
Smoking also increases carboxyhemoglobin levels, which shifts the oxygen-hemoglobin saturation curve to the left. The net result is decreased oxygen-carrying capacity by direct competitive inhibition from carbon monoxide. Other effects caused by smoking include decreased prostaglandin I2 (prostacyclin) production, increased platelet aggregation and blood viscosity, decreased collagen production, decreased red blood cell deformability, increased fibrinogen production, and decreased leukocyte function (mediated by hydrogen cyanide). The net effect is a prothrombogenic state with impaired inflammation that also contributes to slow wound healing. Although fibrinogen production is increased and leukocyte function is decreased, the primary mechanism by which wound healing is impaired is related to the nicotine-induced vasoconstriction of the subdermal plexus.
Rhytidectomy patients who smoke are 12.5 times more likely to develop skin necrosis compared with patients who do not smoke. One study showed a 47.9% rate of wound-healing problems in abdominoplasty patients who smoked compared with 14.8% in those who did not smoke. Another large study of patients undergoing breast reconstruction using a free transverse rectus abdominis musculocutaneous (TRAM) flap showed no difference in free flap survival in those patients who smoked, but the smoking population had a significantly higher rate of mastectomy skin flap loss, abdominal donor-site complications, and hernias. Current recommendations for smokers who desire elective cosmetic surgery are to avoid smoking and all nicotine products for 4 weeks before and after surgery.
2015
A 45-year-old man sustains a facial laceration and develops a keloid scar. Compared with a hypertrophic scar, this patient’s scar is most likely to have which of the following characteristics?
A) Decreased fibroblast density
B) Increased fibroblast proliferation rates
C) Increased ratio of type III to type I collagen
D) Regression of the scar over time
E) Smaller and thinner collagen fibers
The correct response is Option B.
Hypertrophic scars generally arise during the first few weeks following the initial scar, grow rapidly, and then regress. On the other hand, keloid scars appear later following the initial scar, and then gradually proliferate, often indefinitely.
Both keloid and hypertrophic scars demonstrate increased fibroblast density.
Keloid scars demonstrate increased fibroblast proliferation rates compared with hypertrophic scars.
Keloid scars demonstrate a decreased ratio of type III to type I collagen. This is not observed in hypertrophic scars.
Keloid scars demonstrate thicker, larger, and more randomly oriented collagen fibers compared with hypertrophic scars.
2015
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.
2015
An 87-year-old woman with a history of squamous cell carcinoma on the left lower extremity comes for evaluation because of the ulcer shown in the photograph. When the tumor did not resolve 9 months ago, she underwent radiation therapy for 4 weeks followed by excision. All margins were negative. Coverage of the wound with a split-thickness skin graft 6 months ago was not successful. Physical examination shows an ulcerated area over the anterior compartment. There is moderate fibrinous debris within the ulcer. Which of the following is the most likely underlying cause of the impeded wound healing?
A) Decreased vascularity B) Elevated oxygen tension C) Enhanced angiogenesis D) Fibroblast hyperplasia E) Peripheral margin hypokeratosis
The correct response is Option A.
Radiation therapy produces many changes in the skin, whether it is directed at the skin, such as for skin cancer, or directed at deeper structures. Direct damage to blood vessels in the wound bed (obliterative endarteritis) produces decreased oxygen tension. Unlike nonirradiated wounds, radiated wounds do not respond with increased angiogenesis. Decreased breaking strength of radiated wounds is caused by both edema of collagen bundles and direct injury to the fibroblasts that would otherwise repair them. Radiated wounds have hyperkeratotic edges, which impair both contraction and keratinocyte migration.
2015
A 60-year-old woman is seen in the hospital for a pressure ulcer in the lumbar region. A photograph is shown - necrotic tissue at base of wound. A sponge for negative pressure wound therapy is about to be applied directly to the wound. Which of the following is the most likely complication of this therapy in this patient?
A) Enterocutaneous fistula B) Excessive bleeding C) Excessive wound drainage D) Infection E) Retained sponge in wound
The correct response is Option D.
Infection due to retained necrotic tissue would be the most likely complication in this patient. The vacuum-assisted negative pressure wound closure device should not be used in place of good wound care principles such as debridement.
Use of negative pressure wound therapy has been used for pressure ulcers, open abdomen, traumatic extremity wounds, chest wounds, burns, and skin grafts. Negative pressure wound therapy works through mechanisms that include fluid removal, drawing the wound together, microdeformation, and moist wound healing. Several randomized clinical trials support the use of negative pressure wound therapy in certain wound types. Serious complications include bleeding and infection.
Negative pressure wound therapy devices should be used with caution in infected wounds. They should not be used until the wounds are adequately debrided. This wound has not been adequately debrided and negative pressure wound therapy should not be used until necrotic tissue has been removed.
Bleeding is the next most common complication, but is usually seen in anticoagulated patients and after debridement. Use of a conventional gauze dressing for several hours after a debridement before placing a sponge-based negative-pressure wound therapy device may decrease the risk of excessive bleeding. Most significant bleeding has occurred secondary to disruption of major vessel grafts, cardiac bypass grafts, or the ventricle itself when sponges are placed directly on the structures. This wound is not near any major blood vessels.
Use of a single sponge or a long roll of gauze within any deep wounds is recommended to avoid retained foreign bodies.
Negative pressure wound therapy has been used to control wound drainage. Increased drainage would be caused by the lack of debridement and infection.
Even in clean wounds, a recent report on abdominal wound closure found the most likely complication to be infection rather than recurrent hernia or enterocutaneous fistula. This wound is on the back and would not be likely to have an enterocutaneous fistula. Although initially contraindicated for use with enterocutaneous fistula, recent reports have shown its use to be safe and effective in selected cases.
2014
A 56-year-old woman who has been undergoing treatment for breast cancer has pain around the port site 6 hours after the extravasation of paclitaxel from a subcutaneous tunneled subclavian vein catheter. The patient is hemodynamically stable and breathing comfortably. Moderate swelling and tenderness are observed between the port and clavicle. Which of the following is the most effective management?
A) Application of calcium gluconate gel B) Application of topical collagenase C) Line change over a wire D) Line removal and observation E) Operative debridement
The correct response is Option D.
This patient has paclitaxel extravasation due to a malpositioned or leaking catheter with minimal symptoms; therefore, removal of the line and observation is warranted. Calcium gluconate gel is indicated after generously washing areas exposed to hydrofluoric acid as it neutralizes the fluoride ion. Topical collagenase is indicated in wounds with limited tissue necrosis and thus has no role in this patient. Changing this patient’s line over a wire is contraindicated as the catheter is either malpositioned or broken. Although operative debridement is sometimes indicated in extravasation injuries, it is unusual, and expectant management is the norm. As this patient has no acute signs of compartment syndrome or tissue necrosis, line removal and observation are indicated.
The incidence of extravasation is 0.01 to 6%. Chemotherapeutic agents that cause reactions are classified as irritants or vesicants. Irritants cause immediate and typically limited local reactions such as erythema, warmth, and tenderness. Common irritants are: bleomycin, carboplatin, carmustine, cisplatin, dacarbazine, etoposide, ifosfamide, and thiotepa. Vesicants can cause erythema, blistering, and skin necrosis. Itching in the absence of pain is common. In addition, vesicants can cause delayed ulceration that is self-perpetuated when the vesicant is rereleased upon lysis of affected cells. Common vesicants are: dactinomycin, daunorubicin, epirubicin, idarubicin, mechlorethamine, mitomycin, mitoxantrone, paclitaxel, vinblastine, vincristine. Paclitaxel is derived from the bark of the Pacific yew tree and induces microtubular assembly and stabilization, which leads to cell death. It is a vesicant, and if extravasation occurs, symptoms can range from localized pain, swelling, and erythema to severe skin necrosis and ulceration requiring surgical debridement. The vast majority of extravasations are managed non-operatively.
2014
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.
2014
A 73-year-old man is evaluated for a non-healing wound on the medial aspect of the calf. The wound has been present for 8 months, and he has undergone several months of serial debridements and moist wound care without improvement. A photograph is shown. Ten years ago, he was diagnosed with squamous cell carcinoma of the medial calf skin, and the condition was managed solely with radiation therapy. Which of the following is the most appropriate next step in management?
A) Hyperbaric oxygen therapy B) Negative pressure wound therapy C) Wound biopsy and culture D) Wound debridement and skin graft E) Continued observation and wound care
The correct response is Option C.
Based on the clinical scenario described, wound biopsy and culture is the most appropriate management option. Despite wound debridement and moist wound care, the wound has not improved and is in the region of a previous malignancy. Wound biopsy would allow the diagnosis of recurrent malignancy and aid in the determination of further surgical intervention. Wound culture would allow the diagnosis of soft-tissue infection contributing to the wound’s persistence.
Although wound debridement would be beneficial in this case, application of a skin graft in the face of possible recurrent malignancy and probable marked radiation injury would be associated with increased risk of delayed wound healing and may delay management of recurrent malignancy. If the wound was attributed only to radiation therapy, a better strategy would be to excise the irradiated soft tissues and cover the whole defect with a well-vascularized flap.
Hyperbaric oxygen therapy has been shown to be beneficial for the management of radiation soft-tissue injury. This therapeutic modality should only be instituted after a complete evaluation of the patient’s wound, which would include soft-tissue biopsy because the patient previously had a malignancy in the region.
Complete evaluation of the wound would include pertinent history and physical examination, evaluation of the patient’s nutritional status, examination of extremity vascular inflow and outflow, diagnosis and treatment of wound infection, and optimization of wound characteristics.
The patient has already undergone debridement and wound care for several months; therefore, continued observation and wound care would be an inadequate management option.
It is inappropriate to perform negative pressure wound therapy in an irradiated wound without diagnosis by tissue biopsy.
2014
A 29-year-old man comes to the office because of scarring 12 weeks after he sustained extensive chemical burns to 30% of the total body surface area. Examination shows thick hypertrophic scarring of the upper extremities and anterior torso. Which of the following is the most appropriate management?
A) Injection of a corticosteroid B) Scar band revision C) Serial casting D) Topical application of vitamin E E) Use of pressure garments
The correct response is Option E.
Compression decreases blood flow to active scars, leading to decreased production of collagen fibers. This results in a balance of collagen synthesis and lysis that produces a flatter, softer, less vascularized scar. Clinically, burn scar hypertrophy is managed by use of pressure garments and inserts that must be worn almost 24 hours per day. They should be initiated as soon as all burn wounds have closed enough to tolerate wear and continued until the burn scar has matured. Initially, the pressure applied is low (15 to 17 mmHg). Then, as the scar progresses in maturation, custom-made pressure garments that provide 24 to 28 mmHg of pressure may be fabricated for the patient.
The prompt institution of splinting techniques after the acute phase of burn injury can limit the development of long-term deformities. Splinting can combat edema, protect exposed structures and balance soft-tissue lengths to prevent contracture formation and compensate for functional deficits. Later, during the remodeling phase, serial casting can be a great adjunct to a therapeutic exercise program to restore normal range of motion. Surgical lengthening and scar band revision are options that are evaluated if hypertrophic scarring and contractures still develop after appropriate rehabilitation and management.
Although the depth and distribution of the injury factor into the development of scars, the patient’s own genetic predisposition also plays a role in scar formation and maturation.
Injection of a corticosteroid can improve hypertrophic scars, but its use is limited to small, focused areas. Metabolic effects can be considerable. Due to the extent of scarring in this patient, corticosteroids are not an appropriate option.
Although other topically applied therapies, such as creams containing vitamin E, have been widely used with the intent to improve wound healing, there is not substantial evidence to support regular use. Thirty-three percent delayed hypersensitivity reaction can be seen with topical vitamin E.
2014
A 33-year-old African American woman has a large recurrent keloid of the left earlobe. Reexcision with postoperative radiation therapy is planned. Which of the following is the most likely long-term complication of this therapeutic plan?
A) Altered pigmentation B) Desquamation C) Itching D) Skin cancer E) Telangiectasia
The correct response is Option A.
The patient described has a recurrent keloid after previous excision. Surgery alone has recurrence rates of over 50%, and combination therapies including injection of a corticosteroid, pressure earrings, and surgery can have marked recurrence rates.
For recurrent keloids, post-excision radiation therapy, usually given in one to three fractions, has efficacy rates between 6 and 98%. The most common long-term complications of radiation therapy include hypo- or hyperpigmentation (62%) and telangiectasias (27%). Skin desquamation is an acute reaction to radiation therapy and occurs in 24% of patients. Secondary malignancies after radiation therapy for keloids are very rare. Itching from keloids is usually improved with treatment.
2014
A male newborn is evaluated because of the scalp anomaly shown in the photograph - absence of all skin layers including epidermis, dermis, subcutaneous fat. Which of the following is the most appropriate initial management of the affected area?
A) Application of a skin substitute B) Local wound care with antibiotic ointment C) Primary closure D) Skin grafting E) Tissue expansion
The correct response is Option B.
This child has aplasia cutis congenita, or cutis aplasia, of the scalp. First described in 1767 by Cordon, cutis aplasia is the congenital absence of all skin layers including the epidermis, dermis, and subcutaneous fat. This process most commonly affects only focal areas of tissue but involvement can be extensive. The majority of cases involve the scalp, but this process can occur in any cutaneous area of the body. Cutis aplasia can occur in isolation or as part of a syndrome, the most common being Adams-Oliver syndrome. Cutis aplasia of the scalp can range from small areas of involvement that often heal in utero and appear at birth as a “congenital scar” to massive defects that are devoid of scalp and cranium. Most small- or intermediate-sized full-thickness defects heal quickly (as in the patient described) if kept moist and the resultant scar can be excised secondarily. Bone healing is often complete in small lesions, and residual defects can be reconstructed when the child is older if needed. Large areas are more problematic and extensive scalp defects that threaten dural integrity may require early operative intervention. Cutis aplasia involving large areas of the scalp has a reported mortality ranging from 20 to 55%, typically as a result of sagittal sinus hemorrhage or associated congenital defects. In such cases, coverage of the dura can be life-saving. Described methods of soft-tissue coverage include skin graft, cultured allograft, acellular dermis, and immediate or delayed reconstruction with a flap. Tissue expansion of the scalp in a newborn presents many challenges and is not recommended.
2014
A 12-year-old boy is brought to the emergency department with a soft-tissue injury to the left knee after falling while playing football. Which of the following types of cells is most likely to appear first at the wound site?
A ) Fibroblast B ) Lymphocyte C ) Macrophage D ) Neutrophil E ) Platelet
The correct response is Option E.
The process of wound healing occurs as a sequence of overlapping processes. The appearance of cell types in an acute wound occurs in the following order: platelets, neutrophils, macrophages, lymphocytes, and fibroblasts, during the inflammatory phase.
Tissue injury causes injured vessels to constrict rapidly, with primary hemostasis being a platelet-mediated process. Platelets trapped in the clot contain growth factors that initiate the coagulation and wound-healing cascade.
The ensuing phases of wound healing consist of inflammation, collagen synthesis, angiogenesis, epithelialization, and remodeling.
During the inflammatory phase, after platelet aggregation and degranulation, chemoattractants, activation factors, and vasoconstrictors are released. An efflux of neutrophils occurs at the wound site to primarily sterilize the wound. Within 2 to 3 days, the inflammatory cell population shifts to monocytes that differentiate into macrophages, which orchestrate the repair process. Collagen synthesis occurs as circulating bone marrow-derived cells migrate into the wound and develop a fibroblastic cell function. These cells and local, activated fibroblasts synthesize and secrete the replacement collagen scar. Fibroblasts become the predominant cell type by 3 to 5 days in clean, noninfected wounds. As fibroplasia progresses, granulation tissue forms as a consequence of neoangiogenesis and the directed growth of vascular endothelial cells stimulated by platelet and activated macrophage and fibroblast products. Wound reepithelialization occurs as keratinocytes at the wound margins migrate and proliferate once epidermal continuity is reestablished. Remodeling of the resultant scar is a dynamic process that occurs slowly over months to years. Collagen deposition and degradation occur to yield a mature scar; however, maximum tensile strength of a wound reaches only approximately 80% of noninjured skin.
2012
A 50-year-old man with a history of organ transplantation is scheduled to undergo resection of a squamous cell carcinoma of the scalp followed by reconstruction with a flap. This patient is most likely to avoid postoperative wound-healing complications if he is currently undergoing which of the following immunosuppressive therapies?
A ) Antilymphocyte antibody (basiliximab)
B ) Antimetabolite (azathioprine)
C ) Calcineurin inhibitor (cyclosporine)
D ) Glucocorticosteroid (prednisone)
The correct response is Option A.
Many immunosuppressive agents used in organ transplantation have been shown to impair wound healing. Thus, free tissue transfer or major reconstructive surgery has been associated with higher complication rates. Immunosuppressive agents can be categorized as antilymphocytes (lymphocyte immune globulin [Atgam], thymoglobulin, basiliximab), antimetabolites (azathioprine, mycophenolate mofetil), calcineurin inhibitors (cyclosporine, FK-506), and glucocorticosteroids. Only antilymphocyte therapy has been shown not to impair wound repair.
2012
Which of the following characteristics best distinguishes keloid scar tissue from hypertrophic scar tissue?
A ) Collagen fibers parallel to the direction of wounding
B ) Extension beyond original scar
C ) Improved by surgical excision alone
D ) Increased fibroblast density
E ) Location on flexor surfaces and areas of motion
The correct response is Option B.
Keloid scars differ from hypertrophic scars in that they can extend beyond the original scar, whereas hypertrophic scars are confined to the original boundary.
Collagen fibers are wavier in keloids and more parallel in hypertrophic scars. Light and electron microscopic studies demonstrate that collagen in keloids is disorganized compared with normal skin. The collagen bundles are thicker and wavier, and the keloids contain hallmark “collagen nodules” at the microstructural level.
Surgical excision alone has a high rate of recurrence for keloids.
Increased fibroblast density occurs in both hypertrophic scars and keloid scars and cannot be used to differentiate between the two. Keloids have increased fibroblast proliferation rates.
Hypertrophic scars commonly occur on flexor surfaces and joints. Keloids have a high predilection for the sternum and earlobe.
2012
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.
2012
A 17-year-old boy undergoes excision of a congenital nevus of the scalp. Prior to excision, he underwent placement of a subgaleal tissue expander. Which of the following growth factors is most likely to be upregulated during ischemia in this patient?
A) Epidermal B) Keratinocyte C) Platelet-derived D) Transforming E) Vascular endothelial
The correct response is Option E.
Vascular endothelial growth factor (VEGF) is an important mediator of wound healing and is necessary for angiogenesis. It was originally discovered as a protein secreted by tumor cells to increase the permeability of local blood vessels to circulating macromolecules. It has been shown to increase endothelial growth and migration and enhance glucose transport in the endothelial cell, which is needed to match the increased energy required during angiogenesis. Hypoxia has been shown to be a potent stimulus for the expression of VEGF, and current research has been directed at utilizing VEGF to augment healing and viability in situations of tissue ischemia.
The remaining growth factors are all important in the wound-healing process, relating primarily to reepithelialization and wound contraction, but are not directly involved in angiogenesis.
2011
A 10-year-old girl is referred to the office because of a large, full-thickness cranial defect after sustaining a traumatic injury. Reconstruction with a split cranial bone graft is performed. Which of the following is the most likely mechanism by which the bone graft heals?
A) Dural ossification B) Osteoconduction C) Osteogenesis D) Osteoinduction E) Vasculogenesis
The correct response is Option B.
The most likely mechanism of split cranial bone graft healing is osteoconduction. The split cranial bone graft is primarily cortical. After it is separated from its blood supply, it serves as a nonviable scaffold for the ingrowth of blood vessels and osteoprogenitor cells from the recipient site. This process of osteoconduction, or “creeping substitution,” eventually leads to resorption and replacement of most of the graft with new bone. The graft becomes fully osseointegrated with the recipient site.
Spontaneous dural ossification can heal full-thickness cranial defects in infancy. After 12 to 18 months of age, the dura will not spontaneously ossify.
Osteogenesis is the primary mechanism of bone graft healing for cancellous or vascularized bone grafts. Because these grafts are revascularized rapidly, osteoblasts survive the transplantation and produce new bone at the recipient site.
Osteoinduction involves the stimulation of mesenchymal cells at the recipient site to differentiate into bone-producing cells. Demineralized bone and bone morphogenetic protein produce new bone primarily by osteoinduction.
Vasculogenesis, the de novo formation of blood vessels from precursor cells, occurs during embryogenesis. Revascularization of split cranial bone graft occurs by angiogenesis, the production of new vessels from preexisting vasculature.
2011
A 24-year-old woman comes to the office because of painful nodules in both buttocks. She underwent buttock augmentation with injections of liquid silicone by an unlicensed practitioner 4 years ago. Excision of the affected area is performed. Histology of a specimen obtained from the excised tissue is most likely to show which of the following?
A) Acellularity B) Calcification C) Granuloma D) Necrosis E) Thrombosis
The correct response is Option C.
Free silicone liquid has a long history of use for soft-tissue augmentation. Little regulation of the practice and variable degrees of purity of the silicone have resulted in many disastrous complications, often occurring years after the initial injections. Potential adverse sequelae following silicone injection include migration, chronic induration and pigmentary changes, painful subcutaneous nodules, chronic infection, and ulceration. Many of the treated areas require radical resection and reconstruction.
Histologic study of postsilicone injection nodules typically shows granulomas which develop after initial inflammation and fibrosis. Histologic evaluation of typical capsule formation around solid alloplastic prostheses, including breast prostheses, shows acellularity and organized layers of collagen. In the breast, free silicone injection may result in ductal obstruction, which may appear as calcification on mammography. Necrosis may be noted in ulcerative-type complications seen in intradermal injection. Intravascular injection can result in thrombosis and, rarely, embolism, resulting in death.
2011
A 15-year-old boy undergoes negative pressure wound therapy (NPWT) of a traumatic abdominal wound. Which of the following is the most likely mechanism by which NPWT expedites the healing of this wound?
A) Decrease in bacterial burden B) Deformation of the wound C) Desiccation of the wound D) Increase in matrix metalloproteinase activity E) Maintenance of exudate from the wound
Please note: Upon further review, this item was not scored as part of the examination.
The correct response is Option B.
The most likely mechanism by which NPWT expedites healing is deformation of the wound. NPWT causes both macrodeformation and microdeformation of a wound. Macrodeformation maintains approximation of the tissues, preventing loss of domain and facilitating earlier closure by delayed primary or secondary intention. Microdeformation at the interface of the sponge and wound bed changes cell shape, which then affects gene transcription via the cytoskeleton (mechanotransduction). These microdeformational forces, for example, stimulate cellular proliferation and angiogenesis in the wound.
The effect of NPWT on bacterial burden is unclear. Some studies have suggested that NPWT reduces bacterial counts in the wound, possibly by direct removal or by increasing blood flow. Other studies have found that NPWT may increase certain bacterial levels.
NPWT prevents desiccation of the wound. The semiocclusive polyurethane drape limits permeability to gases and water vapor and thus maintains a favorable, moist wound environment.
NPWT decreases matrix metalloproteinase activity in the wound. Elevated matrix metalloproteinases inhibit wound healing as well as neovascularization.
NPWT decreases exudate of the wound by removing excess fluid through suction. The reduction in exudate may facilitate wound healing by removing toxic inflammatory mediators and proteinases. Minimizing wound edema also may improve the diffusion of oxygen and nutrients to the wound.
2011
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 - desiccated, possibly necrotic tendon, brown discoloration of tendon. 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.
2011
A 67-year-old woman comes to the office for follow-up examination 6 months after debridement of a chronic nondiabetic wound to the lower leg. Following the procedure, the patient was treated with moist dressings. Physical examination shows that the wound is healing less than 15% weekly. Persistent bacteria are suspected. Application of which of the following is the most appropriate nonsurgical management at this time?
A) Alginate dressings B) Collagenase C) Film or transparent dressings D) Hydrogel dressings E) Silver ion-impregnated dressings
The correct response is Option E.
Silver ions kill a broad spectrum of bacteria. No resistant organisms have been identified, and it is nontoxic to human cells. Alginates absorb up to 20 times their weight and are used to exudate wounds. Films and transparent dressings are waterproof and would be impermeable to bacterial contamination. Hydrogels are generally waterproof and would prevent bacterial contamination.
2011
Epithelial cell migration across an acute skin laceration is initiated by which of the following mechanisms?
A ) Contraction of myofibroblasts
B ) Deposition of collagen into the wound
C ) Formation of a fibrin-fibronectin plug
D ) Loss of contact inhibition
E ) Secretion of anti-inflammatory products
The correct response is Option D.
Epithelial cell migration is initiated by loss of contact inhibition and occurs from the periphery of the wound and adnexal structures. Cell division occurs in 48 to 72 hours, resulting in a thin epithelial cell bridge across the wound. A key role is played by epidermal growth factors.
Myofibroblasts are involved in wound contraction and play no role in epithelialization. Collagen deposition is seen in the remodeling phase of wound healing. Fibronectin produced by fibroblasts serves as an adhesion molecule anchoring cells to collagen or proteoglycan substrates. Release of cytokines from platelets plays an important role in the initiation of the hemostatic initial phase.
2010
A 65-year-old woman is evaluated because of nonhealing sores on her lower extremities. She has a history of alcoholism and is homeless. She appears cachectic, pale, and severely malnourished. She has lost most of her teeth; the gums are purplish and spongy in appearance. Skin examination shows numerous petechiae. Large, superficial, nongranular sores are noted on the legs. Scurvy is suspected. Which of the following processes is most likely to be adversely affected by this patient’s nutritional deficiency?
A ) Collagen cross-linking B ) DNA synthesis C ) Epithelialization D ) Fibroblast proliferation E ) Immune modulation
The correct response is Option A.
The patient described most likely has a vitamin C deficiency. Vitamin C is an essential nutrient for collagen cross-linking via the hydroxylation of proline and lysine to hydroxyproline and hydroxylysine, respectively. The lack of cross-linking results in impaired collagen synthesis and a decrease in collagen tensile strength. Collagen-containing tissues, such as skin, dentition, bone, and blood vessels, are therefore affected, leading to the development of scurvy. The hallmark signs of scurvy are hemorrhaging in any organ (ie, petechiae, swollen gums), loss of dentition, and a lack of osteoid formation. Deficiency of vitamin C is rare in the United States; however, it can be seen in patients who are severely malnourished; have a history of alcoholism; or have restrictive diets for medical, social, or economic reasons.
Other nutrients also play a major role in healing. Folate and vitamin B6 (pyridoxine) are integral in DNA synthesis and cellular proliferation. Vitamin A is an essential factor in epithelialization and fibroblast proliferation. Vitamin E is a strong antioxidant and immune modulator. Zinc is one of the most important micronutrients, as it acts as a cofactor for numerous metalloenzymes and proteins. It is essential for proper protein (like collagen) and nucleic acid synthesis.
2010
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.
2019
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.
2019
A 23-year-old woman comes to the office for evaluation of bilateral ear keloids. She reports that the keloids developed after she had her ears pierced 5 years ago. She has not had previous surgery for this problem. Which of the following is the most likely recurrence rate after surgical excision with injection of a corticosteroid?
A) 5% B) 15% C) 35% D) 50% E) 75%
The correct response is Option B.
Earlobe keloid formation after piercing is reported to affect approximately 2.5% of the population. Various adjuvant therapeutic modalities, including radiation therapy, intralesional corticosteroids, interferon, 5-fluorouracil, topical silicone, and pressure devices, are used to decrease recurrence rate after surgical excision.
A recent meta-analysis looked at the recurrence rate of keloid formation after surgical excision with the use of radiation therapy and intralesional corticosteroids. Recurrence rate after excision with radiation therapy was found to be 14%. The recurrence rate after excision with intralesional corticosteroids was 15.4%.
Although radiation therapy had an overall reduced recurrence rate, it was associated with higher cost and more significant potential complications. Five cases of carcinogenesis after radiation therapy have been reported. The main disadvantage of corticosteroid injections was found in most studies to be the pain of injection. Adjuvant corticosteroid injections in conjunction with surgery were performed preoperatively, intraoperatively, or postoperatively in various studies.
2019
E-cigarettes are similar to traditional cigarettes in that the negative effect of nicotine on wound healing is primarily due to which of the following?
A) Endothelial cell injury B) Increased inflammatory response C) Increased prostacyclin production D) Peripheral microvascular vasoconstriction E) Platelet aggregation
The correct response is Option D.
Cigarette smoke contains thousands of different chemical substances including chemical toxins and carcinogens in addition to nicotine. While e-cigarettes are believed to have fewer health risks because tar and many other harmful chemicals have been removed, they do deliver vaporized nicotine. Nicotine-induced vasoconstriction in the periphery leads to relative skin ischemia and poor wound healing.
Platelet aggregation is incorrect. Nicotine does not have a direct effect on platelets. In some studies, platelet aggregation appears to be reduced with long-term administration of nicotine. Increased prostacyclin production is incorrect.
Prostacyclin is a local vasodilator with effects that minimize platelet aggregation.
Nicotine has been shown to inhibit synthesis of prostacyclin. Increased inflammatory response is incorrect. Nicotine causes a diminished inflammatory response by a weakened chemotaxis, reduced migration, impaired bacterial killing by inflammatory cells and a subnormal release of proteolytic enzymes and inhibitors. Endothelial cell injury is incorrect. While nicotine can alter the structural and functional characteristics of vascular smooth muscle and endothelial cells, it does not cause cell injury. Several studies show increased number of endothelial cells in venous blood after nicotine administration in cigarette smokers, but not in non-cigarette smokers, suggesting that other harmful chemicals found in tobacco may contribute to cell injury.
2019
Hyperbaric oxygen therapy (HBOT) is most appropriate for a patient with which of the following conditions?
A) Acute osteomyelitis of the tibia B) Anaerobic necrotizing soft-tissue infection C) Chemical burn because of lye exposure D) Stevens-Johnson syndrome E) Wagner grade 2 diabetic foot ulcer
The correct response is Option B.
Hyperbaric oxygen therapy (HBOT) is an accepted adjunct to surgical debridement, appropriate antibiotic therapy, and indicated critical care measures for necrotizing soft-tissue infections such as necrotizing fasciitis and Fournier gangrene. The increased oxygen delivery of HBOT improves leukocyte function and can enhance penetration of certain antibiotics such as aminoglycosides. The clinical effects include slowing of the progress of the infection and decreased risk of both amputation and mortality.
There is not adequate evidence to justify HBOT in diabetic foot ulcers (DFUs) with Wagner grade 2 (extension to bone, tendon, or capsule) or less. However, there is moderate evidence to suggest benefit in DFUs with Wagner grade 3 (deep ulcer with osteomyelitis or abscess) or greater.
HBOT may be indicated in the treatment of chronic osteomyelitis but not in the acute setting. It plays no role in the treatment of Stevens Johnson syndrome, and may be beneficial in acute thermal burns but is not indicated for chemical burns.
The complete list of approved indications for HBOT, as determined by the Undersea and Hyperbaric Medical Society and the U.S. Food and Drug Administration, includes the following:
- Air or gas embolism
- Carbon monoxide poisoning
- Clostridial myositis and myonecrosis (gas gangrene)
- Crush injury, compartment syndrome, and other acute traumatic ischemias
- Decompression sickness
- Arterial insufficiency
- Severe anemia
- Intracranial abscess
- Necrotizing soft-tissue infections
- Refractory osteomyelitis
- Delayed radiation injury (soft tissue and bony necrosis)
- Compromised grafts and flaps
- Acute thermal burn injury
- Idiopathic sudden sensorineural hearing loss
2019
Which of the following mechanisms is most likely to inhibit normal wound healing in a patient who smokes cigarettes?
A) DNA strand breaks and helical cross-linking
B) Increased cosubstrate for enzymes involved in collagen production
C) Increased platelet aggregation
D) Increased tissue oxygen delivery
E) Nicotine-induced vasodilation
The correct response is Option C.
The detrimental effects of smoking on wound healing are due primarily to nicotine, carbon monoxide, and hydrogen cyanide. One of the effects of nicotine is increased platelet aggregation due to enhanced adhesiveness of the platelets themselves. This leads to thrombus formation and decreased oxygen delivery. Nicotine does not produce vasodilation, but rather vasoconstriction. Both of these effects can lead to local tissue ischemia, which inhibits the normal wound healing process.
One of the major mechanisms by which ionizing radiation inhibits wound healing is production of DNA strand breaks and helical cross-linking, but smoking is not significantly involved.
Vitamin C is the vitamin which plays the greatest role in wound healing. It is required as a cosubstrate for hydroxylase enzymes, which are involved in the production of collagen. Vitamin C deficiency has long been known to inhibit wound healing (scurvy). However, supplemental vitamin C in the nondeficient patient has not been shown conclusively to produce any beneficial wound-healing effects.
2019
Compared with standard wound dressings, postoperative negative pressure wound therapy is most likely to produce which of the following outcomes?
A) Better delayed primary fascial closure rates for salvage laparotomy
B) Better split-thickness skin graft incorporation
C) Increased inflammatory response
D) Increased postoperative dressing changes
E) Increased risk of infection
The correct response is Option B.
Multiple studies have shown the benefits of negative pressure wound therapy (NPWT) when used in conjunction with skin grafts, both as a bolster over a skin graft as well as wound bed preparation.
NPWT has been shown to decrease the risk of infection in complex and traumatic wounds in some studies, while others have shown no difference in infection rates in complex wounds when the patient has multiple comorbidities or when used to cover uncomplicated incisions for elective orthopedic operations. However, there is no evidence to suggest NPWT increases infection risk compared with standard wound dressings.
NPWT reduces both inflammatory response and edema formation.
When used for damage control laparotomy and abdominal compartment syndrome, studies have failed to show any benefit of NPWT over standard dressings. Furthermore, at least one study has suggested an increased rate of enteric fistula formation is associated with NPWT.
NPWT has been shown to decrease both the number of postoperative dressing changes and the number of additional operative interventions in complicated diabetic wounds.
2019
A 48-year-old woman undergoes excision of a 3-cm recurrent keloid of the presternal chest. Immediate reconstruction with a collagen-glycosaminoglycan scaffold dermal regeneration template is performed, followed by thin (0.008-in) epidermal autografting 21 days later. After it has healed completely, punch biopsy is performed. The absence of which of the following histologic features is most likely to indicate regenerated skin in this patient?
A) Capillary loops at the dermal-epidermal junction B) Elastic fibers C) Hair follicles D) Neovascularization E) Rete ridges
The correct response is Option C.
Regenerated skin is clearly quite different histologically from scar and, in fact, shares many characteristics with normal physiologic skin. Regenerated skin shows mechanical competence, vascularization, and heat and cold sensitivity. Furthermore, the dermal-epidermal junction shows formation of rete ridges and capillary loops. Regenerated skin displays elastic fibers and increased collagen fiber density in the reticular dermis, and it often exhibits nerve fiber regeneration as well. Regenerated skin, even when resurfaced with a split-thickness skin graft, however, does not have the dermal appendages such as hair follicles and sweat glands, that are present throughout normal skin.
2019
A 52-year-old man presents with a chronic ulcer of the lower extremity. Current medications include prednisone for management of rheumatoid arthritis. In addition to standard local wound care, which of the following treatments is most appropriate?
A) Folate B) Hyperbaric oxygen therapy (HBOT) C) Long-acting insulin D) Vitamin A E) Vitamin C
The correct response is Option D.
Malnutrition is a well-established risk factor for the development of chronic wounds. Vitamin A has been shown in multiple studies to offset the detrimental effects of corticosteroids on wound healing.
Appropriate glucose management is critical to the treatment of diabetic ulcers, but insulin would not be indicated in the absence of uncontrolled diabetes mellitus.
Vitamin C is required as a cosubstrate for enzymes involved in collagen production, and its supplementation is recommended for the nutritionally deficient. However, vitamin C has not been shown to be of any benefit to wound healing in the setting of chronic corticosteroid therapy per se.
Hyperbaric oxygen therapy delivers oxygen to tissues by both hemoglobin-dependent transport and vastly increased dissolved oxygen content in blood when a patient breathes 100% oxygen at pressures well above atmospheric level. This improves wound healing by multiple cellular mechanisms in select wounds. However, benefits in treatment of chronic corticosteroid use have not been demonstrated.
Elevated serum homocysteine has been associated in multiple studies with impaired wound healing and increased risk of coronary and cerebrovascular disease due to its enhancement of clotting pathways. Folate supplementation is often used to treat hyperhomocysteinemia, but conclusive benefit in chronic wounds is not as well-established.
2019
