Microsurgery Flashcards
A 54-year-old woman undergoes breast reconstruction using a deep inferior epigastric artery perforator (DIEP) flap. Arterial thrombosis is noted after performing the microanastomosis. Which of the following is more likely to occur with local administration of tissue plasminogen activator (tPA) as an adjunct to revision microanastomosis as compared with revision microanastomosis alone (without tPA)?
A) Decreased flap salvage rate
B) Decreased incidence of fat necrosis
C) Increased flap salvage rate
D) Increased incidence of fat necrosis
E) Increased incidence of operative hematoma
The correct response is Option B.
Administration of tissue plasminogen activator (tPA) during revision of a microanastomosis has a decreased rate of subsequent fat necrosis. The suspected mechanism of action is thrombolysis of distant “shower” emboli in the microvasculature.
The administration of tPA as an adjunct to microanastomotic revision has no effect on flap salvage rates. In addition, there is no change in hematoma risk since the dose is low (2 mg) and is usually injected directly into the flap artery, which is maintained locally in the flap. Only if larger doses of tPA were given systemically would there be a risk of operative hematoma.
2018
An 18-year-old man is brought to the emergency department for thumb replantation. After an uneventful microsurgical anastomosis of the digital arteries and veins, papaverine is applied to the vessels. This medication works as a vasodilator through which of the following mechanisms?
A) Blocking calcium channels
B) Decreasing platelet aggregation
C) Inactivating thrombin and factor Xa
D) Inhibiting glycoprotein IIb/IIIa
E) Inhibiting phosphodiesterase
The correct response is Option E.
Papaverine is a phosphodiesterase inhibitor and is a commonly used vasodilating agent in microsurgery. It is administered as a liquid, directly to the adventitia of blood arteries, leading to vasodilation. The proposed mechanism of action of papaverine is by induced increase in cyclic adenosine monophosphate (AMP) levels, causing smooth muscle relaxation in the vessels. It is this mechanism of papaverine that has also led to its use for treatment of cardiac and neurovascular vasospasm.
Nifedipine is another common topical vasodilator, which is a calcium channel blocker. The remaining choices are all used to prevent clotting. Glycoprotein IIb/IIIa inhibitors are antiplatelet agents along with aspirin. Heparin inactivates thrombin and factor Xa through an antithrombin dependent mechanism.
2018
A 42-year-old woman presents with a Gustilo Type IIIB open tibial fracture with a large area of soft-tissue loss. Rectus abdominis free flap reconstruction is planned. CT angiography shows a patent posterior tibial artery; however, the peroneal and anterior tibial vessels are not suitable for use because they do not traverse past the level of the fracture. Compared with end-to-end anastomosis, which of the following is the main advantage to using end-to-side arterial anastomosis in this scenario?
A) Allows anastomosis in zone of injury
B) Decreases ischemia time
C) Facilitates visualization
D) Minimizes kinking of vessels
E) Preserves distal blood supply
The correct response is Option E.
In this clinical scenario, the patient has a one-vessel runoff in the lower extremity. Preservation of the distal blood supply is critical and that is the main advantage of an end-to-side anastomosis.
In general, an end-to-side anastomosis is more technically difficult with longer ischemia time. Kinking of the vessels is still possible with end-to-side anastomosis and therefore is not a major advantage to this technique. There is no added benefit in visualizing the vessel and it is generally more difficult to see the entire vessel compared to an end-to-end anastomosis. This technique does not preferentially allow for an anastomosis in the zone of injury.
Finally, it is controversial whether or not the flap survival rate is different between end-to-side and end-to-end anastomosis. An early paper by Godina shows an advantage for end-to-side; however, many subsequent papers have contradicted these results.
2018
A 50-year-old woman undergoes reconstruction of a postburn neck contracture with a free anterolateral thigh flap. On postoperative day 2, the flap is explored for vascular compromise and is successfully salvaged. On postoperative day 3, the flap suffers vascular compromise and is explored again. During the operation, the anastomoses are revised using vein grafts. Which of the following factors is most strongly associated with unsuccessful flap salvage in this patient?
A) Anatomic site
B) Multiple reexplorations
C) No use of anticoagulants
D) No use of thrombolytic agents
E) Postoperative day of initial reexploration
The correct response is Option B.
The need for multiple reexplorations has been found to be a predictor for unsuccessful free flap salvage.
Free flap reconstruction of the breast has been associated with higher flap survival rates than other anatomic areas, such as the head and neck and extremities.
Higher free flap survival rates have been observed when vascular compromise occurs earlier in the postoperative period (postoperative days 0 to 2) compared with later.
Anticoagulants, such as heparin, are sometimes used during free flap salvage attempts. However, their use has not been found to impact flap survivability. The same has been found with regard to thrombolytic agents, such as tissue plasminogen activator.
2018
A 48-year-old woman undergoes delayed reconstruction of the right breast with a deep inferior epigastric artery perforator (DIEP) flap. Medical history includes failed tissue expander–based right breast reconstruction because of infection 5 months ago. On postoperative day 5, the patient comes to the emergency department with a swollen, purple flap, which she noticed after showering. The venous anastomosis is revised and flap thrombolysis is performed with tissue plasminogen activator, successfully restoring flap perfusion. Which of the following clinical factors is LEAST likely to increase this patient’s risk of thrombotic flap complications?
A) Antiphospholipid syndrome
B) Antithrombin deficiency
C) BRCA1 or BRCA2 genetic mutation
D) Factor V Leiden mutation
E) Perioperative tamoxifen therapy
The correct response is Option C.
This patient has developed a late venous thrombosis and may be predisposed to a hypercoagulable state. The BRCA1 and BRCA2 genes are tumor suppressor genes involved in DNA repair. Mutations in these genes dramatically increase a woman’s risk of developing breast and ovarian cancer over her lifetime, and are the most common cause of hereditary forms of breast and ovarian cancer. But BRCA genetic mutations do not appear to increase the risk of blood clots over baseline and would be unlikely to contribute to this patient’s condition.
The other options are incorrect because each carries higher than average risk of blood clots. Perioperative tamoxifen therapy increases the risk of thromboembolic events in general and for flap complications and flap loss during microvascular breast reconstruction in particular. Tamoxifen is an estrogen receptor antagonist and is used both to treat and prevent breast cancer. Some authors recommend cessation of tamoxifen at least 14 days prior to microvascular breast reconstruction to minimize thrombosis risk.
Factor V is a protein involved in the coagulation cascade. Factor V Leiden mutation is an inherited condition that confers a hypercoagulable state, increasing the risk of thrombotic complications.
Antithrombin III is a protein similarly involved in anticoagulation. Deficiency may be either inherited or acquired, and it confers an increased risk of venous thrombotic events.
Antiphospholipid syndrome is an acquired autoimmune disorder which also confers a hypercoagulable state. Venous or arterial thrombosis, as well as fetal loss, are characteristic of this disorder. Some patients will have an associated autoimmune disease, such as systemic lupus erythematosus.
2018
A 55-year-old man with a history of squamous cell carcinoma undergoes glossectomy and reconstruction with a free radial forearm flap. Intraoperatively, the patient experiences hypotension, and norepinephrine is administered. Which of the following is the most likely effect of this treatment on the outcome of the free flap?
A) Delayed wound healing
B) Microvascular thrombosis
C) Partial flap loss
D) Total flap loss
E) No effect
The correct response is Option E.
In patients undergoing free flap reconstruction, the use of vasopressors is typically avoided when possible because of concerns that vasoconstriction of the anastomoses will result in microvascular thrombosis. When feasible, intravenous fluid administration should be attempted first to address hypotension. However, numerous studies have examined the effect of intraoperative vasopressors on free flap reconstructions and have generally not found an increased risk of postoperative complications.
2017
A 72-year-old man undergoes composite mandibular resection followed by fibula osteocutaneous free flap reconstruction. Patient history includes squamous cell carcinoma of the oropharynx. The morning after surgery, ischemic compromise of the flap is noted. Urgent exploration of the microvascular anastomosis is performed. Which of the following causes of flap compromise is most likely to result in failure of salvage attempts?
A) Arterial thrombosis
B) Hematoma
C) Pedicle kinking
D) Venous thrombosis
The correct response is Option A.
Arterial thrombosis is associated with lower flap salvage rates than venous thrombosis or mechanical causes. Bui et al. demonstrated salvage rates of 40%, 71%, and 90% for arterial thrombosis, venous thrombosis, or hematoma, respectively. Selber et al. demonstrated a similar tendency toward flap failure after arterial thrombosis. They also documented a 92% flap salvage rate for mechanical causes of ischemia, compared with 64.9% for vessel thrombosis. Mechanical or extrinsic causes of flap ischemia are generally easy to correct and are less likely to be associated with vessel injury. It is postulated that arterial thrombosis is more likely to be associated with endothelial injury than venous thrombosis.
2017
A 45-year-old woman undergoes reconstruction of the right breast with a deep inferior epigastric artery perforator flap. Postoperatively, the flap shows signs of ischemia and is reexplored. During flap salvage, which of the following agents should be administered to inactivate thromboxane?
A) Aspirin
B) Dextran
C) Heparin
D) Hirudin
E) Streptokinase
The correct response is Option A.
Aspirin, or acetylsalicylic acid, inhibits the enzyme cyclooxygenase. Cyclooxygenase ordinarily functions to form multiple compounds from arachidonic acid, including thromboxane and prostacyclin. Thromboxane is a platelet aggregator and vasoconstrictor. Prostacyclin is also a platelet aggregator. By decreasing formation of these compounds, aspirin acts as an anticoagulant.
Dextran is a polysaccharide whose mechanism of action is thought to involve decreasing platelet aggregation by altering the electric charge of platelets, as well as by decreasing blood viscosity. Dextran also acts as a volume expander.
Heparin is a glycosaminoglycan that binds to antithrombin III and enhances its ability to inactivate thrombin (which ordinarily converts fibrinogen to fibrin), as well as clotting factors IX, X, XI, and XII. Heparin may also additionally decrease thrombosis by causing nitric oxide-mediated vasodilation.
Hirudin is derived from the medicinal leech Hirudo medicinalis and functions by directly inhibiting thrombin, in contrast to heparin, which requires the antithrombin III cofactor.
Streptokinase is a thrombolytic agent that functions by activating plasminogen and its conversion to plasmin. In turn, plasmin breaks down fibrin into fibrin degradation products.
2016
A 38-year-old woman undergoes bilateral breast reconstruction using microvascular free tissue transfer from the abdomen. The patient is evaluated 8 hours later because the right breast flap appears mottled and engorged. Administration of which of the following is CONTRAINDICATED in this patient?
A) Heparin irrigation to the flap vessels
B) Papaverine to the flap vessels
C) Systemic heparin
D) Systemic thrombolytics
E) Thrombolytics to the flap vessels
The correct response is Option D.
Heparin may be used locally or systemically during flap salvage attempts in an effort to encourage further propagation of clot and irrigate existing thrombus. Papaverine and thrombolytic agents are used locally on or within the flap vessels, but not systemically due to concern for systemic complications.
2016
A 28-year-old woman with a traumatic lower extremity wound undergoes free tissue transfer reconstruction. Venous anastomosis is completed with a 3-mm coupler device. Which of the following is the proven benefit of using a coupler device?
A) Decreased anastomosis time
B) Decreased thrombosis
C) Decreased twisting of vessels
D) Ease of use
E) Improved kinking
The correct response is Option A.
The only reliable information gleaned from available data is that the use of a coupler for venous anastomoses does decrease the operative time in performing the vascular technique. Most studies point to an improved patency rate in venous anastomoses as well, but this remains open to interpretation.
All the available published data point to one factor with the greatest influence on patency rates: adherence to sound and well-established microvascular technique principles. There is no proof that end-to end, end-to-side, running or interrupted, eversion or mattress, etc., has any superiority over other techniques in patency rates.
At the present time there are no adequate reliable data regarding use of sutureless techniques and their long-term outcomes in a clinical setting.
Other options have not been proven as benefits of a coupler device over other techniques.
2015
A 39-year-old woman successfully undergoes immediate bilateral breast reconstruction with coverage with free deep inferior epigastric artery perforator free flaps. Postoperative flap monitoring is planned. Vascular compromise is most likely to occur during which of the following time periods postoperatively?
A) 0–1 days
B) 2–3 days
C) 4–5 days
D) 6–7 days
E) 8–9 days
The correct response is Option A.
Free flaps can be monitored by several different modalities in the postoperative period. The main reason for monitoring free flaps postoperatively is to detect vascular complications in a timely fashion, before permanent injury to the flap occurs, and to maximize the possibility of flap salvage. Reviews of large consecutive series of free flaps indicate that the most likely time period for a vascular compromise is early on, usually within the first 24 hours after successful transfer from the operating room. Therefore, postoperative monitoring protocols should be designed to closely follow flap perfusion during this period of time. Vascular events leading to issues with flap perfusion do occur at later times, but such events are generally infrequent and more difficult to salvage.
2015
A 43-year-old woman is evaluated 6 hours after undergoing delayed breast reconstruction with deep inferior epigastric artery perforator flaps. On Doppler examination, arterial signals are present. Capillary refill time is 3 seconds on the right and 1 second on the left. A photograph is shown. Which of the following is the most appropriate management of the left breast?
A) Administration of systemic heparin
B) Administration of systemic tissue plasminogen activator
C) Application of leeches
D) Return to the operating room
E) Observation
The correct response is Option D.
The most appropriate management is exploration of the left flap to assess anastomotic patency and pedicle orientation. This flap is hyperemic with brisk capillary refill and present arterial signals. These are all signs of venous insufficiency, and emergent exploration is indicated to assess the vascular pedicle for kinking or thrombosis. Application of leeches will drain excess blood from the flap but will not address the underlying problem. Observation is unacceptable because there are signs of venous insufficiency, and this requires urgent intervention. Systemic heparin will prevent further clot formation but will not dissolve an acute clot or resolve pedicle kinking. Systemic tissue plasminogen activator would greatly increase this patient’s risk of bleeding. This agent should only be used within a flap.
2015
A 48-year-old woman is evaluated for immediate bilateral breast reconstruction using coverage with deep inferior epigastric artery perforator free flaps. Which of the following conditions is most likely to be associated with hypercoagulable state?
A) Celiac disease
B) Graves disease
C) Rheumatoid arthritis
D) Systemic lupus erythematosus
E) Type 1 diabetes mellitus
The correct response is Option D.
In some cases, patients with systemic lupus erythematosus (SLE) can develop antibodies against platelet membrane phospholipids, increasing adhesion and aggregation of platelets, and producing a state of hypercoagulability. Although not all patients with SLE will develop these antibodies, a history of SLE should raise concern when evaluating a patient for a free flap reconstruction.
All of the other options are autoimmune diseases, but none are typically associated with coagulopathies.
2015
A 48-year-old woman had delayed microsurgical breast reconstruction. Two hours after surgery, the patient has swelling of the breast and increased drain output. On examination at the bedside, the flap appears purple with capillary refill time of 1 second. Heart rate is 70 bpm, blood pressure is 110/60 mmHg, and most recent hematocrit is 28%. An arterial signal is identified in the skin paddle with a handheld Doppler. Which of the following is the most appropriate next step in management?
A) Application of nitroglycerin paste
B) Operative reexploration
C) Pinprick of the flap
D) Placement of leeches
E) Streptokinase therapy
The correct response is Option B.
The patient described has venous insufficiency after microsurgery and the next step in management is emergent reexploration in the operating room.
Multiple studies confirm that earlier reexploration improves flap salvage rates. The rate of reexploration ranges from 6 to 14%; in these cases, the flap salvage rate ranges from 36 to 94%. Time of return to the operating room is associated with flap salvage. The majority of microvascular complications occur in the first 48 hours, and the majority of these complications are due to venous thrombosis. Common presenting signs include a purple or blue skin discoloration, brisk capillary refill, edema, oozing, or hematoma.
Release of sutures and pinprick of a flap and application of nitroglycerin paste can improve venous congestion in pedicled flaps, but do not obviate the need for reexploration in a microsurgical flap. Placement of leeches is a salvage option and often used when intraoperative maneuvers are unsuccessful. Streptokinase has been described for use in cases where a clot is found within the vascular system, but this should be reserved for use during reexploration, not before.
2014
A 69-year-old woman with breast cancer undergoes bilateral breast reconstruction using free deep inferior epigastric perforator (DIEP) flaps. During surgery, she has onset of hypotension that is unresponsive to standard crystalloid and colloid solutions. The anesthesia team elects to administer norepinephrine to correct her blood pressure. Which of the following flap-related outcomes is most likely?
A) Flap loss
B) Hematoma
C) Reoperation
D) Wound dehiscence
E) No effect
The correct response is Option E.
There are no known increased flap complications with use of vasopressive medications. In fact, one study has shown decreased intraoperative flap complications compared with controls with the use of ephedrine. Traditional dogma is that vasopressors should be avoided during free tissue transfer due to concern that vasoconstriction or thrombosis could occur, resulting in compromised flap perfusion and subsequent flap loss. Most authors argue for standard intravenous fluid replacement or adjustment of anesthetic medications when feasible to first address the hypotension. However, numerous articles have suggested the safety of vasopressive medications in the setting of free tissue transfer. In fact, there are studies correlating excess intravenous fluid administration with increasing complication rates in free transverse rectus abdominis musculocutaneous (TRAM) flaps. As such, vasopressive medications should be considered when standard anti-hypotensive remedies have failed.
The original concern about vasoconstriction of the flap vessels with systemic vasopressor administration and resultant decreased perfusion or thrombosis has largely been disproven. This occurs likely because of sympathetic denervation due to flap transfer, sympathectomy with adventitial removal, and topical use of vasodilators, such as papaverine or nicardipine. Additionally, any vasoconstrictive effect on the flap vessels is more than overcome by increased flap perfusion caused by an elevated blood pressure.
2019
A 45-year-old male fitness instructor has squamous cell carcinoma of the oral cavity requiring reconstruction with a soft-tissue free flap. The patient is very concerned about maintaining all muscular function at the flap donor site. To address the patient’s concern, which of the following fasciocutaneous flaps should be used for reconstruction to minimize muscular donor site morbidity?
A) Anterolateral thigh flap
B) Deep inferior epigastric artery perforator flap
C) Medial sural artery perforator flap
D) Parascapular flap
E) Profunda artery perforator flap
The correct response is Option D.
The benefit of perforator flaps over traditional musculocutaneous flaps is the ability to preserve muscle at the donor site. Depending on perforator anatomy, it can either traverse between surrounding myofascial units requiring no muscle sacrifice, or alternatively pass through the muscle substance requiring division of a small amount of muscle to liberate the flap. The anterolateral thigh (ALT) or deep inferior epigastric artery perforator (DIEP) flaps have variable perforator anatomy containing either septal or muscular perforators, or both within the same flap. The profunda and medial sural artery perforator flaps have vessels that pierce the adductor magnus and gastrocnemius muscles, respectively. Of the options listed, only the parascapular flap consistently has a septal perforator located between the teres major, teres minor, and the triceps.
2019
A 51-year-old woman is undergoing free flap breast reconstruction. Following anastomosis, the patient sustains a venous thrombotic event, and the decision is made to flush the flap with tissue plasminogen activator (tPA). Which of the following is the primary mechanism of action of tPA as used in this scenario?
A) Antithrombin III activation
B) Fibrinolysis
C) Inhibition of platelet aggregation
D) Protein C activation
E) Prothrombin cleavage
The correct response is Option B.
During microsurgical procedures, the normal clotting mechanism may disrupt flow at the anastomosis. Multiple medications are available to limit clotting following the failure of an anastomosis. However, only certain medications are fibrinolytic and actively break down clots, whereas others limit the formation of further clots. Tissue plasminogen activator (tPA) is one such fibrinolytic agent, which increases the cleavage of the zymogen, plasminogen, to its active form, plasmin. Plasmin is directly fibrinolytic.
Prothrombin cleavage, to form activated thrombin, is primarily facilitated by factor X and results in increased thrombogenesis. Aspirin is a common drug that inhibits platelet aggregation, but this does not have a fibrinolytic effect and is not the mechanism by which tPA functions. Antithrombin III activation is the main mechanism of action of heparin, which limits multiple points in the thrombosis pathway. This medication is not fibrinolytic. Activated protein C is a powerful anticoagulant that inhibits both factors V and VIII in the coagulation cascade. Use of a recombinant protein C has been used in septic shock, but its benefits remain controversial. tPA does not function by protein C activation.
2020
A 57-year-old woman undergoes microsurgical breast reconstruction using a muscle-sparing transverse rectus abdominis musculocutaneous (MS-TRAM) flap. Near-infrared spectroscopy (NIRS) is used to monitor the flap in the postoperative setting. NIRS measures which of the following parameters?
A) Arterial oxygen saturation (SaO2)
B) Mixed venous oxygen saturation (SvO2)
C) Partial pressure of oxygen (PaO2)
D) Peripheral oxygen saturation (SpO2)
E) Tissue oxygen saturation (StO2)
The correct response is Option E.
Near-infrared spectroscopy (NIRS) is a noninvasive modality that allows continuous monitoring of tissue oxygenation and perfusion. It measures relative changes in the concentration of oxygenated and deoxygenated hemoglobin. Tissue oxygen saturation (StO2) is the percentage of hemoglobin in tissue that is oxygenated. Since StO2 measures oxygen saturation in the vascular bed of tissue, it measures both venous and arterial saturation and, thus, reflects both oxygen delivery and consumption. This provides a good surrogate for tissue perfusion. Peripheral capillary oxygen saturation (SpO2), measured by pulse oximetry, measures arterial oxygen saturation, which may not reflect perfusion. Arterial (SaO2) and mixed venous oxygen saturation (SvO2) as well as the partial pressure of oxygen (PaO2) are measured directly from blood and are indicative of systemic rather than local tissue oxygenation.
2020
A healthy 55-year-old woman underwent bilateral breast reconstruction with free deep inferior epigastric perforator (DIEP) flaps. Tissue oximetry-based flap monitoring is used. Which of the following is the main advantage of this technique over a hand-held Doppler with clinical assessment?
A) Direct blood flow measurement
B) Ease of use
C) Improved flap salvage rate
D) Less expensive modality
E) Operator must be bedside
The correct response is Option C.
The main advantage of using tissue oximetry-based monitoring is that it improves flap salvage rates. Tissue oximetry, or near-infrared spectroscopy, is increasing in popularity among microsurgeons and has been shown to be the third most commonly used technique after clinical examination and hand-held Doppler. Rather than directly monitoring flow, tissue oximetry uses infrared light to measure the relative concentrations of oxygenated and deoxygenated hemoglobin. By measuring oxygenation rather than flow, the probe is relatively unaffected by movement artifacts. Recent studies emphasize its value in identifying flap compromise before clinical signs of arterial or venous thrombosis. In a 2011 study, Lin et al. reported an increased flap salvage rate at their institution with the use of near-infrared spectroscopy, from 57.7 to 93.8% (p = 0.015), despite no significant increase in their rate of reexploration, attributing this improvement to earlier recognition of vascular compromise. In a recent small prospective cohort study, Lohman et al. followed 38 free flaps with physical examination and five technologies, including handheld Doppler, implantable Doppler, and tissue oximetry. Although primarily a descriptive study, they concluded that tissue oximetry was the first technology to record signs of flap compromise.
Though tissue oximetry-based flap monitoring is easy to use, so is a hand-held Doppler, so that is not the main advantage. It does have a higher financial investment to buy the system, but over time it could be argued it more than pays for itself given the improved flap salvage rates. Unlike the hand-held Doppler, this modality has a continuous read on the monitor, the examiner need not be in the presence of the patient, and, in fact, can visualize the readings on a smart phone through an app.
2020
When compared with liberal fluid administration for pressure support, vasopressors have which of the following effects on the overall success of deep inferior epigastric artery perforator (DIEP) flap breast reconstruction?
A) Delay in postoperative patient mobilization
B) Increase in the risk of total or partial flap loss
C) Increase in the risk of venous congestion
D) No difference in the rate of pedicle thrombosis
The correct response is Option D.
Traditionally, the use of vasopressors in free flap surgery has been avoided due to the presumed risk of pedicle vasospasm leading to flap failure. However, recent studies have indicated that this assumption may not be accurate. Additionally, the fear of vasopressor-associated flap complications has led to the practice of liberal fluid administration, which has failed to demonstrate any benefits when compared with a fluid-restrictive vasopressor strategy. Multiple prospective interventional trials and meta-analyses have reported that the use of vasopressors results in no detectable negative impact on flap survival or overall patient outcome. Specifically, intraoperative use of phenylephrine, ephedrine, or calcium chloride as an intravenous bolus does not increase in the risk of total or partial flap loss, delay postoperative patient mobilization or increase the risk of venous congestion. The use of vasopressors in free flap surgery is not contraindicated.
2021
A 52-year-old man is admitted to the intensive care unit (ICU) for monitoring after debridement and anterolateral thigh free flap coverage of a traumatic lower extremity wound. He has a history of smoking and type 2 diabetes mellitus. Which of the following methods of free flap monitoring is associated with the highest salvage rate following microvascular compromise?
A) Clinical examination
B) Fluorescent angiography
C) Hand-held Doppler
D) Hyperspectral imaging
E) Near-infrared spectroscopy
The correct response is Option E.
Near-infrared spectroscopy has been shown to detect vascular compromise before it becomes clinically obvious, which likely explains the improved salvage rates seen in studies comparing it with clinical monitoring alone. Implantable Doppler probes have also been shown to result in improved salvage rates when compared with clinical monitoring, but they do have a higher false-positive rate. Hand-held Doppler is part of clinical examination and as such does not itself offer an advantage. Hyperspectral cameras image deoxygenated hemoglobin have shown some promise in preclinical studies, but strong clinical data are lacking. Fluorescent angiography, commonly using indocyanine green, may be useful to predict areas of ischemic compromise during surgery, but this technology has not been established as a method for monitoring free flaps postoperatively.
2021
A 59-year-old right-hand–dominant woman with type 2 diabetes and coronary artery disease undergoes a radial forearm adipofascial perforator flap for palmar contracture release and resurfacing to treat a severely contracted burn scar. Which of the following characteristics is a benefit of this flap choice?
A) It can be designed as a myofascial flap
B) It has a distal pivot point at the radial styloid
C) It has robust, 1.5- to 2-mm perforators
D) It is a reliably thin, pliable flap
E) It is a sensate flap
The correct response is Option D.
The radial forearm adipofascial perforator flap is a reliably thin, pliable flap. As such, the flap is a good option for reconstruction of the distal upper extremity when a thin flap is desired, such as for palmar/dorsal hand coverage, revision carpal tunnel/median nerve surgery, and radioulnar synostosis surgery. Other advantages of this flap include avoiding the need to sacrifice the radial artery, shorter operative time compared with free tissue transfer, and low donor morbidity. The vascular supply to the flap is a series of roughly 10 small 0.3- to 0.9-mm septocutaneous radial artery perforators found in the septum between the flexor carpi radialis and the brachioradialis tendons. The most distal perforator arises approximately 1.5 cm proximal to the radial styloid. Therefore, the pivot point for this flap is safely 4 cm proximal to the radial styloid. Since the flap is supplied by the adipofascial perforating vessels superficial to the radial artery, the inclusion of muscle in the flap design is not reliable. During flap elevation, the superficial radial nerve and lateral antebrachial cutaneous nerves are identified and preserved, but are not included into the flap.
2021
A 45-year-old woman with a history of systemic lupus erythematosus requires a free flap reconstruction of her right lower extremity. She has never had a thrombotic event. She is on corticosteroids for collagen vascular disease. Which of the following perioperative measures is most appropriate?
A) Intraoperative and postoperative anticoagulation
B) Intraoperative anticoagulation alone
C) Preoperative and postoperative aspirin therapy
D) Preoperative hypercoagulability workup
E) Preoperative vitamin A therapy
The correct response is Option D.
The most appropriate management would be to get a formal hematology consult and anticoagulation workup prior to surgery. Collagen vascular diseases target connective tissues and have multiorgan manifestations secondary to deposition of antigen-antibody complexes. Affected patients are intrinsically prone to thrombosis from the inflammation of the connective tissue disorder itself and the synergistic effect of having increased chances of having concurrent hypercoagulability risk factors such as anticardiolipin or lupus anticoagulant.
Therefore, in this patient population with the threat of vascular compromise, it is most prudent to perform preoperative hematologic evaluation, especially if they exhibit a history of previous clotting and flap failure. As a more prudent measure, all of these patients should have a detailed hypercoagulability evaluation, including a detailed history and hematology consultation with a laboratory panel looking for hypercoagulability factors. If positive, steps should be taken perioperatively to decrease the risk of thrombotic complications, and chemical anticoagulation should be considered, but if negative with no history of previous thrombotic complications, then no added chemical anticoagulation is needed. Studies have not shown an increase in thrombotic flap failures in such patients, despite their intrinsic risk of thrombosis.
Aspirin therapy has not been shown to decrease flap loss rates. Vitamin A is indicated in this patient, not to decrease thrombotic flap loss rates, but rather to counteract the immunosuppressive medications.
2021
When harvesting the profunda artery perforator flap for breast reconstruction, which of the following structures does the perforating vessel travel through in the majority of patients?
A) Adductor longus muscle
B) Adductor magnus muscle
C) Gracilis muscle
D) Septum between the adductor longus and sartorius muscles
E) Septum between the adductor magnus and semimembranosus muscles
The correct response is Option B.
Proximal thigh profunda artery perforators most commonly course through the adductor magnus muscle not the adductor longus muscle. In these cases where musculocutaneous proximal perforators are used, fibers of the adductor magnus muscle will be divided for PAP flap harvest.
The profunda artery perforator (PAP) flap is a fasciocutaneous flap frequently employed for breast reconstruction as an alternative to the deep inferior epigastric artery perforator flap. The PAP flap has also been described for lower extremity resurfacing and burn scar contracture release, as well as pedicled for perineal reconstruction. The PAP flap skin paddle is harvested as either a transverse skin paddle beneath the gluteal and groin crease or with a vertical skin paddle harvested in the frog leg position. The most common donor site skin paddle orientation for breast reconstruction is a transverse ellipse of skin inferior to the gluteal crease to camouflage the donor site scar.
The profunda artery perforators emerge from the profunda vessels longitudinally down the postero-medial aspect of the thigh. Most patients have a proximal perforator that supplies the transverse ellipse of skin and adipose tissue most commonly employed for breast reconstruction. However, enough variability exists in perforator location, that preoperative CT angiography is recommended to confirm the presence of a proximal perforator.
The PAP flap perforating vessel may travel in a septocutaneous plane between the gracilis and adductor magnus at the level of the deep investing fascia and between the adductor longus and magnus closer to its origin but not between the muscles listed as alternate septocutaneous choices. The transverse upper gracilis (TUG) flap perforator travels through the gracilis muscle before perfusing the medial thigh skin.
2021
