Perforator Flaps

    What is the arterial source of a perforator flap?


Either septocutaneous branch or musculocutaneous branch passing through muscle to nourish the fasciocutaneous flap from its mother vessel.


image    What is an angiosome?


The angiosomes of the body are distinct vascular territories that are composed of muscle and the overlying skin and the adipose tissues. The angiosomes define the anatomical borders from which tissues are available for composite transfer.


image    How are the cutaneous vessels defined according to their course?


They are defined as septocutaneous and myocutaneous vessels. Septocutaneous vessels course either between the tendons or muscles following the intermuscular septa. Myocutaneous perforators penetrate through the muscle to nourish the subcutaneous tissue.


image    What is the anatomical basis for perforator-based skin flap design and harvest?


The size, length, direction, and connections of the cutaneous perforators provide basis of flap design. At least one adjacent anatomical cutaneous vascular territory can be captured with safety when based on a particular perforator.


image    What is the contribution of Taylor and Daniel to the evolution of the perforator flap surgery?


These authors were the first who attempted to harvest skin flaps on the septocutaneous and myocutaneous perforators that they had identified during their vascular anatomy studies on cadavers. They mapped the vascular anatomy of the skin and identified an average of 374 dominant cutaneous vessels of 0.5 mm or greater in diameter, and introduced the angiosome concept for further perforator flap surgery.


image    What is a true perforator flap?


A “true” perforator flap relies on perforator vessels from a given source vessel that must first penetrate a muscle before piercing the deep fascia to reach the skin.


image    What are the advantages of the perforator flaps?


1.  Less donor site morbidity.


2.  Muscle sparing and allows thin flap harvesting.


3.  Versatility in design to include as little or as much tissue as required.


4.  Improved postoperative recovery of the patient.


5.  Increased versatility in flap design and more economic flap application, including chimeric flap design or harvesting more than one flap basing on the same mother vessel.


image    What is the definition of a reliable perforator vessel?


The reliable perforator is defined as a perforator that sprouts from the carrier muscle with a “visible” pulsation, usually greater than 1 mm in diameter. A reliable perforator is believed to have the ability to expand its perfusion over its territory after the perforator flap elevation.


image    How are the perforator vessels identified?


Currently, the most practical, simple, safe, speedy, and inexpensive method is the use of handheld Doppler ultrasound probe. Other techniques include computed tomographic angiography, magnetic resonance imaging angiography, and color-flow duplex scanning.


image    How are the axial artery and perforators discriminated with the Doppler probe?


The axial artery has a unidirectional pulsating course whereas there is no evident pulsating sound around the perforator.


image    What are the available preoperative tools to identify the exact location of the perforators?


The available and reliable image studies include multidetector-row helicon computed tomography angiography and magnetic resonance imaging.


image    What is the most common consequence when a tiny perforator is selected?


Marginal flap necrosis beyond the territory of the perforators.


image    What are the requirements for an acceptable perforator flap donor site?


1.  Predictable and consistent blood supply;


2.  At least one large perforator with the diameter greater than 1 mm;


3.  Sufficient pedicle length;


4.  Primary closure of the donor site with the absence of excessive wound tension.


5.  Provision of similar soft-tissue volume that matches the recipient defect


6.  Donor site with well-hidden scar is more favorable


image    What are the most commonly used perforator flaps?


Anterolateral thigh perforator flap, deep inferior epigastric perforator (DIEP) flap, super gluteal artery perforator flap, inferior gluteal artery perforator flap, thoracodorsal perforator flap, tensor fascia lata perforator flap, medial plantar perforator flap, deep circumflex iliac perforator flap, superficial circumflex iliac artery perforator flap, medial sural artery perforator flap, transverse gracilis perforator flap, internal mammary artery perforator flap, profunda artery perforator flap, anterior obturator artery perforator flap, lumbar artery perforator flap, intercostal artery perforator flap, and submental artery perforator flap.


image    What is a free-style free flap?


An anatomic region that is not the traditional flap territory with the appropriate size, color, and pliability is selected, and the skin perforators in that region are mapped using a Doppler probe. Mapped perforators are dissected toward source vessels to provide adequate vessel length and size. By applying the concept of free-style free flap, small- or moderate-sized flap can be designed and harvested from almost any part of the body as long as the donor site appearance is acceptable to the patient.


image    What is the main advantage of a free-style free flap?


The advantage of this concept is that it provides the surgeon an extra sense of freedom and variability when approaching a flap harvest and choosing the recipient site. Once perforators can be identified, any area of the body can serve as donor site for flap harvesting. There is no limitation on the flap selection and more flaps can be harvested for reconstruction, even in areas that had been used as flap donor site before.


image    What are the most common causes of the perforator thrombosis?


Stretching, twisting, drying, compression of the perforator and technical error.


image    What are the strategies to reexplore a thrombosed perforator flap?


1.  Explore early.


2.  Resect the thrombosed vessel segment and reanastomose with or without vein graft. Vessels with damaged intima should be resected as much as possible.


3.  Open the vessels and squeeze the proximal vessel to evacuate the thrombus. Thrombus can also be suctioned out gently with smooth needle and manually applied suction force with syringe.


4.  Do not inject any solution from the cut end since this maneuver may cause migration and plugging of thrombus into the smaller perforators.


5.  Relieve the tension from the flap.


6.  Inject few thrombolytic agents, such as urokinase, streptokinase from the donor artery and drain it out from the donor vein in an attempt of thrombolysis.


7.  Systemic infusion of low-dose heparin 2,500 to −5,000 units/day.


8.  If the flap remained unperfused, the whole pedicle should be checked under microscope.


9.  Inappropriate flap inset can cause twist of the pedicle and subsequent thrombus formation. All the stitches can be released to make sure the flap is inset in appropriate manner.


image    What are the principles in “thinning” of a perforator flap?


1.  Preserve the fat and the fascia within a circle of 1 cm diameter around the perforator;


2.  Use loupes or microscope to perform the procedure;


3.  Perform thinning when there is circulation in the flap, either before division of pedicle or after restoration of blood circulation.


image    What is “supermicrosurgery” as a technique?


Supermicrosurgery technique involves division of the perforator flap pedicle above the deep fascia and anastomosing small vessels that are less than 1 mm (0.5–0.7 mm) using 12-0 nylon with a greater magnification microscope. It allows free transfer of flaps on vessels harvested without breaching deep fascia, the so-called “perforator-to-perforator” free flap transfer. The technique of supermicrosurgery has also been expanded in lymphatic surgeries, such as lymphatico-lymphatical anastomosis or lymphaticovenous anastomosis with various anastomosis techniques for lymphedema treatment.


image    What are the advantages in applying supermicrosurgery technique in perforator flap surgery?


The donor site morbidity is reduced since the fascia remains intact and the muscle is not dissected. Flap harvest can be performed quickly without intramuscular dissection. Besides, only a short vascular pedicle is taken without sacrificing perfusion to the surrounding tissues.


image    What are disadvantages to apply supermicrosurgery technique in perforator flap surgery?


The primary disadvantage is the short and small pedicle rendering the inset and the difficulty of performing anastomosis on tiny diameter vessels on a short pedicle.


image    What is the “supermicrosurgery” impact on management of extremity lymphedema?


Multiple lymphaticovenular anastomoses on a single limb were reported to improve the lymphedema significantly. It also serves as prophylactic procedures in patients receiving lymph node dissection with the potential risk of developing lymphedema in the future.


image    List the perforator flaps and their accompanying nerves that can be harvested as a sensate flap.


Thoracodorsal perforator flap—lateral branch of the intercostal nerve


Medial plantar artery perforator flap—medial plantar nerve


Anterolateral thigh flap—lateral femoral musculocutaneous nerve


Deep inferior epigastric perforator flap—sensory branch of the intercostal nerve


Superior gluteal artery perforator flap (SGAP)—super and middle gluteal nerve


image    What is a pedicled perforator flap?


By applying the concept of perforator flap into regional reconstruction, a perforator flap close to the defect is dissected and transferred by meticulous intramuscular dissection of the perforator without division and reanastomosis of the vascular pedicle. One of the recently highly applied areas was the perineal reconstruction using perforator flaps from the medial and posterior thigh, such as the, gracilis perforator flap (medial circumflex femoral artery perforator flap), profunda artery perforator flap, anterior obturator perforator flap, gluteal artery perforator flap and more distant pedicle perforator flap, such as pedicle ALT flap and pedicle DIEP flap.


image    What are the advantages of pedicled perforator flap?


The microsurgical anastomosis is eliminated and the potential risk of flap loss diminished. A perforator flap is designed close to the defect and can be based on traditional flap design, like rotation, transposition, advancement and interposition/island flaps and transposed to the recipient site based on the perforator. Many of the traditional used reconstruction method can be modified to a more reliable and more versatile manner, such as converting the gracilis myocutaneous flap to gracilis perforator flap to vulvar reconstruction. Traditional flaps can be designed with improvement of providing an axial and reliable blood supply. Owing to the preservation of the perforator, the traditional pedicle flap length-to-width rule is no longer needed.


image    List examples of pedicled perforator flap in head and neck reconstruction.


1.  Submental artery perforator flap


2.  Facial artery musculomucosal flap


3.  Temporoparietal artery perforator flap


4.  Internal mammary artery perforator flap


image    Who described the anterolateral thigh flap?


Song et al. described it as a septocutaneous perforator flap in 1984.


image    What is the source artery of the ALT perforator flap?


Septocutaneous or musculocutaneous perforators derived from the descending, oblique or transverse branch of lateral circumflex femoral system.


image    What is the landmark for the perforators in the anterolateral thigh region?


A line is drawn from anterior superior iliac spine to the lateral border of the patella and the perforators are usually located in a circle 3 cm around the midpoint of this line.


image    What is the ratio of septocutaneous versus myocutaneous perforators in the anterolateral thigh perforator flap?


In different reported series, only 12% to 33% of the patients were reported to have septocutaneous vessels while 67% to 88% had myocutaneous perforators only.


image    What can be the maximum dimension of an anterolateral thigh perforator flap?


8 × 20 cm.


image    What are the advantages of thinning anterolateral thigh perforator flaps?


1.  Uniformly thin and pliable flaps become available especially for reconstruction of oral cavity, neck, hand and fingers, axilla, forearm, and anterior tibial area, when the flap is thicker than required.


2.  Avoids secondary defatting or liposuction procedure.


3.  Improved sensory recovery.


4.  Early range-of-motion training when used in hands and fingers and better and quicker postoperative functional recovery in buccal and tongue reconstruction.


image    What is the upper width limit of the anterolateral thigh flap that can be usually closed primarily?


Although the laxity is important for this issue, generally up to 8 cm defect can be closed primarily.

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Aug 28, 2016 | Posted by in Reconstructive surgery | Comments Off on Perforator Flaps
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