Random Pattern Cutaneous flaps

Question 1

Secondary defect definition

Answer 1

The operative wound created by flap elevation and closure of the primary defect

Question 2

Primary flap motion

Answer 2

The direction of tissue movement that closes the primary defect

Question 3

Secondary motion

Answer 3

The direction of tissue movement that closes the secondary defect that resulted from the flap’s primary motion

Question 4

Primary lobe

Answer 4

The portion of a flap that is designed to cover the primary defect

Question 5

Secondary lobe

Answer 5

The portion of a flap that is used to cover the secondary defect

Question 6

Flap size (surface area)

Answer 6

The entire area of flap elevation combined with the primary operative defect

Question 7

Tension vector

Answer 7

The direction of force on a given motion of the flap

Question 8

Pivot point

Answer 8

The point at the base of the flap about which the flap rotates and/or transposes

Question 9

Because the normal perfusion of skin is approximately 10 times the blood flow needed to provide basic nutritional support, appropriately designed flaps can predictably survive

Answer 9

T

Question 10

Because properly designed flaps have reliable perfusion, flaps can also be used successfully to cover relatively avascular tissues such as cartilage or bone

Question 11

With proper planning and surgical technique, the healing from flap repairs is often much more rapid than the healing of granulation or skin grafting. The morbidity and complications associated with skillfully performed surgical flap reconstructions should be similar to those of skin grafting procedures.

Question 12

When possible, flaps should be designed so that incision lines do not cross convexities with underlying bone such as the ramus of mandible, the zygomatic arch, or the clavicle, because hypertrophic scarring is more common in these situations.

Question 13

Many elderly patients have surprisingly atrophic skin and subcutaneous tissue, and flaps that require relatively high wound closure tensions should be avoided in these patients because the tensile strength of the thinned dermis will be unable to support the required wound closure tensions.

Question 14

Highly sebaceous skin has a low compliance, does not easily stretch or bend, and can be brittle to work with. In addition, it is generally advantageous to avoid placing incision lines within thick, sebaceous skin, because the resultant suture lines frequently track and invert.

Question 15

Finally, when possible, flaps should not rely on pedicles based on previously scarred or irradiated skin because in addition to the inelastic nature of this tissue, the perfusion of this skin is often suboptimal and usually unpredictable.

Question 16

Most surgical complications that follow reconstructive facial surgery involve difficulties in hemostasis

Question 17

When anticoagulants have been withheld for cutaneous surgical procedures, major thrombotic episodes, including stroke and myocardial infarction have been reported

Question 18

The risk of major bleeding following flap reconstruction in patients who are anticoagulated with warfarin is slightly higher than the risk of bleeding without anticoagulation, but the likelihood of catastrophic hemorrhage remains low.

Answer 18

Patients on multiple anticoagulants such as warfarin and clopidogrel have an even higher rate of bleeding, but again, the risk of major hemorrhage is small. In patients taking warfarin, it is reasonable to check a recent international normalized ratio (INR). If the patient has a markedly elevated INR, warfarin may be withheld for several days to bring the INR back into the normal therapeutic range.

Question 19

Because aspirin irreversibly inhibits cyclo-oxygenase, the drug’s effects on hemostasis last for up to 2 weeks, and aspirin use may therefore predispose to intraoperative and postoperative bleeding.

Answer 19

The authors of this chapter discontinue aspirin 1 week before surgery for patients on aspirin for primary prevention, but not for individuals on aspirin for secondary prevention of further stroke or heart attack.

Question 20

Newer agents such as clopidogrel and dabigatran do predispose to bleeding, but given the indications for which they are prescribed (cardiac stents, carotid stenosis), in general it is advisable to have patients remain on their medications and obtain hemostasis with great care.

Question 21

Smoking is not a contraindication to flap reconstruction, but smokers do have higher incidences of flap failure and distal flap necrosis, wound dehiscence, and wound infection

Answer 21

As a result of potential ischemia of the distal or peripheral margins of a flap, the scars that accompany reconstructive surgery in smokers tend to be more visible than the scars in non-smokers. When feasible, it is therefore advisable for patients to discontinue smoking several weeks before and for at least 1 week after flap repairs.These individuals should be advised that their continued smoking during the perioperative period puts them at higher risk of operative complications.

Question 22

In areas prone to sensory disturbance such as the forehead or upper lip, it is also essential to inform patients about likely postoperative numbness, paresthesias, and the potential for developing neuropathic-type pain.

Answer 22

Fortunately, most sensory disturbances associated with flap repairs are temporary.

Question 23

The face is endowed with a rich, deep arterial supply from multiple branches of the internal and external carotid arteries. External carotid branches such as the facial and superficial temporal arteries and internal carotid branches such as the supraorbital, infraorbital, and supratrochlear arteries divide into a myriad of small vessels that penetrate the facial muscles and deeper fascial planes. From the subcutaneous and intrafascial axial vessels, there are numerous perforating arteries that feed into an extensive subdermal plexus. This plexus is extensively redundant with numerous anastomotic connections. From the subdermal plexus, tiny vessels ascend to an intradermal plexus that ultimately nourishes the overlying skin

Question 24

Scalp flaps, which are routinely elevated beneath the galea, typically contain larger vessels and therefore also have a robust blood supply.

Question 25

Most random pattern flaps are based on the unnamed but highly redundant vasculature of the subdermal plexus

Answer 25

The intradermal plexus is, in general, insufficient to sustain flap viability. The most abundant blood supply to the skin lies just beneath the dermis in the smaller, dense fat lobules of the subcutaneous tissue. Accordingly, for random patterned flaps, the most critical blood supply lies in the shallow subcutaneous tissues. Flaps elevated in the loose, deeper subcutis therefore have, by definition, a predictably reliable blood supply. If flaps are elevated within the dermis or within the very shallow subcutaneous fat, the flaps are at risk for ischemic failure given their unreliable, tenuous perfusion.

Question 26

Paramedian forehead flaps, which is an axial flap, and certain banner flaps can be created at length: width ratios of 6: 1 or 7: 1 (or greater) if the flaps' arterial supplies are not twisted or kinked and if all wound closure tensions are directed along the flaps' secondary motion.

Question 27

The venous drainage of a flap is equally important to its arterial supply. In general, the venous drainage of a flap parallels the arterial supply, but it is not always an exact match. While the arterial supply of a flap has a pressure-based viability, the venous system is a low or negative pressure system, and the small veins of a flap can become occluded and fail. This can result in venous congestion and surface slough, heralded by a blue–purple discoloration of the epidermal surface. In flaps elevated at a deeper plane, the muscle often provides reliable venous drainage, and flaps with a muscular blood supply rarely suffer venous congestion or arterial failure.

Question 28

When an operative defect lies near a free margin such as the vermilion border or close to a defined facial boundary such as the nasolabial fold, any proposed linear repair may violate the free margin or the facial boundary and may therefore be technically infeasible or aesthetically undesirable. In such cases, an advancement flap frequently allows for optimal closure.

Answer 28

in distinction to rotation and transposition flaps, advancement flaps do not have the advantage of being able to redirect wound closure tension to a more favorable axis.

Question 29

Bilateral advancement flap (H-plasty) is most suitable for repair of defects within the eyebrow where scars can readily be hidden. Elsewhere the H-plasty produces a complex scar and other repairs are generally favored.

Answer 29

. Excision of the dog-ear redundancies that result from tissue advancement further complicates the rather unaesthetic arrangement of the scar. Also, if there is any ischemia of the flap's advancing edge(s), this vertical closure is likely to leave behind a slightly depressed scar Simpler closures, even a vertically oriented linear repair, are frequently more suitable. If there is sufficient laxity to allow the direct advancement of two adjacent flaps, there is nearly always sufficient laxity to allow a primary linear closure. The surgeon is rewarded for selecting the more appropriate simple linear repair, with simplicity of design and operative ease, and the patient is rewarded with a lower risk procedure, less (if any) sensory loss above the closure, and a more visually pleasing scar.

Question 30

In the A–T repair, a linear repair of the operative wound is designed perpendicular to a free margin or to a pre-existing cosmetic junction. Instead of extending a primary linear repair across a cosmetic boundary or free margin, incisions are designed along the margin of the operative defect, a free margin, or a cosmetic boundary, perpendicular to the linear repair axis. In this manner, one line of the repair is hidden in a cosmetic junction or dynamic rhytid.

Question 31

Closely related to the A–T advancement flap is the O–T rotation flap. Conceptually similar, the flaps both create a T-shaped incision. Where the A–T flap relies upon linear tissue advancement, the O–T flap relies upon flap rotation.

Question 32

The A–T flap is useful for perialar defects where the top of the T can be hidden in the alar crease and the vertical limb of the T can be hidden in the nasolabial fold. Above the brow or on the forehead, the base of an inverted T can be hidden either just above or just below the brow or within a horizontal forehead rhytid

Answer 32

Although the classic A–T flap is rather simplistic from a design perspective, great care must be taken to align the advancing tissue edges. If the leading edges of the advancement(s) traverse a great distance to close a large defect, distracting dog-ear redundancies can be produced. Sometimes, these tissue redundancies need to be excised in the areas that the surgeon was initially reluctant to manipulate, so undermining flap utility. Often, a single limb advancement flap will suffice to displace a dog-ear far away from a free margin into a natural crease

Question 33

Commonly used sites for advancement flaps are the nasal sidewall superior to the alar crease, the upper lateral lip superior to the vermilion border, and the supraorbital forehead lateral to the midpupillary line.

Question 34

Question 35

Undermining is effective, and animal studies have demonstrated that the force required for a one-dimensional closure of a linear repair of an in-vivo porcine operative wound is reduced between 18.6% and 47.4%, with simple undermining of the wound's edges.

Answer 35

T

Question 36

Undermining of the flap, the tissue surrounding the flap, and the primary defect may also minimize the risk of developing pin-cushioning in the later postoperative period because the wound contractile forces are distributed in more directions and over much greater distances.

Question 37

Undermining comes at a cost, however. Undermining, particularly at a flap's base, can transect vital arterial input to the flap, and overly aggressive undermining can therefore introduce an ischemic risk. Paradoxically, undermining that is too extensive can also impede tissue movement

Question 38

Sharp undermining produces less blunt force trauma and shear force on surrounding structures and can limit postoperative swelling. Blunt undermining on the other hand can be useful when undermining near vital neurovascular structures that need to be spared. When a fascial plane such as the SMAS or muscular plane is encountered, undermining can often be accomplished with great precision using electrosection.

Question 39

For ideal flap repairs, the thickness of the elevated flap should closely match the depth of the primary surgical defect except when the defect is deeper than the plane desired. Cheek flaps are usually elevated within the subcutaneous fat. Flaps that are elevated within the subcutis should generally be undermined in the larger, looser fat lobules near the mid to deep subcutis. The fat lobules of the superficial subcutis are smaller, laced with fibrous tissue, and richly vascularized, making flap elevation more challenging. Thicker subcutaneous flaps have a more predictable pattern of perfusion, and elevation just above a superficial fascial plane will often produce greater flap mobility than elevation in the superficial subcutaneous plane.

Question 40

what structures are there to be aware of when doing surgery on the nose?

Answer 40

nasociliary nerve, angular artery

Question 41

what is the preferred plane of undermining for the lip area?

Answer 41

just above orbicularis oris

Question 42

what is the preferred plane of undermining for the forehead?

Answer 42

just above frontalis Flaps on the forehead are typically elevated just above the frontalis musculature. Although this plane of elevation requires careful separation of the subcutis from the underlying skeletal muscle, it prevents the numbness and arterial transection that can occur with deeper flap elevation.

Question 43

What is the preferred plane for undermining the scalp?

Answer 43

Scalp flaps are most appropriately elevated beneath the galea in the bloodless tissue plane immediately above the periosteum. Because the flap elevated under the galea has limited tissue mobility/stretch, incision in the galea or excisions of a portion of the galea may be useful to provide an added component of tissue advancement.

Question 44

What is the preferred plane for underming for the nose?

Answer 44

Some small nasal flaps are elevated above the nasal musculature, while more complicated flaps, such as the bilobed transposition flap and the dorsal nasal flap, are most appropriately elevated just above the perichondrium and periosteum. This deeper plane of undermining on the nose is associated with far less hemorrhage than undermining within the nasalis musculature, and the inclusion of richly perfused skeletal muscle with the bases of these flaps makes the flaps nearly immune to ischemia. Rhinoplasty surgeons also choose this plane of undermining because they consider that this plane allows the most proper tissue movement while minimizing the scar formation that inevitably accompanies any surgical intervention. Flaps on the ear should be undermined over perichondrium while those involving periorbital skin should be undermined just above orbicularis oculi musculature.

Question 45

Suspension or tacking sutures are sutures that anchor a portion of a flap to underlying immobile structures such as the periosteum. This technique is used to shift tension away from the edges of a flap, to reorient the tension vector of a flap, or to tack a flap down at a point of facial concavity where the flap would otherwise tent and create a potential dead space. Tacking for facial closures is usually carried out with a 4–0 absorbable or clear non-absorbable suture. The frontal bone, lateral orbital wall, zygomatic arch, nasal bones, and medial maxilla are the most frequently used anchoring sites for tacking sutures.

Answer 45

Similarly, it is often useful to tack large cheek and temple rotation flaps to either the zygoma or to the lateral orbital rim or temple

Question 46

One flap that frequently benefits from a tacking suture is the nasolabial flap. Tacking from the center of the flap to the underlying fascia at the alar crease can help avoid tenting of the flap and may assist in maintaining an otherwise ablated alar crease

Question 47

Running sutures are time-efficient and offer an ability to distribute wound closure tensions evenly. In our experience, epidermal everting sutures, such as the horizontal or vertical mattress sutures, can produce subtle wound edge ischemia when used on the face and are therefore avoided.

Question 48

As an alternative to this open-wound care regimen, the original dressing can be left in place for the entire 5–7 days before suture removal or wound check

Answer 48

the sutures of facial flaps are routinely removed 4–7 days postoperatively

Question 49

Because hematomas are associated with an increased risk of flap ischemia and tissue death, hematoma that compromises wound integrity should be evacuated. Interestingly, the cause of flap death associated with the formation of a hematoma is not because of hydrostatic compression of the flap's vascular input. Rather, the accumulated blood is an abundant source of iron, which catalyzes the formation of tissue-injuring free radicals. When a dynamic hematoma is detected, the sutures are immediately removed, the hematoma is evacuated, the bleeding is addressed, the wound is copiously irrigated, and the flap is resutured. Prophylactic antibiotics are appropriate in cases where a static hematoma is detected as well as when the wound needs to be reopened to control surgical hemorrhage.

Question 50

When wound infections occur, most are caused by Staphylococcus aureus , and empiric antibiotic therapy should be commenced until culture results become available. If abundant purulent debris is present, the surgeon should consider removing buried sutures (a nidus for infection) and allowing the wound to granulate. Because surgical complications are so closely interwoven, it is not uncommon for the infected skin flap to then undergo wound dehiscence. The resulting poor aesthetic result can be revised after the wound has entirely healed by second intention

Question 51

With experience, the incidence of flap necrosis should be low (<5–10%). 10 When cutaneous flaps fail, tissue loss is usually heralded by a dusky purple–blue and white discoloration at the time of closure. It may be difficult to judge flap perfusion in the immediate postoperative period as a result of vasoconstriction associated with the use of epinephrine-containing anesthetic solutions, and some dusky flaps will survive without necrosis.

Question 52

Superficial epidermolysis of the distal flap will not typically affect the eventual appearance of the healed wound, but full-thickness necrosis of the flap will produce a deep wound that is most appropriately allowed to heal by second intention. Because an accurate assessment of the depth of tissue necrosis in the failing flap cannot be obtained with a simple visual inspection, the surgeon should resist all temptation to manually debride the wound, even if a densely adherent dry eschar is present. Continued wound care is required until the entire flap has healed. Surgical revision procedures can be contemplated later for aesthetic refinement.

Question 53

the alar rim often needs to be supported by a cartilage graft to ensure patency of the airway before covering the complicated distal nasal wound with a flap. Similarly, the eyelids and the mouth serve obvious functions, and reconstructive alternatives should therefore be carefully selected. Functional compromise associated with flap reconstruction can be difficult to revise later and should be avoided whenever possible.

Question 54

One complication that produces an unaesthetic result of any flap repair is the development of the trapdoor (or pin-cushioned) deformity. This globular, protuberant appearance of a flap commonly appears at 3–6 weeks and is particularly common and apparent on the nose.

Answer 54

This globular, protuberant appearance of a flap commonly appears at 3–6 weeks and is particularly common and apparent on the nose. Many post-surgical phenomena (e.g., lymphatic obstruction) have been postulated as the cause of the trapdoor deformity, but the most reasonable explanation for the development of this tissue protrusion involves the circumferential contraction of the scar surrounding the flap's recipient site. As the scar contracts, the flap decompresses anteriorly, the only direction in which the flap is not tightly anchored.

Question 55

Transposition flaps (particularly the nasolabial flap) are especially prone to developing the trapdoor deformity, and the risk of the deformity is elevated when the procedures are carried out on thick, sebaceous skin. Like most surgical complications, pin-cushioning is easier to prevent than to manage. The most important technique involved in reducing the risk of this complication is to properly size the flap. If too much flap is “stuffed” into the primary defect, the flap has little hope of escaping the trapdoor deformity as scar maturation occurs. Accordingly, the flap should be trimmed to just the right size to minimize tissue redundancy. The ideal flap should be even with the adjacent skin's surface (or even slightly recessed) at the completion of the reconstructive procedure.

Question 56

Additional interventions that have been suggested to minimize the development of protuberant flaps include widely undermining the flap's recipient site and “squaring off” the flap's edges, both of which could conceivably disperse or reorient tension vectors. If the flap undergoes pin-cushioning despite these techniques, intralesional corticosteroids, after allowing the flap to “settle,” may help to improve the flap's contour. When corticosteroids are used in an attempt to introduce subcutaneous atrophy and contour refinement, especially in thick-skinned areas, relatively high concentrations must be used. Several monthly injections may be required before significant improvement can be detected. Additionally, aggressive massage along the scar line can help to improve the appearance of the flap. Rarely, a surgical revision procedure is required to lift the flap and subsequently sculpt the underlying tissues to restore a more appropriate contour.

Question 57

Even if the surgeon has meticulously planned and expertly performed a flap in a healthy patient who practices diligent wound care, some flaps fail to meet patient and physician expectations. In such cases, flap revision procedures can be contemplated if the patient has appropriate aesthetic expectations and if the surgeon can offer reasonable hope for improvement. On occasion, the incision lines of flaps can be improved with laser resurfacing or dermabrasion. Manual dermasanding with sterilized, industrial-grade sandpaper or an abrasive electrocautery cleaning pad typically works as well as the mechanical dermabrasion with diamond fraises, and the ideal time to abrade a wound for aesthetic refinement is between the fourth and eighth postoperative weeks. Resurfacing procedures may be complicated by the production of textural alterations and distracting hypopigmentation of the skin (even in the absence of the use of refrigerants designed to produce skin firmness and vasoconstriction before the dermabrasion procedure).

Question 58

If improper flap design or unanticipated flap contracture produces bothersome distortion, a Z-plasty procedure can effectively reorient wound tensions and relocate adjacent structures. The Z-plasty technique offers seemingly endless flexibility, and accurate degrees of tissue motion can be accomplished if the Z-plasty's arms and angles are thoughtfully constructed. On occasion, flap redundancies can be addressed with secondary procedures designed to thin the flap and restore a more appropriate contour. When these interventions are planned, all operative incisions should be placed through pre-existing scars or along natural anatomic boundaries so that additional cosmetic burdens are not introduced. Some flaps, because they necessarily blunt anatomic structures such as the alar groove, need planned revision procedures to reintroduce normal facial structures.