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Flashcards in Tissue Expansion Deck (23):
1

A 15-year-old girl comes to the office 2 months after undergoing unsuccessful scalp replantation following an avulsion injury. The resulting defect is treated with negative pressure wound therapy. Physical examination shows a clean, granulating lesion that encompasses approximately 50% of the total area of the scalp. Which of the following is the most appropriate method for reconstruction?
A) Coverage with bilateral temporo-parieto-occipital (Juri) flaps
B) Coverage with a free latissimus muscle flap with immediate split-thickness skin grafting
C) Orticochea procedure (three-flap technique) with skin grafting of the secondary defect
D) Serial excision and closure
E) Split-thickness skin grafting and staged tissue expansion

E) Split-thickness skin grafting and staged tissue expansion

Approximately 50% of the scalp can be reconstructed with expanded tissue, resulting in minimal change in hair density.

No other tissue or donor site in the body will approximate the hair-bearing qualities of scalp tissue. Simply, the best replacement for scalp tissue is scalp tissue. In addition to calvarial coverage and wound closure, the reconstructive surgeon should strive for a cosmetically pleasing outcome. In patients with nearly 50% scalp loss, tissue expansion will provide the optimal functional and aesthetic outcome. Tissue expansion should be considered when local tissue rearrangements are inadequate because of defect size, trauma, or unacceptable rearrangement or distortion of the hairline. Tissue expansion increases the amount of locally available tissue, preserves sensation, andmaintains hair follicles and adnexal structures.

The Orticochea and temporo-parieto-occipital (Juri) flaps are ill-suited for large defects (greater than 30% of the scalp) orin the location described (vertex).

Serial excisions are useful for smaller defects. The amount of scar and deformity is much less when using tissue expanders versus serial reductions and complex rotation flaps.

2

How much of the scalp can be reconstructed with expanded tissue?

Approximately 50% of the scalp can be reconstructed with expanded tissue, resulting in minimal change in hair density.

3

Pro s to tissue expansion for scalp coverage

issue expansion increases the amount of locally available tissue, preserves sensation, andmaintains hair follicles and adnexal structures

4

Where should tissue expanders for scalp reconstruction be placed?

When performing expansion, the largest tolerated expander(s) should be placed in the subgaleal plane. Rectangular and crescent-shaped prostheses provide more expansion than circular devices.

5

How much expansion should be done per scalp defect?

To account for tissue recoil, expansion should continue until the expanded flap is approximately 20% larger than the expected defect.

6

Disadvantages to tissue expansion

Disadvantages of tissue expansion include prolonged time to complete the expansion process (up to 3 months is not uncommon), need for at least two operations, and a high rate of complication (6 to 48%).

7

Juri flaps

Juri flaps are useful for frontal or frontoparietal defects. The flap is based on the parietal branch of the superficial temporal artery and is best used after surgical delay of the distal aspect.

8

Orticochea procedure

The Orticochea procedure (three-flap technique) was classically described for reconstruction of acquired defects of the occiput. Each flap in the design must include a vascular pedicle, and the technique can be used to cover up to 30% of the scalp.

9

Outcome from orticochea flap vs tissue expanders

The cosmetic outcome using Orticochea flaps is often inferior to what can be obtained using tissue expansion because of unnatural resultant hair orientation. For this reason, tissue expansion should be considered rather than Orticochea flaps, if possible

10

When to use free tissue expander for scalp reconstruction

Free tissue transfer is best utilized for reconstruction of total or near total scalp defects, particularly in the setting of irradiation or oncologic reconstruction.

11

Suitable free flaps for scalp reconstruction

The latissimus dorsi muscle free flap is one of the best choices in such cases because of its large area and long pedicle. With time, the muscle will atrophy and conform to the underlying bone well. Other appropriate options include the radial forearm, anterolateral thigh, or parascapular flaps.

12

Tissue expanders vs serial reductions and complex rotation flaps for scalp reconstruction

Serial excisions are useful for smaller defects. The amount of scar and deformity is much less when using tissue expanders versus serial reductions and complex rotation flaps.

13

A 47-year-old woman with a history of excision of a giant nevus of the scalp and skin grafting as a child desires removal of the skin graft and primary closure. Tissue expanders are placed, and weekly expansions are initiated. Which of the following is the most likely mechanism by which the surface area of this patient’s tissue is increased?
A) Apoptosis and cellular replacement
B) Cell division
C) Cell proliferation in the adjacent non expanded tissue
D) Expansion of intracellular cytoskeleton
E) Stretch-induced cell volume expansion

B) Cell division

Tissue expansion results in increased cell division through stretch-induced signal transduction pathways involving growth factors, the cytoskeleton, and protein kinases. The net result is an increase in protein synthesis, keratinocyte growth, and new skin production to restore resting tension.

Although cell morphology changes, it is not the mechanism by which new tissue is recruited. Cells in adjacent, nonexpanded areas are not affected. Expansion of the intracellular cytoskeleton alone does not result in increased tissue generation.

14

Tissue expansion results in what on a cellular level?

Tissue expansion results in increased cell division through stretch-induced signal transduction pathways involving growth factors, the cytoskeleton, and protein kinases.

The net result is an increase in protein synthesis, keratinocyte growth, and new skin production to restore resting tension.

15

A 20-year-old woman underwent subgaleal placement of two rectangular tissue expanders for an 8-cm area of burn alopecia at the vertex of the scalp. During the expansion, the skin over both expanders became red and mottled. The patient is afebrile and leukocyte count is within normal limits. Which of the following is the most appropriate next step?
(A)Collect aspirate from expanders for culture
(B)Continue the expansion procedure
(C)Deflate both expanders
(D)Initiate intravenous antibiotic therapy
(E)Remove both expanders

(B)Continue the expansion procedure

In a patient undergoing tissue expansion, redness and mottling of the skin over the implant is common. The next step in management is to do nothing and continue expansion.

16

What to do when a patient undergoing tissue expansion has redness/mottling over the implant

In a patient undergoing tissue expansion, redness and mottling of the skin over the implant is common. The next step in management is to do nothing and continue expansion, IF no fever, erythema, frank pus.

IF fever, erythema or frank pus, aspirate expander fluid, and/or IV abx, and/or remove expander

17

Which of the following has been shown in animal studies to occur following tissue expansion of random-patterned skin flaps?
(A) Decreased collagen content within the flap
(B) Decreased surface area of the flap
(C) Increased elasticity of the flap
(D) Increased likelihood of flap survival
(E) Thickening of the dermis

(D) Increased likelihood of flap survival

Several experimental animal studies have shown increased flap survival following tissue expansion. This increase is similar to that seen with the delay effect and has been shown to occur with both random-patterned and island flaps.

18

___________ likely hood of flap survival has been found following tissue expansion of ___________ flaps.

Several experimental animal studies have shown increased flap survival following tissue expansion. This increase is similar to that seen with the delay effect and has been shown to occur with both random-patterned and island flaps.

19

Tissue expansion effects on surface area, tensile strength, elasticity

Tissue expansion also results in an increase in the total surface area of the flap. However, tensile strength and elasticity are decreased

20

Histology of expanded skin after tissue expansion

Large bundles of compacted collagen fibrils have been demonstrated within the expanded dermis, and the total collagen content of the flap is increased.
Histopathologic examination has consistently demonstrated thinning of the dermis, but the stratum spinosum of the epidermis becomes thickened.

21

A 9-year-old girl is evaluated because of an 8-month history of alopecia of the scalp caused by a skin graft over the periosteum. A photograph is shown. Which of the following is the most appropriate method to correct this patient’s alopecia? Approx 50%

A) Coverage with a latissimus dorsi musculocutaneous free flap
B) Follicular hair transplantation
C) Full-thickness skin grafting from hair-bearing scalp
D) Serial excision of the skin graft
E) Tissue expansion

E) Tissue expansion

Tissue expansion effectively expands hair-bearing scalp that can then be rotated, advanced, and/or transposed over the area of alopecia to correct the deformity. A latissimus dorsi musculocutaneous free flap does not contain hair, and thus, would cause a similar area of alopecia. Follicular hair transplantation would not be efficacious for a large area of alopecia, and the split-thickness graft over periosteum would be insufficient tissue to accept the grafts. Serial excision of the skin graft is not possible because of the large defect and absence of normal scalp tissue on either side of the defect. A full-thickness graft from the hair-bearing scalp would cause a similar area of donor site alopecia.

22

Which of the following thickens when a tissue expander is placed and inflated?
A) Dermis
B) Epidermis
C) Fat
D) Muscle

B) Epidermis

Data have shown that there are predictable changes that occur to the layers of the skin and soft tissue in response to tissue expansion. Of all the layers listed, only the epidermis displays an increased thickness as a result of tissue expansion. Specifically, the epidermis becomes thicker through a process of hyperkeratosis. There is also narrowing of intercellular spaces and an increase in mitotic activity. The dermis actually thins up to 50% with fragmentation of the elastin fibers and flattening of dermal papillae. Sweat glands and hair follicles drift farther apart. Muscle decreases in both thickness and mass, although its function remains unchanged. Fat thins with some permanent loss of total fat mass. In cases of aggressive expansion, fat necrosis and fibrosis may also occur.

23

A 14-year-old boy with a history of extensive burns and skin grafting as a child comes to the office because of multiple tight and uncomfortable scars. Examination shows raised, thick, and moderately contracted scars on the scalp, back, abdomen, upper arms, and thighs. Tissue expansion followed by scar excision is planned. Which of the following areas is most likely to have the highest rate of tissue expander failure in this patient?
A ) Abdomen
B ) Back
C ) Scalp
D ) Thigh
E ) Upper arm

C ) Scalp

In a 10-year follow-up study of 256 pediatric burn patients, 36 patients (14%) required expander removal due to extrusion, infection, or expander rupture of loss of the port. An additional 26 patients (10%) had inadequate expansion or inability to fully carry out the operative plan. The most common site of failure was the scalp, (27/36 patients implant removal, 18/26 inadequate expansion). Other studies show far higher complication rates in the lower leg and urge caution in expander reconstruction below the knee.

Tissue expansion is a highly effective technique for scar contracture release. Patients with scalp and leg expansion may be counseled about a higher failure rate or only partial correction of the deformity. In areas of increased tissue laxity and pliability, such as the abdomen, back, thigh, and upper arm, complication rates appear lower.