Skin reconstruction techniques: Full-thickness mesh grafts - Veterinary Medicine
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Skin reconstruction techniques: Full-thickness mesh grafts
Areas that are particularly difficult to close, such as uneven surfaces and locations with lots of movement, benefit from mesh grafts that include the entire epidermis and dermis.


VETERINARY MEDICINE



Figure 4. The graft is expanded and attached to the granulation bed with simple interrupted monofilament sutures.
After the graft has been incised, gradually elevate it and roll it over your finger or a gauze role, or simply hold it in tension as you dissect all subcutaneous tissue away from the dermis.1 Alternatively, you can harvest the graft and then stretch it and secure it, epidermal side down, to a piece of sterile cardboard with stay sutures or hypodermic needles. Use sharp-sharp scissors or a scalpel blade to remove all subcutaneous tissue (Figure 3). Aggressive d衲idement can result in poor hair growth because of damage to the follicles. A properly prepared graft will have a white glistening surface with a cobblestone appearance as the hair follicles become visible through the dermis.1,6 Once the subcutaneous tissue has been removed, mesh the graft with a No. 11 scalpel blade. The size and number of slits depend on how much drainage and expansion are desired. The slits are often 1 cm long, placed 0.5 to 1 cm apart, and arranged along the length of the graft paralleling the direction of hair growth. Larger slits provide greater expansion but will result in a less cosmetic appearance than will smaller openings.


Figure 5. Tacking sutures (arrows) are placed around graft tissue and through fenestrations to increase graft-to-bed contact.
The graft is usually attached to the donor site with sutures or staples (Figure 4). For all grafts, orient the direction of the hair growth with respect to the recipient site.3,6 To ensure that mesh slits remain open for drainage, secure the graft to one side of the wound with sutures or staples. If the mesh slits are open when the opposite graft and wound edge are apposed, place the remaining sutures or staples. If the mesh slits are not open, stretch the graft until the slits reach the desired width and excise the excess skin before completing the closure.6 Tacking sutures must be placed between some slits to further stabilize the graft (Figure 5). Tacking sutures are especially critical to obtain graft-wound contact on concave and convex areas of the wound.6


Figure 6. Maceration from excessive application of antibiotic cream (silver sulfadiazine). The skin proximal to the recipient site (arrows) has also been affected.
After a mesh graft is performed, bandages are essential to absorb drainage, immobilize the graft, and protect it from trauma. The contact layer should be a nonadherent dressing that is lightly coated with antibiotic ointment; too much ointment will make the pad occlusive to the draining fluid (Figure 6), resulting in maceration of graft tissue. A thick layer of absorbent secondary material should cover the contact layer to draw fluid away from the graft.6,8 The final layer of elastic or adhesive material is used to conform the primary and secondary layers of the bandage to the grafted area and prevent the bandage from slipping.6 Avoid excessive pressure because it can decrease the absorptive capacity of the bandage as well as decrease blood flow to the wound or distal regions.3 If the graft is near a joint, incorporate a splint or half cast in the bandage to immobilize the area.

Healing process


Figure 7. Three days after graft placement. Granulation tissue fills the mesh holes. The central portion of the graft appears necrotic.
The frequency of bandage changes depends on the amount of fluid produced. If the bandage becomes too wet, the skin may macerate, and bacteria may wick through the bandage to the wound.3 However, frequent rebandaging increases the risk of graft disruption. A weak fibrin seal forms within the first few hours after grafting but is gradually replaced by collagen.6 Daily or every-other-day rebandaging is usually required for the first five to seven days after surgery in dogs. Rebandaging should be done carefully, especially before the collagen fixation has had a chance to form, to prevent damage to the graft.3 After the first week, fluid production should decrease to a point where bandage changes are needed every three to five days. Splinting can be discontinued at 10 days if the graft has healed well, but bandaging is usually continued for three weeks after surgery. In cats, grafts heal quickly and drainage is less than that in dogs, so bandages may be changed less frequently and used for a shorter duration. The sutures are usually removed 10 to 14 days after grafting.


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Source: VETERINARY MEDICINE,
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