| |
 |
|
|
|
Grafting with AlloDerm in the OR
|
To Rehydrate AlloDerm for Grafting
When preparing to use AlloDerm for grafting in the operating room (OR), the following rehydration procedure should begin early enough to allow for adequate rehydration prior to intended grafting.
For best results when rehydrating AlloDerm, use liberal amounts of warmed saline solution in a two-step bath with light agitation.
Normal rehydration of AlloDerm is usually accomplished in 20-40 minutes, depending on thickness.
Equipment required:
- 2 sterile dishes (e.g., kidney dishes)
- Sterile normal saline or steril lactated Ringer's solution that is sufficient to completely submerge the graft
- Sterile atraumatic forceps
Rehydration Step 1:- Tear open outer foil bag at the notch and remove inner peel-pouch (Keep both the foil bag and peel-pouch OUT of the sterile field).
- With AlloDerm tissue aseptically removed from its peel-pouch packaging (backing left on), place in first bath of saline solution.
- For tissue less than 21cm², use at least 50ml of rehydration fluid per sheet. For tissue greater than 21cm², use 100ml per sheet.
Tip: Warming saline to approximately 37ºC and using gentle movement of AlloDerm in the solution speeds the rehydration process. However, do not heat saline above 37ºC.
Tip: When rehydrating multiple pieces, ensure the pieces are not touching or clumping together as this may slow down the process. Use multiple bowls if necessary. - Submerge the tissue completely and soak for a minimum of 5 minutes or until the backing separates from the AlloDerm.
Tip: Keep AlloDerm fully submerged by weighing it down, e.g. with sterile forceps.
Rehydration Step 2:- Using sterile gloves or forceps, remove and discard the backing once it separates from the tissue. Then, aseptically transfer the tissue to a second bath filled with at least 50ml of rehydration fluid per graft.
- Submerge completely and soak until the tissue is fully rehydrated (thicker grafts may take up to 40 minutes).
Tip: Keep AlloDerm fully submerged by weighing it down, e.g. with sterile forceps.
When AlloDerm is fully rehydrated, it is soft and pliable throughout. At this stage, it is ready for application to the surgical site. AlloDerm may be aseptically trimmed to required dimensions. - Important: Use AlloDerm within 4 hours of rehydration.
Considerations:- If you are having a problem with rehydration, (with a sterile gloved hand), gently wipe/rub both sides of AlloDerm to remove any excess cryo-protectant that may be creating a barrier between the AlloDerm and the saline.
- If not completely rehydrated, AlloDerm will appear to be of uneven thickness and have a mottled appearance.
- Animal studies have shown that implanting dry AlloDerm induces a mild inflammatory response.
- Antibiotics may be added to the second rehydration solution.
To Determine Orientation of AlloDerm for a Graft Procedure- AlloDerm has two distinct sides. The basement
membrane is the upper side and the dermal surface is the lower side. - In a grafting procedure, the dermal side must be placed against the wound bed.
How to distinguish sides
- Physical appearance.
- Basement membrane side: Rough and dull.
- Dermal side: Smooth and shiny.
- Distinguishing Sides Using the Blood test
- Add a drop of blood to both sides and rinse with rehydration solution. Since blood readily infiltrates the vascular channels within the matrix, the dermal side will look bright red. The basement membrane side will look pink.
- Marking
- Premeshed grafts contain a row of the letter “L” in the mesh pattern. When oriented correctly (basement membrane side up) the “L” row should appear as it does in the diagram below.
To Prepare AlloDerm for a Graft- After AlloDerm has been rehydrated, it is ready for wound grafting.
- If needed, AlloDerm can be aseptically meshed using a standard skin mesher. (Some varieties of AlloDerm are packaged pre-meshed.)
- In all cases, be sure that AlloDerm is correctly oriented before
application. - Important: Use AlloDerm within 4 hours of rehydration.
To Prepare Site for AlloDerm Graft- Excise the wound as completely as possible to provide a
clean, viable, vascularized wound bed with no active bleeding. - If hemostasis is incomplete (even minor or trace bleeding), AlloDerm should be meshed or perforated—but not expanded—before application to the wound bed. The overlying autograft should be meshed as well.
To Apply AlloDerm Graft- Using aseptic technique, transfer AlloDerm (basement membrane side up) to excised wound bed.
- If AlloDerm overlaps wound margins, trim to fit wound bed. Do not
overlap adjacent pieces of AlloDerm. - Secure AlloDerm with sutures, staples or tissue sealant.
- Cover AlloDerm with thin autograft.
- Follow dressing instructions below.
Special Considerations- Thick layer: A thick continuous layer of autograft can retard diffusion of wound-bed nutrients through the autograft and inhibit migration of keratinocytes into AlloDerm. A thin, meshed autograft contributes to optimal engraftment rates for both grafts.
- Dessication/Overhydration: To achieve maximum engraftment, the wound dressing should maintain hydration of AlloDerm. Dessication will inhibit fibroblast repopulation and neovascularization, and may lead to graft breakdown. Overhydration can result in maceration and dissolution of the graft.
- Mechanical Trauma: Mechanical disruption during early dressing changes may cause separation of the graft from the wound bed. Unless infection or necrosis causes removal, AlloDerm should not be disturbed until is has vascularized completely—usually a minimum of 7 days.
Dressing Instructions
The following multi-layered dressing is recommended to protect the graft site from shearing forces, to prevent surface desiccation/maceration and to provide a microbial barrier.
- Inner layer: Fine mesh gauze impregnated with bacitracin or other petrolatum-based antimicrobial ointment.
- Middle layer: Damp saline gauze wrap (antibiotic may be added to saline, if desired).
- Outer layer: Dry gauze wrap followed by Ace® bandage or other wrap/splint.
Other Important Considerations- The dressings should not be saturated, as this may cause maceration of the AlloDerm, resulting in poor autograft engraftment.
- Do not change inner dressing layer for at least 7 days.
- Outer dressing layers may need frequent changing during first few days. When changing, be extremely careful not disturb inner dressing layer or the graft.
- On or about day 7, the inner dressing layer may be removed. Saline soaks and generous application of petrolatum-based ointment may prevent stress to graft area at this time.
- Some areas of the graft may appear white/yellow. This is normal at this point.
- Until revascularization and reepithelization are complete, grafts should be re-dressed with antibiotic-impregnated fine mesh gauze or other nonadherent dressing. (Damp saline dressing layer may be eliminated at this time.)
- On day 7, the autograft may seem whiter than surrounding epidermis and may only weakly adhere to site. This is also normal at this point.
- Occasionally, all or part of the autograft may come off with the dressing. This does not necessarily mean regrafting is needed, since enough epidermal cells may have migrated to the basement membrane to make regrafting unnecessary.
- With a meshed graft, epithelial cells growing under the thin dermal layer of the autograft may cause detachment. However, the autograft may have already seeded the surface of the AlloDerm with enough keratinocytes to provide partial covering. Carefully examine the surface to determine if regrafting is needed.
- As the epidermis establishes over the entire AlloDerm surface, and keratinocytes differentiate to form a cornified layer, protective dressings may be eliminated. Once a cornified layer is established (10-14 days), bathing with mild soaps and limited activity may commence.
|
|
|
|
