Grafts Flashcards
What are the two most common sites to take cartilage from for repair of the nasal ala/grafting?
the antihelix, and the conchal bowl (larger lesions) (anterior or posterior approach)
What are the 4 stages of graft uptake?
Imbitiion (passive transfer of nutrients), Inosculation (anastomoses form between the wound bed and graft vessels), Neovascularization (new vascular proliferations occur), Maturation (full circulation is restored and epidermal proliferation occurs, innervations starts too)
What should be done if a graft is dropped on the ground?
Inform the patient
Wash the graft in povidone-iodine or chlorhexidine and proceed with the procedure after the patient has been informed
What are the 4 main types of grafts used in dermatology surgery?
Full-thickness skin graft, split-thickness skin graft, composite grafts, and free cartiledge
Which types of grafts make the best tissue matches?
Full-thickness skin graft and composite skin grafts
What grafts have the highest nutritional needs?
Composite (highest), full-thickness skin grafts, and free cartiledge grafts (also high)
What graft has the lowest nutritional needs?
Split thickness graft
What graft can be placed over cartilage, bone, etc?
Split thickness (lowest metabolic need)
What are the differences in function between the 4 different types of skin grafts?
Full-thickness and composite grafts have the best function (full-thickness maintains adnexal function). Split thickness grafts lose adnexa, thus function is inferior
How long does the imbition stage last and what is it?
24-48 hrs
Fibrin attaches graft to bed, graft sustained by passive diffusion of nutrients from the wound bed’s exudate
graft becomes edematous as a result during this period
What is the timeline of the inosculation phase and what occurs during this phase?
48-72 hrs after surgery, lasts 7-10 days
Revascularization from linkage of dermal vessels between graft and recipient wound bed
When does the neovascularization phase occur? What occurs during this phase?
Occurs alongside inosculation (7 days)
Capillary and lymphatic ingrowth occurs, edema begins to resolve
When does reinnervation/maturation occur and what occurs during this stage?
Final stage, starts at 2 months
Slow maturation of the vessels and re-innervation
What are the advantages of a full-thickness skin graft?
Match with receipient skin q
By how much should a full-thickness skin graft be oversized by to account for graft shrinkage after harvesting?
10-20%
What are the most common donor sites for a full-thickness skin graft of the nasal dorsum/sidewalls/tip?
Preauricular region, supraclavicular region, or lateral neck (if large)
What is the preferred donor site for a full-thickness skin graft for the nasal tip?
Preauricualr region, conchal bowl, nasolabial fold
What is the preferred donor site for a full-thickness skin graft for the junction of the nasal dorsum/tip?
Burrow’s graft
What is the preferred donor site for a full-thickness skin graft for the ear?
Postauricular sulcus, preauricular
What is the preferred donor site for a full-thickness skin graft for the lower eyelid/medial canthus?
Upper eyelid, postauricular sulcus
What is the preferred donor site for a full-thickness skin graft for the scalp?
Supraclavicular region, lateral neck, inner upper arm
What is the preferred donor site for a full-thickness skin graft for the forehead?
Burrow’s graft, supraclavicular region, lateral neck, inner upper arm (if large)
What is the purpose of a bolster dressing?
Graft immobilization leading to increased graft adherence to wound bed
What is a bolster dressing?
A dressing that is sewn on to the graft
What is delayed grafting and when is it used?
Used for deep defects that can’t be filled by a full-thickness skin graft by itself. Key: >25% periosteum or perichondrium lacking over a large defect
Allow wound to granulate 1-3 weeks –> then graft
What is a Burrow’s graft?
The graft is taken from skin adjacent to the defect (removed Burrow’s triangle)
What can be done post-op after a full-thickness skin graft to improve cosmesis? What is the timeline for this procedure?
Dermabrasion can be done 4-6 weeks postop
What is the appearance of necrotic graft and what should be done about it?
It looks black (not purple like in the congestion phase, this is normal!)
KEY POINT: Do not remove graft if necrotic!! This serves as a biologic bandaid, also you can’t tell how much of the graft really died under the surface
What are the advantages of a split-thickness graft?
Can cover a larger defect size (>5cm), increased chance of survival (less metabolic need), easier detection of tumor recurrence
What are some disadvantages of a split-thickness skin graft?
Decreased cosmesis, increased contraction (don’t use near free margins), lacks adnexal structures, less anchoring to BMZ which means bullae can form in the graft size, need specialized tools, and pain at donor site
How are split-thickness grafts classified?
By thickness, thin (0.005-0.012 inches), medium (0.012-0.018)[head and neck], thick (0.018-0.030) inches [trunk/extremities]
What is a Weck blade?
Specialized free-hand knife w/ templates for various graft thicknesses (for split-thickness grafts)
What is a Zimmer?
An electric dermatome that can be used for harvesting large split-thickness skin grafts
What is a Mesher?
Flat bed w/ a roller that compresses split-thickness skin graft on plastic template w/ a grid-like etched pattern w/ fine fenestrations
What are the advantages of meshing a split-thickness skin graft?
Enlarges size by 25-35%, increases flexibility, allows serosanguineous drainage improving adherence and survivability
What is a major disadvantage of meshing a split-thickness skin graft?
Fenestrations are often permanent which worsens cosmesis
What is a composite graft?
Full-thickness skin graft with one other type of tissue (cartilage most commonly, but also fat)
What is a common site where a composite graft w/ cartilage is used/needed?
The nasal ala (prevents anatomic distortion or alar collapse)
How should a composite graft be sized?
10-15% bigger so that edges can be “tucked”into the subdermal spaces of the defect
What is a xenograft and what is its function?
Split-thickness skin graft taken from pig most commonly –> used as a biologic dressing to promote granulation tissue
How long should a xenograft stay in place?
7-14 days
What are some advantages to a xenograft?
Decreased wound care demands for patients, protect/preserve bone, cartilage, tendons, and nerves, decreased postoperative pain at granulating site
What are some disadvantages of a xenograft?
Must be replaced in 1-2 weeks after putting on, contraindicated in pts w/ a pork allergy, malodorous after 10-14 days
When is the earliest time point where dermabrasion can be safely performed on a graft?
6-8 weeks
