Excessive Granulation Tissue and Skin Grafting Flashcards
Are wounds on the body or on the limbs more efficient at contraction?
On the body (1mm/d vs. 0.2mm/d)
Where does proud flesh most commonly occur?
Distal limb wounds
Why is healing potential of distal limb wounds limited?
No muscle/excessive tissue, close to contamination, constant movement
What is often the only option for distal limb wound closure?
2nd intention healing
Excessive granulation tissue
Proud flesh
How do you treat proud flesh?
Resection and bandage, delayed 2* closure, skin grafts
Why does proud flesh occur?
Inefficient and protracted inflammatory phase of healing = excessive proliferative phase
Maintain their synthetic role rather than differentiating into myofibroblasts (which allow for contracture)
Fibroblasts
s stay higher longer and release pro-inflamm. mediators = exuberant granulation tissue
PMNs
How does excessive granulation tissue affect healing?
Delays it
Why is only sedation and not a local block required to resect proud flesh?
Proud flesh doesn’t have nerves
How much will proud flesh bleed during resection?
A LOT
In which location is proud flesh most likely to occur?
MC/MT
Simple to perform and often performed in a standing sedated horse
Skin grafts
How can you ensure the wound bed is healthy enough to receive a skin graft?
Topical abx (Ticarcillin) for a few days
What are indications for skin grafts?
Wounds too large to heal otherwise, open wounds that can’t be sutured
Type of graft in which the graft remains connected to the donor site
Pedicle graft
Type of graft that is completely separated from the donor site blood supply
Free graft
Best cosmesis and hair growth but more difficult to survive
Full thickness skin graft
Better success but less cosmetic outcome
Split thickness skin graft
Epidermis and entire dermis
Full thickness skin graft
What is the amount of dermis required for a split thickness graft proportional to?
Durability and cosemesis
Where are allograft donor sites most often in horses?
Underneath the mane or ventrum of abdomen
How does a graft adhere to a recipient site?
Fibrin
Nourisment by plasma-like fluid via capillary action
Serum imbibition
How quickly does neovascularization occur at a graft site?
48hr
How soon does revascularization occur at a graft site?
4-5d
Why does the epidermis of the graft thicken in the first weeks?
Organization of collagen to match recipient site
What are the different types of island grafts?
Punch, pinch, and tunnel
Which types of island grafts are more often done because they are the least amount of work and most responsive?
Punch and pinch
What are different types of sheet grafts?
Solid or meshed
GA not required, minimal equipment, minimal technical expertise, complete failure is rare
Punch and pinch grafts
Recipient holes of a punch graft are _____ than the harvested skin of the donor site
Smaller
Poor cosmesis and little hair regrowth
Punch and pinch grafts
How are recipient holes organized?
6mm apart in symmetrical pattern stating distally
What is the % chance that a punch graft survives?
60-75%
Tent skin and transect 3mm disc w/#11 blade
Pinch graft
Where are pinch graft pieces stored prior to placing on the donor site?
Saline moistened gauze
What are the 3 main reasons for graft failure?
Hemorrhage, motion, and infection
What is the most common cause for graft failure in hoses?
Infection
How does hemorrhage cause graft failure?
Hematoma prevents fibrin from attaching graft to wound
What bacteria can infect a wound with lower concentration than 10^5 bacteria/g tissue?
B-hemolytic strep and Pseudomonas
What is the most important thing for suvival of a free graft?
Prep of recipient site
Resist trauma better than split thickness graft and has the best cosmetic appearance
Full thickness sheet graft
Allows graft to cover wound larger than itself
Meshing sheet graft
Prevents fluid from disrupting graft from fibrinous and vascular attachment
Meshing sheet graft
Conforms to irregular surfaces
Meshing sheet graft
How do you secure a sheet graft to a wound?
Tack at the wound margin
How long should you wait to change the bandage over a graft?
4-5d OR change daily
