Wound Management/Granulation tissue Flashcards
What should you do if a horse has sustained a penetrating wound at its vaccination status is unknown?
Booster with tetanus toxoid
What should you do if a horse sustains a penetrating wound and is unvaccinated?
Give tetanus toxoid AND tetanus antitoxin
T/F: the golden period is the time in which there is less than 10^5 in a wound of a horse
False
There is NO golden period in equine wound management
What is primary closure? What type of wounds can this be used on?
Immediate closure
Clean and clean-contaminated wounds
What is delayed primary closure? What type of wounds would you do this in?
2-5days after injury (before granulation tissue production)
Contaminated wounds / questionable viability
Edema/tension
What is secondary closure and in what type of wounds is it used?
Closure after more than 5days (granulation tissue has formed)
Contaminated/infected wound
What is second intention healing?
Wound edges are not apposed. Granulation tissue, wound contracture, and epithelialization
What are the three phases of wound healing?
Inflammation/ lag (hemostasis and acute inflammation)
Proliferative (tissue formation)
Remodeling (regaining of strength)
What occurs in the inflammation/lag phase of healing?
Hemostasis
—> platelet aggregation
—> vasoconstriction followed by vasodilation
—> fibrin formation
Inflammation
—> activated platelets release wound repair mediators
—> PDGF, TGF-B
—> PMNs, macrophages and fibroblasts (remove damaged tissue, release chemoattractatns, PMNs decrease after 2days, macrophages persist for days to weeks)
What occurs during the proliferative phase of healing?
Macrophages release tissue growth factors and initiates proliferation
Angiogenesis Fribroplasia and granulation tissue Collagen deposition Epithelialization Wound contraction
What initiates angiogenesis in wound healing?
Decreased O2 tension
High lactate
Low pH in wound
What is the purpose of fibroblasts in wound healing?
Release collagen, GAGs, HA, and glycoproteins
Release proteases to digest fibrin clot
Help arrange collagen molecules into fibers then bundles aligned parallel to wound surface
What type of collagen is present initially in a wound and what type is present as the wound remodels?
Collagen type III — initial wound healing with dense blood vessel population
Collagen type I — remodeling
When does epithelialization begin?
Immediately after wounding
Rapid in superficial injuries
New epidermis lacks __________ resulting in less strength and elasticity
Dermis
Contraction of wounds begins how long after injury?
2weeks
Fibroblasts differentiate into __________ allowing for wound contraction
Myofibroblasts
Remodeling phase begins when and can last how long?
2weeks post injury and can last 1-2years
What are the steps for optimal wound care?
Adequate restraint
Analgesia
DEBRIDEMENT
Lavage
Closure
Bandage
What A2 agonists can be used for restraint/analgesia and what is their duration of action?
Xylazine IV: 15-20mins
Detomidine IV: 30-45mins (can last longer if combined with butorphanol)
What steps do you do prior to debridement to prep a wound?
Wear gloves!
Clip
Can put a water soluble gel in would to prevent hair from going into the wound
Evaluate
What is the most important factor in success of wound healing
Debridement
—> remove necrotic tissue, decease bacterial load and remove microscopic foreign
Sharp
Irrigation (hydraulic)
Direct contact
What solutions can be used for wound lavage?
Non toxic solutions — LRS, Normosol, or saline
DO NOT used antiseptics —> cytotoxic
Preventing bacterial infection of wounds can be done with what methods?
Effective wound cleaning/debridement
Appropriate use of dressings and procedures for bandage changes
Appropriate use of topical antimicrobials
T/F: scarlet oil is a good topical product to increase healing of distal limb wounds
false
Scarlet oil is used to stimulate granulation tissue
Distal limbs a prone to over granulation
Scarlet oil is appropriate for large areas that need to be filled in. Eg over the shoulder or over the abdomen
What is the use of white lotion in wounds?
No use! Has lead in it, very bad
What is Panalog?
Steroidal antibiotic/antifungals
Steroids reduce the rate of healing (epithelialization)
Why should nitrofurazone never be used in wound managment?
Carcinogenic — can cause ovarian cancer
What are the only appropriate topical agents for wound healing?
Silver sulfadiazine
Polysporin (
Wha type of wound dressing would you use on an exudative or necrotic wound?
Hypertonic saline dressing
— draws fluid out of wound
Change Q24-48hrs
What is the best antimicrobial dressing?
Kerlix AMB
Active agent is polyhexamethylene biguanide
Should be changed q3-7days or sooner if soiled, wet, or slips
T/F: corticosteroids can be used on wounds to reduce formation of granulation tissue
False
Never use
T/F: all open joints are septic joints
True
How can you determine is a found is penetrating into a synovial structure ?
Distend joint with sterile isotonic solution —> open if there is drainage from wound
How would you treat a wound at the level of the fetlock with significant granulation tissue formation?
Debridement, cut out excessive amounts of granulation tissue
Bandage and cast (pressure /contact inhibiton prevents excessive granulation tissue formation)
What synovial structures would you be concerned about is there is a laceration at the level of the pastern?
Deep digital flexor tendon sheath
Pastern joint
What synovial structure would you be concerned about with heel bulb lacerations?
Coffin joint
What synovial structures wound you be concerned about if you had a puncture wound to the sole/frog?
Navicular bursa
What type of closure would you choose for a heel bulb laceration with excessive granulation tissue?
Chronic wound — debride out granulation tissue
Second intention healing — not enough tissue to close in this area
What type of wound closure would you do for a wound at the level of the metacarpal? This would is acute and very edematous.
Delayed primary
— allows wound to declare itself and for edema to decrease
How would you manage a degloving inury that has exposed bone?
Debride exposed bone back to refresh the capillaries
Second intention wound heleaind
Must truly immobilize the limb with cast/splint
When are casts/splints indicated in wound management?
Extensive soft tissue loss
Loss/disruption of supportive soft tissue structures (look for changes in the angle of the limbs)
What specific concerns to do you have for a wound in the axillary region?
Highly mobile area
Can become a sucking wound
—> in extension the wound is open allowing air to enter
—> in flexion the wound is closed and traps air
Can lead to crepitus, SQ emphysema, and pneumomediastinum
Why must full thickness eyelid lacerations be repaired surgically?
To maintain functionality, comsemtics, and protection of the globe (abrasion, ulceration, and exposure keratitis)
How can you repair an eyelid laceration if there is less than 1/3rd of the eyelid margin missing ?
Direct apposition
2-layer primary repair
Suture should never be exposed to the cornea —> ulceration
How can you repair an eyelid laceration if there is greater than 1/3rd of the eyelid margin missing?
MUST use a grafting technique to achieve functional closure
T/F: all full thickness lip lacerations must be repaired surgically
True
Debridement and a 2 layer closure
A lot of option in the lips
Do wounds on the body or the limbs ave faster healing ?
Body : more efficient contraction (1mm/day)
Limb wounds: slow (0.2mm/day)
What is another name for excessive formation of granulation tissue? Why are distal limb wounds more prone to development of this?
Proud flesh
Higher motion and lower vascularity
Inefficient a protracted inflammatory phase —> excessive proliferative phase
Fibroblasts maintain synthetic role
Chronic inflammation and pro-inflammatory mediators released by PMNs —> profibrotic state and exuberant granulation tissue
What wound closure methods are best for preserving function and cosmetic appearance of distal limb wounds
Primary or delayed primary closure
However, second intention healing is often the only option
How would you treat proud flesh?
Resection (back to level of skin) and bandage
—> very vascular, work distal to proximal,
—> no nerve endings
Delayed secondary closure
Skin grafts
T/F: excessive granulation tissue can be inhibited by bandage
True
—contact inhibition
Excessive granulation tissue is most likely to occur in which location?
A. Metacarpaus
B. Pectoral region
C. Thorax
D. Head and neck
A. Metacarpus
What are indications for skin grafts?
Large wounds that wont heal otherwise
Any open wound that cant be sutured
What are the two classifications of skin grafts?
Pedicle graft — remains attached to donor site
Free graft— completely separated from blood supply
What type of skin graft provides the best cosmesis and hair growth?
Full thickness — epidermis and dermis
T/F: the amount of dermis in a graft is indirectly proportional to the ability to survive
True
— amount of dermis directly proportional to grafts durability and cosmesis and inversely proportional to the ability to survive
What is required for graft acceptance?
Adherence — adhered by fibrin
Serum imbibition — nourished by plasma like fluid via capillary action
Revascularization
—> 48hrs : inosculation, neovascularization
—> 4-5days: revascularization
Organization —epidermis thickens in the first 2 weeks
What are the types of island grafts?
Punch
Pinch (seed)
Tunnel
What are the advantages to punch and pinch grafts ?
General anesthesia is not required
Minimal equipment
Minimal expertise needed
Compete failure is rare
What are the disadvantages of punch and pinch grafts?
Poor consensus
Little hair regrowth
Where can you harvest punch grafts?
Under the mane or ventrolateral abdomen (excise SQ fascia and fat)
T/F: recipient holes for a punch graft should be made with smaller punch than the graft
True
How do you harvest a pinch graft?
Tent skin with burred needle (best) or forceps
Transection 3mm disc with blade
Store in saline moisten gauze
What are the three main reasons for graft failure?
Hemorrhage (fluid accumulation ) —> hematoma/seroma prevents fibrin from attaching graft to the wound
Motion
- Infection *
—> 10^5 bacteria/g tissue, some can infect with lower amounts
B-hemoltytic strep and pseudomonas
What are the requirements for a recipient site to have good graft acceptance?
Clean, healthy granulation tissue
Granulation tissue flush with skin
Topical antibiotic 24-48hrs prior to grafting (Ticarcillin)
What instruments are used to make split thickness sheet grafts?
Watson knife
Drum dermatome (Padgett )
Power dermatome (brown pneumatic or Stryker electric)
Why would you use a mesh sheet graft
Allow graft to cover wound larger than itself
Prevent fluid from disrupting graft from fibrinous and vascular attachments
Conforms irregular surfaces
Allows drainage —> prevents fluid accumulation between graft and granulation tissue
What do you do for aftercare for grafts?
Cover with sterile non-adherent dressing (telfa, release, adaptic)
Secure with elastic rolled gauze
Routine bandaging
Change bandage ever 4-5days (or daily, Dr. Little preference)
Heavily sedate horse for bandage changes
What is the most common reason for skin graft failure in horses
Infection
