Wound healing Flashcards
What are the 4 main stages in wound healing?
1) coagulation
2) inflammation
3) new tissue formation / proliferation
4) remodelling / maturation
What are the main cells seen during inflammation?
platelets
macrophages
neutrophils
What are 4 jobs of macrophages during inflammation?
1) remove wound debris and degrade matrix
2) cell recruitment and activation
3) angiogenesis
4) matrix synthesis regulation
Main cells types needed for tissue formation?
macrophages lymphocytes fibroblasts epithelial cells endothelial cells
What are the 8 stages of new tissue formation?
1) single keratinocyte layer migrates under the fibrin clot to re-surface the wound (angiogenesis, ECM production, dissolve non-viable tissue)
2) Differentiation and stratification of neo-dermis
3) Fibrin clot secrets factors to promote re-epithelialisation
4) Angiogenesis stimulated by keratinocytes and macrophages
5) Fibroblasts at wound edge promote angiogenesis and synthesis and deposit ECM
6) Fibroblasts become myofibroblasts and express contractile proteins
7) Myofibroblasts contract pulling wound together
8) Now have granulation tissue (takes 3-5 d)
What is proud flesh?
Normal exuberant granulation tissue in horses
How long can the remodelling phase last?
over a year
dont get any appendages grow on it (hair etc)
What are Esmarch’s principles of wound management?
- non-introduction of anything harmful
- tissue rest
- wound drainage
- avoidance of venous stasis
- cleanliness
What are 6 reasons for swelling at the incision site?
1) acute haemorrhage and haematoma
2) swelling and oedema
3) seroma
4) acute infection
5) abscess
6) diehescence of underlying body wall
How can haemorrhage be classified?
primary
delayed primary
secondary
What can haematoma do to a wound?
physical separation of wound edges prevention of adherence of flaps and grafts barrier to leucocyte migration growth medium for bacteria pain deformity
What can swelling and oedema do to a wound? How to treat it?
dehiscence
reduce vascularity
- massage, support dressing, remove constricting sutures
What is a seroma?
Collection of serum and tissue fluid in dead space
How can a seroma affect a wound?
tissue serparation
tension on sutures
intereferes with blood supply and WBC migration
What can cause a seroma?
inflammation lymphatic injury poor haemostasis traumatic surgery implants movement dead space
2 main categories of dehisccence?
excessive force on incision
poor wound holding strength
6 groups of things that can delay/complicate wound healing
1) swelling at incision site
2) dehiscence
3) wound infection
4) tissue necrosis / sequestration
5) scarring / contracture / adhestions
6) draining tracts
Problem with excess scarring and how to avoid it?
- may limit movement over joints and cause closure of orifices
- avoid by atraumatic surgery, control of infection, early wound closure
What is the problem with wound contracture? how can it be prevented?
loss of function of a body part due to excessive scarring
prevent by early wound closure
When do adhesions occur? and what are they caused by?
when equilibrium between normal fibrin depostion and fibrinolysis is disrupted
caused by ischaemia, haemorrhage, foreign body, infection
how can adhesions be prevented?
atraumatic handling
keeping tissues moist
asepsis
What is a sinus draining tract?
Blind ending tract that extends from an epithelial surface
What is a fistula?
communicating tract extending from one epithelial surface to another
What can draining tracts be due to?
necrotic tissue resistant bacteria / fungi underlying osteomyelitis or sequestrum foreign bodies neoplasia
