Surgical Technology Flashcards
Outline the layers of the skin
- Epidermis
- Dermis
- Hypodermis/Subcutaneous
Epithelium of the epidermis
Keratinised squamous epithelium
Where do the skin’s natural tension lines lie
Right angles to the angle of contraction of the underlying muscle
What constitutes a superficial wound
Involve only epidermis and dermis
What constitutes a deep wound
Involve layers deep to the dermis
Describe primary intention wound healing
- Occurs in uncontaminated wounds with minimal tissue loss
- Wound edges easily approximated
- Wound heals by rapid epithelialisation and formation of minimal granulation tissue
Describe secondary intention wound healing
- Occurs in wounds with substantial tissue loss
- Wound is left open and allowed to heal from deep aspects by granulation, epithelialisation and contraction
Describe tertiary intention wound healing
- Wound is closed several days after its formation
- e.g. Delayed primary closure
List the 3 phases of wound healing
- Acute inflammatory phase
- Proliferative phase
- Maturation phase
Outline the inflammatory phase of wound healing
- Initial trauma
- Vasodilatation and increased vascular permeability
- Influx of inflammatory cells (neutrophils) and fibroblasts
- Platelet activation and initiation of the coagulation and complement cascades
When do neutrophils arrive at the wound
0-1 days
When do macrophages arrive at the wound
1-2 days
When do fibroblasts arrive at the wound
2-4 days
When do myofibroblasts arrive at the wound
2-4 days
When do endothelial cells arrive at the wound
3-5 days
Outline the proliferative phase of wound healing
Characterised by migration and proliferation of:
- Epithelial cells
- Fibroblasts
- Endothelial cells
When is epithelial closure usually achieved
48 hours
What is the role of fibroblasts in the proliferative phase of wound healing
Synthesise extracellular matrix components including collagen and ground substance
What is granulation tissue
Temporary structure that forms during the proliferative stage. Contain capillaries, fibroblasts, macrophages and endothelial cells. Has a characteristic pink, granular appearance.
How long does skin take to regain full strength
6 months
How long does bowel and muscle take to regain full strength
1 month
How long does full maturation of the scar take
12-18 months
What vitamin aids the cross-linking of the fibrils in matrix remodelling
Vitamin C
Describe Neuropraxia
- Temporary and reversible loss of function lasting 6-8 weeks (motor function first to be lost)
- No axonal disruption
- Crush, stretch, or contusion of the nerve
Describe Axontmesis
- Axonal disruption
- Supportive tissue framework is preserved
- Wallerian degeneration occurs
- Regeneration takes weeks to months
What is Wallerian degeneration
- Occurs when a nerve is cut or crushed
- Part of the axon that is separated from the neuron’s cell nucleus degenerates
- Begins 24 hours following injury during which time the distal axon remains excitable
What supportive tissues are preserved in Axontmesis
- Epineurium
- Perineurium
Describe Neurotmesis
- Both the supportive tissue and the axon are disrupted
- Neuroma forms at the proximal stump
How long does mucosal integrity take to return after uncomplicated GI tract surgery
24 hours
How is liver regeneration achieved
- Stimulated by reduction in liver mass:body ratio and release of TNF and IL-6
- Achieved by proliferation of all cell types (hepatocytes, biliary epithelial cells, Kupffer cells)
What clinical sign precludes wound dehiscence
Pink serosanguinous fluid from the wound
At what rate does nerve regrowth occur when it happens
1mm/day
List the drugs that impair wound healing
- NSAIDs
- Steroids
- Immunosuppressive agents
- Anti-neoplastic drugs
Outline the two types of abdominal wound dehiscence
- Superficial = skin alone fails
2. Complete = all layers fail
List the common factors that increase the risk of wound dehiscence
- Malnutrition
- Vitamin deficiencies
- Jaundice
- Steroid use
- Major wound contamination
- Poor surgical technique that does not follow Jenkins rule
How should sudden dehiscence be managed
- Analgesia
- IV fluids
- IV broad-spectrum antibiotics
- Cover wound with saline impregnated gauze
- Arrange return to theatre
How can scar contractures be treated
Z-plasty
Define a Hypertrophic scar
Excessive remaining scar tissue confined to the site of the original wound due to fibroblast overactivity
Define a Keloid scar
Excessive scar tissue that extends beyond the original wound
List the risk factors for Keloid scar formation
- Young age
- Male sex
- Dark pigmented skin
- Genetic
- Site (shoulders, sternum, head, neck)
- Tension on wound
- Delayed healing
Does hair removal prior to surgery reduce surgical site infection
No evidence to suggest this
What is the ideal theatre temperature
20-22 degrees
What are the stages of the WHO surgical checklist
- Before induction of anaesthesia
- Before skin incision
- Before patient leaves operating room
What suture should be used for abdominal mass closure
1 PDS