Ch 75 Primary wound closure Flashcards
(38 cards)
What are the 3 division of the vascular supply to the skin?
- Superficial/Subpapillary plexus
- Middle/Cutaneous plexus
- Deep/subdermal/subcutaneous plexus
cutaneous angiosome
A given region of skin supplied by a regional artery and vein
What are the main differences regarind the cutaneous angiosomes in dogs and cats?
- Dogs have a greater density of collateral SQ vessels
- Cats have a smaller number and wider distribution of curaneous perforating vessels
These differences apply mainly to the trunk
Cutaneous circulation
The subdermal plexus is formed and supplied by terminal branches of direct cutaneous vessels at the level of the cutaneous trunci muscle in dogs and cats.
- parallel relationship of the direct cutaneous vessels to the overlying skin compared with the perpendicular orientation of musculocutaneous vessels in humans.
Define the following terms in relation to wound closure:
Primary wound closure (First intention healing)
Delayed primary wound closure
Secondary Closure (Third intention healing)
Second intention healing
- Primary wound closure = Sutured wounds
- Delayed primary wound closure = suturing 2-5 days after wound initial, before granulation tissue development
- Secondary Closure = Closure of the would after granulation tissue has formed in the wound bed
- Second intention healing = Heals without suturing - usually va contraction and epithelialisation
What is the rate of epithelialisation in primary wound healing?
1mm/day.
A perfectly apposed wound can therefore be epitheliased within 24-48hr
What is the reported %strength of wounded skin in comparison to normal skin at the following time points:
14 days
3-4 weeks
Several months
14 days - 5-10% strength
3-4 weeks - 25%
Several months/1 year - 70 - 80% strength
“False healing”
- more frequently in cats than dogs
- wound appears to be healed from superficial observation, but dehiscence occurs after suture removal as soon as the stress of normal motion occurs
differences between dogs and cats
CATS
- lower cutaneous perfusion for the first week after surgery (then more rapid second week)
- 2 weeks: no difference in cutaneous perfusion in the two species.
- lower wound breaking strength than dogs at 1 week
- open wounds seem to heal more by contraction along wound edges,
DOGS
- open wounds heal more by central “pull” of fibroblasts and epithelialization.
cats may have more wound healing problems associated with poor vascular supply or tension in the first postoperative week
Subcutaneous Tissues and Healing
- subcutaneous tissues removed under primary closed wounds > cutaneous perfusion was significantly reduced at 7 and 14 days postoperatively in both cats and dogs
- lack of significant effect on healing of primary sutured wounds
List the 5 braod categories which can effect wound healing
Tension
Pressure
Motion
Self-Mutilation
Patient Health
How does tension affect wound healing?
Tension can disrupt cutaneous perfusion and retard wound healing
defects should be created and closed parallel to tension lines
What patient health factors can significantly retard epithelialisation?
Uraemia
Exogenous steroid excess
- Hyperadrenocorticism (wound healing can be delayed and the immune system’s ability to fight infection can be impaired)
- Steroids prolong the inflammatory phase and delay cutaneous wound healing
Geriatric
- Decreased cutaneous perfusion, increased skin fragility, increases risk of infection
Malnutrition
- delayed neovascularisation, decreased collagen synthesis, prolongation of inflammation, decreased leucocyte phagocytosis, B- and T-cell dysfunction, decreased mechanical skin strength
- Methionine, cysteine and arginine all important
- FAs (within cell membranes, vital for cell function)
- VitC (collagen synthesis, cell mitosis and monocyte migration)
- Zinc and iron (enzymatic reactions in production of DNA and RNA and proteins including collagen)
What are the reported benefits of using a scalpel for a skin incision over electrocautery/CO2 laser/radiowaves?
Meticulous intraoperative hemostasis is critical
- Scalpel incision have approximately twice the wound strength at 10-12 days post-op compared to electrocautery
- Produce less drainage with faster and stronger healing
- Skin incised with radiowave, CO2 laser and monopolar, char will penetrate the skin laterally 0.172, 0.215 or 0.255mm respectively
In humans, studies have concluded that incision made with electrocautery were faster and resulted in less post-op pain with no difference in scar formation of post-op infection
primary closure
- Freshly incised
- clean
- clean-contaminated wounds
- traumatic > occurred within 3 to 6 hours
Dehisced wounds
- converted to primary
- secondary closure
- heal by second intention.
What is meant by the ‘golden period’ for wound management?
- bacteria within a minimally contaminated wound can multiply to 10^5 per gram of tissue, at which point the risk for infection increases dramatically.
- also depending on the type of bacteria and host and local environmental factors
How long may it take for the degree of trauma to be fully established after a crushing injury?
3-7 days
Suture Material and Knot Type When Suturing
What is a chain stitch knot?
What are its advantages?
An aberdeen knot!
Greater relative knot security and less volume
What is the recommended suture tag length of buried knots?
3-5 mm
Which suture materials require 3-6 square knots for security (as apposed to 4-6)?
Polyglactin 910
Polyglytone (Caprosyn)
Nylon
Prolene
For size 3-0
How many throws are required when tying to a loop at the end of a continuous pattern?
at least 5
List 2 options of continuous pattern closure of the SQ
Simple continuous (bits perpendicular to incision)
Running horizontal mattress (Bites parallel to incision)
