What is primary wound closure?
direct apposition of wound edges with suture before the presence of granulation tissue
What are the advantages of primary wound closure? (5)
- simple wound care
- less need for bandages
- faster healing
- reduced pain
- less scarring
What is second intention healing?
a wound that heals without suturing; full thickness wound undergoes epithelialization and contraction; partial thickness wound undergoes adnexal re-epithelialization
What is third intention healing?
primarily closing a wound after the presence of granulation tissue; start with open wound management until you have enough skin, pre-stretch skin, use flap or graft
What is the blood supply to the skin?
direct cutaneous vessels that come from the subdermal plexus [don't dissection the subQ b/c subdermal plexus comes deep to this]
What wounds are able to be closed primarily?
- clean, clean-contaminated, or VERY RARELY contaminated
- traumatic wounds less than 6 hours old (non-crushing wounds, non-degloving) in healthy patients
What direction are the lines of tension in the lateral, ventral, and dorsal aspects?
- Lateral trunk: vertical (dorsal to ventral)
- Lateral limbs: horizontal
- Ventral trunk: horizontal (midline to lateral trunk)
- Dorsum: horizontal
What sutures do you use for primary closure of fascia?
PDS, Maxon (0, 2-0, 3-0)- needs to be there for a while because fascia grows slowly
How od you make an incision with respect to lines of tension?
make incision ALONG LINES OF TENSION, never perpendicular to tension lines
What type of sutures do you use for primary closure of subQ tissue?
monocry, biosyn (3-0, 4-0- small to bury)- subQ heals faster
What type of suture do you use to close skin for primary wound closure?
Nylon, staples (3-0, 4-0)
What are challenges to closing large defects in the skin?
- dog ears occurs when closing circular defects
- cosmetic issue (make incision elliptical for fusiform to begin with) (resect dog ears)
- possibility for seroma
How do you handle step defects?
place sutures at equal levels for epidermis
What are methods of managing tension or large defects? (4)
- local tension relieving techniques
- local or subdermal plexus flaps
- axial pattern flaps
What is a safe method of undermining for local tension relieving?
undermine by blunt dissection DEEP TO PANNICULUS (preserve blood supply)
What are local tension relieving techniques? (6)
- walking sutures
- tension relieve suture patterns
- skin stretching
- relaxing incisions (mesh, bipedicle flap, V-Y plasty, Z plasty)
- change shape (close triangular defects as Y, close rectangular defects as X or double Y, close circle and trim dog ears or by S plasty)
What is "walking sutures"?
- staggered rows of interrupted sutures in dermis to fascia
- advance undermined skin, "walking" it towards the center of the wound
What are methods of skin stretching? (3)
- mechanical creep and stress relaxation
What is mesh expansion?
making multiple small incisions, creating multiple wounds that heal by second intention
What is a simple relaxing incision?
(aka bipedicle flap) single parallel incision, creating new wound; used near orifices
Why is Z plasty useful?
- changes direction of skin tension
- useful for areas of contracture
Describe Z plasty incision.
central arm of Z is perpendicular to the long axis of the wound
Describe a V-Y plasty incision.
point of V away from defect, then close it as a Y shape
What are subdermal plexus flaps?
- vascularized skin in local vicinity used to close defect
- used for acute or chronic wounds
What are the principals of subdermal plexus flaps? (4)
- elevate UNDER panniculus to keep blood supply intact
- wide base
- length sufficient to close defect
- must be able to close donor site
What are axial pattern flaps? What are the advantages?
- incorporate a direct cutaneous artery and vein
- can make larger flaps that have better survival, can rotate 180 degrees
What is a disadvantage of axial pattern flaps?
limited to area of elbows and stifles because skin from trunk can't reach distally
What are types of skin grafts? (6)
- pinch and punch grafts- small pieces of skin places into granulation tissue
- paw pad grafts- small pieces of paw pad placed into wound
- full thickness grafts
- partial thickness grafts
- meshing grafts
- microvascular free grafts
How do partial thickness wounds heal?
- adnexal re-epithelialization
- [contrast to full thickness wounds- granulation tissue, epithelialization, and contracture]