Principles of Wound Closure

Question 1

what should you ask when deciding to close a wound or not?

Answer 1

1. is the patient stable?
2. is the wound highly contaminated?
3. tissue viability: are you sure the tissues are healthy and viable?
4. will closure preclude normal function?
5. is there too much tension?

Question 2

what are the 4 wound management strategies?

Answer 2

1. primary closure: first intention healing
2. delayed primary wound closure
3. secondary wound closure
4. second intention healing: contraction and epithelialization

Question 3

describe primary closure (2)

Answer 3

1. suture: for surgical wounds created in aseptic conditions and for contaminated wounds converted to clean wounds with the 7 Cs and Abs
2. only suture if: devitalized tissue is removed, blood supply appears adequate, there is no obvious infection, and the wound can be closed without tension

Question 4

describe delayed primary wound healing (3)

Answer 4

use with mildly contaminated or traumatized wounds not clean enough for primary closure

1. wound management: lavage and debridement
2. leave unsutured and place sterile dressing
3. surgical closure after wound considered healthy; typically 3-5 days from wounding, prior to formation of granulation tissue

Question 5

describe secondary wound closure (3)

Answer 5

1. strategy for severely contaminated or highly traumatized wounds; suture the wound ONLY AFTER granulation bed has formed
2. allows for formation of granulation bed
3. usually done 5 days or more after injury

Question 6

describe second intention wound healing

Answer 6

1. wound is allowed to heal on its own by wound contraction and epithelialization; NO surgical closure
2. disadvantages: extended time to closure, risk of incomplete contraction and epithelialization, potential impaired function and poor cosmesis
3. used for smaller wounds, bite wounds

Question 7

what are 6 complications of wound healing?

Answer 7

1. hematoma
2. seroma
3. cellulitis
4. infection
5. dehiscence
6. adhesion formation

Question 8

describe hematoma (4)

Answer 8

1. accumulation of blood within the wound
2. prolongs inflammatory phase since neutrophils and macrophages can’t swim
3. prevents apposition of tissues
4. excellent medium for bacteria = increase risk of wound infection

Question 9

describe seromas (3)

Answer 9

1. accumulation of fluid in the wound, usually the result of dead space
2. painless fluctuant swelling (like hematoma)
3. don’t drain because it is not contaminated at this stage and draining could actually contaminate the wound, just ignore, wrap, and compress to decrease infection risk

Question 10

describe cellulitis (3)

Answer 10

1. infection within the fascial planes caused by contamination or foreign bodies
2. warm to the touch, painful, firm diffude swelling
3. hella common in horses

Question 11

describe infection (3)

Answer 11

1. contaminated wounds progress to infected wounds when bacterial numbers excess 10^5 organisms per gram of tissue
2. clinically, this may appear as purulent discharge, a draining tract, and systemic signs (fever, malaise, reduced appetite)
3. enhanced by presence of devitalized tissue, foreign material, compromised blood supply, and inappropriate surgical technique

Question 12

describe dehiscence (5)

Answer 12

1. separation of sutured wound edges
2. any factor that prolongs any stage of wound healing predisposes to dehiscence, especially if the inflammatory phase is prolonged
3. can be due to poor surgical technique: traumatic tissue handling and tension on closure

Question 13

describe adhesion formation

Answer 13

1. joining of serosal (abdomen) or pleural (thoracic) surfaces by fibrous connective tissue
2. trauma to these surfaces leads to fibrin deposition and subsequent fibrous tissue
3. not a problem in dogs except for repeat offenders (labs)
4. BIG problem in horses: belly jelly (carboxymethylcellulose)

Question 14

how do you deal with dead space?

Answer 14

if contaminated, provide drainage, if not no drainage and tack down those tissues!

Question 15

what are the 4 indications for placing a drain?

Answer 15

1. draining or evacuation of wound fluid
2. dead space
3. contamination
4. infection

Question 16

what are the 2 principles for drain placement?

Answer 16

1. wound drains are not a substitute for proper debridement, lavage, and wound care
2. drains should be left in place for as long as needed, but not longer; evaluate the character and amount of drainage; when the amount of drainage starts to plateau, remove the drain

Question 17

what are the 2 types of drains?

Answer 17

1. gravity dependent: penrose drains, drain exits wound ventrally, place drain exit away from incision, at most gravity dependent ventral spot and cover with an absorptive bandage (drainage occurs AROUND the drain, not THROUGH the drain)
2. closed suction drains

Question 18

describe penrose drains (4)

Answer 18

1. drain exits wound ventrally, place drain exit away from incision, at most gravity dependent ventral spot and cover with an absorptive bandage (drainage occurs AROUND the drain, not THROUGH the drain)
2. advantage: easy, effective, cheap
3. disadvantages: messy, bandaging is best but requires bandage upkeep, higher incidence of ascending infection; may not drain adequately, easy to remove too early, could enlarge dirty area
4. technique: after debridement and lavage, advance drain to proximal/dorsal most aspect of the wound and tack proximally through the skin

Question 19

describe closed suction drains (4)

Answer 19

1. AKA Jackson pratt, JP, or bulb drains, creates a continuous negative pressure within the wound; drain can exit wound at any location!
2. advantages: enables you to quantify drainage and evaluate it microscopically, is cleaner and less likely to get infected, can last longer, can exit anywhere, does not require a bandage
3. disadvantages: can become clogged, will not work if incision leaks air, expensive
4. placement: exit drain at convenient location, avoid piercing skin flaps, do not exit through incision, can be dorsal or proximal, secure with stretch bandage

Question 20

describe tacking down tissues (3)

Answer 20

1. useful for noncontaminated dead space
2. tissue layers are sutured together to diminish dead space
3. can be done with walking sutures if tension is also an issue

Question 21

describe tension as it relates to wound closure (2)

Answer 21

1. tension is a killer for wound healing! minimizing tension is a critically important surgical principle
2. strategies to decrease tension: preop planning, mark and measure, undermine tissues, use tension relieving suture patterns, use skin flaps/grafts, understand local tissue tension prior to cutting, orient your incision to minimize tension with closure, consider function of local structures when considering tension (limbs, eyes, mouth) (KEEP ROM)

Question 22

describe undermining tissue

Answer 22

1. always the first step to minimize tension
2. blunt and sharp dissection
3. include (undermine beneath) as much SQ as possible to preserve vascular supply

Question 23

describe tension relieving suture patterns

Answer 23

1. tension should be deep to the skin, NOT IN the skin
2. cruciate, vertical mattress, horizontal mattress