Wound Healing and Closure

what are the 3/4 phases of wound healing?

- vascular = formation of fibrin plug

- inflammatory

- proliferative = re-epithelialization

- remodeling = remodeling and contraction

in the inflammatory phase, what cell type predominates in the first 72 hours?

after 72 hours?

after 6 days?

neutrophils

macrophages

lymphocytes

what occurs during the inflammatory phase of wound healing?

- generalized on non-specific inflammation around wound edges

- leukocytes mobilize to injured area to remove debris and bacteria (neutrophils and monocytes)

how long does the inflammatory phase last if there is little to no contamination of the wound?

3 days

what indicates the start of the proliferative phase of wound healing?

activation of macrophages

phase of wound healing that is characterized by fibroblasts and collagen production

epithelialization (proliferative)

how long do fibroblasts synthesize collagen?

what is the purpose of this process?

approximately 6 weeks

helps to increase tensile strength of tissue around wound and is highest at end of stage

phase that includes remodeling of collagen by formation of intermolecular cross links

fibroplasia and contraction (maturation)

how long does the maturation phase last?

what is the end result?

6-12 months

paler, flatter scar with minimal change in tensile strength

what are the three classifications of wound healing?

- primary intention

- secondary intention

- tertiary or delayed primary intention

what is a primary intention closure?

recent, clean wounds that are closed by sutures

- typically irrigated and debrided to remove foreign material

- tissues brought to close and accurate approximation to provide optimal healing

in primary intention closures, suture choice and removal are dependent on what?

location of wound

what are the characteristics of a wound closed via primary intention?

- typically becomes red, raised, and pruritic

- over 9-12 months scar will flatten and become paler

what is a secondary intention closure?

wounds are left open to heal without intervention

- prolonged inflammatory phase

- wound heals from edges to central aspect and from bottom up (at about 1 mm/day)

secondary intention closures are indicated for what type of wounds?

why is secondary intention closure preferred for these wound types?

severe infections and contaminated wounds

lowers risk of abscess formation

what is a tertiary intention closure?

closure of wound that was initially left open or not repaired

tertiary intention closures are indicated in what types of wounds?

- high bacterial content (dog, human bites)

- long time since injury (usually 3-5 days)

- severe crush injuries

good results of tertiary intention closures are dependent on what factors?

- decreasing bacterial load

- good preparation of wound edges

- debridement of foreign material

what factors can inhibit the inflammatory response involved in wound healing?

- steroid use

- immunosuppressants

- chemotherapy

what factors can inhibit wound healing?

- vit A deficiency

- zinc deficiency

- malnutrition (acute worse than chronic)

what factor can stop granulation tissue formation in the wound healing process?

excessive inflammatory response (toxins, septic shock, gram neg infections)

what factors and increase the inflammatory response in wound healing?

massive trauma (cytokine release, increased lactate production)

what are the post-operative factors that can affect wound healing?

- cardiac failure

- hypoxia

- poor tissue perfusion (sympathetic nervous system activity)

- vasoconstriction

which suture type:

- absorbable

- made from purified connective tissue (collagen) from bovine intestines

- used in OB/GYN, GI, plastics, and oral surgeries

- loses tensile strength in 14-21 days, complete absorption in 90-120 days

chromic gut

what is the risk associated with chromic gut sutures?

inflammatory reaction d/t foreign protein nature

which suture type:

- absorbable

- braided

- used for subcuticular approximation and ligation of vessels

- tensile strength for 14-21 days, absorption in 8-10 weeks

- made from polyglycolic acid, dyed vs undyed

vicryl

what is the risk associated w/ vicryl sutures?

risk of potentiating infections, as it draws moisture and bacteria migration to the wound

which suture type:

- synthetic

- absorbable

- monofilament

- increased tensile strength compared to vicryl

- poor knot security, difficulty to tie

- tensile strength decreases about 25% every 2 weeks

PDS

for what type of wounds would you use PDS sutures?

- "tissue under tension"

- contaminated wounds

which suture type:

- braided or entwined thread from silkworm larva

- non-absorbable

- treated w/ silicone to increase strength

- higher risk for suture abscess ("spit stitches")

- used in ocular, neural, closure of oral mucosa, and CV surgery

silk sutures

for what procedures can silk sutures not be used?

grafts or prosthetic cardiac valves

which suture type:

- synthetic monofilament

- high tensile strength initially but loses tensile strength w/in 1-2 weeks

- absorbable w/in 12 days

- easier to work with than PDS

- used in face, eyes, ears, neck, and abdomen

monocryl sutures

why is monocryl preferred in subcuticular closures?

less scarring risk, especially keloid/hypertrophic scars

which suture type:

- nonabsorbable monofilament that is typically dyed

- easy removal d/t lack of tissue adherence

- used in CV, ophtho, neurosurg procedures

- brittle and difficult to tie good knots

prolene

for what types of wounds is prolene suture used?

- infected and/or contaminated wound closures

- used in wounds w/ high tension

which suture type:

- nonabsorbable monofilament

- low skin reactivity

- good tensile strength

- lower risk of knot issues compared to PDS and prolene

nylon sutures

for what types of wounds are nylon sutures used?

laceration repair and surgical incision closures

suture technique mostly used in lacerations and incision closures (approximated tissue w/ no tension)

simple interrupted

what are the potential complications associated with simple interrupted sutures?

- infection

- scarring

- ischemia and/or necrosis from excessively tight sutures

suture technique used in incision or wounds that are under tension, allowing for greater closure strength and distribution of tension

- allows edges to evert

- far to far, near to near, knot tied on side of incision where first throw was made

vertical mattress

vertical mattress sutures are good to use in areas w/ ______________ surfaces (i.e. posterior neck)

convex

what complication is associated w/ vertical and horizontal mattress sutures?

how can this be avoided?

railroad track scarring

early removal (4-6 days for vertical)

suture technique used in incisions or wounds that are under tension

- anchoring stitch for skin flap closures

- promotes skin eversion which helps limit scarring

horizontal mattress

this suture type can be alternated with horizontal mattress to prevent wound dehiscence w/ early removal of horizontal mattress sutures

simple interrupted sutures

suture technique used when closing large or gaping wounds; helpful in reducing tension over the course of the wound

- suture is passed from deep to superficial then superficial to deep, resulting in a buried know

- good for deep wounds/incisions to help close deep space

- usually requires another layer of closure at skin

deep dermal

for deep dermal sutures, what type is preferred in laceration repairs?

in surgical setting?

monofilament

braided (Vicryl)

suture technique that is placed into epidural layer, running stitch being most common

- absorbable vs nonabsorbable

- easy to bend needle and dull/break tip so must be gentle and not force needle

subcuticular

suture technique used in longer incisions/wounds with minimal tension

- offers faster closure

- can be used to hold skin grafts in place

- only requires failure of one knot to allow for dehiscence

- nylon most common

running stitch

what technique can be used in running stitches to avoid knot failure/dehiscence?

Aberdeen technique

when placing a running stitch, what must you be careful to avoid?

avoid overlap/inversion of one side of skin

closure technique that allows for quick wound closure that is secure with low risk of failure

- material may be an irritant

- quick removal but might be painful

staples

what are the complications associated with staples?

- concern for skin overgrowth if not removed in a timely fashion

- important to avoid inversion to avoid wound breakdown/slower healing

- possible allergic reaction

what knot type is the typical surgical knot?

square knot

how many "throws" make a knot?

how many throws are required for a complete tie?

2

4-8

how should every stitch start?

surgeon's knot

surgeon's knots require _______ loops in the first throw, then _____ loop thereafter

2; 1

what are the benefits of a surgeon's knot?

- good for incisions/wounds under tension

- helps prevent loosening and locks in stitch for second throw

- helps prevent making initial knot too tight and prevents strangulation of tissue

what are the characteristics of a one-hand knot?

- faster

- tension difficult to control

- potentially less secure

- better for tight spaces

what are the characteristics of a two-hand knot?

- better control of knot

- more consistent tension

- slower

what is the removal time for face/lip sutures?

3-5 days

what is the removal time for scalp sutures?

7-10 days

what is the removal time for chest/abdomen/back sutures?

10-14 days (C)

what is the removal time for limb sutures?

10-14 days (L)

what is the removal time for hand sutures?

10-14 days (H)

what is the removal time for nailbed sutures?

trick question, nailbeds are sutured with absorbable material