Suture Material and Needles Flashcards
What is suture? In what 2 ways does it play an important role in wound repair?
strand of material used to tie off vessels and approximate tissue
- provides hemostasis
- supports wound healing
What are the 9 characteristics of an ideal suture?
- easy to handle (consistent performance)
- minimally reacts in tissue
- inhibits bacterial growth
- secures hold when knotted (high knot security and safety)
- resist shrinking in tissue
- absorbs with minimal reaction (good and predictable)
- no capillarity
- gentle passage through tissue
- maximum tensile strength with high breaking strength
What is tensile strength? How is it related to size?
measure of the ability of the suture material to resist breakage or deformation (time to lose 70-80% of initial strength)
exponentially proportional to size (large size = high strength)
What is pliability/flexibility? What 2 things does it depend on? What is desirable for vessel ligation?
ease when suture material is handled
- material
- size
more flexibility is better for vessel ligation - falls tighter
What is memory? Why type of material tends to have a lot of memory?
tendency of suture material to return to its original shape
monofilament > multifilament
What is surface friction? What type of material tends to have a high surface friction?
the roughness of the outer surface and its tissue drag (ease when the suture is pulled through the tissue)
braided suture has more drag (high surface friction) than monofilament suture
- rough = more damage
What is knot security? How is it related to suture size?
ability of suture material to hold a knot
inversely proportional to suture size (large size = low security)
What is capillarity? What sutures have and do not have capillarity?
process by which fluid and bacteria are carried into the interstices of multifilament fibers, allowing infection to persist in suture
- monofilament = noncapillary
- multifilament/braided = capillary
(DON’T use multifilament fibers in infected/contaminated tissues)
What is tissue reactivity? How does the type of fiber affect the degree of tissue reactivity?
degree to which the body tends to react to the presence of a particular suture material
natural fiber > synthetic suture
multifilament > monofilament
What is important to note with suture selection?
no single suture is ideal for every surgical situation - certain materials are better suited for different wound environments and uses
What are the 5 ways of classifying sutures?
- FIBER ORIGIN: synthetic (manmade, nylon) vs. natural (biological, silk)
- STRUCTURE: monofilament vs. multifilament
- BEHAVIOR: absorbable vs. nonabsorbable
- ANTIMICROBIAL: “plus”
- SIZE
Suture samples:
What is the difference between absorbable and nonabsorbable sutures?
NONABSORBABLE: maintains >50% of tensile strength for greater than 60 days
ABSORBABLE: loses >50% of tensile strength in less than 60 days
How does tensile strength relate to absorption?
loss of tensile strength does not equal rate of absorption
Why is it important to select the suture with the appropriate absorption rate to the healing rate?
accelerated and premature absorption can lead to post-operative complications if the suture is absorbed before the wound is repaired
- ongoing infection and fever, and pH can affect absorption
How are natural fibers and synthetic fibers absorbed? How do they compare?
NATURAL: enzymatic digestion —> rate of absorption increases in the presence of infection and inflammation
SYNTHETIC: hydrolysis —> water molecules penetrate suture material causing the breakdown of suture polymer chain
synthetic hydrolysis leads to less tissue reaction than natural enzymatic digestion
What does suture duration include?
loss of tensile strength (suture strength) and absorption
What should be considered when choosing suture?
- How long will the sutures need to be in?
- How does the suture material affect the tissue and process of healing?
- How great is the risk of infection?
- What strength of suture is required?
- Is the material flexible enough for the given purpose and is it possible to knot in the space provided?
Why are multifilament sutures avoided when dealing with potentially contaminated tissue? What should be used?
it will most likely convert the contaminated wound into an infected one
absorbable monofilament!
What is the origin of surgical gut? What is its structure?
NATURAL - sheep intestine submucosa or bovine serosa (<90% collagen)
- enzymatic digestion/phagocytosis
multifilament (more drag)
Why is surgical gut not commonly used in practice? How does the type of surgical gut affect this?
marked inflammatory response, especially in cats (most reactive suture material)
chromic gut is treated with chromic acid salts and is less reactive
What is surgical gut most commonly used for?
vascular pedicle ligation
What is another name for polyglactin 910? What is its origin and structure? What is its reactivity like?
vicryl
SYNTHETIC; braided, multifilament (more drag)
minimal tissue reactivitty
What is another name for polyglactin 910? What is its origin and structure? What is its reactivity like?
vicryl
SYNTHETIC; braided, multifilament (more drag)
- monofilament is only 9-0 and 10-0
minimal tissue reactivity
How does Vicryl (Polyglactin 910) absorb?
- 25% of strength is lost by day 14
- completely absorbed by 60-70 days
What are 4 common uses of Vicryl (Polyglactin 910)?
- soft tissue approximation
- hollow organs
- ophthalmic procedures
- subcutaneous procedures
How is Polyglactin 910 altered to make Vicryl Rapide? How does absorption compare to Vicryl?
exposed to cobalt 60 radiation to increase the rate of absorption
- 50% of strength lost by day 5-6
- almost 100% by day 14
- completely absorbed by ~42 days
What are 5 common uses of Vicryl Rapide (Polyglactin 910)?
(skin and mucosa —> quickly healing
- perineal repair
- lacerations
- mucosa in oral cavity
- periocular skin
- skin repairs where rapid absorption may be beneficial (NOT over joints, in body wall or fascia, and in high-stress/tension areas)
How is Polyglactin 910 altered to make Vicryl Plus? When does it completely absorb?
coated with Triclosan, a broad spectrum antibacterial, to reduce bacterial growth at the suture line
56-70 days
What are 6 common times to use Vicryl Plus (Polyglactin 910)?
- contaminated and infected sites
- reproductive tract
- ligation
- general closure
- bowel
- orthopedic procedures
What is the origin and structure of Polydioxanone? What is its tissue reactivity like?
(PDS II vs. PDS Plus)
SYNTHETIC, monofilament
minimal tissue reactivity
When does Polydioxanone completely absorb?
180 days (6 months), usually between 180-210
What are 5 common uses of Polydioxanone?
- soft tissue approximation
- fascia closure
- blood vessel anastomosis
- orthopedic procedures
- tissues that require long-term strength (linea alba, bladder)
What is another name for Polyglecaprone 25? What is its origin and structure? What is its tissue reactivity like?
Monocryl (Plus)
SYNTHETIC monofilament with a high initial strength
minimal tissue reactivity
What is the absorption of Polyglecaprone 25 (Monocryl) like?
- 70-80% strength loss at 14 days
- complete absorption ~100 days (90-120 days)
Which sutures are nonabsorbable? When should they NEVER be used?
- silk
- nylon (polyamide)
- polyester
- polypropylene
- stainless steel
intradermal pattern —> patient must come back to get it removed 10-14 days post
What is the origin and structure of silk? What is its tissue response like?
NATURAL - harvested from cocoon of silkworm
braided, multifilament
moderate tissue/inflammatory reaction
What is the most reactive of the nonabsorbable sutures? What is a possible adverse effect?
silk
potential nidus for calculus formation in the bladder or gallbladder
What are 5 common uses for silk?
- vessel ligation
- cardiovascular procedures
- ophthalmic procedures
- neurological procedures
- amputations
What is another name for Nylon (polyamide)? What is its origin and structure?
Ethilon
SYNTHETIC, monofilament
What is the tissue reaction of Nylon (polyamide) like? What are 3 common uses?
minimal tissue reaction and breakdown
- soft tissue approximation
- ophthalmic procedures
- ligation
What is another name for Polyester? What is its origin and structure?
Mersilene
SYNTHETIC, multifilament +/- coating
- monofilament only 10-0 and 11-0
What is the strongest non-metallic suture?
Polyester
What is the tissue reaction of Polyester (Mersilene) like? How does this compare to other synthetic suture?
intermediate tissue reaction
causes more reaction than any other synthetic suture
What is Polyester (Mersilene) most commonly used for?
stabilizing unstable joints
What is another name for Polypropylene? What is its origin and strucutre?
Prolene
SYNTHETIC monofilament with high memory
What is the least reactive nonabsorbable suture?
Polypropylene (Prolene)
What are 3 common uses for Polypropylene (Prolene)?
- vascular surgeries
- neurological surgeries
- tendon repairs
What is the most common structure of stainless steel suture? What are 3 common uses?
monofilament (can be multifilament)
- orthopedics
- sternotomy repair
- hernia repair
What is the range of suture sizes? What suture has its own dimensions?
notated by the standard US Pharmacopeia - 12-0 (smallest) to 7 largest
- cat gut 2-0 is larger than 2-0 PDS
Why is it important to select the appropriate-sized suture?
- prevents wound dehiscence and promotes wound healing
- larger material tends to increase tissue reaction and delayed healing
(vets tend to use excessively large sutures)
How does suture size affect security?
- 4-0 requires fewer throws than 2-0 (4 throws vs 5 throws)
- 0 requires 5 throws, since large suture throws tend to unravel
(LARGER suture = MORE throws needed for knot security)
What structures of sutures are most likely to cause surgical site infections? What is wicking?
multifilament > coated multifilament > monofilament
fluid and bacteria are carried into the interstices of multifilament fibers, leading to infection (like capillarity)
What is dehiscence? What 5 practices can lead to this?
failure of sutures to hold incision closed (leaks!)
- apposition of unlike tissues
- overtightening sutures
- too much tension on sutures
- poor suture technique
- incorrect size of suture
What causes the formation of seromas at a surgical site?
increased dead space
Anatomy of a surgical needle:
What is the composition of suture needles? Where does it attach to the suture?
stainless steel wire
swaged end
What is the difference between tapered and cutting suture needles?
TAPERED = minimal trauma, dainty (must cure wrist to follow needle)
CUTTING = facilitates tough tissue penetration
- REGULAR = cutting edge on concave surface
- REVERSE = cutting edge on convex surface
How are straight suture needle shapes used?
hand-held and in easily accessible areas
What are 4 common-sized suture needles used? What are they used for?
- 1/4 circle: ophthalmic surgery
- 1/2 circle: many tissue types and procedures
- 3/8 circle: skin/superficial tissue
- 5/8 circle: confined locations or deep tissue
What suture needle shape is rarely used?
half curved
What are the 6 types of suture needle tips?
- TAPERPOINT: sharp tip that pierces and spreads tissue without cutting - intestines, SQ tissue, fascia
- TAPERCUT: combination of reverse cutting and taperpoint - heavy and thick fascia, tendons
- CUTTING: cutting edge on concave point - cuts out tissue
- REVERSE CUTTING: cutting edge on convex surface reducing the risk of tissue being cut out - skin
- SPATULA POINT: flat on top and bottom - ophthalmic
- BLUNT POINT: blunt point that dissects through friable tissues without cutting - soft parenchyma organs, like liver and kidneys
What are tissue adhesives (tissue glue)? How long does it typically take to set? What can delay this?
cyanocrylate liquid that becomes solid within seconds of contacting water in the tissues used to close short skin incisions (<5 cm) and lacerations
< 1 min - delayed when applied to wet areas
Why is it important to bury the knot before applying tissue adhesives? In what 6 situations should tissue adhesives NEVER be used?
can delay healing, cause tissue reactions, cause granuloma formation, and/or promote wound infection
- bite wounds or other heavily contaminated wounds
- puncture (deep) wounds
- lacerations >5 cm
- mucous membranes
- near the eye
- in SQ tissues
What are skin staples? How are they applied?
rectangular shaped appositional staples
apply the staples perpendicular to the incision after aligning and apposing the edges with thumb forceps with staples spaces ~5-6mm apart
What is the main advantage to using skin staples? 4 disadvantages?
rapid application once you get used to it
- cost
- risk of eversion and rotatiom
- single use
- time saved in placement is lost in removal
What are the main 3 types of specialized staplers?
- THORACOABDOMINAL: 2 or 3 parallel rows of B staples used for lung/liver lobe resections, partial splenectomies, and partial gastrectomies
- GASTROINTESTINAL ANASTOMOSIS: 4-6 rows of B staples with cuts in the middle to create a side-to-side anastomosis
- END-TO-END ANASTOMOSIS: creates circular end-to-end anastomosis (intestine)
What type of suture is typically used on skin? What 3 types are most common? Size?
non-absorbable with minimal tissue reactivity
- nylon
- polypropylene
- monocryl
4-0 to 2-0 depending on the patient
What are the 5 most common suture patterns used on the skin with no tension? 3 with tension?
- simple interrupted
- simple continuous
- +/- cruciate
- intradermal
- Ford interlocking
~ horizontal/vertical mattress
~ cruciate
~ near-far patterns
What type of suture is typically used in subcutaneous tissue? What are the 3 most common choices? Size?
rapidly absorbable (not getting taken out, heals quickly) with minimal tissue reactivity
- monocryl
- vicryl
- PDS
4-0, 3-0, +/- 2-0
What 2 suture patterns are most commonly used on subcutaneous tissue?
- simple continuous
- simple interrupted
What type of suture is most commonly used on body walls and fascia? What suture is most commonly used? Size?
slowly absorbable (takes longer to heal) with high tensile strength and good knot security
PDS
3-0 to 0
What is the holding layer when the body wall or fascia is getting sutured? What 3 patterns are most common?
external rectus sheath
- simple interrupted
- simple continuous
- cruciate
What type of suture is most commonly used on the stomach? What 2 are most commonly used? Size?
slowly absorbable with good tensile strength and knot security
- PDS
- monocryl
4-0, 3-0, +/- 2-0
What are the 4 most common suture patterns used on the stomach?
- simple continuous
- Lembert
- Halstead
- Connell/Cushing
What type of suture is most commonly used on the small intestine? What 2 are most commonly used? Size?
slowly absorbably with good knot security
- PDS
- monocryl
4-0 +/- 3-0
What 3 suture patterns are commonly used on the stomach?
- simple interrupted
- simple continuous
- Gambee
What type of suture is most commonly used on the urinary bladder? What 2 are mostly used? Size?
rapidly absorbable (heald quick) with good tensile strength and knot security
- monocryl
- PDS
4-0 and 3-0
What 2 suture patterns are commonly used on the urinary bladder?
- simple continuous
- Cushing
What type of suture is most commonly used on the colon? What is a good option? Size?
slowly absorbable with good knot security (no leakage!)
PDS
4-0, 3-0
What 2 patterns are most commonly used on the colon?
- simple interrupted
- simple continuous
What type of suture is used for vessel and pedicle ligation? What is a good option? Size?
slowly absorbable with good knot security and tensile strength
PDS
VESSELS = 4-0 to 3-0
PEDICLES = 3-0 to 0
What 3 knots are most commonly used for vessel and pedicle ligation?
- square knot
- modified Miller’s* - friction, stays tight on high-energy animals
- surgeons knot*
What type of suture is used on tendons and ligaments? What is the best option? Size?
nonabsorbable with good tensile strength and knot security
Nylon
3-0 to 1
What 2 types of soft tissue tend to invert? What patterns are recommended?
- bird and reptile skin
- dog and cat oral mucosa
everting patterns
How should larger hollow organs with aggressive eversion of mucosa be closed?
inverting or modified Gambee patterns
Is one or two layer closer preferred? What is a common exception?
one-layer closures
hollow organ repairs = two layer acceptable
In what 2 organs is double-layered closure most common? What should still be considered?
- stomach
- bladder
two-layer closures have the disadvantage of compromising the lumen and can be a source for bleeding and irritation
(won’t do a double layer on small lumen organs)
