17 Flashcards
how are needles define
fraction of a circlecord length (bite width)needle lengthneedle diameterneedle radius
channel vs laser drilled swaged needles
channel: suture is crimped in a depression in the body of the needlelaser: suture is crimped in a hole drilled in the body of the needle (less drag, better grip with needle holders)
breaking strength of suture
the stress value on a stress-strain curve at which the suture acutely fails
capillarity of suture
degree to which absorbed fluid is transferred along the suture linemultifilament > monofilament
creep of suture
tendency of suture to slowly and permanently deform under constant stress
elasticity of suture
degree to which suture will deform with load applied and return to normal shape when load is removed
knot pull out strength of suture
load required to break a suture deformed by a knotknots generally decr suture strength by 10-40%
knot strength of suture
force necessary to cause a knot to slip
memory of suture
tendency for a suture to return to its original shape after deformation
plasticity of suture
degree to which a suture will deform without breaking and will maintain shape after removal of the deforming force
pliability of suture
the ease of handling and the ability to change shape of suture
stress relaxation of suture
the ability of suture to reduce stress under constant strain
suture pull out value
the weight required to full a suture loop from tissuedepends on type of tissue fat < muscle< skin < fascia
tensile strength of suture
measure of a sutures ability to resist deformation and breakage and the stress at which it deforms (yield strength) or rupture (breaking/ultimate strength) occurs
general characteristics of monofilament vs multifilament suture
monofilament =less pliable, more susceptible to catastrophic damage from crushing/nicking, lower tissue drag and is smoothermultifilament =greater strength & pliability, more tissue drag, greater capillarity and tendency for bacT colonization
T/FCatgut is monofilament
FALSECatgut is multifilament suture with TWISTED not braided filaments
newer types of sutures
polyblend suture (core polymer and braided exterior): extremely strong and resistant to failureSelf anchoring, barbed suture: surface barbs, decrease bulky knots, monofilament
water soluble vs insoluble suture coating in terms of knot security
water soluble coatings improve knot securitywater insoluble coatings reduce knot security
antibiotic coating for suture
+PLUStriclosan: inhibitor of bacT fatty acid synthesis
study of PDS PLUS with % percent of wound infections
PDS PLUS (polydiaxone w triclosan)11% wound infection PDS5% wound infection PDS PLUS
two major mechanisms of suture absorption
- hydrolytic: synthetics2. enzymatic: Catgut (acid phosphatase, leucine amino peptidase)
PDS in sterile urine vs infected urine
PDS polydioxanonesterile urine: lost all strength 3 daysinfected urine: lost all strength 1 day (Proteus)
Dexon in sterile urine vs infected urine
Dexon polyglycolic acidsterile urine: lost 64% strength in 10 daysinfected urine: lost all strength 1 day (Proteus)
T/F rates of suture absorption are dramatically increased in infected urine
TRUE
what sutures degrade more rapidly in alkaline pH
moncryl (polyglecaparone 25)maxon (polyglyconate)biosyn (glycomer 631)
what suture loses tensile strength rapidly in acidic pH
PDS polydioxanonenylon (even thought considered non absorbable)
T/Fprestraining suture material to reduce suture memory will enhance suture degredation
true
catgut characteristics
natural twisted multifilament intestinal submucosa/serosaabsorbable (variable) via enzymaticweak, not uniformhigh tissue reactioncompletely absorbed in 2-3 weeks
do NOT use catgut in
harsh environments (GI, urinary surgery)areas requiring prolonged strength (>5days)important structures (body wall closure, fascial repair)
list rapidly absorbing suture
Polyglycolic acid (dexon)polyglactin 901 (vicryl)–braided multifilamentpolyglecaparone 25 (monocryl)polyglytone 6211 (caprosyn)
list slowly absorbing suture
polydioxanone (PDS)polyglyconate (Maxon)glycomer 631 (Biosyn)
list nonabsorbable suture
SilkPolypropryleneNylonpolymerized caprolactampolyesterstainless steel
dexon
polyglycolic acidbraided multifilrapidly absorbabletensile strength 50% at 2-3 weeksabsorption 60-90 daysgreat knot security
vicryl
polyglactin 910braided multifilrapidly absorbabletensile strength 50 % at 2-3 weeks (0% at 2-3 weeks if rapide)absorption 56-70 days (42 days if rapide)
monocryl
polyglecaparone 25monofilrapidly absorbabletensile strength 50% at 1 week 70-80% at 2 weeksabsorption 119 days
caprosyn
polygytone 6211monofilrapidly absorbabletensile strength 0% at 2-3 weeksabsorption 56 days
PDS II
polydioxanonemonofilslowly absorbabletensile strength 50% at 5-6 weeksabsorption 180 days
Maxon
polyglyconatemonofilslowly absorbabletensile strength 50% at 4-5 (5-6) weeksabsorption 180 days
Biosyn
glycomer 631monofilslowly absorbabletensile strength 50% at 2-3 weeksabsorption 90-110 days
silk characteristics
silk-braided multifilament nonabsorbablefibroin and sericinactually slowly degraded by hydration (gone in 2 years)good for knots around large vesselshigh tissue reactivity
polypropylene
nonabsorbable monofilamentvery stronghighest energy to break pointgood handling
nylon
nonabsorbable monofilamentBUT susceptible to degradaton via hydrationwill elongate
steam sterilization and elongation of nylon leader line
steam sterilization resulted in 2-4x increase in elongationit did NOT effect ultimate strength
Vetafil
polymerized caprolactamtwisted multifilamentskin only
canine sternotomy closurestainless steel vs polybutester
20 g stainless steel wire had less displacement and appeared more stable than #2 polybutester suture
fiberwire vs orthocord polyblend suture
2 suturefiberwire = greatest maximal failure load (263 N)orthocord = greatest elongation (50%)
knitted vs woven mesh
woven is stiffer, stronger and less porous than knittedknitted is anisotropic, more porous, flexible and less strong/stiff
types of knitted polypropylene mesh
prolene and marlex mesh
pore size of polypropylene meshes
macroporous0.6=0.9 mmporosity 28-32%MUCH bigger than expanded polytetrafluoroethylene 20-25 micrometers
type of collagen found in mesh with a large pore size
type I collagen ingrowth
name a synthetic mesh that prevents adhesions to viscera
expanded polytetrafluoroethylene ePTFE
biologic material used to cover defects
pericardiumfascia lataporcine small intestinal submucosa
characteristics of porcine small intestinal submucosa
SISmultilaminatebioscaffoldinflammatory (intense WBC infiltration; more than polypropylene mesh)not apparent histologically after 3 months
polypropylene Mesh, fascia lata, SIS multi and single in terms of best strength
fascia > Marlex polypropylene > multi SIS > single SIS
recommendations for overlapping mesh with or without the presence of tension
with tension 1 cm overlapwithout tension 0.6 cm overlap
complications of mesh
failure: migration, extrusion (fails at tissue-mesh interface)fistulainfectionadhesionreduce complications with use of muscle or mental pedicle and use the smallest amount of mesh possible
Frey et al 2010 compared stifle surgeries closed with nonmetallic vs metallic sutures and what % were infected
9.1% skin staples infected5.1% non metallic sutures infected
basic principles of vascular clip application
- skeletonize the vessels2. diameter of vessel should be no more then 2/3 and no less than 1/3 the length of the clip3. clip is applied several mm away from the cut edge4. arteries and veins clipped separately
green TA
giant double rows4mm w x 4.8mm Hclose 2.0 mm
blue TA
middle double rows4 mm w x 3.5 mmm Hclose 1.5 mm
white TA
three rows ONLY 30 mm length3 mm w x 2.5 mm Hclose 1.0 mm
tissue thickness recommendations when using circular staplers
circular staplers should NOT be used if tissue is < 1 mm or greater than 2.5 mmdouble staggered circular rows
