Ch 16 Suture, staples, ligation Flashcards
Tensile strength and early healing of self-locking and
surgeon’s knots
Weatherall 2020
Study design: In vivo, experimental.
Animals: Twenty-one horses.
Closure of VMC with self-locking knots resulted in biomechanical
and healing features similar to those with a traditional closure technique,
with neither restoring the tensile strength of the linea alba.
Ex vivo comparison of different thoracoabdominal stapler
sizes for typhlectomy in canine cadavers
Brad M. Matz
Study design: Randomized, experimental cadaveric study.
Animals: Twenty-four fresh canine cadavers
The results of this cadaveric study support the use of
any of the stapler sizes evaluated in similarly sized dogs. A prospective study is needed to be able to correlate stapler size and clinical outcome.
Thoracoscopic-assisted lung lobectomy in cat cadavers using a
resorbable self-locking ligation device
Nylund 2019
In situ cadaveric study. LigaTie or a TA
Animals: Ten feline cadavers.
cranial lung lobes only. Airway pressures were tested to a maximum pressure of 40 cmH2O.
Lung lobectomies were consistently performed at the hilus only when
the LigaTie was used. Lung lobectomies were less likely to leak when performed
with the LigaTie rather compared with TA staples.
Clinical significance: The LigaTie may be an effective alternative
Ex vivo comparison of different thoracoabdominal stapler
sizes for typhlectomy in canine cadavers
Matz 2022
Study design: Randomized, experimental cadaveric study.
Animals: Twenty-four fresh canine cadavers
Conclusion: Each stapler size that was evaluated resulted in a mean ILP in
excess of typical intraluminal pressures under normal circumstances. There
were no differences among groups
Ex vivo comparison of intradermal closures with conventional
monofilament suture vs unidirectional barbed suture in dogs
Regier 2019
Study design: Experimental study.
Sample population: Forty-eight full-thickness wounds in canine cadavers.
Conclusion: Monofilament sutures resulted in stronger constructs, whereas barbed
suture constructs provided a better watertight seal.
Clinical significance: While unidirectional barbed sutures may improve watertight
skin closure, surgeons should consider using conventional monofilament sutures
when mechanical strength of the closure is of primary concern.
Tensile properties of synthetic, absorbable monofilament suture
materials before and after incubation in phosphate-buffered
saline
Tobias 2020
suture material should not be based on size and percentage tensile
strength retention but on known characteristics such as baseline tensile strength, stiffness, and elongation
tensile properties of 2-0 and 3-0 absorbable
monofilament suture were influenced by size, composition,
brand, and incubation. For a given suture size, baseline strength
and maximal extension varied by up to 63.6% and 34.3%,
respectively, with Maxon suture having the greatest strength
and elongation and Biosyn having the greatest stiffness. For
some sizes and compositions, strength of more rapidly absorbable
suture after 7 or 14 days of incubation was greater than
baseline strength of slowly absorbable suture.
Freezing and thawing of cadaveric jejunal tissues prior to investigative use is not recommended because leak pressure data may be falsely low.
when finishing a continuous pattern,
the number of twists within the ending loop may not increase the risk of failure at the knot; however,
it can decrease the maximum load to failure at a knot, particularly as the suture size increases.
Therefore, care should be taken not to twist the suture when handling.
In vitro holding security of four friction knots
of monofilament or multifilament suture used
as a first throw for vascular ligation
Tremolada 2020
280 friction knot constructs in vitro
surgeon’s throw, Miller knot, Ashley modification of the Miller knot, and strangle knot)
2-0 monofilament (polyglyconate, polydioxanone, poliglecaprone-25, and glycomer-631) and braided multifilament (silk, lactomer, and polyglactin-910)
statistically significant, may not have been clinically relevant.
the surgeon’s throw should be avoided as a first throw for pedicle ligation and that poliglecaprone-25 may be more prone to friction knot slippage than the other suture materials evaluated.
ligasure 5mm (2019)
Handsets can successfully be reused until activation button failure without negative effects on the vascular seal or increased risk of infection to the patient.
Ligasure (2018)
consider discarding handsets after 9 cycles for the
Small Jaw and after 16 cycles for the Impact.
endoscopic 3-mm sealing device (2020)
safe to use for up to nine reuse-and-resterilization cycles
Investigation of the in vitro antimicrobial activity of triclosan-coated suture material on bacteria commonly isolated from wounds in dogs
McCagherty 2020
a topical biocide
6 types of suture material and 10 isolates each of methicillin-susceptible Staphylococcus pseudintermedius, methicillin-resistant S pseudintermedius, Escherichia coli
Surface characteristics of suture materials may be as important or more important than triclosan coating for microbial inhibition; however, triclosan coating appeared to affect bacterial adherence for multifilament sutures
clinical studies needed.
Influence of barbed epitendinous sutures combined with a
core locking-loop suture to repair experimental flexor
tendon lacerations
Eby 2020
Stratafix barbed suture eliminates the requirement for
knot tying and seems to be equivalent to smooth monofilament suture when
used as an ES in this pattern.
experimetnal study
List some reported used of barbed suture
Gastropexy
Gastrotomy
Enterotomy
Intestinal anastomosis
SDFT and gastrocnemius tendon repair
In GIT surgery, results in faster repair with equivalent or better bursting strength and leakage
However, significantly underperforms smooth knotted suture in tendon repair for ultimate tensile strength and gap formation
What are the 2 major methods of suture absorption?
Enzymatic (predominates in natural materials)
Hydrolytic (Predominates in synthetic sutures)
List the disadvantages of Catgut
Relatively weak
Not uniform
High tissue reaction
Absorption is extremely variable and unpredictable
very rapis absorption in gastric or intestinal surgery
What are the disadvantages of Nylon Leader Line
It was not designed as an implantable biomaterial. It will elongate under constant loads and its physical properties are significantly influences by steam sterilisation
Steam sterilisation resulted in a 204x increase in elongation
What is the strongest form of suture?
Polyester composite sutures eg FiberWire (multifilament UHMW polyethylene core surrounded by braided polyester and polyethylene exterior
needles
Standard cutting needle – triangular w cutting surface on concave surface
* Creates triangular defect with vertex directed toward the incision
* May increase suture pull through
Reverse cutting needle – cutting surface on concave surface
* Creates triangular defect with flat edge parallel to incision
* Theoretically less risk of inadvertent needle hold elongation during needle passage and less risk of suture pull through
properties of suture
o Breaking strength - stress value on the stress-strain curve at which suture acutely fails
o Tensile Strength – similar to ultimate strength, breaking strength, or yield strength
Measure of sutures ability to resist deformation and breakage and stress at which deformation (yield stress) or rupture (breaking or ultimate strength) occurs
o Creep - tendency of suture to slowly and permanently deform under constant stress
o Elasticity – degree to which a suture will deform under stress or load and return to its original form when load is removed
o Memory – tendency for suture to return to its original shape after deformation
o Knot pull-out strength – load required to break a suture deformed by a knot
Deformations caused by knot placement generally results in 10-40% loss of strength
morphology
monofilament: less pliable and less tissue drag
Multifilament: * Greater strength and pliability
* Greater tissue drag or friction
* Greater capillarity – increased tendency for bacterial colonization
o Composit or Polyblend – core of one polymer and braided exterior of a different polymer
o Barbed
absorbable suture material 5
Monocryl Poliglecaprone 50% 1-2wk
vicryl rapid 0% at 2-3wk
Vicryl (polyglactin) 50% 2-3wk
Dexon polyglycolic acid 50% 2-3wk
Maxon polyglyconate 50% 4-5wk
PDS polydioxanone 50% 5-6wk
MVDMP
nonabsorbable suture 6
silk
nylon
polypropylene
fibre wire
polytetrafluoroethylene (gortex)
steel
surgical mesh 3 function
Close defects,
buttress primary tissue repair
augment repair of slow healing tissues (tendons, ligaments, etc.)
- Synthetic polymers (woven, knitted, or expanded)
woven mesh
: stronger, stiffer, and less porous
warp and weft directions; more elastic and fluid in direction 45 degrees from warp and weft (cross-grain direction); two bias directions 90 degrees from each other
Warp – set of lengthwise filaments aligned in one direction
Weft – filaments woven over and under the warp at perpendicular
knitted mesh
– intermeshing loops of one continuous filament; more porous and flexible; less strong
Anisotropic – elongation in one axis (the course) is greater than elongation along the other (wale)
Course - the row of distensible loops across a fabric
Wale – the column of loops along the length of the fabric
What is meant by the pore size and porosity of mesh materials? How does this effect its properties?
The ratio of material to air
Polypropylene mesh - pore size 0.6-0.9mm with porpsity 28-32%
ePTFE pore size 20-25nm
Very small pore size will prevent capillary ingrowth causin encapsulation rather than incorporation
What biologic materials have been used as mesh? 4
Porcine SI submucosa
Bovine pericardium
Acellular dermal matrix
Canine fascia lata
3months after implantation, porcine SIS is histologically non apparent and has been replaced
Fascia lata consistently has shown the best biological properties followed by polypropylene
recommendations for implantation of mesh?
Trimming with electrosurgery may seal edges and prevent frayinf
Create a hem
Horizontal mattress sutures will engage more mesh
If under tension, should overlay 1cm of tissue
Little or no tension, 0.6cm overlap
- Study comparing pull-out strength, tensile strength, and push-through strength
Fascia lata > polypropylene mesh> multilaminate submucosa > single laminate submucosa
Are skin staples appositional, inverting or everting?
* Absorbable, titanium, or 316L stainless steel
slightly everting
What are the principles of vascular clip application?
advantage = speed at which they can be placed
disadvantage = reduced security compared with suture ligation
LDS (ligate-divide-staple) device
Vessel is skeletonised prior to application
Diameter of the vessel should be no more than 2/3 and no less than 1/3 the length of the clip
Clip applied several mm from cut edge
Arteries and veins clipped seperately
What sized staples are in the coloured cartridges of TA devices?
Green - 4.8mm compress 2.0mm
Blue - 3.5mm to 1.5mm
White - 2.5mm to 1mm
What can linear staplers be used for?
Pulmonary Sx
Cardiac Sx
GI
hepatobiliary
reproductive
GIA staplers
50/80/90/100mm length
3.5 or 4.8mm staple
staggered rows then incise tissue inbetween
use: side-side anastamosis
circular
end-to-end, end-to-side, or side-to-side anastomosis GIT
require preplacement of a pursestring suture
o When the stapler is fired, staples are placed and a stoma is created. A “doughnut” of tissue remains in the stapling device.
What are the rules regarding tissue thickness for circular stapling devices?
Should not be used when combined tissue thickness is less than 1mm or greater than 2.5mm
surgeon evaluate this doughnut for luminal patency and inclusion of all layers
What are the byproducts of cyanoacrylate glue?
Cyanoacetate and formaldehyde
What are the benefits of using cyanoacrylate glue for wound closure?
Speed
No need for suture removal
Reduced cost
Barrier to microbial penetration
Antibacterial effects
In people, a study has shown that wounds closed with glue had significantly fewer post-op infections than sutures wounds
