Flashcards in Suturing materials and epidermal closure techniques Deck (154):
Buried sutures can be used to close dead space, redistribute tension, decrease dehiscence and increase wound eversion.
When undermining wound edges, skin hooks are the least traumatic means of stabilising and mobilising wound edges.
The configuration of a suture denotes its composition.
Advantages of suture braiding include lower propensity for infection.
F Increased propensity to retain microorganisms.
Advantages of suture braiding include increased tensile strength.
Advantages of suture braiding include decreased fraying of cut ends.
Newer innovations include suture coating with either antibacterial or antitumor qualities
Disadvantages of braided sutures include poorer handling and knot-tying properties.
Disadvantages of braided sutures include more resistance when pulled through tissue.
Sutures coated with silicone, Teflon and wax decreases friction.
Capillarity denotes a suture’s ability to wick fluid from an immersed end to its dry end.
Braided sutures have decreased capillarity.
Sutures with increased capillarity are more likely to harbor bacteria
Tensile strength refers to the weight necessary to break a suture divided by the cross-sectional area.
Larger sutures have decreased tensile strength.
Synthetic sutures tend to have decreased tensile strength compared to sutures of natural materials.
Tensile strength can be decreased by physical factors, such as wetness or increased age of sutures
Due to shearing forces between the strands, braided sutures have decrease tensile strength
The number/size ranks of sutures refer to their tensile strength – the greater the tensile strength, the fewer the zeros.
T Ie 2-0 suture has more strength than 6-0.
All sutures with the same tensile strength will have the same calibre.
F Eg. The calibre of a 5-0 nylon will be smaller than a 5-0 gut because nylon is stronger.
Knot strength refers to the security of a tied knot and is defined by the degree of slippage that occurs in a knot.
Sutures with a decreased coefficient of friction slide more easily and have a lower knot strength.
Memory is the ability of a suture to return to its original size and shape after being stretched.
F This is true for elasticity.
Elasticity denotes the ability of a suture to regain its former shape after bending.
F This is true for memory
Knots in sutures with increased memory (eg. polypropylene and nylon) have a greater tendency to untie themselves.
T Should throw extra ties with these sutures.
Sutures with increased memory are less difficult to handle.
F More difficult
Elasticity is a desirable quality for a surface suture as it means the suture will stretch with the tissue and also recoil when the swelling subsides.
Plasticity refers to a suture’s ability to retain their deformed shape rather than return to their original shape when stretched.
Plasticity is advantageous in knot tying because deformation of the suture may lead to a more secure knot.
Sutures made of natural materials are less immunogenic than synthetic materials.
F More immunogenic.
Sutures with a multifilament configuration are more immunogenic than those with a monofilament configuration.
Non-absorbable sutures are more immunogenic than absorbable sutures.
F Less immunogenic. The immune response elicited by absorbables cause their dissolution.
Large diameter sutures are more immunogenic than small diameter sutures.
All sutures exhibit at least some inflammatory response when placed in tissue.
Sutures made of natural material are degraded by proteolysis in contrast to synthetic sutures which are degraded by hydrolysis
Non-absorbable sutures cause less tissue reaction because they induce a fibrous shell which coats the suture and decreases the host response.
True suture allergy does not occur.
Absorbable sutures are defined as those that lose the majority of their tensile strength within 60 days after placement in living tissue.
T non-absorbable sutures maintain their tensile strength for periods >60 days.
The presence of wound infection does not affect suture absorption.
F Increases suture absorption.
Suture placement location does not affect the rate of suture absorption.
F Mucosa absorbed faster.
Surgical gut is the only absorbable suture made of natural materials.
Surgical gut is a twisted multifilament suture composed mostly of collagen.
Fast absorbing gut is recommended for internal use
There are two varieties of gut sutures: plain and chromic.
F Three varieties. Also fast-absorbing.
Plain surgical gut loses much of its tensile strength in 3 weeks.
F 7-10 days.
Plain surgical gut is completely absorbed by 70 days.
Fast-absorbing gut is heat treated for more rapid deterioration.
Fast absorbing gut is used in facial wound closure, or the placement of skin grafts where rapid absorption of the suture is desirable
Nearly all of the tensile strength of a fast-absorbing gut suture is lost within 7 days, and complete absorption takes 21-42 days.
PDS II has lower tensile strength than fast-absorbing gut initially does
F Fast-absorbing gut –low initial tensile strength, PDSII high initial tensile strength, 50% at 4 weeks, 25% at 6 weeks
The initial tensile strength of Glycomer 631 (Biosyn) has not been studied
T Known at have 49% retained tensile strength at 3 weeks
Chromic gut has been treated with chromate salts which increases the rate of absorption in tissue.
Decreases rate of absorption
Chromic gut maintains its tensile strength for 10-21 days and is completely absorbed after approximately 90 days.
Chromic gut is best used to suture skin edges.
F Ligate vessels or suture mucosal wounds.
A history of chromate sensitivity does not preclude use of the chromic gut suture.
dont use if chromate sensitivity/allergy
Disadvantages to gut sutures include unpredictable absorption rates, low tensile strength, and increased tissue sensitivity.
Polyglycolic acid (Dexon) is a synthetic absorbable suture.
Polyglycolic acid is a non-braided suture.
F Braided multifilament suture.
Polyglycolic acid sutures can be coated with polycaprolate coating to reduce drag when pulled through tissues.
The polyglycolic acid suture retains 65% of tensile strength for 2 weeks after placement and 35% 3 weeks after implantation.
The polygycolic acid suture is completely resorbed between 30-60 days after placement.
F 60-90 days.
Advantages to using the polyglycolic acid suture include good handling and knot security and low tissue reactivity.
Polyglactin 910 (Vicryl) is a coated braided multifilament suture.
Polyglactin 910 consists of a copolymer made from 90% glycolide and 10% l-lactide.
Polyglactin 910 has similar handling properties to polyglycolic acid but has less tense strength.
F More tensile strength.
Polyglactin retains 75% of its tensile strength at 2 weeks and 50% at 3 weeks, and it is completely resorbed after 56-70 days.
Vicryl-rapide is a more rapidly dissolving form of polyglactin 910.
Vicryl-rapide loses 50% of its tensile strength at 5 days and essentially all tensile strength within 10-14 days.
Lactomer (Polysorb) is a coated braided multifilament suture made of copolymers of lactic and glycolic acids
Lactomer retains 80% of its tensile strength at 5 weeks and over 30% at 10 weeks. respectively.
F 2 and 3 weeks
Polydioxanone (PDS) if a multifilament synthetic absorbable suture.
Polydioxanone has increased tensile strength when compared to polyglactin 910 or polyglycolic acid.
F Decreased tensile strength.
Polydioxanone is more slowly resorbed and retains its strength for longer than polyglactin 910 or polyglycolic acid.
Polydioxanone retains 70% of its original tensile strength at 2 weeks, 50% at 4 weeks, and 25% at 6 weeks.
Complete absorption of polydiaxanone takes approximately 3 months.
F 6 months. Absorption is negligible until 3 months.
Polydiaxanone may be useful in wounds under high tension or wounds that require prolonged dermal support.
Polytrimethylene carbonate (Maxon) is a multifilament synthetic absorbable suture.
Polytrimethylene carbonate has lower initial tensile strength than polydiaxanone.
F Higher initial tensile strength.
Polytrimethylene carbonate retains 81% of initial tensile strength at 2 weeks, 59% at 4 weeks, and 30% at 6 weeks.
Polytrimethylene carbonate is absorbed more slowly than polydiaxanone.
F More quickly. Its absorption starts 60 days after implantation.
Polytrimethylene carbonate has worse knot strength and handling properties compared to polydiaxanone, polyglycolic acid and polyglactin 910.
Poliglecaprone 25 (Monocryl) is a monofilament absorbable synthetic sutre with superior handling and tying properties due to its increased pliability.
The knot strength of poliglecaprone is superior to polydiaxanone, polyglycolic acid, polyglactin 910 and polytrimethylene carbonate sutures.
Poliglecaprone has lower initial tensile strength than PDS II or Maxon.
Poliglecaprone’s strength diminishes more quickly than the other monofilament synthetic sutures.
Poliglecaprone 25 retains 60% of its initial tensile strength at 7 days, 30% at 2 weeks, and loses all of its tensile strength by 3-4 weeks.
Dyes Maxon sutures retain their tensile strength and remain in tissue slightly longer than the clear sutures.
Absorption of both clear and dyed poliglecaprone sutures is essentially completed by 2-3 months.
F 3-4 months.
Fast absorbing gut is a multifilament, with poor knot strength, high tissue reactivity and loses its tensile strength in 3-7days
Surgical silk is a multifilament suture composed of braided fibres of protein harvested from the cocoon of the silkworm larva.
Surgical silk is not absorbed.
F Completely absorbed within 2 years.
Surgical silk loses almost all of its tensile strength 6 months after implantation
F 1 year
Silk suture is very soft. It should not be used on mucosa or intertriginous areas
Silk suture has superior handling and knot tying characteristics
Silk suture use is limited due to its tendency to cause tissue reactions
Silk is a monofilament
Silk had low tensile strength
Silk has poor knot strength
Silk has low memory
Polypropylene (prolene) has excellent knot strength
Polybutester (novafil) has excellent knot strength
Nylon sutures have high tensile strength and are absorbed at a rate of 15-20% per year if left in tissue.
Monofilamentous nylon has a high degree of memory, decreasing its pliability, handling and knot security.
Nylon sutures are unaffected by moisture.
F Made more pliable by moisture.
Polypropylene (Prolene) is a multifilament synthetic suture.
Polypropylene has a lower tensile strength than other synthetic non-absorbable suture.
Polypropylene has low tissue reactivity and an extremely low fiction coefficient.
T therefore decreased knot security.
Polypropylene will eventually be degraded if left in tissue.
F therefore good to reapproximate ear cartilage
Polypropylene has significant plasticity.
Polyester is a braided multifilamentous synthetic suture that is soft and pliable.
Polyester has a high tensile strength, which is only exceeded by metal sutures.
Polyester is generally uncoated.
F Coated with Teflon, silicone or polybutylate.
Polybutester (Novofil) is a monofilament suture composed of polyglycol terephthate and polybutylene terephthate.
Polybutester exhibits elasticity.
Polyhexafluoropropylene-VDF (Pronova) is a monofilament non-absorbable suture composed of a polymer blend of polyvinylidene fluoride and polyvinylidene fluoridecohexafluropropylene.
Pronova has a high coefficient of friction.
Most suture needles are composed of stainless steel.
An ideal suture needle is malleable, strong and sharp.
Malleability refers to a needle’s resistance to breaking under a given degree of bending.
Reshaping a bent needle generally does not affect the needle’s strength or lead to breakage.
Sharp needles result in less tissue trauma and better cosmetic results.
Needles are often coated with silicone or other lubricants to improve the ease of needle penetration.
There are two parts to a suture needle – the shank and the point.
F Three parts – also the body.
The shank is the portion of the needle that attaches to the suture.
The point is the weakest part of the needle.
F The shank is weakest.
The point is the largest pat of the needle-suture unit, and hence it determines the size of the suture tract.
F This is true for the shank.
The point of the needle extends from the tip of the needle to the largest cross-section of the body.
The body is the middle portion of the needle between the shank and the point.
The body is the strongest portion of the needle and this part should therefore be grasped with the needle holder.
A conventional cutting needle has its primary cutting edge on the outside of the curve.
Reverse cutting needles have their primary cutting edge on the inside of the curve.
Reverse cutting needles result in less tissue tearing by the suture after tying.
Rounded needles cause less tissue tearing than conventional or reverse cutting needles.
T Use in delicate areas or in fascia.
Staple placement is 50% faster than suture placement.
F 80% faster.
Staples have an increased risk of tissue strangulation, reactivity and infection than sutures. .
F Decreased risk
Flaps that are stapled have a lower risk of partial necrosis compared to sutured flaps.
F Higher risk.
Tissue adhesives are made of cyanoacrylate compounds.
Histoacryl is octyl cyanoacrylate.
F Dermabond is.
Dermabond is N-butyl-2-cyanoacrylate.
F Histoacryl is.
Octyl cyanoacrylate has improved flexibility, less tissue toxicity, and at least three times the bonding strength of n-butyl-2-cyanoacrylate.
Octyl cyanoacrylate is used with application of a single layer.
F Triple layer.
Horizontal mattress sutures should not be used when suturing flaps because there is a greater theoretical risk of dermal strangulation.
T Also shouldn’t used in poorly vascularised wounds.
Locking horizontal mattress suture is helpful for wounds that need wound edge compression or haemostasis
Horizontal mattress stitches can be placed with half of the suture buried in the dermis
The half-buried horizontal mattress stitch is often used as a ‘tip stitch’ to secure the triangular tips of flaps.
Half buried horizontal mattress stitch uses non absorbable suture
A running epidermal stitch is stronger than an interrupted stitch
A running locked suture can facilitate haemostasis.
The running subcuticular stitch minimises epidermal puncture points, allowing sutures to be left in place longer.
A buried vertical mattress suture results in more wound eversion than a buried butterfly suture.
Suture tracks occur when sutures have been left in place too long, needles and suture calibre is too large, or if sutures are tied too tightly.
Purse string suture decreases the diameter of a wound
The purse string suture involves vertically orientated bites spaces 5-10mm apart placed continuously along the circumference