Sutures and needles

Question 1

what is suturing used for?

Answer 1

hemostasis, ligation, and apposition of tissue with suture material, needles, knots, patterns, staples, clips, and tissue adhesives
also tighten/stabilize joints and attach catheters

Question 2

square knot

Answer 2

most desirable
combines 2 simple or half knots one on top of the other
reverse direction on each successive simple knot
maintain even tension on both strands
pull strands parallel and horizontal to the plane of the knot and skin

Question 3

which knots are undesirable?

Answer 3

granny: successive simple knots without reversing direction
half-hitch: made when there is failure to keep even tension on each strand or when 1 strand is pulled upward and not kept horizontal

Question 4

surgeon’s knot

Answer 4

essentially square knot where the 1st simple knot is made using a double throw (or loop)
double throw increases the friction of the knot and yields better holding power under tension

Question 5

interrupted suture pattern

Answer 5

individually tied and if one breaks the rest will still be intact
good for spay/neuter in puppies/kittens
simple interrupted: precise tension along the incision, easiest pattern to use but takes longer and uses more material

Question 6

mattress suture pattern

Answer 6

resist tension
horizontal mattress: may be used with stents
vertical mattress: may be used with stents
cruciate or cross mattress: can take the place of 2 simple interrupted sutures, good for closing circular holes (like punch biopses)

Question 7

simple uninterrupted suture pattern

Answer 7

saves time and material, can seal incisions better and evenly distributes tension along incision, but if breaks all can unravel

Question 8

subcuticular suture pattern

Answer 8

subcanteous: closes SQ tissues, decreases dead space, and if there is very little skin tension it can be used to hold skin closed without skin sutures

Question 9

suture needle shapes

Answer 9

can be half curved, straight, half circle, or 3/8 circle
usually described by shape, size, tips, and eyes
sizes determined by numbers: larger number = smaller needle

Question 10

taper suture needle tip

Answer 10

traumatic and similar to sewing needle tip, hard time penetrating tougher tissue like skin so used on tissue that is easily torn/cut, tip makes best air and liquid tight hole

Question 11

cutting suture needle tip

Answer 11

has a cutting edge on concave surface

Question 12

reverse cutting suture needle tip

Answer 12

has a cutting edge on convex surface

Question 13

suture needle eyes

Answer 13

can be round, square, french or split
needle eyes also include swaged which has suture material permanently attached to the eye end of the needle

Question 14

what are the properties of good suture material?

Answer 14

available in all sizes, be sterile, be low in cost, hold knots well, be non-irritating and non-carcinogenic, be strong and have increased tensile strength, absorb completely after healing without reactions, inhibit bacterial growth or wicking, have desirable handling characteristics (friction, memory, drag, chatter)

Question 15

monofilament suture material

Answer 15

1 stranded
smooth surface, less friction than multifilament (less drag and chatter= less tissue trauma, no wicking, more memory than multifilament, less overall strength than multifilament

Question 16

multifilament suture material

Answer 16

more than 1 strand twisted together (aka braided)
has opposite characteristics of monofilaments

Question 17

absorbable suture material

Answer 17

requires an immune response to phagocytize material, there must be some inflammation for this to occur

Question 18

natural absorbable suture material

Answer 18

catgut: retains tensile strength for the shortest time (3-5 days), faster absorption= greater inflammatory response, comes from sheep intestinal submucosa
chronic catgut: “tanned” cat gut, slows inflammatory response and tensile strength is held longer (10-15 days)

Question 19

synthetic absorbable suture material

Answer 19

PDS II-polydioxanone: slowest absorbed and has the least inflammatory response

Question 20

nonabsorbable suture material

Answer 20

never goes away, becomes encapsulated by tissue

Question 21

natural nonabsorbable suture material

Answer 21

silk: strongest material, braided and often coated to decrease wicking, has some of the least memory and handles well so often good choice for cardio and ophthalmic surgery
cotton/linen: sterile strips of fabric used in large animal, can have static electricity, wicks

Question 22

synthetic nonabsorbable suture material

Answer 22

nylon: slippery
Caprolactams: (Veetifil, Supramed, Braunamid), these are coated multifilament suture materials
stainless steel wire: very strong, difficult to handle, bulky knots, no give

Question 23

other wound closure methods

Answer 23

staples: used for skin closure and muscle closure
clips: used for ligating, hemoclips is a common brand
tissue adhesive: type of super glue, to be used at or above skin layer, typically glue not absorbed but it is sloughed off or if buried under skin, it is extruded through the skin

Question 24

suture removal

Answer 24

1. swab area to remove debris
2. apply tension with fingers to see if incision will separate (even the commonly expected 10-14 days for skin healing can be incorrect if wound healing is delayed by wetness, trauma, poor hygiene, infection, or it is under tension
   don’t tear the suture through the skin
3. cut off extra suture material above the skin so that it isn’t dragged under the surface when the sutures are removed