How to suture
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General Principles:
Avoid damaging the suture material while handing. Beware of the crushing of
suture with surgical instruments.
Using excessive tension while knot typing will cause the suture to break, and
may even cause suture to tear through tissue.
APPROXIMATE, DON’T STRANGULATE.
o Sutures are intended to approximate tissues and should not be tied
too tightly.
Principles of knot tying:
o The completed knot must be firm, and tied so that it will not slip.
o The knot should be as small as possible to prevent tissue reaction or
foreign body reaction (use small filament suture – aka thin suture)
o While tying knots, avoid friction between the two strands, as this
weakens the suture.
o After the first loop of the knot is tied, you must maintain traction on
one end to avoid loosening of the throw.
o Tension on the knots should be horizontal and in the direction of the
wound.
o You can change position to place a knot securely and flat.
o Extra ties do not strengthen the knot; they only add to the bulk.
Loading the needleholder
 Always load the suture needle at
a 90 degree angle to the needleholder.
 You should grasp the needle
about 2/3 from the point (as shown)
 Always grasp the needle in the
very tip of the needleholder.
Types of suture
 Materials
o There are a variety of suture types from which to select.
 Types are listed in the chart below.
Suture
Types
Raw
Material
Tensile
Strength
Absorption
Rate
Contraindications
Uses
Determined by
individual
tissue
characteristics
75% remains
at 2 weeks;
50% at 3
weeks
55% remains
at 1 week; 25%
at 2 weeks
Absorbed by
proteolytic
enzymes
Not used for extended
approximation of
tissues under stress
Soft tissue
Absorbed by
hydrolysis;
complete by 5070 days
Absorbed by
hydrolysis;
complete by 91119 days
Not used for extended
approximation of
tissues
Soft tissue
Not used for extended
approximation of
tissues or for wound
support >7 days
Superficial soft
tissue
approximation of
skin and mucosa
only
70% remains
at 2 weeks;
50% at 4
weeks; 25% at
6 weeks
Absorbed by
hydrolysis;
minimal until 90
days and
completely
resorbed by 6
months
Not used for extended
approximation of
tissues under stress
Progressive
degradation
may result in
gradual loss
over time
Indefinite
Gradual
encapsulation
by fibrous
connective
tissue
Nonabsorbable
Patient allergy or
sensitivity
Soft tissues
Sternal closure
Progressive
hydrolysis
may result in
gradual loss
over time
No
degradation
Gradual
encapsulation
by fibrous
connective
tissue
Nonabsorbable
Patient allergy or
sensitivity
Should not be used
for permanent tensile
strength
None
Soft tissue
Absorbable Suture
Surgical
“Cat” Gut
Plain or
chromic
Collagen
derived from
beef/sheep
Vicryl
Braided or
monofilament
Copolymer of
lactide and
glycolide
Monocryl
Monofilament
Copolymer of
glycolide and
epsiloncaprolactone
PDS II
Monofilament
Polyester
polymer
Nonabsorbable Suture
Silk
Braided
Organic
protein,
fibroin
Stainless
steel
Nylon
Monofilament
Stainless
steel
Long-chain
aliphatic
polymer
Prolene
Monofilament
Monofilament
or braided
Stereoisomer
of
polyprolene
Soft tissue
 Choosing the Suture:
o Certain circumstances dictate which suture material is most appropriate. The
following guidelines are useful:
 In a wound with maximal strength, sutures are no longer
needed:
 Tissues healing slowly like skin, fascia and tendons
should be closed with nonabsorbable sutures.
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Tissues that heal rapidly like stomach, colon, and
bladder may be closed with absorbable sutures.
Foreign bodies or potentially contaminated tissues may
convert contamination to infection:
 Avoid multifilament sutures, which may increase risk of
infection.
 Use monofilament or absorbable sutures in potentially
contaminated tissues.
When cosmetic results are important, close and prolonged
apposition of wounds and avoiding irritants will produce the
best results, thus:
 Use the smallest monofilament suture possible, such as
nylon or polypropylene.
 Avoid skin sutures and close subcuticularly when
possible.
 To secure close apposition of skin edges, a topical skin
adhesive or skin closure tape may be used.
Foreign bodies in the presence of fluids containing high
concentrations of crystalloids may act as a nidus for stone
formation.
 In the urinary and biliary tract, use rapidly absorbable
sutures.
 Suture size
o Ranges from 11-0 (smallest) to 6 (largest).
 Size 5-0 (“five-oh”) is best though of as 0.000001, and is
smaller than 5.
 Smaller suture is used for more delicate tissue:
 Eye, blood vessels, skin of face, etc.
 Larger suture is used for structures with more tension:
 Bowel, muscle, fascia, tendon, joints, etc.
 Needle type
o Taper (round) – used for soft tissue
o Cutting (triangular) – used for skin.
Simple Interrupted
 Load your suture on the needleholders.
 Take a “bite” ~1 cm from wound edge on both
sides. (sometimes it helps to take this “bite” in two
steps, reloading the suture from the center of the
wound before the second “bite”)
 Tie knots (instrument or hand) to approximate
tissues. Keep knots lateral to wound.
 Cut suture with ~2-3cm tails.
 Repeat to close wound, leaving ~1-1.5 cm
between sutures.
Simple Continuous
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Load the suture on needleholder.
Take a “bite” identical to the simple interrupted suture.
Tie the knot, but do NOT cut the suture.
 Instead of cutting the suture, continue taking evenlyspaced (~1 cm apart) bites of skin until you reach the end
of the wound.
 To tie the simple continuous, leave a “loop” of suture
on the final bite (do not pull the suture all the way to the
skin). Then, use the loop as your tail and instrument or
hand-tie the knots. Cut the suture with ~2 cm tails.
Horizontal Mattress
 Load the suture on the needleholder.
 Take a “bite” like a simple interrupted (maybe a
little larger; bigger bites are stronger).
 Instead of tying a knot, travel ~0.5 cm and make
another “bite” towards your suture tail.
 Tie a knot using the two ends on the same side of
the wound.
 Repeat with sutures ~1-2 cm apart until the
wound closure is sufficient.
**This particular suture type helps relieve wound tension.
Vertical Mattress
 Load the suture on the needleholder.
 Take a large bite across the wound (at least 1.5
cm from the wound edge).
 On the same side as the suture exited, take small
bites (0.5 cm) on both sides of the wound, finishing
with the suture near your tail.
 Tie the suture , with the knot being on the same
side of the wound.
 Repeat with sutures ~1-2 cm apart until the
wound closure is sufficient.
**This particular suture type helps relieve wound tension.
Subcuticular
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 Typically, a resident will begin this type suture
for the student. (see below for instructions for
starting subcuticular sutures)
 Travel horizontally across the wound, taking a
“bite” that is parallel with the skin surface in the
subcuticular tissue.
**At the wound edges, take as small “bites” as possible!!
 Travel horizontally back across the wound, and
repeat this motion in a zig-zag form until you close
the entire wound.
 Tie a knot using the “loop” of your last bite of
skin. Do NOT cut the suture. Bury the knot by taking a bite through the wound,
bringing the needle up lateral to the wound.
Often, subcuticular sutures are finished using a type of skin adhesive and gauze
dressing. Be sure to ask the resident or attending how to dress the wound.
Starting a subcuticular suture:
*Always be sure to ask the surgeon’s preferences with technique
before starting subcuticular suturing.
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Option 1: Take a small, deep bite of subcuticular tissue on ONE side only. Tie a
knot and trim the tail. Push the point of the needle through the apex of the
wound, coming out just under the skin in the subcuticular tissue.
o Subcuticular sutures NEVER go through the skin.
Option 2: Take a small, deep bite of subcuticular tissue and travel horizontally to
take a second bite, much like a horizontal mattress. The suture tail should be in
the center of the wound, and your second bite should come out in the wound. Tie
these two ends together. Trim the tail, then push the point of the needle through
the subcuticular tissue at the apex of the wound, coming out just under the skin.