VM 733 – Spring 2012 Lectures 4 and 5 - Suture ... - CSU PVM 2014

1-24-2012 

Lectures 4 and 5 - Suture Patterns 

Catriona MacPhail, DVM, PhD, Diplomate ACVS 

VM 733 – Spring 2012 

Lecture Objectives: 

Build on fundamental suture pattern principles learned in Foundations Fall 2011 

Recognize common suture patterns 

Understand advantages and disadvantages of mostly commonly used patterns 

Identify common clinical applications or scenarios for specific suture patterns 

Suture patterns categorized by: 

Anatomic area placed 

Appositional, inverting, or everting 

Ability to neutralize tension 

Interrupted or continuous 

Surgical knots: 

Simple – one throw 

Square knot – two throws; opposite direction 

Surgeon’s knot – two passes on first throw 

Slip square knot = half-hitch 

List of Common Suture Patterns: 

Simple interrupted 

Simple continuous 

Continuous Ford interlocking 

Continuous intradermal 

Interrupted cruciate sutures 

Interrupted vertical mattress 

Interrupted horizontal mattress 

Far-near-near-far 

Far-far-near-near 

Inverting patterns: 

Cushing 

Connell 

Lembert 

Interrupted 

Easy to place 

Adjustable tension 

Good strength and security 

More time and material 

Square knots are super secure 

Provides friction, but it may be a false 

sense of security--extra material within 

the knot creates a weaker knot overall 

Continuous 

Speedier 

Less suture material 

Easier to remove 

Better tissue apposition 

Break in line or loss of knot could be 

disastrous

Knot Tying 


The knot is the weakest point of a suture. A knot consists of at least two throws 

laid on top of each other and tightened. The throws can be joined parallel, as in a square 

knot, or crosswise, as in a granny knot. Correct knot-tying technique is important, 

because incorrectly tied knots (e.g., tumbled knots, half-hitches, or granny knots) may 

lead to dehiscence. Factors that influence knot security are the material coefficient, the 

length of the cut ends, and the structural configuration of the knot. The most reliable 

configuration for a knot is superimposition of squared knots. 

A surgeon’s (friction) knot involves passage of suture material twice on the first 

throw. Due to the extra suture material, this knot cannot be easily tightened and can 

withstand only a slight strain on the suture loop. Although it often is used in areas of 

tension, it generally is not recommended for use with coated or monofilament 

materials, and should be avoided unless tissue tension is such that use of the standard 

square knot would result in poor tissue apposition. It is not recommended to use a 

surgeon’s knot to ligate vessels. 

Multifilament sutures generally have better knot-holding properties than 

monofilament materials; however, coating the suture to decrease tissue drag reduces 

knot security. To prevent strangulating tissue, excessive tension should be avoided 

when tying knots (except when ligatures are applied for hemostasis). Excessively tight 

skin sutures cause the patient discomfort and increase the likelihood that the animal 

will remove the sutures prematurely. 

Instrument Ties 

In veterinary medicine, instrument ties are more commonly used than hand ties 

because it is thought there is less waste of the suture. The first loop is made, after which 

the suture should not be lifted or have uneven pressure applied to either end, or the 

throw will loosen. If one end is pulled with greater tension than the other, a half-hitch 

will form. Opposing suture ends should be pulled perpendicular to the long axis of the 

incision. Lifting one hand causes the suture to tumble, forming a sliding two half-hitch 

knot. Failure to correctly cross the hands results in a granny knot.

Hand Ties 


Hand ties are particularly useful in confined or hard to reach areas or when 

sutures have been preplaced, as in a thoracotomy closure. Hand ties generally require 

that suture ends be left longer than for an instrument tie, but can be placed much faster 

and more securely than instrument ties. A one-handed or two-handed technique may 

be used. The two-handed technique generally allows better control and accuracy; 

however, the one-handed technique is more useful in confined areas. 

INTERRUPTED SUTURE 

GOOD 

Easy to place 

Adjustable tension 

Good strength and security 

Loss of a single knot/suture is less 

disastrous 

BAD 

More time and material 

Two big types: 

Simple = single massage on each 

side, then tied 

Mattress = two passages on each 

side, then tied 

0.5 cm from wound edge, 0.5-1 cm 

apart (in skin--smaller and closer in 

viscera) 

Maximum wound holding with 

minimal interruption of blood supply 

Motion: forehand placement 

Right to left (right handed) 

Left to right (left handed) 

Follow your forceps... 

Direction: from point most distant to 

point closest (not an absolute rule) 

1-27-2012 

CONTINUOUS SUTURE 

GOOD 

Fast placement 

Uses less material 

Easy to remove 

Better seal, esp. good for intestine 

BAD 

Loss of knots or suture breakage is 

more disastrous--lose part of the line 

and you could use the whole line

Surgical Knots 

Buried intradermal 

--series of connected simple interrupted 

--crosses the wound on the diagonal 

--pay attention to spacing and tension 

--tie across to last raised loop 

--if too tight will necrose, evert, or 

invert 

Simple continuous 

Simple interrupted 


--usually appositional, but 

can evert or invert if too 

tight 

--mild to moderate effect on tension 

--commonly utilized for skin closures 

--two simple interrupted passes in the 

Interrupted cruciate 

same horizontal plane, tie to form 'X' 

across incision 

Continuous Ford interlocking 

--less likely to fail with breakage or knot 

loosening 

--better tissue apposition 

--greater tissue stability 

Continuous intradermal (Modified horizontal mattress) BUT takes more material and time and 

--placed within dermis (subcuticular) 

may cut into tissue if under too much 

--begin with buried, interrupted knot 

tension 

--pass sutures in dermis parallel to incision 

--each passage is linked to previous 

--good for opposing edges 

passage 

--need absorbable suture & a cutting needle 

--lass pass is a backhand pass across

--unlike vertical, instead of staying in same vertical plane, 

move horizontally before making backhand pass 


--can be more traumatic than vertical because they cover 

more area, but stronger as a result 

--may interfere with blood supply to edges of skin --forehand pass then backhand pass vs. pulley 

which is forehand pass, cross incision, then 

forehand again 

--no suture material on top of the incision line 

--apposition to slight eversion 

--relieves tension 

Interrupted horizontal mattress 

with and without stents 

Near and far mattresses 

--tension relieving 

--variation of vertical mattress 

aka Pulley 

(relative to the incision) 

Interrupted vertical mattress 

Lembert --for closure of hollow viscera 

--suture passed perpendicular to 

Cushing (above); Connell (below) 

incision 

--for closing hollow viscera 

--suture enters and exits tissue on the 

--continuous 

same side of the incision 

--suture passed parallel to incision 

--partial thickness 

From Slatter D (ed.), Textbook of Small Animal Surgery, 2003, pp215-220 

--Cushing - partial thickness 

--often used as second layer on a 

--Connell - full thickness (ends up in 

double layer pattern 

lumen) 

--inverting 

--submucosa is the holding layer for 

viscera, so she prefers Connell 

because it ensures you get that layer

Cases 

Gastrotomy Closure - FB Ingestion 

--Stomach heals relatively well, so can use 

rapidly absorbable suture 

--Synthetic, monofilament (want it to slide 

well and not wick), absorbable 

--3-0, taper needle (don't want to cause more 

trauma with a cutting needle 

--Closure: double layer continuous inverting 

(first layer Cushing/Connell/simple continous, 

second layer Lembert) 

OR single layer simple continous 

OR single layer simple interrupted 

== all are acceptable 

Probably do not need two layers in normal, 

healthy skin 

Gastrectomy Closure - GDV 

--resecting portion of devitalized tissue 

--double layer would be a good choice here-inflamed, 

friable, injured tissue 

Cystotomy Closure 

--bladder heals quickly, so rapidly 

absorbable suture is a good choice 

(e.g. Caprosyn)

VM 733 – Spring 2012 Lectures 4 and 5 - Suture ... - CSU PVM 2014

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