Sutures 05 Parts

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Sutures 05 Parts

This subsection has text and images from an interactive multimedia training program on basic 
surgical skills called PrimeSkills in Surgery.
You can use this subsection on its own or follow the whole program (further details at the end of 
this subsection).


Characteristics.

Monofilament v braided.

For.

Against.

Braided.

For.

Against.

Materials.

Natural.

Silk.

Catgut.

Synthetic

Absorbable versus non- absorbable.

Sutures for skin.


Characteristics.


The immediate aims of the surgeon are to use a suture that will be easy to handle, will not break


on insertion into the tissues and will knot without slipping.


Later requirements are that the material remains strong enough until the body's repair tissues can


take over, without causing intense inflammatory reactions.


Modern sutures have many different characteristics designed to fulfil these functions, though the


ideal material has not been identified.


Suture strength


The manufacturers usually describe percentage reductions in tensile strength of their suture materials over weeks and


months.


They do not declare on each packet, the breaking strengths of individual sutures at the moment of suturing or knotting.


This is quite a fundamental omission.


The knotted breaking strength can easily be assessed using a spring balance, but this equipment is rarely, if ever found in the


operating room.


When offered a suture, the surgeon can apply the simple, but crude, test of breaking the suture in his hands.


We choose sutures according to the job in hand and also according to individual preference.


The properties listed below should make the trainee aware of the differences, advantages and


disadvantages at some of the materials.


They are not a criticism of the materials themselves.


Monofilament v braided


The monofilament suture.

101822000-MONOFILAMENT.jpg


For.


It is very smooth and has a low friction in the tissues.


The suture runs very easily through the tissues.


Several continuous stitches can be pulled easily through the tissue without causing damage.


This is a common technique in vascular anastomoses.


The surface of the suture tends not to harbour organisms and is accessible to antibiotics.


So stitch abscesses are less common than with a braided suture.


The surface of the suture attracts platelets less than a braided suture.


This prevents thrombus forming on vascular anastomoses.


Against.


It is slippery for an assistant to hold.


It is slippery for knot tying..


It may kink or snap.


It requires more throws for security than a braided suture.


The knots may slip.


It is a disadvantage when relying on a stitch not slipping.


It is actually an advantage when snugging down 2 throws of a knot.


The knots may unravel.


This is a nuisance if friction from clothing make the knots undo.


It is intolerant of the twisting effect of a series of stitches.


It tends to form loops more than a braided suture.


It is more springy than a braided suture.


It may flip onto unsterile parts of the patient when used for skin stitches.


It has more memory. e.g. It resists being straightened if it has been coiled up in its packet.


Braided.

101822300-BRAIDED.jpg

The main differences from a monofilament suture stem from the braided suture's higher friction and

higher compliance.


For.


It is less slippery.


It easier to handle.


It has less memory. e.g. Stretching it will permanently remove most coils and zigzags.


It is easy to handle and to knot.


Knots tend not to slip.


Fewer throws are needed on knots.


Its friction can be used to advantage in subcuticular stitches.


Against.


Its friction means it does not run as easily as a monofilament suture.

Even with a single stitch, there is a danger of the pull to overcome friction causing damage to


the tissues.


Pulling the braided suture through more than one stitch at a time is hazardous, except for

a subcuticular stitch.


There is more chance of infection lodging in the braided suture and not being accessible to


antibiotics- particularly a non-absorbable stitch.


Materials.

101822400-MATERIALS.jpg

C = Catgut

S = Silk

P = Polypropylene (Prolene)

N = Nylon

D = Dexon (Polyglycolic acid)

V = Vicryl (Polyglactin acid)


There is a very wide range of materials used for sutures - each with different properties.

Natural.


Natural materials are silk and catgut.


Silk.


Silk has been largely replaced by synthetic materials.


Silk is very strong and handles nicely.


The main disadvantages are:


Tissue reaction, with persistence of infection and stitch abscesses.


Catgut.


Catgut has been withdrawn from most parts of the world.


It was made from pig or cow intestine, not from the gut of a cat.


Pure catgut causes an intense tissue reaction as it is absorbed within 3-5 days.


This makes it largely unacceptable today.


Catgut soaked in chromic acid, chromic catgut, causes a less intense reaction and is absorbed

faster than most synthetic absorbable stitches.


It is sometimes used to suture skin where a good cosmetic effect is not necessary e.g. in the

scrotum.


Catgut is rather tough when dry and tends to fray.


It is difficult to knot.


When wet, catgut is slippery and the knots slip.


Synthetic


These synthetic fibres are long chains of very simple molecules which have been linked

together (made into polymers).


You will recognise some listed below.


Polyamide (Nylon).


Polyethylene (Polythene).


The same ethylene with four fluorine atoms when polymerised, gives us polytetrafluorethylene

(PTFE).


Polypropylene (Prolene).


Polymers of simple carbohydrates give fibres which are absorbable.


Such as:


Polyglycolic acid (Dexon).


Polyglactin (Vicryl).


Polydioxenone (PDS).


The synthetic fibres may have coverings with other plastics to improve the feel.


These extras are in the field of individual preference and do not make much difference to the


overall performance of the sutures to a trainee.


Absorbable versus non- absorbable.


Stitches are one way of giving strength to a wound until the body's tissues are strong enough

to take over.


Overall, the non-absorbable stitches are used where strength is needed for weeks or months.

e.g. abdominal wall wounds.


Absorbable stitches are used if healing will be strong enough within a week or two.


e.g. subcutaneous tissues.


Sutures in skin.


Absorbable stitches are used in skin if the tissue reaction will be slight enough to give an

acceptable cosmetic scar. e.g. Vicryl anywhere except in the face and perhaps the neck.


Non-absorbable stitches have to be removed when the strength of the skin is sufficient


(3-15 days according to the site).


Monofilament synthetic non-absorbable stitches probably give the best results in premium cosmetic


sites.


e.g. Prolene in facial wounds.



Next subsection, click on Sutures 06 How sutures work
Last subsection, click on  Sutures 04 Introduction 
Surgical Education and Training page, click on Surgical Education and Training
Whole program on WikiSurgery, click on PrimeSkills in Surgery
Whole program on CD-ROM, click on Michael Edwards