Sutures- Types, Strength And Features

Physical Structure Of Suture 

o Monofilament Sutures

·         Multifilament Sutures

Monofilament

The monofilament suture is smooth, composed of a single strand, and readily passes through tissue; nevertheless, it becomes ruined when the needle holder is gripped. Their memory is strong. They are therefore challenging to handle or knot, reduced tissue reactivity, reduced infection risk, and very little possibility of sinus formation.

Multiple Filament

Breaded sutures are formed of several strands that are twisted together; they are simple to handle and tie, but they are not smooth. They become smooth with the silicon coating. Their surface area is thousands of times larger than that of monofilament sutures, increasing capillary action + interstitial space = increased risk of infection/infection risk of sinuses.

Absorbability                      

Sutures can also be classified as absorbable or non-absorbable based on how absorbable they are. It is advisable to use absorbable sutures for the urinary or biliary systems. Long-lasting strength and increased tensile strength are provided by non-absorbable sutures.

Biological Nature

Sutures can also be classified as natural or synthetic based on their biological makeup. Since synthetic sutures don't include any foreign objects, there isn't much of a tissue reaction.

Foreign bodies are present in natural or biological sutures; tissue reactivity is stronger. Hydrolysis is the primary method of absorption for synthetic absorbable sutures. The absorption of natural or biologically absorbable sutures occurs through enzymatic breakdown, phagocytosis, or proteolysis.

Strength Of Sutures

Strength depends on material, thickness, and reactivity to diverse tissues. Thickness is graded according to its diameter in tenths of millimeters. The suture will be thicker, which will reduce the likelihood of fracture and facilitate suture knotting.

The force needed to split a suture while yanking its two ends apart is known as the suture's tensile strength. Tensile strength of absorbable sutures deteriorates with time.  The tensile strength of non-absorbable sutures is infinite. Biological sutures deteriorate with time and lose tensile strength; synthetic sutures have an infinite tensile strength.

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Flexibility and Deformability

 • Elastic: When tension is relieved, the material reverts to its initial length.
• Plastic: When stress is relieved, a material does not revert to its initial length.

More memory, less knot security. Memory is the suture's ability to return to or curl back into its original position at the moment of packaging.

Features Of Non-absorbable Sutures

1.  Silk

Silk is a naturally occurring suture made from multifilament breaded sutures and raw silk from silkworms that may be covered in silicone or wax.  Silk elicits a moderate to strong tissue reactivity.

Where long-term tissue approximation under stress is required, such as in vascular anastomosis, vascular prosthesis, and skin, silk is contraindicated.  Tensile strength is lost 80–100% by six months after the sutures are placed and totally destroyed by one to two years.  The most typical application for silk sutures is in brain fixation.

2.  Polypropylene

 Polypropylene, a polymer of propylene, is a naturally occurring suture. Graft monofilament. Tensile strength is unlimited (100% tensile strength for more than a year) and tissue reactivity is minimal. Hernias, vascular prosthesis, plastic surgery, ophthalmic procedures, and vascular anastomosis can all benefit from this non-degraded polymer that is encapsulated in the body.

Contraindications: Not recommended for use with the kidney or biliary systems.

3. Nylon 

It is a synthetic, non-absorbable suture made of polyamide and comes in monofilament or braded multifilament forms.
The tissue response is minimal.  Tensile strength degrades between 15 and 20 percent annually, and for ophthalmic, plastic, and skin closure procedures.

Contraindications: stay away from areas where the biliary or urinary systems are vulnerable to stone formation.

4.  Stainless Steel

Alloys containing nickel, iron, and chromium are used to make synthetic sutures.  Tensile strength is unlimited and tissue reactivity is negligible. There will be 100% tensile strength for almost a year.
It stays encased in the body and doesn't break down.
  Apply to close sternotomies.  C/I: This prosthesis should not be used with any other metal prosthesis.

5. Polyester 

 Monofilament or multifilament braided sutures; synthetic, non-absorbable sutures made from polymer polyethylene terephthalate.  It can be left uncoated or coated with silicone or polybutylate.
The tissue doesn't break down and stays encapsulated in the body, with a mild tissue reaction and an indefinite tensile strength (100% for more than a year).  For surgeries related to the heart, plastic surgery, and ophthalmology.  C/I: None, but stay away from the area where stones are formed.

6. Polybutester 

 A polymer of polybutylene terephthalate with polytetramethylene ether glycol and a synthetic suture
  Very elastic, more frequently used in plastic surgery; Monofilament suture, tissue reactivity is low;  Tensile strength is infinite (100% for > 1 year); it doesn't deteriorate and remains encapsulated in the body; C/I: None

7.  Linen 

Twisted multifilament sutures have a moderate tissue reactivity; 50% of tensile strength is lost by 6 months, and 30% is left by 2 years.  Natural, non-absorbable suture made from long-stapled fibers.  It is no longer widely utilized; it doesn't break down and stays encapsulated in the body.

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Features Of Absorbable Sutures

1.  Catgut 

It can be ordinary catgut or chromic catgut (treat with 20% chromic acid), which assists in handling and prevent degeneration of tissue. Organic sutures. Source: derived from the collagen of the submucosal layer of the stomach of the sheep. For plain catgut, multifilament suture and tissue reactivity are high, whereas for chromic catgut, they are mild.

Phagocytosis or enzymatic breakdown are examples of absorption techniques.  Tensile strength in plain catgut is lost in 7–10 days, whereas in chromic catgut, it is lost in 21–28 days.
  Complete absorption occurs in 7–10 days for pain catgut and 90 days for chromic catgut.  Applies to: subcutaneous tissue for superficial vascular ligation.  C/I: Any tissue requiring ongoing assistance.

2.  Polyglactin (Workhouse Suture of General Surgery)

Multifilament-braided synthetic absorbable suture.  Source: it is a 90:10 co-polymer of glycolide and lactide. Calcium stearate and polyglactin cover it.  There is little tissue reactivity.  Hydrolysis is the absorption process.

After two weeks, 60% of the tensile strength remains, and after two weeks, 30% of the tensile strength remains.  In sixty to ninety days, it is fully absorbed.  Applications: gastrointestinal tract; biliary tract; urine system.  C/I: locations where an approximation is prolonged under stress.

3. Polydioxanone 

 Monofilament suture; synthetic absorbable suture; polyester polymer. The tissue response is minimal.  Hydrolysis is the absorption process.  After two weeks, 70% of the tensile strength is still present, and after four weeks- 50%.

It takes 180 days to absorb it fully. Applications: gastrointestinal tract; biliary tract; urine system.  C/I: Vascular synthetic graft and prosthetic prosthesis.

4. Polyglycolic Acid 

Polymer of polyglycolic acid;  Inert and absorbable surfactant polyxamer 188 is coated to provide a smoother and more manageable handling experience.  Braided multifilament suture

There is little tissue reactivity.  Hydrolysis is the absorption process.  After two weeks, 40% and 20% of the tensile strength, respectively, are still present.  It takes 90–120 days for it to be fully absorbed.  Applications: gastrointestinal and biliary anastomoses;  C/I: extend approximation under strain.

5. Polyglycaperone 

Absorbable synthetic suture.  Glycolide and caprolactone copolymer.  Suture for monofilament.  There is little tissue reactivity.  Hydrolysis is the absorption process.  The maximum duration of tensile strength is 21 days.  It takes 90–120 days for it to be fully absorbed.  Usage: subcuticular suturing is done with it.  C/I: extend the approximate tissue under stress.

Also Read: Image Based Discussion On Laproscopic, Diathermy Or Electrosurgery

Important Questions  

Q. Monofilament suture is made up of?

Ans.  single stranded filament, which  is smooth and can easily pass through tissue.

Q. Which suture is called a braided suture?

Ans. Multifilament suture

Q. Why is the surface area of multifilament suture a thousand times greater than that of monofilament?

Ans. It helps to increase interstitial space and capillary action.

Q. Absorbable sutures are preferred for?

Ans. biliary or urinary systems.

Q. Biologically absorbable sutures are absorbed by?

Ans. Proteolysis, phagocytosis, and enzymatic degradation

Q. The strength of the suture depends on?

Ans. Material thickness and response to various tissues.

Q. Define the tensile strength of the suture?

Ans. It is defined as the force required to break it when pulling two ends apart.  

Q. What is the tensile strength of synthetic sutures? 

Ans. Synthetic sutures have an indefinite tensile strength.

Q. Define memory in terms of suture?

Ans. Memory is the property of a suture to come back to its original position at the time of packaging.

Q. What is the use of a silk suture?

Ans. The most common use of a silk suture is for the fixation of the brain.

Q. Polypropylene is obtained from?

Ans. It is a natural suture obtained from the polymer propylene.

Q. What are the uses of silk sutures?

Ans.  It is useful for vascular anastomosis, vascular prostheses, hernia, plastic surgeries, and ophthalmic surgeries.

Q. Nylon is contraindicated in?

Ans. Urinary or biliary systems

Hope you found this blog helpful for your NEET SS General Surgery preparation. For more informative and interesting posts like these, keep reading PrepLadder’s blogs.