Why Is It Called Catgut? Understanding Catgut Uses, Types, and Benefits

Understanding Catgut: Uses, Types, and Benefits

When an animal sustains an injury, it is sometimes severe enough to cause significant damage to its tissues and skin. In such cases, the tissue and skin are so extensively cut that healing is not possible without external assistance. In these situations, veterinarians use sutures to bring the edges of the wound closer together, facilitating faster healing. Proper precautions must be observed during the suturing process.

What is Catgut?

Catgut is a type of natural absorbable suture material obtained from the intestines of various animals. It is primarily made from the submucosa layer of the small intestine of sheep and the serosa layer of the small intestine of cows. In medical practice, this thread is widely used for suturing because its main advantage is that it does not need to be removed after placement. It is absorbed by the skin over time and is biodegradable, meaning it can be broken down biologically.

Why Is It Called Catgut? 

Catgut was first used in surgeries on cats, which is why it came to be known as "catgut." In the context of animals, the word "gut" is commonly used to refer to the digestive system (intestines). Due to these two facts, the combination of "Cat" and "Gut" gave it the name "catgut."

Types of Suture Materials

There are various types of suture materials available today, which are divided into two categories:

1. Absorbable Suture Materials
2. Non-Absorbable Suture Materials

Absorbable sutures, such as catgut, are most commonly used in surgeries.

1. Absorbable Suture Materials

These are suture materials that are absorbed or dissolve on their own after the wound has healed. Absorbable suture materials are typically used in surgeries involving internal organs. The main advantage is that there is no need to remove the sutures after placement; they are absorbed by the skin after some time.

Examples:

• Catgut
• Kangaroo Tendon
• Cargile Membrane
• Fascia Lata
• Collagen
• Polyglycolic Acid
• Polyglaction 910
• Polydioxanone

A) Natural Absorbable Suture Materials

Catgut, Kangaroo Tendon, Cargile Membrane, Fascia Lata, and Collagen are natural absorbable suture materials as they are derived from natural sources.

B) Synthetic Absorbable Suture Materials

Polyglycolic Acid, Polyglaction 910, and Polydioxanone are synthetic absorbable suture materials because they are produced in laboratories.

2. Non-Absorbable Suture Materials

These suture materials are not absorbed by the body after the wound has healed. Non-absorbable suture materials need to be removed after the wound has healed and are mainly used in surgeries involving external tissues.

Examples:

• Silk
• Cotton
• Linen
• Umbilical Tape
• Horse Hair
• Nylon
• Vetafil
• Stainless Steel Wire

Manufacture and Absorption of Catgut

Catgut is mainly derived from the submucosa of the small intestine of sheep. When used directly, its absorption time is very short. To prolong the absorption time, it is treated with chromic acid to produce chromic catgut. This type of catgut is stronger and absorbs more slowly, causing less reaction with tissues. It is used for wounds that take longer to heal so that the sutures remain effective for a longer time.

Sterilization of Catgut

After obtaining catgut, it is crucial to maintain its sterility. Catgut is sterilized with 95% isopropyl alcohol to destroy any microorganisms. It is then packed in aluminum foil to keep it secure and ready for use. This process ensures that the catgut remains fully sterilized and safe for surgical use.

Autoclaves are used to sterilize surgical instruments and most suture materials because they operate at 121°C with 15 pounds per square inch pressure for 15 minutes. They use moist heat, which effectively destroys bacteria and other microorganisms. However, natural suture materials like catgut cannot be sterilized in an autoclave as the high temperature can damage them. Therefore, catgut is sterilized using 90 to 95% isopropyl alcohol, making it safe and ready for use. 

Key Points on Sterilization

Sterilization: Sterilization means the complete destruction of all types of microorganisms, including their spores, in all forms. In veterinary science, various sterilization methods are used based on specific requirements and equipment.

1. Autoclave (Moist Heat Sterilization)

• Principle: The autoclave operates on the principle of moist heat.
• Temperature and Pressure: 121°C at 15 pounds per square inch pressure for 15 minutes.
• Applications: Sterilizes surgical instruments such as scissors, forceps, surgical packs, aprons, gowns, drapes, suture materials, culture media, solutions, dressings, cotton, and artificial vaginas.

2. Isopropyl Alcohol Sterilization

• Applications: Used for sterilizing Catgut suture materials with 90-95% isopropyl alcohol.

Antiseptics: Antiseptics are chemicals used to sterilize living surfaces (tissues).

• Examples: Povidone iodine (Betadine), Dettol (chloroxylenol), chlorhexidine, potassium permanganate (P.P / KMnO₄), boric acid (for eye sterilization), ethyl alcohol, hydrogen peroxide, and isopropyl alcohol.

Disinfectants: Disinfectants are chemicals used to sterilize inanimate surfaces.

• Examples: Phenol, phenyl, formaldehyde, glutaraldehyde, bleaching powder, hypochlorite, sun rays, UV rays, and chlorine gas.

Types of Catgut

1. Plain Catgut / Type A Catgut

• This type is directly obtained from the submucosa layer of the small intestine of sheep and goats and is sterilized without treatment with chromic acid. 

• Its absorption time is approximately 10 days. It is referred to as natural catgut.

2. Mild Chromic Catgut / Type B

• This type is treated with chromic acid, and its absorption time is about 15 days.

3. Medium Chromic Catgut / Type C

• Also treated with chromic acid, this type has an absorption time of around 20 days.

4. Extra Chromic Catgut / Type D

• This type is treated with chromic acid and has an absorption time of approximately 40 days. It is used for wounds that take longer to heal.

Among these, Type C or Medium Chromic Catgut is most commonly used.

Advantages of Treating Plain Catgut with Chromic Acid

1) Absorption Time:

• Plain Catgut treated with chromic acid has a longer absorption time. Untreated catgut absorbs in about 10 days.
• Mild Chromic Catgut (Type B) absorbs in about 15 days.
• Medium Chromic Catgut (Type C) absorbs in around 20 days.
• Extra Chromic Catgut (Type D) absorbs in up to 40 days.

2) Tensile Strength:

• Treating Plain Catgut with chromic acid increases its tensile strength and durability, making it more reliable during surgery.

3) Tissue Reaction:

• After treatment with chromic acid, Plain Catgut causes less reaction with tissues, making it safer to use. Additionally, it exhibits a non-capillary effect, meaning it does not draw fluids into the tissues, reducing the risk of infection.

Uses of Catgut

Catgut is used in surgeries involving internal organs such as the rumen (the first stomach of ruminants), uterus, and urinary bladder. It is used because it absorbs over time, eliminating the need for suture removal and reducing risks associated with suture removal.

Type C or Medium Chromic Catgut is most frequently used in internal organ surgeries due to its suitable absorption time and strength.

Benefits

• Internal Use: Utilized for suturing internal organs like the rumen, uterus, and urinary bladder to avoid the need for suture removal and associated risks.
• Pain Relief: Helps avoid pain associated with suture removal for the animal.
• Absorption Capability: Absorbed by the body, eliminating the need for removal.
• Strong Suture Line: Catgut thread allows for secure knotting, providing strength to the suture line.

Different Sizes of Catgut

Catgut threads come in various sizes, such as 2-0, 3-0, 4-0, 5-0, 6-0, etc. The choice of size depends on the location of application. Thicker threads are used in areas under more pressure, while thinner threads are used in less pressured areas.

Catgut is a natural absorbable suture made from animal intestines, commonly used in medical procedures. Learn how it biodegrades and eliminates the need for removal.

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