What are stitches made of? A Guide to Surgical Sutures

September 21, 2025 •

3 min read

Over 200 million surgical procedures involving sutures are performed annually worldwide, highlighting the critical role stitches play in modern medicine. This fundamental medical practice relies on a wide array of sophisticated materials, both natural and synthetic, to repair and close wounds effectively. Understanding what are stitches made of provides insight into the science behind effective wound closure and the healing process.

Quick Summary

Stitches, or sutures, are made from either absorbable materials that dissolve within the body or non-absorbable materials that must be removed. These can be natural, such as silk or catgut, or synthetic, like nylon, polypropylene, and various polymers designed for specific surgical needs, each offering unique properties for wound healing.

Key Points

Absorbable vs. Non-Absorbable: Stitches come in two main types—absorbable, which dissolve naturally in the body, and non-absorbable, which require removal.
Natural Materials: Some stitches are made from natural sources like processed animal intestines ("catgut") or silk.
Synthetic Materials: Modern synthetic polymers such as nylon, polypropylene, and Vicryl are widely used for their predictable performance and low tissue reactivity.
Internal and External Use: Absorbable sutures are ideal for internal tissues, while non-absorbable types are often used for skin closures.
Monofilament vs. Multifilament: Sutures also differ in structure—single-strand monofilament or braided multifilament—each with different handling and healing characteristics.
Material Matters: The choice of material is critical for proper wound healing, influencing tensile strength, knot security, and the body's inflammatory response.

The Core of Wound Closure: Understanding Surgical Sutures

Sutures, or stitches, are a cornerstone of surgical and emergency medicine, used to approximate and ligate body tissues after injury or surgery. The material used for these sterile threads is chosen based on the wound location, tissue type, required healing time, and desired aesthetic outcome. The fundamental distinction is between absorbable and non-absorbable materials, which determines whether the stitches dissolve harmlessly in the body or need to be removed by a healthcare professional.

Absorbable Sutures: Dissolving for Internal Healing

Absorbable stitches are a marvel of medical technology, designed to be broken down and absorbed by the body's natural processes over a period of weeks or months. This eliminates the need for a follow-up visit to have them removed and is particularly useful for internal procedures or in fast-healing tissues.

Natural absorbable sutures: Historically, these included "catgut," a misnomer for material derived from the intestines of sheep or cattle. Though still used for some applications, modern versions are more sterile and processed.
Synthetic absorbable sutures: Today, most absorbable stitches are made from advanced synthetic polymers. These include polyglycolic acid (PGA), polyglactin 910 (commonly known as Vicryl), and polydioxanone (PDS). These materials are designed to degrade predictably through hydrolysis, ensuring consistent and reliable absorption.

Non-Absorbable Sutures: Providing Long-Term Support

For areas requiring prolonged strength and support, or for superficial skin wounds that need removal, non-absorbable sutures are used. These materials are not broken down by the body and are either left in place permanently (for internal applications like heart surgery) or removed once the wound has healed.

Natural non-absorbable sutures: Silk is a classic example, valued for its excellent handling properties and knot security. However, it can occasionally cause a tissue reaction. Other materials like cotton were used historically but are less common now.
Synthetic non-absorbable sutures: Modern synthetic options are inert, causing minimal tissue reaction. Common examples include:
- Nylon: A monofilament suture known for its smooth passage through tissue and minimal tissue drag.
- Polypropylene: An extremely inert monofilament suture, often used in vascular surgery due to its smooth surface and resistance to adherence.
- Polyester: A braided suture with high tensile strength, ideal for fascia and orthopedic procedures.
- Stainless steel: Used primarily in orthopedic and thoracic surgery for its exceptional strength and durability.

Monofilament vs. Multifilament: The Physical Structure of Stitches

Beyond the material composition, the physical structure of a suture also plays a vital role in its performance.

Monofilament sutures: Consist of a single, smooth strand. They offer less friction and a lower risk of harboring bacteria but can be harder to handle and tie securely.
Multifilament sutures: Made of several smaller strands braided or twisted together. They are stronger and more pliable, with better knot security, but their braided nature can increase the risk of infection and cause more tissue drag.

Comparison of Suture Types


Feature	Absorbable Sutures	Non-Absorbable Sutures
Breakdown	Absorbed by the body over time.	Remain in the tissue permanently or require removal.
Use Case	Internal stitches, deep layers of skin, muscle repair.	Skin closures, high-tension areas, cardiovascular surgery.
Example Materials	Catgut, Vicryl (Polyglactin 910), PDS (Polydioxanone).	Silk, Nylon, Polypropylene, Stainless Steel.
Removal	No removal necessary.	Must be removed by a healthcare professional.
Tissue Reaction	Can cause a localized inflammatory response as they dissolve.	Minimal tissue reaction, especially with inert synthetics.

Conclusion

The composition of surgical stitches is a nuanced topic, with the choice of material dictating the wound's healing trajectory and potential complications. From ancient animal-derived threads to modern synthetic polymers, suture materials have evolved to provide optimal conditions for tissue repair, whether they are designed to dissolve away or to provide long-term strength. This understanding underscores the precision and science behind wound management and surgical care.

For more information on the history and development of surgical sutures, refer to resources like the AORN Journal.

Frequently Asked Questions

Dissolving stitches, or absorbable sutures, are made from materials that the body can naturally break down and absorb. Common examples include natural materials like processed animal intestines ("catgut") and synthetic polymers such as polyglycolic acid (PGA) and polyglactin 910 (Vicryl).

Non-dissolving stitches, or non-absorbable sutures, are made from materials that are not broken down by the body and must be removed. These include synthetic materials like nylon, polypropylene, and polyester, as well as natural materials like silk and stainless steel.

No, not all stitches are synthetic. Suture materials can be broadly classified as either natural or synthetic. While modern medicine heavily relies on synthetic polymers for their predictable qualities, natural materials like silk and catgut are still used for specific procedures.

Different types of stitches are used because a surgeon must select the right material for the specific wound. Factors like the type of tissue, location of the wound, required healing time, and desired aesthetic outcome all influence the choice between absorbable, non-absorbable, monofilament, and multifilament sutures.

The difference lies in their physical structure. Monofilament sutures are a single, smooth strand, which glides through tissue easily. Multifilament sutures are braided or twisted together from multiple strands, providing greater strength and knot security, but can also have more tissue drag.

While not technically stitches, surgical staples are an alternative closure method often used for skin or internal wounds. They are typically made from stainless steel or titanium, materials that are strong, durable, and well-tolerated by the body.

The choice of suture material is a complex medical decision made by the surgeon. They consider factors such as the wound's location, tissue type, how quickly the tissue heals, the amount of tension on the wound, and the risk of infection to ensure the best possible healing outcome.