Complete Guide to Surgical Suture Types

What Are Surgical Sutures?

Surgical sutures are sterile medical devices used to hold body tissues together after injury or surgery. A suture consists of a strand of material — natural or synthetic — attached to a surgical needle. The strand approximates wound edges, allowing the tissue to heal with minimal scar formation and maximal tensile strength recovery.

Sutures remain the most widely used wound closure method in surgery, despite the availability of staples, adhesive strips, and tissue adhesives. Their versatility, predictable performance, and ability to achieve precise tissue approximation across a range of tissue types and anatomical locations make them indispensable across all surgical specialties.

Modern suture materials are manufactured to strict international standards (ISO 13485, USP, EP) that define allowable diameters, minimum tensile strength requirements, sterility assurance levels, and biocompatibility criteria. Every suture must be individually packaged in a sterile environment and maintain its sterile barrier until the point of use.

Classification by Absorbability

The most fundamental classification divides sutures into two categories based on whether the body can break down and absorb the material over time.

Absorbable Sutures

Absorbable sutures are degraded and eventually eliminated by the body through hydrolysis (synthetic materials) or enzymatic degradation (natural materials like catgut). They are used when temporary wound support is sufficient and suture removal would be impractical or unnecessary — for example, in deep tissue layers, internal organ repair, or pediatric patients.

The key parameters for absorbable sutures are tensile strength retention (how long the suture maintains its load-bearing capacity) and absorption profile (how long until the material is completely eliminated from tissue). These two timelines are distinct: a suture may lose all functional strength well before the material itself is fully absorbed.

Modern synthetic absorbable sutures degrade by hydrolysis — water molecules cleave the polymer chains in a predictable, reproducible fashion. This makes their absorption profiles more consistent than natural absorbable materials, which rely on enzymatic processes that vary with tissue type, infection status, and patient metabolism.

Desmo Care manufactures a full range of absorbable sutures: DesmoNex (PGA braided), DesmoPol (PDO monofilament), DesmoCryl (PGCL monofilament), and DesmoCapro (PLLA-PCL monofilament).

Non-Absorbable Sutures

Non-absorbable sutures are not broken down by the body and remain in tissue indefinitely unless surgically removed. They are indicated when permanent tissue support is required, or when the suture will be removed after initial healing (e.g., skin closures).

Applications requiring permanent suture support include cardiovascular anastomoses, hernia mesh fixation, tendon repair, and sternal closure. In these procedures, the tissue either never regains sufficient intrinsic strength or the mechanical demands on the repair site persist indefinitely.

Desmo Care's non-absorbable range includes DesmoMid (polypropylene monofilament), DesmoSilk (silk braided), DesmoSter (stainless steel monofilament), and DesmoLen (linen twisted).

Classification by Material Origin

Natural Sutures

Natural suture materials are derived from biological sources. Silk — a protein fiber produced by the Bombyx mori silkworm — is the most widely used natural suture material today. Linen, derived from flax plant fibers, is used in specific gastrointestinal applications. Cotton sutures, while historically common, have largely been replaced by synthetic alternatives.

Natural materials generally offer superior handling characteristics — they are pliable, easy to tie, and hold knots securely. However, they typically provoke a greater inflammatory tissue reaction compared to synthetic materials, and their degradation in tissue is less predictable.

Synthetic Sutures

Synthetic sutures are manufactured from polymer chemistry. The major synthetic absorbable polymers include polyglycolic acid (PGA), polydioxanone (PDO), polyglyconate (PGCL), and poly(L-lactide-co-epsilon-caprolactone) (PLLA-PCL). Non-absorbable synthetic materials include polypropylene, polyamide (nylon), and polyester.

Synthetic sutures offer highly reproducible mechanical properties, predictable absorption timelines, and generally lower tissue reactivity. Their manufacturing process allows precise control of diameter, tensile strength, and surface characteristics. Most modern surgical practice relies on synthetic materials for the majority of suturing applications.

Classification by Filament Structure

Monofilament Sutures

Monofilament sutures consist of a single strand of material. Their smooth surface generates less friction during tissue passage, reduces tissue drag, and resists harboring bacteria in interstices (since there are none). Monofilament sutures are preferred in contaminated or infected wounds and in vascular surgery where thrombogenicity must be minimized.

The trade-off is handling: monofilament sutures tend to have greater “memory” (tendency to return to their packaged coil shape), which can make them more difficult to manipulate. They also require additional throws per knot to achieve secure knot fixation. Examples include DesmoPol (PDO), DesmoCryl (PGCL), DesmoCapro (PLLA-PCL), and DesmoMid (polypropylene).

Multifilament (Braided) Sutures

Braided sutures are constructed from multiple strands woven or braided together. This construction provides excellent flexibility, superior handling, and high knot security. Braided sutures are easier to tie and require fewer throws per knot. Many surgeons prefer braided sutures for their tactile feedback and ease of manipulation.

The primary disadvantage is capillarity — the tendency to wick fluids and bacteria along the interstices between filaments. Modern coating technologies (such as the polycaprolactone and calcium stearate coating on DesmoNex) significantly reduce this effect while preserving handling characteristics. DesmoSilk is another braided suture valued for its exceptional handling in ophthalmic and oral surgery.

Absorbable Suture Materials: Properties and Applications

The following table summarizes the key properties of absorbable suture materials available from Desmo Care. All data represents typical values under standard test conditions per USP/EP requirements.

Non-Absorbable Suture Materials: Properties and Applications

Non-absorbable sutures provide permanent tensile strength in tissue. The choice of material depends on the required inertness, handling characteristics, and specific surgical application.

USP Suture Sizing System

The United States Pharmacopeia (USP) defines the standard suture sizing system used worldwide. Suture size is designated by a number that corresponds to a specific diameter range. The relationship between USP designation and diameter is as follows:

• Sizes 12-0 through 1-0: The number before the zero indicates the number of zeros. More zeros means a finer suture. 6-0 (000000) is approximately 0.07 mm diameter; 2-0 (00) is approximately 0.35 mm.
• Size 0: The baseline reference diameter, approximately 0.35-0.40 mm depending on material type.
• Sizes 1 through 7: Progressively larger diameters. Size 2 is approximately 0.50 mm; size 5 is approximately 0.70 mm. Size 7 (used in stainless steel sutures like DesmoSter) is the largest standard suture gauge.

The USP also specifies minimum tensile strength (knot-pull and straight-pull) requirements for each size and material class. Absorbable and non-absorbable sutures have different minimum strength requirements at the same USP size, reflecting their different polymer properties.

In clinical practice, the surgeon selects the smallest suture size that provides adequate strength for the tissue being approximated. Using a smaller suture reduces tissue trauma, foreign body reaction, and scarring. Common size selections include 6-0 to 8-0 for ophthalmic procedures, 4-0 to 5-0 for skin closure on the face, 3-0 to 4-0 for subcutaneous tissue, and 0 to 2 for fascia and tendon repair.

Suture Selection: Key Clinical Factors

Selecting the appropriate suture involves balancing multiple factors. No single suture is ideal for all situations. The following framework guides clinical decision-making:

1. Tissue Type and Healing Rate

Different tissues heal at different rates and require different durations of suture support. Mucous membranes heal rapidly (7-14 days) and need only short-term support — fast-absorbing sutures like DesmoNex Rapid are appropriate. Fascia and tendons heal slowly (6-12 weeks) and require extended support from materials like DesmoPol or DesmoCapro. Cardiovascular tissue may need permanent support, requiring non-absorbable sutures such as DesmoMid.

2. Wound Location and Tension

High-tension wound closures (abdominal wall, sternum) demand sutures with high tensile strength and prolonged or permanent strength retention. DesmoSter stainless steel is the strongest option for sternal and abdominal wall closure. For lower-tension areas like the face or eyelid, finer sutures with minimal tissue reactivity minimize scarring.

3. Infection Risk

In contaminated or potentially contaminated wounds, monofilament sutures are preferred because their smooth surface does not harbor bacteria. Braided sutures should be avoided in infected fields unless their handling advantages are clinically necessary. If a braided suture must be used, a coated product like DesmoNex (with polycaprolactone coating) reduces bacterial adherence compared to uncoated braids.

4. Required Suture Support Duration

The suture must maintain adequate tensile strength until the tissue can bear physiological loads on its own. The required support durations by tissue type are approximately:

• Skin and mucosa: 7-14 days
• Subcutaneous tissue: 14-21 days
• Fascia: 30-60 days
• Tendons and ligaments: 42-90 days
• Bone and cartilage: 60-180+ days

5. Cosmetic Considerations

When cosmetic outcome is a priority — facial wounds, hand surgery, breast reconstruction — suture selection should minimize tissue reaction and scarring. Monofilament synthetic sutures produce the least tissue reaction. Using the smallest adequate size further reduces track marks and scarring. Subcuticular closure techniques with absorbable monofilament sutures (such as DesmoCryl) eliminate the need for suture removal and avoid suture marks entirely.

Frequently Asked Questions