Non-Absorbable Sutures 510k

A non-absorbable suture is a type of suture made from materials that are not metabolized by the body. These sutures, such as silk, nylon, polypropylene, or polyester. These sutures may come with coatings that improve their performance and are generally used to close skin wounds. They are typically removed after a few weeks.

In heart surgeries, such as vascular anastomosis, non-absorbable sutures are preferred due to the constant movement and pressure on the heart. They tend to cause less scarring because they induce a minimal immune response, making them suitable for procedures where cosmetic results are important. Depending on the severity of the wound, these sutures might be left in place permanently or removed later.

Sutures are surgical threads or materials used to sew together tissues or wounds. Classification is based on several factors, including the material used, the size of the suture, the shape of the needle, and the intended use.

Non-absorbable sutures are primarily divided into two categories: natural and synthetic. Natural materials used as sutures are silk, linen, and cotton. The various types of non-absorbable synthetic sutures are polypropylene, polyester fiber, and polyamide sutures, to name a few. Stainless steel is a metallic non-absorbable suture.

Silk sutures: Silk sutures have been in use across the world since the 1890s. The soft structure of silk makes it easy to handle for the surgeon; it has excellent knot-tying properties, and it usually does not cause any allergic reactions. Silk sutures tend to degrade in two years. Its tensile strength is also low, so the sutures are likely to break under high tension.

Polyester sutures: Polyester sutures have better tensile strength than silk and work great in moist tissue ligation. They are useful in providing long-term wound support to the tissue.

Stainless steel wire sutures: These soft and malleable sutures have optimum strength and flexibility and offer excellent knot security. The most significant advantage is that stainless steel wire sutures are sterile, so there is no risk of infection. The one disadvantage of stainless-steel wire sutures is that they are springy, making them difficult to work with.

Polypropylene sutures: They have a less severe tissue reaction and accommodate tissue swelling very well. The disadvantage of polypropylene sutures is that they are stiff and have a high memory, making their knot security poor. Surgeons normally need to perform thermocautery (destroy the tissue applying a heated needle) to fuse the knots.

Polyethylene sutures: Polyethylene sutures are flexible, have a silky feel, soft on gloves and tissues, and are non-abrasive. The low knot profile allows for precise placement, a smooth tie-down, and superior knot break strength.

Polyamide or Nylon sutures: These are the most used sutures in surgery. They are composed of a material known as caprolactam. The material has high tensile strength but loses over six months if buried in tissue. The one disadvantage of polyamide sutures is that nylon is stiff, making handling and tying it difficult.

General Intended use of non-absorbable sutures: The surgical sutures are intended for general soft tissue approximation and/or ligation, such as use in ophthalmic, cardiovascular, neurological, Orthopedic, and dental procedures.

Silk sutures are generally used for mucosal tissues or to close intertriginous areas. Hence, their best use is in dental surgery.

Polyester sutures are widely used in orthopaedic surgeries, cardiac surgeries, and nerve and tendon repair surgeries.

Stainless steel wire sutures are used in orthopaedic procedures and Sternum closures because of their strength and resistance to stretching.

Polypropylene sutures are used when there is a need for long-term dermal support. It is used for suturing skin and is known for its strength and durability.

Polyethylene sutures are used in Orthopedic and cardiovascular procedures because of the tighter knot security provided during the tying process.

Polyamide or Nylon sutures are generally used for soft tissue surgeries, namely cardiovascular, ophthalmic, and neurological.

Non-absorbable sutures are described as multifilament or monofilament, non-absorbable, sterile or non-sterile, flexible, metallic, natural, or polymeric thread intended for uses such as soft tissue approximation and ligation, abdominal wound closure, intestinal anastomosis, hernia repair, and sternal closure. It may be coated or uncoated, undyed or dyed with an approved colour additive, and provided with or without an attached needle(s).

Surgical sutures must meet the requirements of 21 CFR 70.5(c) regarding the use of colour additives in sutures.

Refer Absorbable Suture section. Absorbable Suture

Classification as per U.S Pharmacopeia:

Class I sutures are made from silk or synthetic monofilament fibres, either twisted or braided, with coatings that don’t notably alter thickness (e.g., braided silk, polyester, nylon, or monofilament nylon/polypropylene).

Class II sutures are made from cotton, linen, or coated natural/synthetic fibres, with coatings that affect thickness but not strength (e.g., virgin silk sutures).

Class III sutures consist of monofilament or multifilament metal wire.

FDA regulates sutures as class 2 and class 3 medical devices, which require pre-market approval (PMA) or FDA 510K Clearance depending on the intended use of the suture.

*PMA is required as it belongs to class 3.

We recommend that you conduct biocompatibility testing for your device as described in the guidance entitled, Use of International Standard ISO-10993, Biological Evaluation of Medical Devices Part 1: Evaluation and Testing.

The contact type and duration for surgical sutures will depend on the intended use. For a prolonged or permanent contact duration suture in contact with tissue/bone, the following endpoints should be addressed in your biocompatibility evaluation.

• Cytotoxicity test according to ISO 10993-5: 2009
• Skin Sensitization test according to ISO 10993-10: 2021
• Skin Irritation or Intracutaneous Reactivity and Ocular irritation test (if intended use have ophthalmic use) according to ISO 10993-23 :2021
• Acute systemic toxicity test according to ISO 10993-11:2017
• Material-mediated pyrogenicity test according to ISO 10993 -11:2017 (E)
• Subacute/Subchronic Toxicity test according to ISO 10993-11:2017
• Genotoxicity test according to ISO 10993-3 2014-10
• Clinically relevant implantation test according to ISO 10993-6:2016
• Chronic Toxicity test according to ISO 10993-11:2017
• Carcinogenicity test according to ISO 10993-3 2014-10-1

Additional endpoints for prolonged or permanent contact duration sutures in contact with blood include:

• Hemocompatibility, Haemolysis test according to ISO 10993-4; ASTM F756
• Complement Activation test according to ASTM F1984-99 (Reapproved 2018)
• Thrombogenicity

Refer Absorbable Suture section. Absorbable Suture

For devices labelled as sterile, sterilization methods are to be performed as per below mentioned standard;

• ISO 17665-1 Sterilization of health care products – Moist heat – Part 1: Requirements for the development, validation, and routine control of a sterilization process for medical devices
• ISO 11135-1 Sterilization of health care products – Ethylene oxide – Part 1: Requirements for development, validation, and routine control of a sterilization process for medical devices
• ISO 11137-1 Sterilization of health care products—Radiation—Part 1: Requirements for development, validation, and routine control of a sterilization process for medical devices.
• ISO 20857 Sterilization of health care products — Dry heat — Requirements for the development, validation and routine control of a sterilization process for medical devices.
• ISO 11607-1 Packaging for terminally sterilized medical devices – Part 1: Requirements for materials, sterile barrier systems and packaging systems.
• ISO 11607-2 Packaging for terminally sterilized medical devices – Part 2: Validation requirements for forming, sealing and assembly processes.