Surgical Sutures are normally classified into two types, absorbable and non-absorbable. They can also be classified based on their construction, either mono-filament or multi-filament, coating provided, absorption profile and also whether they are made from natural or synthetic materials. Sutures can also be classified according to their usage e.g. cardiovascular sutures, ophthalmic sutures, general sutures, orthopaedic sutures etc. Absorbable and Non-absorbable sutures Sutures can be divided into two types – those which are absorbable and will break down harmlessly in the body over time without intervention, and those which are non-absorbable and must be manually removed if they are not left indefinitely. The type of suture used varies on the operation, with the major criteria being the demands of the location and environment and depends on the discretion and professional experience of the Surgeons. Sutures to be placed internally would require re-opening if they were to be removed. Sutures which lie on the exterior of the body can be removed within minutes, and without re-opening the wound. As a result, absorbable sutures are often used internally; non-absorbable externally. Sutures to be placed in a stressful environment, for example the heart (constant pressure and movement) or the bladder (adverse chemical presence) may require specialized or stronger materials to perform their role; usually such sutures are either specially treated, or made of special materials, and are often non-absorbable to reduce the risk of degradation. Absorbable sutures include :- Polyglycolic Acid sutures, Polyglactin 910 , Catgut, Poliglecaprone 25 and Polydioxanone sutures. Non-Absorbable sutures include :- Polypropylene sutures, Nylon (poylamide), Polyester, PVDF, silk and stainless steel sutures. Monofilament and Multifilament Sutures Sutures can also be divided into two types on the basis of material structure i.e. monofilament sutures and multifilament or braided sutures. Braided sutures provide better knot security whereas monofilament sutures provide better passage through tissues. In general, Monofilament sutures elicit lower tissue reaction compared to braided sutures. Multifilament sutures are braided and often coated with various materials like silicon, wax, PTFE, polycaprolactone, calcium stearate etc. Monofilament sutures include :- Polypropylene sutures, Catgut, Nylon, PVDF, Stainless steel, Poliglecaprone and Polydioxanone sutures. Multifilament or braided sutures include :- PGA sutures, Polyglactin 910, silk and polyester sutures. Classification of sutures based on suture size Surgical Sutures and ligatures are available in a number of sizes. Sutures are classified into different sizes based on the diameter of the thread. United States Pharmacopeia's classification of sutures into various sizes is widely accepted across the world. The following U.S.P. and metric suture sizes chart shows the diameter range for collagen and synthetic sutures. Synthetic and Natural Sutures Surgical sutures can also be divided into two types on the basis of raw material origin i.e. natural and synthetic sutures. Natural sutures include silk and catgut sutures whereas all other sutures are synthetic in nature. Coated and Un-Coated Sutures Some types of sutures are available with specialized coatings on the surface to enhance properties like knotting, easy passage through tissue and reduce tissue reaction. Normally, coating is applied to braided sutures rather than monofilament sutures. It is easier to coat braided sutures compared to monofilaments. Coating materials like chromium salt, silicon, wax, PTFE, polycaprolactone, calcium stearate. Polymeric coating materials are known to be more bio-compatible than conventional coating materials like chromium salts, beeswax, pafaffin, gelatin etc. There are new functional coatings like antibacterial or antimicrobial coating given to both monofilament and multifilament sutures, stem cell coating for improving healing properties. Coated sutures include :- PGA sutures, Catgut Chromic, Polyglactin 910, silk and polyester sutures, braided or twisted nylon, Poliglecaprone and Polydioxanone sutures. Un-coated sutures include :- Monofilament Polypropylene sutures, monofilament Nylon, PVDF, Stainless steel. Sutures Classification based on usage Sutures are also classified into various types based on the usage or application. Sutures are normally classifed into general sutures, cardiovascular sutures, valve sutures, orthopaedic sutures, dental sutures, gynaec, veterinary sutures, cosmetic surgery sutures, ophthalmic sutures etc. A variety of suture materials may be used for a particular application based on the requirements. However, the suture sizes, length, needle profiles, etc., will be with a small change for a particular application. Source
