Surgical sutures have been used by healers and surgeons for centuries and date as far back as 3000 BC in Ancient Egypt.
Sutures are usually composed of strands of fibres that are used to form a stitch or a series of stitches to hold body tissue together. Stitches are usually made by using a needle and an attached thread in order to close lacerations or incisions from surgery. In many cases sutures are short term devices that allow for the healing of trauma.
There are many different kinds of sutures and they can be either synthetic or natural (biological). Originally, sutures were made of plant materials (flax, hemp, and cotton) as well as animal materials (hair, tendons, arteries, muscle strips, nerves, silk, and catgut). The thread material used for sutures have developed over the years and the 20th century saw the first synthetic thread being produced. Nowadays, most sutures are made from synthetic polymer fibres.
The different kinds of sutures are classified as either absorbable or non-absorbable, depending on whether the body will naturally degrade and absorb the suture material over time, or not. Absorbable sutures break down harmlessly in the body over time, while Non-Absorbable sutures are manually removed or left in indefinitely.
Absorbable sutures are naturally biodegradable in the body, which makes it ideal for internal use. These sutures hold the body tissues together long enough to allow healing and then they disintegrate on their own, without requiring further procedures or manual removal. Dissolvable sutures can be made of either natural or synthetic materials. Natural materials include those derived from naturally occurring sources such as animal or plant tissues. Absorbable sutures were originally made of the intestines of sheep, but these days gut sutures are made by twisting together strands of purified collagen. These biological sutures are identified as foreign proteins and then naturally degraded by the body’s proteolytic enzymes – the enzymes that digest proteins.
However, the majority of absorbable sutures are now industrially produced from synthetic polymer fibres that can still be broken down successfully by the enzymes in the human body. Synthetic absorbable sutures are industrially produced from polyglycolide, polylactide, polydioxanone, and caprolactone. The chemical structures of these materials are similar to sugars and acids and they are therefore easily eliminated. Absorption takes place by hydrolysis, which is the chemical breakdown of the compound due to its reaction with water or moisture.
Non-dissolvable sutures are made of materials which are not metabolised by the body. They are used either on skin wound closures where the sutures can be removed after the wound has healed, or permanently implanted in the body where absorbable sutures will not suffice. Several materials are used for non-dissolvable sutures. The most common is a natural fibre; silk. Other sutures are made from synthetic fibres, like polypropylene plastics, polyester or nylon. Finally, stainless steel sutures are commonly used in orthopaedic surgery and for sternal closure in cardiac surgery. Non-absorbable sutures often cause less scarring because they provoke less immune response.
However, the technology, research and development around sutures is a constantly ongoing and changing one, and we can probably expect to see even more advancements and many more different kinds of sutures used in the nearby future.