Most surgical or traumatic wounds require skin closure of some kind. Most commonly, this closure is done by suturing, as opposed to staples or surgical glues. A closure is a mean of primary closure to promote wound healing. Suturing offers advantages like low dehiscence rates and greater tensile strength than other closure methods.
Historically, some form of wound closure mechanisms have been employed and were very similar to modern sutures. Several thousand years before the common era (BCE) eyed needles, sometimes made of bone, were used to pass a suture through wounds. The suture materials themselves included hemp, flax, hair, linen, pig bristles, grass, reeds, and sometimes other plants. Sushruta described suturing with materials made of bark, tendon, hair, and silk in the year 500 BCE. Other famed surgeons also described the use of primitive sutures like Galen and Antyllus, as did Pare´and Lister . At one point, the mouth of pincher ants was used to approximate wounds before the modern suture was devised, which became in vogue in the mid 20 century.
Presently, there are innumerable options for sutures. Therefore, to appropriately choose a suture type, it is necessary to understand the characteristics of different sutures. The ideal sutures are easy for the surgeon to handle, provide appropriate strength and secure knots, can tolerate wound changes like swelling and recoil, cause minimal inflammation or infection risk, are easily visible, and relatively inexpensive. There is no known suture possessing all of these qualities. However, along with good technique, proper choice for each incision can help lead to improved aesthetic results. It is essential to understand all of the attributes of each type of suture. To correctly choose, it is necessary to understand the differences between different string types and different needles and in which clinical situations they are designed to be used.
There are many different types of sutures, and these get grouped by several different characteristics. Understanding these characteristics allows for ideal suture selection.
The main factors used to classify sutures types are:
1- Absorbable vs. non-absorbable
2- Synthetic vs. natural
3- Monofilament vs. multifilament
The first main suture category is absorbable versus non-absorbable sutures. Sutures are considered absorbable if they lose most of their tensile strength over variable periods ranging from few weeks to several months. Absorbable sutures are often employed for deep temporary closure until the tissues heal, or when it is not easy to otherwise remove them. In this fashion, they are useful for approximating edges of tissue layers, closing deep spaces or defects, and facilitating wound healing as part of a multi-layered closure. When used superficially, they can have more inflammation, which can lead to more scarring. If using absorbable sutures superficially, the recommendation is that a rapid absorbing suture is employed.
Absorbable sutures can also classify as natural and synthetic sutures. Natural sutures are derived from purified animal tissues (usually collagen) and are sometimes made of the purified serosa of bovine intestines. Silk and catgut (made from sheep submucosa) are all types of natural sutures. Natural sutures are different than synthetic sutures in that they degrade (if absorbable, like catgut) by proteolysis, while synthetic sutures degrade by hydrolysis. Hydrolysis causes less of an inflammatory reaction than proteolysis, which is why natural sutures can be known for causing more inflammation at the suture site. Catgut sutures can be treated with an aldehyde solution to strengthen the material (plain catgut sutures) and can undergo further treatment with chromium trioxide (which also strengthens and helps them last longer before absorption) like chromic catgut.
Non-absorbable sutures are used for long term tissue closure like vessel anastomosis, permanently ligating internal tubular structures or vessels, performing a second layer bowel hand sawing anastomosis, hernia fascial defects closure and other uses.
Another important suture category is monofilament and multifilament. Monofilament sutures are single filaments (as their name implies) with less surface area than a multifilament (braided or twisted suture). Monofilament sutures have higher memory which demands more handling care. They typically require more knots to ensure security, but tend to fracture less then multifilament sutures, they pass through tissues more easily and cause a less inflammatory reaction than their multifilament counterparts. Conversely, multifilament sutures are more pliable; they hold knots more securely, have less memory and easier handling by the surgeon. However, multifilament sutures also cause more friction through tissue and have increased capillarity and surface area, increasing their proclivity to inflammation and infection. Multifilament sutures can be coated to make them slide through tissues more easily and have properties more similar to a monofilament suture. They can also be coated with antibiotics to make them more infection resistant. However, they are more expensive than traditional sutures.
Any suture can have the addition of a dye. The dye helps with suture visualization. However, if sutures are under the epidermis, it is preferable to have them undyed so that they are not visible.
Most sutures have a smooth surface. However, there are newer sutures manufactured with barbs. These barbs help approximate wounds and do not require knots for security. They more evenly distribute tension along the wound. These sutures are also known to be more time efficient.
Another critical property of a suture is its tensile or breaking strength that generally comes from suture width. Sutures are numbered by their size relative to their diameter. Thick suture numbering is from 0-10, with #10 being the largest diameter. Thin sutures are those that have the greatest number of zeroes after them and range from 1-0 to 12-0 (12-0 having the least breaking strength). There is about .01 to .05 mm diameter difference between sizes.
The next important aspect of sutures is the needle. The needle is made up of three main parts, the eye, body, and point. The eye is where the suture attaches to the needle; this can be an actual needle eye, where the string threads through or a point where the suture thread gets swaged on to the needle (most modern needles are of this latter type). The body is the most substantial part of the needle and connects the eye to the point and determines the shape of the needle. The needle can be straight or curved, which is more common. The circle of a curved needle comes in different lengths, but most curves are 1/4, 1/2, 3/8, or 1/3 of a circle. The curve is vital in helping the surgeon know where the tip of the needle is at all times. Most skin closure sutures are curved, and usually 3/8 of a circle.
Amongst needles, there are different types based on the needle tip, mainly cutting or taper needles. Cutting needles have a tip with three sharp edges, with a conventional cutting needle having the cutting surface inside the needle and a reverse cutting needle having it on the outside of the needle. Reverse cutting needles are commonly used for sewing skin.
Taper needles are rounded and can be either sharp or blunt. They work by piercing the tissue without cutting it, essentially spreading the tissue as it passes through it. These are good for soft and delicate tissues.
Table 1. Classification of sutures
Figure 1. Needle Anatomy
Figure 2. Common Types of Needles
While there are many properties to sutures, it is most important to be able to determine which sutures are best for individual clinical scenarios. This determination depends on the thickness and location of the tissues, the amount of tension across the wound, and the risk of infection. One needs to choose the caliber, type of filament (absorbable or non-absorbable), and the tissue and needle needs.
There is no specific algorithm for suture choice; however, a few rules are helpful. For instance, if there is a high infection risk, a monofilament absorbable suture is chosen. For running intradermal sutures, thin monofilament absorbable sutures with minimal reactivity are typically used. When suturing the skin, particularly in cosmetically sensitive areas, the smallest suture for the area should be used. Trials have shown no major differences between absorbable and non-absorbable sutures in terms of cosmesis and complications, scars and patient satisfaction. For absorbable sutures, if more strength is required, choose a suture with a longer absorption time. Slow healing tissues, like fascia and tendons, should be closed with non-absorbable or slow absorbing sutures. While faster healing tissues like stomach, colon, and bladder require absorbable sutures. Urinary and biliary tracts are prone to stone formation, so synthetic absorbable sutures are better in this situation, while sutures prone to digestive juices should be those that last longer. Natural sutures do very badly in the GI tract. A non-absorbable suture is best when prolonged tension (fascial closure, tendon repair, bone anchoring, or ligament repair) is required for suitable healing to take place.
In general, surgeons typically use either polypropylene or polydioxane sutures for fascia, depending on how strong the repair needs to be. Deep dermis closure is with either polyglycolic acid or poliglycaprone 25 sutures. If closing the epidermis with a running subcuticular suture, poliglycaprone 25 is preferred. If one is performing interrupted sutures on the skin surface, nylon is ideal; polydioxane for near dark hair and fast absorbing or chromic gut suture if it is on a child or in an area where sutures are difficult to remove. Many good choices exist depending on provider preference, experience, and the desired result.
|||Lloyd JD,Marque MJ 3rd,Kacprowicz RF, Closure techniques. Emergency medicine clinics of North America. 2007 Feb; [PubMed PMID: 17400073]|
|||Yag-Howard C, Sutures, needles, and tissue adhesives: a review for dermatologic surgery. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.]. 2014 Sep; [PubMed PMID: 25158874]|
|||Swanson NA,Tromovitch TA, Suture materials, 1980s: properties, uses, and abuses. International journal of dermatology. 1982 Sep; [PubMed PMID: 6752052]|
|||Pillai CK,Sharma CP, Review paper: absorbable polymeric surgical sutures: chemistry, production, properties, biodegradability, and performance. Journal of biomaterials applications. 2010 Nov; [PubMed PMID: 20971780]|
|||Moy RL,Waldman B,Hein DW, A review of sutures and suturing techniques. The Journal of dermatologic surgery and oncology. 1992 Sep; [PubMed PMID: 1512311]|
|||Bennett RG, Selection of wound closure materials. Journal of the American Academy of Dermatology. 1988 Apr; [PubMed PMID: 3286691]|
|||Lober CW,Fenske NA, Suture materials for closing the skin and subcutaneous tissues. Aesthetic plastic surgery. 1986; [PubMed PMID: 3544739]|
|||Xu B,Xu B,Wang L,Chen C,Yilmaz TU,Zheng W,He B, Absorbable Versus Nonabsorbable Sutures for Skin Closure: A Meta-analysis of Randomized Controlled Trials. Annals of plastic surgery. 2016 May; [PubMed PMID: 25643187]|
|||Kudur MH,Pai SB,Sripathi H,Prabhu S, Sutures and suturing techniques in skin closure. Indian journal of dermatology, venereology and leprology. 2009 Jul-Aug; [PubMed PMID: 19584482]|
|||Firestone DE,Lauder AJ, Chemistry and mechanics of commonly used sutures and needles. The Journal of hand surgery. 2010 Mar; [PubMed PMID: 20193865]|
|||Hope WW,Tuma F, Incisional Hernia . 2019 Jan [PubMed PMID: 28613766]|
|||Farooqi N,Tuma F, Intestinal Fistula . 2019 Jan [PubMed PMID: 30480947]|
|||Elder T,Tuma F, Bilateral vertebral artery transection following blunt trauma. International journal of surgery case reports. 2018 [PubMed PMID: 30138866]|
|||Guyuron B,Vaughan C, A comparison of absorbable and nonabsorbable suture materials for skin repair. Plastic and reconstructive surgery. 1992 Feb; [PubMed PMID: 1732889]|
|||Tejani C,Sivitz AB,Rosen MD,Nakanishi AK,Flood RG,Clott MA,Saccone PG,Luck RP, A comparison of cosmetic outcomes of lacerations on the extremities and trunk using absorbable versus nonabsorbable sutures. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2014 Jun; [PubMed PMID: 25039547]|
|||Shaydakov ME,Tuma F, Operative Risk . 2019 Jan [PubMed PMID: 30335273]|
|||Krishnan M,Tuma F, Cancer, Intestinal Carcinoid . 2019 Jan [PubMed PMID: 28846270]|