B. Braun is now marketing a new thread made from poly-4-hydroxybutyrate (P4HB).
This new material is an absorbable polyester that shows interesting properties for medical use10, which have been used in the development of an innovative suture thread, Monomax®, for abdominal wall closure.

The European Pharmacopoiea (EP) and the United States Pharmacopeia (USP) are the standard-setting authorities for suture material.
They define a certain number of criteria regarding suture gauge and also properties such as knot breaking strength, linear pull during the critical healing stage, and absorption time.
The European Pharmacopoeia uses the metric system, expressed in decimals (from 0.1 to 10), while the USP system is similar to that used for classifying catheter gauges.
Unlike the USP, the EP makes no distinction between natural and synthetic absorbable sutures. [11]
The USP standard is the most widely used. In this system, zero (0) corresponds to the average basic size of a suture.
The smaller the gauge of a suture, the more zeros are used in sizing the thread; for example, a 6-0 suture is smaller than a 4-0 suture. [12]
The more zeros, the weaker the thread. [4]
There is an equivalence table for these two standards see Metric >>.

Sutures can be made from a single filament (monofilament) or multifilament. Monofilament sutures have interesting qualities such as strength, low tissue drag and a low propensity to harbour bacteria.
The incidence of infection is significantly lower with monofilament sutures than with braided ones. However, monofilament sutures are not as manageable as braided ones.
Multifilament sutures (braided or twisted) are more manageable but it has been shown that they promote infection and tissue reaction. Increased tissue infection is the result of capillary penetration of bacteria and other foreign matter.
A braided suture can harbour bacteria in the interstices between its fibers, which keep the bacteria safe from phagocytosis. [1]
In addition, as they are generally larger in diameter than monofilament sutures, they make bigger holes in the tissues or prostheses. [13]

Plasticity is defined as the capacity of a suture to retain its length and strength after stretching. It means the suture can accommodate the stretch of oedematous tissue without regaining its original shape on remission of the oedema.
Therefore, sutures with high plasticity can become too loose when the oedema resolves, thus preventing correct approximation of wound edges. [1]

The point, along with the body see Body >>, is one of the parts of a surgical needle.
It can be of different shapes (round, triangular, diamond, blunt, etc.) and each of these shapes has a certain impact on the tissues it passes through, making it indication- and tissue-specific.

Examples of use according to the type of point

Round point: penetrates the tissues by separating rather than cutting the fibres. Does not tear soft, fragile tissues; its power of penetration is limited in dense tissue such as the skin. Used mainly in vascular, digestive and urinary surgery and for all friable tissues.
Triangular point: easily penetrates dense tissue (skin, aponeurosis) by cutting the fibres; type of needle used for the skin and muscles.
Diamond point: a strong cutting tip honed on 4 sides, followed by a round, atraumatic body, ensures easy penetration through tissue with minimal trauma.
Blunt point: allows penetration through friable tissues while limiting damage to small blood vessels and parenchyma (hepatic, renal or splenic).
Spatula and lancet point: sharp but flat points, for use in microsurgery and ophthalmology.
Microtip triangular point: precision point with specific, fine-tip geometry and with the apex of the cutting edge on the outside of the curve. Ideal for plastic surgery.

Each type of point is designated by a letter and symbol which are shown on the packaging for identification

HRT 26 = 1/2 circle round body, diamond point, 26 mm

* Distance in millimetres measured from the point end of the needle to the attachment end, following the body of the needle

Polyester is a polymer which contains the ester functional group in its main chain. Premicron® is a non-absorbable, braided polyester suture, suitable for a number of uses, from anchoring wound drainage systems to anchoring cardiac valves.

The first synthetic absorbable sutures to come onto the market were made from polyglycolic acid. [12]
Polyglycolic acid, commonly known as PGA, is a synthetic biomaterial composed of glycolide polymers.
This material is reabsorbed by hydrolysis in a predictable manner. Its tissue support is excellent and it causes minimal tissue reaction.
PGA sutures rapidly became popular as a result of their better tensile strength and good knot security. [12]
In the B. Braun range the Safil® and Safil® Quick braided see Braided >> sutures are made from PGA and offer the well-known advantages of this class of sutures.
Safil® and Safil® Quick have different absorption times, making them suitable for a number of surgical indications.
These threads are recommended for approximating wound edges, especially in gastrointestinal, gynaecological or urological operations, as well as for subcutaneous sutures and ligatures.

A polymer (from the Greek pollus, many, and meros, parts) is a large molecule (macromolecule) composed of repeating structural units. The terms «polymer» and «macromolecule» are frequently used interchangeably.

Polypropylene, the chemical formula of which is (-CH2-CH(CH3)-)n, is a semi-crystalline, thermoplastic polymer. Non-absorbable polypropylene monofilament sutures such as Premilene® are the sutures of choice for vascular surgery.   

[1] Hochberg J, Meyer KM, Marion MD.; Suture Choice and Other Methods on Skin Closure; Surg Clin North Am. 2009 Jun;89(3):627-41.

[4] M Leclercq; Fils et aiguilles; Prof P. Erpicum 2008-2009.

[11] Chu CC. Classification and general characteristics of suture materials. In: Chu CC, von Fraunhofer JA, Greisler HP, editors. Wound Closure Biomaterials and Devices. Boca Raton, FL:CRC Press; 1997.

[12] Bradley S, David J.; Suture material in cosmetic cutaneous surgery; Journal of Cosmetic and Laser Therapy. 2007, 9:41-45.

[13] Tremblay S., Mantovani D.; Les fils de suture: de fil en aiguille; Le médecin du Québec. Biomatériaux; 2003 Oct, 38 (10), 105-108.