What Are Absorbable Sutures?

Absorbable suture refers to a new type of suture material that can be degraded and absorbed by the human body after being implanted into human tissue during surgical suture.

Chinese name: Absorbable suture
Foreign name: Absorbable sutures


Management category: Class III medical devices
Category Name: Medical absorbable suture

Application range of absorbable suture

Can be widely used in gynecology, obstetrics, surgery, plastic surgery, urology, pediatrics, stomatology, ENT, ophthalmology and other surgical and intradermal soft tissue suture. ^[1]

Physical properties of absorbable suture

1. Suture diameter. The unit of diameter of the suture is millimeter, which is usually expressed by several zeros. The thinner the suture, the greater the number of 0s, but the thickness of different suture materials is also different. Try to use thin and strong sutures that have the least response to the tissue. Under the conditions that can withstand the tension of the wound, choose as thin as possible.

2. Tensile strength. The tensile strength of the same kind of suture after knotting is 1/3 of its unknotted. In general, tendon sutures have the highest tensile strength, followed by synthetic materials, and sheep intestinal sutures have the smallest.

3. Structure. Single-strand (monofilament) sutures are not easy to cause infection and are suitable for sutured contaminated wounds, but not easy to operate. Multiple strands (braided threads) are easy to handle but increase the chance of infection and tissue reaction.

4. Coefficient of friction. Low-friction sutures can easily slide through tissue and are often used for intradermal sutures. However, the lower the coefficient of friction, the smoother the sutures, and the easier the knots become loose, requiring more knots.

5. Knot fastness. The stronger the knot, the less likely the wound will crack. A suture knot with a high coefficient of friction has good firmness, but it has high resistance when it passes through the skin and is not easy to use.

6. Resilience. The elastic suture is not easy to cut the tissue when the tissue is edema, and it does not loosen after the edema subsides, and the wound is not easy to crack.

Absorbable suture specifications

It is divided into blue, natural and blue interlaced colors. The line length varies from 45cm to 90cm. Special length sutures can be customized according to clinical surgery needs.

Classification of absorbable sutures

According to the absorbability of suture materials, absorbable sutures can be divided into sheep gut threads, polymer chemical synthetic threads, and pure natural collagen sutures.

Sheep gut line

Sheep gut is made from the collagen matrix in the submucosa of the sheep intestine. There are two types of medical intestines: ordinary intestines and chrome intestines.

Ordinary bowel absorption time is short, only 4-5 days, fast absorption, but the tissue response to the bowel is slightly larger, mostly used to heal faster tissues or subcutaneous tissues to ligate blood vessels and suture infected wounds. , Bladder and other mucosal layers, but the thread tension is poor, and the tissue response is heavy.

Chromium intestine can increase the tensile strength of sheep's intestine and prolong the time of maintaining stress. The absorption time of intestine is long, which takes 14-21 days. It causes less inflammatory response than ordinary intestines, and is used for suture of deep tissues. It is mostly used in gynecology and Urinary system surgery, suture of mucous layers such as stomach, intestine, bladder, ureter and biliary tract. Thicker chrome bowel threads are often used to suture deep tissues or inflammatory peritoneum.

Regardless of the common intestinal or chrome intestine, there are insufficient tension, it is not easy to suture and knot, the absorption effect is not ideal, there is rejection reaction, the in vivo adaptability is not ideal, and the short-term tensile strength loss in the digestive juice and infected environment is short. . ^[2]

2. Polymer chemical synthesis line (PGA polyethylene glycol acid)

PGA fibers have high strength, moderate elongation, low initial modulus, non-toxicity, and good biocompatibility, so the suture has good uniformity, stability, non-toxicity, no antigenicity, no carcinogenicity, and can resist gastric acid , Stomach digestive enzymes and infections, the tissue response is minimal. However, its absorption time is long, and absorption is complete and stable within 60-90 days, which can easily cause injury to the incision new tissue and form a small amount of scars. ^[1]

In addition to PGA polyglycolic acid, there are many other varieties of synthetic fiber threads, such as Maxon (polyethylene glycol carbonate), Vicryl (Polyglactin 910), polylactic acid glycolic acid, PDS (Polydioxanone, polydioxanone ) And PVA (Polyvinyl Acetate). ^[2]

3. Pure natural collagen suture (tendon)

Pure natural collagen suture is also called tendon suture. It is taken from the tendon tissue of special animal otter. The content of pure natural collagen is high. The production process does not involve chemical ingredients. It has many characteristics of collagen material and is similar to other sutures. Compared with tendon characteristics, it has good flexibility and strong tensile force. In addition, it has unique functions such as good absorption effect, promotion of wound healing, and good biocompatibility. It is a fourth-generation suture in the true sense. According to the thickness of the thread body, it is generally completely absorbed within 8-15 days, and the absorption is stable and reliable, and there is no obvious individual difference.

Absorbable suture suture comparison

Type of suture	Silk thread (generation)	Gut (second generation) Common gut	Gut (second generation) Chrome bowel	Synthetic absorbable suture (PGA) (three generations)	Pure natural collagen suture (fourth generation)
Raw materials	Cotton fabric or polypropylene, polyester, etc.	Sheep casings for healthy animals	Sheep casings for treated healthy animals	Polymerization of artificial metabolites (glycolic acid, lactic acid)	Special animal tendon tissue
strength	high	low	low	Well above the gut	Higher than synthetic absorbable sutures
Body strength Holding time	Non-absorptive, can be maintained until the wound is fully healed	7-10 days disappeared, the patient's individual difference affects the rate of disappearance of intensity	21-28 days disappeared, the patient's individual difference affects the rate of disappearance of intensity	More than 85% of the original strength can be maintained in one week, and more than 55% in two weeks. There is no obvious individual difference.	5/0, 6/0 can maintain tension for more than 1 week, 4/0, 4 / 0T can maintain for more than 12 days, the rest is thickened by the diameter of the wire, and the maintenance time is gradually extended.
Absorption method	Non-absorptive	Hydrolyzed and absorbed by body tissue	Hydrolyzed and absorbed by body tissue	Simple hydrolysis process	Enzymatic digestion by body tissues
Products after degradation	no	Carbon dioxide, water	Carbon dioxide, water	Carbon dioxide, water	Amino acid
Absorption speed	Non-absorptive	Usually absorbed within 70 days, but the individual patient's differences affect the absorption process, or even do not absorb	Usually absorbed within 90 days, but individual patients have different influences on the absorption process, even do not absorb	Complete absorption within 60-90 days, stable and reliable absorption and prediction, no obvious individual differences	Completely absorbed in 8-15 days, and the absorption is stable and reliable without obvious individual differences
Tissue response	obvious	Moderate	Moderate but less reactive than normal bowel	Mild, significantly lower than the gut	no
With or without chemical coating	Cotton fabric no, polymer yes	no	no	Have	no
Thread structure	Braided	Single fiber	Single fiber	Single fiber	Single fiber
Whether absorption is complete	Not absorbed at all	A little does not absorb	A little does not absorb	A little does not absorb	Fully absorbed
Protective fluid	no	need	need	no	no

Absorbable sutures for extended reading

[1] Wang Yuanyuan, Ma Aibin, Li Yuhua et al. Research progress on absorbable medical magnesium alloy sutures [J]. Functional Materials, 2015, 46 (A2): 32-37.

[2] Li Jikuan, Zhao Yang. Application and development of medical absorbable sutures [J]. Health Horizon, 2013, (6).