Surgical Suture Threads: Materials, Absorbability and its Sizes

Surgical Suture Threads: Materials, Absorbability and its Sizes


Suture Thread Materials

Surgical sutures are made from numerous and various stuffs like biological materials such as catgut suture and silk. They are also manufactured with the aid of synthetic components, which include absorbables such as polyglycolic acid, polylactic acid, and polydioxanone as well as the non-absorbable nylon and polypropylene.

In Order to reduce or nullify the wound infection, newer methods of coating sutures with antimicrobial substances are being practiced. There are various and different sizes of sutures are employed at different situation and also according to the demand. Sutures should be strong enough to hold the tissues together in order to bind them effectively. They should also have the property called hypoallergic and avoid “wick effect” that would allow fluids and thus infection to penetrate the body along the suture tract.

Suture Thread Absorbability

All sutures falls under two main categories viz Absorbable and Non-Absorbable sutures. Absorbable sutures are naturally degraded while the Non-Absorbable ones are medically removed after the tissues got joined together. Catgut suture comes under absorbable sutures and also some newer synthetics like polyglycolic acid, polylactic acid, polydioxanone, and caprolactone also come under this category. They are as already told biodegradable, and are broken down by various processes like hydrolysis and proteolytic enzymatic degradation.

The process of suturing using absorbable sutures usually takes from 10 days to 8 weeks. They are used in patients who cannot return to the hospital in order to remove the suture or it is used in internal body tissues where it is absorbed by the tissues themselves. In either case, the sutures will hold the tissues together and it disintegrates itself, so that no foreign body will be left. At times, absorbable sutures can cause inflammation and be rejected by the body rather than absorbed.

Special kinds of silk or the synthetics polypropylene, polyester or nylon are employed to manufacture Non-absorbable sutures. Non-absorbable sutures are used in various suturing of the body tissues. For instance, Stainless steel is used in orthopedic surgery as well as in sternal closure in cardiac surgery. Non-absorbable sutures are used for the closure of skin wounds and are also employed in stressful internal body environments where absorbable sutures will not suffice. For example, in heart where constant pressure and movement is observed and also in bladder due to the adverse chemical conditions. They cause only less scaring and are predominantly used where cosmetic outcome is of utmost important.

Suture thread Sizes

United States Pharmacopeia (U.S.P) defines the size of the sutures. The range of the sutures are from #1 to #6, where #1 being the smallest. As the technology advanced, #0 was added to the suture diameters, and later, even thinner threads were manufactured, which were identified as #00 (#2-0 or #2/0) to #000000 (#6-0 or #6/0). Modern Sutures range from #5, which are heavily braided and are used in orthopedics, to #11-0, which are monofilament suture for ophthalmics. Atraumatic needles are produced in different shapes and according to the sizes needed. The actual diameter of thread for a given U.S.P. size differs depending on the suture material classes like Collagen diameter (mm), Synthetic absorbable diameter (mm) and Non-absorbable diameter (mm).

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