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Degradable Sutures, by Cody Siroka: Difference between revisions
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Degradable Sutures, by Cody Siroka (view source)
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1800 CE - Joseph Lister proposes catgut sutures [1],[7] and proves their utility.<br> | 1800 CE - Joseph Lister proposes catgut sutures [1],[7] and proves their utility.<br> | ||
== Motivation== | == Motivation == | ||
Sutures are important in promoting the healing process in damaged tissue and preventing further complications. Degradable sutures are useful in many wound closing applications, especially when the wound is minor. It is important that the best possible suture material is chosen based on the type of wound, bodily location, and other factors. For example, to minimize potential scarring where cosmetic implications are considerable, the smallest suture materials are generally chosen. The materials used to manufacture these sutures dictate the type of immune response, biocompatibility, and mechanical properties, consequently influencing wound treatment. | Sutures are important in promoting the healing process in damaged tissue and preventing further complications. Degradable sutures are useful in many wound closing applications, especially when the wound is minor. It is important that the best possible suture material is chosen based on the type of wound, bodily location, and other factors. For example, to minimize potential scarring where cosmetic implications are considerable, the smallest suture materials are generally chosen. The materials used to manufacture these sutures dictate the type of immune response, biocompatibility, and mechanical properties, consequently influencing wound treatment. | ||
== Current Use and Materials == | |||
Degradable suture materials can be either organic or synthetic. There are many types of materials which have been used over course of their development that are absorbed by the human body. Absorbable sutures tend to be reserved for use inside the body underneath the skin as they are prone to leave a more pronounce scar upon absorption. When later removal poses potential difficulty, their use may be exhausted. For synthetic materials, it is desirable that there is no toxicity associated with its usage, is metabolized fully, long-lasting shelf life, easy to manipulate, and is sterilizable. Many factors affect the performance of a synthetic material, which consequently yields variations among molecular weight, molecular weight distribution, hydrophobicity, and crystallinity. [8] This list encompasses the most commonly used materials today. | Degradable suture materials can be either organic or synthetic. There are many types of materials which have been used over course of their development that are absorbed by the human body. Absorbable sutures tend to be reserved for use inside the body underneath the skin as they are prone to leave a more pronounce scar upon absorption. When later removal poses potential difficulty, their use may be exhausted. For synthetic materials, it is desirable that there is no toxicity associated with its usage, is metabolized fully, long-lasting shelf life, easy to manipulate, and is sterilizable. Many factors affect the performance of a synthetic material, which consequently yields variations among molecular weight, molecular weight distribution, hydrophobicity, and crystallinity. [8] This list encompasses the most commonly used materials today. | ||
=== Natural === | |||
'''Catgut '''<br>[[Image:Wc.absorb.md_.chart_rev.jpg|right|upright=1|''[[Overview of commercial absorbable sutures, strength classification, and degradation time]]'']] | '''Catgut '''<br>[[Image:Wc.absorb.md_.chart_rev.jpg|right|upright=1|''[[Overview of commercial absorbable sutures, strength classification, and degradation time]]'']] | ||
Derived from the walls of animal intestines, including sheep, goat, and cattle, among other animals. It is from the submucosal layer in sheep, or the serosal layer in cattle, found within the small intestine. [1] As it is a material derived from a natural source, it is subject to variations among the material’s chemical structure, which can cause weak points within the material due to the potential lack of uniformity. For this reason, catgut is manufactured in a multifilament fashion to ensure integrity during use. Catgut loses strength rapidly following implementation; approximately 60% of its tensile strength is lost following the first week (4), and continues to diminish until it is broken down by the body completely. Chromic salt coatings on the catgut can prolong the strength of the material and minimize adsorption time. The mechanism by which the degradation of catgut occurs is by proteolytic enzymes found in phagocytes, wherein macrophages, lymphocytes, and other cells accumulate to replace areas within the suture, and eventually, dense accumulations of macrophages replace the suture fully. <br> | Derived from the walls of animal intestines, including sheep, goat, and cattle, among other animals. It is from the submucosal layer in sheep, or the serosal layer in cattle, found within the small intestine. [1] As it is a material derived from a natural source, it is subject to variations among the material’s chemical structure, which can cause weak points within the material due to the potential lack of uniformity. For this reason, catgut is manufactured in a multifilament fashion to ensure integrity during use. Catgut loses strength rapidly following implementation; approximately 60% of its tensile strength is lost following the first week (4), and continues to diminish until it is broken down by the body completely. Chromic salt coatings on the catgut can prolong the strength of the material and minimize adsorption time. The mechanism by which the degradation of catgut occurs is by proteolytic enzymes found in phagocytes, wherein macrophages, lymphocytes, and other cells accumulate to replace areas within the suture, and eventually, dense accumulations of macrophages replace the suture fully. <br> | ||
'''Reconstituted Collagen (RC)'''<br> | '''Reconstituted Collagen (RC)'''<br> | ||
Used exclusively for microsurgery, RC is similar to catgut in that it is prepared from an animal source, but differs in its “polymorphic, aggregated form.” (5) This type of material is from long flexor tendons of cattle, and is processed and extruded into coagulated fibrils, and treated with chromic salts. | Used exclusively for microsurgery, RC is similar to catgut in that it is prepared from an animal source, but differs in its “polymorphic, aggregated form.” (5) This type of material is from long flexor tendons of cattle, and is processed and extruded into coagulated fibrils, and treated with chromic salts. | ||
=== Synthetic === | |||
'''Polyglycolic Acid (PGA)''' | |||
[[Image:Polyglycolic acid suture ( PGA-Dexon) 01.JPG|right|thumb|left|upright=1.5|''[[Degradable PGA suture material. This particular product is called Dexon.]]'']][[Image:PGA Synthesis.png|left|]] Synthetic homopolymer of glycolic acid in a braided multifilament. PGA has a uniform chemical structure, produced by the reaction of glycolic acid with glycolide to create linear polymer chains. The polymer is then processed in particular methods to create suture material with the desired physical properties, where it is subject to heat treatment. The monomer of glycolide is created from the dimerization of glycolic acid in a ring opening polymerization, which does not occur in most organic solvents. The homopolymer must be braided into a multifilament because PGA fibers are otherwise too stiff and strong for usage. The synthetic material is more uniform than its naturally-derived counterparts, and is broken down in the body by hydrolysis. PGA maintains 55% of its initial tensile strength 2 weeks after implementation [4], lose all strength by 4 weeks, and are fully absorbed after 4-6 months [8].<br> | |||
'''Poly(lactide-co-glycolide) (PLG)'''<br>Result of the copolymerization of two monomers, lactide and glycolide. Different stereoisomers of these monomers yield changes in physical properties. Glycolide has a tendency to be amorphous due to the disruption in the regularity of the polymer chain with the combination of another monomer. Similarly, other materials such as trimethylene carbonate can be combined with PGA to create materials with changes in flexibility, and absorption time. [8] [[Image:PLG Synthesis.png|upright=1|]]<br> | '''Poly(lactide-co-glycolide) (PLG)'''<br>Result of the copolymerization of two monomers, lactide and glycolide. Different stereoisomers of these monomers yield changes in physical properties. Glycolide has a tendency to be amorphous due to the disruption in the regularity of the polymer chain with the combination of another monomer. Similarly, other materials such as trimethylene carbonate can be combined with PGA to create materials with changes in flexibility, and absorption time. [8] [[Image:PLG Synthesis.png|upright=1|]]<br> | ||
'''Polyglycan 910'''<br> | '''Polyglycan 910'''<br> | ||
