Surgical sutures

Color additives are routinely added to medical devices such as surgical sutures, surgical cements, and contact lenses (32). Sutures are usually colored to make them more visible during survery and, depending on the appHcation, during removal of the suture after the sutured area has healed. Surgical cements, too, are colored to make them more visible during use (Table 4). 

PLA is a biodegradable polymer that has been widely studied and is used for domestic packaging, and biomedical apphcations, such as resorbable sutures, surgical implants, scaffolds for tissue engineering and controlled dmg-deliveiy devices. PLA can exist as two stereoisomers, designated as D and L, or as a racemic mixture, designated as DL. The D and L forms are optically active while the DL form is optically inactive. Poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) are semicrystalline,... 

Wound dehiscence Avoid in high tension wounds unless in conjunction with deep tension relieving sutures, surgical tapes, and immobilization... 

Vinyl alcohol does not exist as a monomer, but Herrmann and Haehnel (1) were able to obtain the desired product poly(vinyl alcohol) [9002-89-5] (PVA), by polymerizing vinyl acetate and then hydrolyzing the resultant poly(vinyl acetate). This process is employed for the commercial production of PVA even now. The principal concern of the discoverers was development of a suture for surgical operations the fiber then obtained was not suited for clothing use (2). 

Production of both monobasic aluminum diformate, (HO)Al(OOCH)2, and monobasic aluminum formoacetate, (HO)Al(OOCH) (OOCCH ), has declined. One reason could be the ready substitution of inexpensive aluminum formate solution (17—19) for soHd aluminum acetate in formoacetate in most of the common commercial appHcations. Monobasic aluminum formoacetate, mol wt 148.05, mp 350°C, is a fine crystalline powder, prepared from aluminum metal. It is used for fabric water repeUency and in the tanning of coUagen tape for surgical sutures (10). 

Medical Usage. Isopropyl alcohol is also used as an antiseptic and disinfectant for home, hospital, and industry (see Disinfectants and antiseptics). It is about twice as effective as ethyl alcohol in these appHcations (153,154). Rubbing alcohol, a popular 70 vol % isopropyl alcohol-in-water mixture, exemplifies the medicinal use of isopropyl alcohol. Other examples include 30 vol % isopropyl alcohol solutions for medicinal liniments, tinctures of green soap, scalp tonics, and tincture of mercurophen. It is contained in pharmaceuticals, eg, local anesthetics, tincture of iodine, and bathing solutions for surgical sutures and dressings. Over 200 uses of isopropyl alcohol have been tabulated (2). 

In contrast, the total artificial heart (TAH) is designed to overtake the function of the diseased natural heart. While the patient is on heart—lung bypass, the natural ventricles are surgically removed. Polyurethane cuffs are then sutured to the remaining atha and to two other blood vessels that connect with the heart. 

Polylactic Acid. Polylactic acid (PLA) was introduced in 1966 for degradable surgical implants. Hydrolysis yields lactic acid, a normal intermediate of carbohydrate metaboHsm (23). PolyglycoHc acid sutures have a predictable degradation rate which coincides with the healing sequence of natural tissues. 

Surgical sutures are sterile, flexible strands used to close wounds or to tie off tubular structures such as blood vessels. Made of natural or synthetic fiber and usually attached to a needle, they are available ia monofilament or multifilament forms. Sutures are classified by the United States Pharmacopeia (USP) (1) as either absorbable or nonabsorbable. The USP also categorizes sutures according to size (diameter) and Hsts certain performance requirements. Sutures are regulated by the Food and Dmg Administration (FDA) as medical devices under the Food, Dmg, and Cosmetics (FDC) Act of 1938, the Medical Device Act of 1976, and the Medical Device Reporting regulation of 1995. 

Table 1. Surgical Sutures Manufactured in the United States...

Braided Synthetic Absorbable Sutures. Suture manufacturers have searched for many years to find a synthetic alternative to surgical gut. The first successful attempt to make a synthetic absorbable suture was the invention of polylactic acid [26023-30-3] suture (15). The polymer was made by the ring-opening polymerization of L-lactide [95-96-5] (1), the cycUc dimer of L-lactic acid. 

Table 4. USP Specifications for USP Class I Nonabsorbable Surgical Sutures...

No coloi additive oi product containing one can be used in the aiea of the eye, in surgical sutures, or in injections, unless so stated. Also, no colorant can be used to color foods for which standards of identity have been promulgated under Section 401 of the Federal Food, Dmg, and Cosmetic Act, unless the use of added color is authorized by the standard. Colorants without restrictions can be used for coloring foods generally, in amounts consistent with good manufacturing practice. 

D C Green No. 5 (13) Alizarine Cyanine Green F Cl Acid Green 25 [4403-90-1] 61570 nylon-6,6 and nylon-6 nonabsorbable surgical sutures only 0.6% (w/w) max... 

No color additive or product containing one can be used iu the area of the eye, iu surgical sutures, or iujections unless so stated. Colorants without restrictions can be used for coloring cosmetics generally, iu amounts consistent with good manufacturiag practice. 

Use Restrictions. There are numerous restrictions on the use of color additives. They caimot, for example, be employed to deceive the pubHc by adding weight or bulk to a product or by hiding quaUty. In addition, special permission is needed to use colorants or products containing them in the area of the eyes, in injections, in surgical sutures, and in foods for which standards of identity have been promulgated under Section 401 of the Eederal Eood, Dmg, and Cosmetic Act. 

Nylon monofilaments have found application in brush tufting, wigs, surgical sutures, sports equipment, braiding and outdoor upholstery. Nylons 610 and 11 have found extensive application in these fields because of their flexibility but nylon 66 is also used for brush tufting less than 0.0035 in. in diameter. Nylon 66/610 copolymer is used in the manufacture of a monofilament for angling purposes. 

There has been recent interest in lactic acid polymers and copolymers. These materials are environmentally attractive in that renewal and cheap source materials such as potato waste and cheese whey may be used. Such materials have been used for some time in degradable and resorbable surgical sutures but recent efforts have been directed at food packaging applications. There is... 

Despite the universal use of sutures for wound closure, there is a need to utilize adhesives instead, because of their ease of use and the reduced risk of infection. Alkyl cyanoacrylate adhesives have been studied extensively for this use, and a significant amount of research has been performed to evaluate their interaction with living tissue [40,41 J. They have been approved for external use only, because of concerns with the fact that the polymers do not readily biodegrade and can cause inflammation around the area to which it was applied. However, these concerns are reduced for -butyl cyanoacrylate, as compared to the ethyl cyanoacrylate. There is even some evidence that their use as liquid sutures actually reduces the rate of infection around the healing wound or surgical incision [42J. 

The extent to which these new tissue adhesives and hemostats will influence surgical procedures can be seen in the following analogy. An effective carpenter cannot create a masterpiece without a saw to cut wood, nails to ensure local fixation of separate pieces of wood, and glue to cause broad surface apposition between wood surfaces. Similarly, the surgeon presently uses a scalpel to cut and divide tissues as well as a suture to create local fixation of tissues, but until... 

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