Suture compliance

Sustainment activities, 10 166 Suture compliance, 24 214-215 Suture materials, 24 205 categories of, 24 207 coated, 24 212-213 essential properties of, 24 213-214 Sutures, 24 205-224... 

A variety of copolymers having high molar ratios of PDS compared to other monomers within the same linear aliphatic polyester family have been reported for the purpose of improving the mechanical and biodegradation properties [Shalaby, 1994]. For example, copolymer of PDS (80%) and PGA (up to 20%) has an absorption profile similar to Dexon and Vicryl sutures but it has compliance similar to PDS. Copolymer of PDS (85%) and PLLA (up to 15%) results in a more compliant (low modulus) suture than homopolymer PDS but with absorption profiles similar to PDS [Bezwada et al., 1990). 

As with other types of braided sutures, an absorbable coating which improves suture handUng and knot formation has been added to the absorbable braids. To minimize the risk of infection and tissue drag that are sometimes associated with braided sutures, four types of monofilament sutures have been commercialized. The absorbable monofilaments were designed specifically to approach the engineering compliance of braided sutures, by combining appropriate materials to achieve low moduli, for example, polydioxanone and copolymers of glycolide with caprolactone or trimethylene carbonate. 

Abbott W M, Megerman J, Hasson J E, L ltalien G and Warnock D (1987), Effect of compliance mismatch upon vascular graft patency / Vase Surg, 5(2), 376-382. Alcamo J H (1964), Surgical suture , US Patent 3,123,077. 

Han et al. synthesized a SPEsUU from PCL, L-lysine ethyl ester diisocyanate (LDl), and L-lysine ethyl ester (LEE) as chain extender [92], The mechanical properties of the electrospun tubular scaffolds increased with solution concentration, as the fiber diameter was progressively increased. The values of suture-retention strength were higher than those of native blood vessels, whereas the burst pressure strength was slightly lower. No compliance data were reported. The scaffolds displayed no cytotoxicity against L-929 mouse fibroblasts or HUVECs, and in vitro cell attachment proved to be successful. 

Various copolymers with a high PDO content have been synthesized and studied to improve the mechanical performance and increase the rate of resorption [40]. A copolymer with 80 % PDO and up to 20 % PGA has a resorption profile similar to Dexon and Vicryl and yet maintains a compliance similar to PDS . The copolymer with 85 % PDO and up to 15 % PLLA exhibits higher compliance and a lower modulus than the PDO homopolymer, yet its resorption profile is similar to PDS [41]. Copolymers with three or more different monomer units have also been explored. One such example is poly(GA-co-PDO-co-LA), which has been proposed as a possible suture material with suitable crystallinity, good flexibility, better strength retention, and a reasonably rapid resorption rate [42]. Until recently, there was not much interest in developing PDO as a biomaterial, mainly because of the lack of commercial availability and difficulties in its synthesis. However, with the development of new alternative synthesis procedures and the availability of the PDO monomer, there has been more commercial interest in developing PDO as a bioresorbable polymer in recent years (Table 4.6). 

---