Review Paper: Absorbable Polymeric Surgical Sutures: Chemistry, Production, Properties, Biodegradability, and Performance

Among biomaterials used as implants in human body, sutures constitute the largest groups of materials having a huge market exceeding $1.3 billion annually. Sutures are the most widely used materials in wound closure and have been in use for many centuries. With the development of the synthetic absorbable polymer, poly(glycolic acid) (PGA) in the early 1970s, a new chapter has opened on absorbable polymeric sutures that got unprecedented commercial successes. Although several comparative evaluations of suture materials have been published, there were no serious attempts of late on a comprehensive review of production, properties, biodegradability, and performance of suture materials. This review proposes to bring to focus scattered data on chemistry, properties, biodegradability, and performance of absorbable polymeric sutures.

Designing biodegradable multiblock PCL/PLA thermoplastic elastomers

A series of poly(epsilon-caprolactone)/poly(L-lactic acid) (PCL/PLA) biodegradable poly(ester-urethane)s, was synthesized and characterized. The first step of the synthesis consisted of the ring opening polymerization of L-lactide, initiated by the hydroxyl terminal groups of the PCL chain, followed by the chain extension of these PLA-PCL-PLA triblocks, using hexamethylene diisocyanate (HDI). The trimers comprised PCL2000 flexible segments, while the length of each PLA block covered the 550-6000 molecular weight range. The morphology of the copolymers gradually changed, as the length of the PLA blocks increased. The multiblock copolymers produced displayed enhanced mechanical properties, with ultimate tensile strength values around 32 MPa, Young's modulus as low as 30 MPa and elongation at break values well above 600%. The longer the PLA block, the slower the in vitro degradation of the material, with all copolymers degrading faster than the respective homopolymers.

Biodegradable poly(ethylene oxide)/poly(epsilon-caprolactone) multiblock copolymers

A series of poly(ethylene oxide) (PEO)/poly(epsilon-caprolactone) (PCL) containing biodegradable poly(ether ester urethane)s, covering a wide range of compositions, were synthesized and characterized. The synthesis consisted of a two-step process. During the first step, the ring-opening reaction of epsilon-caprolactone was carried out, initiated by the hydroxyl terminal groups of the PEO chain. The second step involved the chain extension of these PCL-PEO-PCL trimers with hexamethylene diisocyanate. By varying either the ethylene oxide/epsilon-caprolactone ratio or the length of both segments, we obtained a series of polymers having different morphologies and displaying a broad range of properties.

Study on microvascular anastomosis of arteries with absorbable polyglyconate suture

A synthetic, monofilament, slowly absorbing suture material, polyglyconate suture was tested to determine its suitability for use in microarterial anastomoses under ordinary tension and under undue tension. Microvascular repair of 34 rat femoral arteries averaging 0.63 mm in diameter using 8-0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 94.1% after 1 to 24 weeks. Microanastomoses of 30 rabbit femoral arteries averaging 1.43 mm in diameter using 8-0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 96.7% when a vessel segment of 3 to 7 mm was resected. Morphological studies included light microscopy and scanning electron microscopy. The results showed that polyglyconate suture retains tensile strength for an adequate period to allow vascular healing and causes a less pronounced tissue response than nonabsorbable nylon suture. Complete absorption of the suture material was followed by a complete regeneration of the vessel wall. These results demonstrated that absorbable polyglyconate suture might be suitable for microvascular anastomosis of arteries under ordinary tension and under tension to a certain degree.