A high-radial strength, flex-resistant PLLA cuff tube for microvascular anastomosis

Vascular anastomosis is the cornerstone in microsurgery. To assist complicated microvascular anastomosis with diameters <0.6 mm, nonsuture cuff technique was developed. However, cuff tube made from polyamide is not degradable, and their long-term retention in the body may cause stiffness in blood vessels at the anastomotic site. Thus, development of a biodegradable cuff tube would greatly enhance surgical operability and biosafety. In this study, biocompatible poly-L-lactic acid (PLLA) was chosen as the raw material to prepare cuff tube for nonsuture cuff technique. A customized 'C' shaped nozzle was adopted during the melting extruding process, and then was subjected to a water-cooling bath to maintain the round shape and inner diameter of 582 microm ± 20 microm. Its crystallization behavior was controlled through the cooling procedure to achieve the expected mechanical properties and operability. Its good hemocompatibility and genotoxicity were validated by various in vitro assays. Consequently, a PLLA cuff tube with a radial tensile strength of 12 MPa and an elastic modulus of 1685 MPa was prepared and used to assist establishing a rat orthotopic hindlimb transplantation model, which indicated that our PLLA cuff tube was suitable for microvascular anastomosis in organ or tissue repair.