| Description |
In microsurgical operating room environments, it is often necessary to cut and reattach vessels multiple times during surgery. The current method of vascular anastomosis is hand suturing. This technique is time consuming, difficult, and requires complex instruments. To solve this problem, researchers have explored alternative ways to improve this technique. Typical examples are staples, clips, cuffing rings, adhesives, and laser welding. The potential of these techniques has been hindered due to the lack of biocompatibility, complex procedures for use, and general inefficiency. As a result, few of these devices have been commercialized. One promising alternative is a ring-pin coupling device. This device has been shown to be useful for venous anastomosis, but lacks the versatility necessary for arterial applications. One purpose of this study was to optimize a vascular coupling design that could be used for arteries and veins of various sizes. To achieve this, finite element analysis was used to simulate the vessel-device interaction during anastomosis. Parametric simulations were performed to optimize the number of pins, the wing pivot point, and the pin offset of the design. The interaction of the coupler with various blood vessel sizes was also evaluated. The optimal vascular coupling device has four rotatable wings and one translatable spike in each wing. Prototypes were manufactured using polytetrafluoroethylene (PTFE) and high-density polyethylene (HDPE). A set of installation tools was designed to facilitate the anastomosis process. Proof-of-concept testing with the vascular coupler using plastic tubes and porcine cadaver vessels showed that the coupler could be efficiently attached to blood vessels, did not leak after the anastomosis was performed, had sufficient joint strength, and had little impact on flow in the vessel. A simplified finite element model assisted in the evaluation of the tearing likelihood of human vessels during installation of the coupler. The entire anastomosis process can be completed in three minutes when using the vascular coupler to join porcine cadaver vessels. A metal-free vascular coupling system that can be used for both arteries and veins was designed, fabricated, and tested. A set of corresponding instruments were developed to facilitate the anastomosis process. Evaluation of the anastomosis by Scanning Electron Microscopy (SEM) and Magnetic Resonance Imaging (MRI) demonstrated that the installation process does not cause damage to the vessel intima and the vascular coupling system is not exposed to the vessel lumen. Mechanical testing results showed that vessels reconnected with the vascular coupling system could withstand 12.7±2.2 N tensile force and have superior leak profiles compared to hand sutured vessels. The anastomotic process was successfully demonstrated on both arteries and veins in cadaver and live pigs. |
