New Absorbable Microvascular Anastomotic Devices Representing a Modified Sleeve Technique: Evaluation of Two Types of Source Material and Design.

The purpose of this study was to create a new absorbable vascular anastomotic coupler and evaluate the patency and degradation degree. Vascular anastomosis was performed in the jugular vein in 31 New Zealand white female rabbits. The coupler consisted of an inner and outer ring. One side of the jugular vein was passed through and overlapped the inner ring. The opposite side of the jugular vein overlapped the everted jugular vein on the inner ring. Then, the outer ring engaged with the inner ring and completed the anastomosis. The outer rings were also constructed with two shapes including an O-type that had no slit and a C-type with a slit on the outer ring of the O-type coupler to allows expandability of the diameter. A Phase I experiment was performed to evaluate the degradability of the source materials, including the poly (lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) couplers. A Phase II experiment was performed to evaluate the patency and anastomosis time of the O-type PLGA and PCL couplers. A Phase III experiment was performed to evaluate the patency and anastomosis time of suture anastomosis (control) and the C-type PLGA coupler. The patency was determined by ultrasonography and open exploration. Histological analysis was performed to determine the degradability of the couplers. In Phase I, the PLGA couplers were completely degraded with good vascular wall remodeling at 8 months, while the PCL couplers demonstrated incomplete degradation. In Phases II and III, the anastomosis time was significantly shorter in the coupler groups than that in the control group. All of the coupler groups demonstrated complete patency of the anastomoses on ultrasonography. In Phase III, the C-type PLGA coupler also demonstrated patency and complete degradation at 8 months. PLGA is a suitable source material for absorbable couplers due to its fast degradability. We devised the O-shaped outer ring for the C-shaped outer ring to increase flexibility, which also demonstrated complete patency during the experimental period. Our absorbable microvascular anastomosis devices could provide rapid and reliable microvascular anastomosis without anastomotic failure.