RESUMO
Objective To develop a magnetic anastomosis device for infrahepatic inferior vena cava and verify its feasibility and safety in rat models. Methods According to the anatomical characteristics of rat inferior vena cava, a magnetic device suitable for end-to-end anastomosis of infrahepatic inferior vena cava was designed and manufactured. The device consisted of the inner and outer rings. The inner ring was a coated neodymium-iron-boron magnetic ring, and the outer ring was made of polyetheretherketone by 3D printing. Ten fine holes are evenly distributed on the outer ring, of which 5 fine holes were used to load the fine needles, and the other 5 fine holes were mutually connected with the fine needles of the contralateral anastomosis ring during anastomosis. The outer ring was uniformly loaded with fine needles and then bonded with the inner ring to form a magnetic anastomosis complex. Bilateral ends of vessels passed through the anastomosis ring and were fixed to the fine needles, and then end-to-end vascular anastomosis was performed by mutual attraction of two magnetic anastomosis rings. Twenty SD rats were selected and received end-to-end anastomosis of infrahepatic inferior vena cava with magnetic anastomosis device. The time of vascular occlusion, postoperative survival, postoperative anastomotic patency, gross observation and histological examination of anastomotic stoma were analyzed. Results All rats successfully completed end-to-end magnetic anastomosis of the infrahepatic inferior vena cava, and the time of vascular occlusion was 4~6 min. One rat died at 10 d after operation, and the other rats survived within postoperative 2 months. The patency rates of anastomotic stoma in surviving rats at postoperative 1 d, 3 d, 1 month and 2 months were 100%, 100%, 95% and 95%, respectively. At 2 months after operation, no obvious displacement and angulation of the anastomosis device were seen. No signs of corrosion and cracking of the anastomosis rings were observed. No evident hyperplasia and edema of surrounding tissues were noted. Bilateral ends of vessels were completely healed, and no obvious stenosis or thrombosis was found at the anastomotic stoma. Histological examination showed high continuity of bilateral vascular walls of anastomotic stoma, the inner surface of anastomotic stoma was covered by endothelial cells, and no thrombus or fibrous tissue was attached. Conclusions It is safe and feasible to utilize the self-designed magnetic anastomosis device to perform end-to-end magnetic anastomosis of infrahepatic inferior vena cava in rat models.
RESUMO
Objective To invent a set of novel veno-venous bypass (VVB) device based on magnetic anastomosis technique which can be used in ex situ liver resection, and verify its clinical value and performance in animal models.Methods Each VVB device was constructed using three magnetic rings and an inverted Y-shaped tube with magnetic rings on each end.The magnetic ring was made of NdFeB with electrode cutting, and the tube was made of polyvinyl chloride (PVC) and preconditioned with heparin coating on the surface of the lumen.Ten dogs underwent the ex situ liver resection, and VVB was established via magnetic anastomosis technique with the novel VVB device during the operation.The time for completing VVB was recorded, and the hemodynamic indexes including the venous flow velocity, carotid pressure, central venous pressure and portal pressure was detected.The changes of intestinal lumen and kidney were also observed.Results It only took 6 ～ 10 minutes to establish VVB by the novel VVB device in the operation,and the hemodynamics stability was maintained smoothly during the anheptic phase.The shunt index of inferior vena cava and portal vein was 76.2％ and 75.5％, respectively.The congestion of intestinal canal and kidney were also alleviated during the anheptic phase.Conclusions It could reduce the time to establish VVB with magnetic anastomosis technique in ex situ liver resection.This study showed that utilizing the novel VVB device for intraabdominal VVB during the anheptic phase could be helpful to maintain the hemodynamics stability.