Shanpei Wang

Fast magnetic reconstruction of the portal vein with allogeneic blood vessels in canines.

BACKGROUND The resection and reconstruction of large vessels, including the portal vein, are frequently needed in tumor resection. Warm ischemia before reconstruction might have deleterious effects on the function of some vital organs and therefore, how to reconstruct the vessels quickly after resection is extremely important. The present study was to introduce a new type of magnetic compression anastomosis (MCA) device to establish a quick non-suture anastomosis of the portal vein after resection in canines. METHODS The new MCA device consists of a pair of titanium alloy and neodymium-ferrum-boron magnet (Ti-NdFeB) composite rings. The NdFeB magnetic ring as a core of the device was hermetically sealed inside the biomedical titanium alloy case. Twelve canines were divided into two groups: a MCA group in which the end-to-end anastomoses was made with a new device after resection in the portal vein and a traditional manual suture (TMS) group consisted of 6 canines. The anastomosis time, anastomotic patency and quality were investigated at week 24 postoperatively. RESULTS The portal vein was reconstructed successfully in all of the animals and they all survived. The duration of portal vein anastomosis was significantly shorter in the MCA group than in the TMS group (8.16+/-1.25 vs 36.24+/-2.17 min, P<0.05). Portography and ultrasound showed that the blood flow was normal without angiostenosis or thrombosis in all of the canines. Hematoxylin-eosin staining and electron microscope scanning showed in contrast to the TMS group, MCA anastomotic intimal was much smoother with more regularly arranged endothelial cells at week 24 postoperatively. CONCLUSIONS The Ti-NdFeB composite MCA device was applicable in reconstruction of large vessels after resection. This device was easy to use and the anastomosis was functionally better than the traditional sutured anastomosis.

Healing of Stoma After Magnetic Biliary-Enteric Anastomosis in Canine Peritonitis Models

OBJECTIVE To assese the healing of stoma after magnetic anastomosis for the reconstruction of biliary-enteric continuity under severe inflammation. METHODS Acute bile duct injury was constructed as a bile peritonitis model in mongrel dogs (n=32). Magnetic anastomosis (group A, n=16) and traditional suture anastomosis (group B, n=16) were performed to reconstruct the biliary-enteric continuity in one stage. Half of the dogs in each group were euthanized on the 30th postoperative day, and the other half on the 90th postoperative day to harvest the stoma region. The healing conditions of the stoma after the 2 anastomotic approaches were observed with naked eyes, under light microscope and scanning electron microscope. RESULTS The stoma leakage rate (50% versus 0% on the 30th postoperative day, 37.5% versus 12.5% on the 90th postoperative day, both P<0.05) and stenosis degree (13.9%±0.3% versus 7.1%±0.3% on the 30th postoperative day, 17.2%±0.4% versus 9.4%±0.4% on the 90th postoperative day, both P<0.01) were significantly higher in group B than in group A. Compared with traditional manual anastomoses, the histological analysis under light and electron microscope showed a more continuous stoma with more regular epithelium proliferation and collagen arrangement, less inflammation in group A. CONCLUSIONS Magnetic anastomosis stent ensures better healing of the stoma even under the circumstance of severe inflammation.