One-knot microvascular anastomosis. An experimental study in rats

Experimental microvascular anastomosis using a glutide copolymer (lactide:glycolide, 80:20) as an external splint was undertaken in 33 rats between the carotid artery and the jugular vein. Both vessels were dissected free over a 1-cm length and cut at the cranial end of the dissected part. The carotid artery was then introduced into a glutide pipe-splint. The arterial wall was turned 180 degrees over the edge of the splint. This reflected artery wall and the glutide were covered by the freed-up jugular vein. One stitch was made around the vein, the artery, and the glutide in a manner similar to binding steel wire over a barrel. Thus, the "one-knot anastomosis" was completed. The patency rate at the anastomosed site was 100%, confirmed by angiography in 30 rats and by direct surgery in three. The time required to produce the anastomosis was between 5 and 7 minutes. Light microscopic observation showed that there was no obstruction by thrombus formation at 1 and 5 weeks after the anastomotic surgery. This technique may be clinically applicable for extracranial-intracranial bypass surgery, reconstruction of venous sinuses, and other vascular procedures.     

Bronchial circulation after experimental lung transplantation: the effect of direct revascularization of a bronchial artery.

Direct revascularization of a bronchial artery has been proposed as a measure to alleviate the problem of bronchial ischemia after lung transplantation. To assess the effect of restoration of arterial blood flow to the transplanted bronchus, bronchial mucosal blood flow was measured in a model of modified unilateral lung transplantation in pigs. Laser Doppler velocimetry (LDV) and radioisotope studies using radio-labeled erythrocytes (RI) were used to measure blood flow at the donor main carina (DC) and upper lobe carina (DUC) after 3 h of reperfusion. The recipient carina was used as a reference point; values obtained by LDV and RI were expressed as percentage of blood flow at the recipient carina. Two groups of animals were studied. In group 1 (n = 6) standard unilateral transplantation was performed; in group 2 (n = 6) a left bronchial artery was reimplanted into the descending thoracic aorta of the recipient. No differences were observed between the two groups with respect to preoperative or postoperative gas exchange or hemodynamics. In group 1, bronchial blood flow at the DC was 37.6 +/- 2.2% (LDV) and 44.1 +/- 14.8% (RI) of reference blood flow. At the DUC, blood flow was 54.9 +/- 7.7% (LDV) and 61.6 +/- 25.7% (RI) of normal flow. In group 2, blood flow was increased at the DC as measured by LDV (55.3 +/- 17.1%; p less than 0.05) and by RI (60.8 +/- 25.3%; p less than 0.2). A similar increase was found at the DUC (LDV: 81.8 +/- 19.3%; p less than 0.05; RI: 88.6 +/- 31.0%; p less than 0.2). It is concluded that there is a significant gradient of blood flow from intra- to extrapulmonary airways after lung transplantation. Reimplantation of a bronchial artery results in significant improvement of graft bronchial blood flow. Restoration of bronchial perfusion to normal levels, however, cannot be achieved, suggesting a possible defect in the microcirculation of the donor airways.     

An experimental study of the effect of infection on microvascular anastomosis

The effect of penicillin-resistant Staphylococcus aureus infection on the patency of microvascular anastomosis was studied in an experimental model. Histological and SEM studies were also performed. It was found that the presence of infection did not significantly lower the patency rate of rat femoral artery re-anastomosis.     

An experimental model for side-to-side microvascular anastomosis

Side-to-side microvascular anastomosis may be required in certain clinical situations, although the technique is difficult and the incidence of usage remains low. A new experimental model using rat femoral vessels for side-to-side microvascular anastomosis is presented, in which 100 percent patency was accomplished immediately and was maintained for 7 days after anastomosis. This model can provide a training tool for acquisition of advanced microsurgical technique for side-to-side anastomosis of small vessels.     

The reapplication of microvascular clamps after venous anastomosis: An experimental study

Albino rats were used to determine the effects of the reapplication of microvascular clamps in veins after anastomosis. The results demonstrate that, if necessary, microvascular clamps can be reapplied either proximal, or both proximal and distal to a venous anastomosis for up to 30 minutes, thus allowing a suture to be redone or the lumen to be explored with no loss of patency.     

Thrombogenesis in experimental microvascular anastomosis

A large number of microvascular anastomoses, involving both arteriovenous and artery-artery end-to-side and end-to-end anastomoses, were carried out in the rat to develop a temporal and morphologic profile of thrombogenesis. While excellent patency rates were obtained in purely arterial preparations, significant thrombus formation occurred in the arteriovenous preparations, both at the suture line and more distally in the vein. Factors contributing to thrombogenesis in these microvascular anastomoses are discussed.     

Lymphaticovenous anastomosis by microvascular technique.

After developing some basic techniques of lymphaticovenous anastomoses in 60 dogs, a further study of these anastomoses in the greyhound was performed with a patency rate of 74 per cent a 1 week and 66 per cent between 6 and 12 weeks. Points of technique and causes of failure are discussed. The use of this method in the treatment of early secondary lymphoedema is mentioned.     

Vascular grafts in microvascular surgery. An experimental study

The patency of microvascular grafts depends on the luminal diameter, which is determined by the amount of fibrin and platelets deposited on the intraluminal surface and the anastomotic site, and the extent of pseudointimal formation. An experimental microvascular model in rats has been developed in our laboratory using Indium-111-labeled platelets to measure the amount of deposition on grafts inserted into the infrarenal aorta. This study was designed to assess the patency rates in these grafts and the pathologic maturation as determined by light and electron microscopy. Our study suggests that substantial patency rates can be achieved in aspirin-treated rats, although there was little influence on the pathologic maturation. Indium-111 oxine-labeled platelets can be used to document platelet aggregation, and the technique can be a valuable adjunct in the study of microvascular grafts.     

Low power CO2 laser-assisted microvascular anastomosis: an experimental study

Low power CO2 laser-assisted microvascular anastomosis (LAMA) was used for saphenous artery autotransplantation in 40 rabbits. Eighty end-to-end anastomoses were performed by three methods (conventional interrupted suture, stay suture + laser, laser without stay suture). The long term patency rate in the three types of anastomosis is 93%, 93%, and 100%, respectively. The time needed for the laser procedure is half to one-third of that required for the interrupted suture method. The tensile strength of the bonding site can withstand up to 250 mm Hg of arterial pressure. We have demonstrated that the CO2 laser can be used in microvascular anastomosis with or without stay sutures. Aneurysm formation is a potential risk of LAMA. Accurate coaptation of the transected vessel, precise control of laser energy, and minimal area exposed to the laser beam are the key points for further improving anastomotic quality.     

吻合血管的同种异体骨移植后移植物再血管化的研究

目的 探讨吻合血管的同种异体骨移植后移植物在宿主体内再血管化过程及其规律.方法 建立吻合血管的同种异体骨移植修复兔股骨大段缺损的模型,实验分成两组,实验组(吻合旋股外血管股骨中上段等位异体骨移植组)和对照组(未吻合血管的股骨中上段等位异体骨移植组).对移植物骨膜、皮质骨及骨髓进行组织学切片,同时对微血管内皮细胞进行免疫组化染色,血管计数后.进行统计学分析,制备墨汁灌注标本,观察各部位微血管再生情况.结果 实验组即可见骨膜、皮质骨和骨髓同时出现再血管化现象,而对照组则由浅至深逐渐出现再血管化现象,在术后2、4、8、16周实验组微血管密度分别为10.0±1.8、15.8±1.5、13.8±1.5、13.8±1.5,对照组分别为2.8±0.8、6.0±0.9、5.5±1.0、6.0±1.1,实验组明显高于对照组;墨染显示实验组墨染范围及程度明显强于对照组.结论 吻合血管的异体骨移植能加快移植物再血管化的过程.     

An alternative technique of microvascular anastomosis

The femoral arteries and veins of rats were severed and reanastomosed, using either the conventional interrupted suture technique or an alternative interrupted technique that allows the lumen to remain visible throughout the reanastomosis procedure. The alternative technique involves placing the sutures in the posterior wall of the vessel, eliminating the necessity of rotating the microsurgical clamp during the anastomosis. Clinically, this method may be advantageous in cases where the anastomosis is being performed in a deep wound in which there is no room to turn over the microclamp. Additionally, this technique allows the posterior wall of the vessel to be observed throughout the anastomosis procedure, reducing the possibility of accidental placement of sutures through the posterior wall and resulting nonpatency. There was no significant difference between the two techniques in terms of operating time, patency rate, aneurysm formation, arteriography, and histological findings.     

Intercostolumbar spinal nerve anastomosis. An experimental study in dogs.

End-to-end anastomoses were done between the motor roots of T12 and T13 intercostal nerves and the ipsilateral transsected L1 lumbar nerve in four dogs. In three of the dogs, the clinical and electrophysiologic findings showed functional viability of the intercostolumbar anastomosis 3.5 months after the anastomosis was done. The method may be practical for reinnervating an injured lumbar nerve with two intercostal nerves or to bypass a spinal cord lesion.     

Free microvascular epiphyseal-plate transplantation. An experimental study in dogs

To evaluate the feasibility of transplanting vascularized epiphyseal plates while maintaining normal growth in the recipient site, twenty-two puppies from known, large breeds were divided into one control and three experimental groups of four animals each and one long-term group of six animals. The control group underwent insertion of a radiopaque marker in the fibular metaphysis bilaterally, and, in addition, a fibular osteotomy was performed on one side. In the experimental groups, a fibular switch was carried out, selecting one fibula as a vascularized graft and the other as a non-vascularized graft. Both the controls and the experimental groups were evaluated using serial roentgenograms, histological examination, fluorescent bone-labeling, and microangiography. One week, six weeks, three months, and seven months postoperatively, animals from each group were killed. Continuous growth was observed in the vascularized epiphyseal transplants and in the controls, with no statistical difference noted, whereas the non-vascularized transplants exhibited considerably less or no growth. Vascularized transplants demonstrated an average 21.2-millimeter increase in length while non-vascularized transplants showed a 6.6-millimeter increase. Histological examination, fluorochrome bone-labeling, and microangiography confirmed the continued viability of the vascularized epiphyseal transplants in contrast to the non-vascularized transplants.