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.     

Re-endothelialization stages at the microvascular anastomosis

After microsurgical suturing, the wound healing process at the rat femoral artery anastomosis was studied with scanning electron microscopy. The reendothelialization was divided into four successive stages, based on the development of a fibrin network and the rate of endothelial regrowth. Within 5 minutes of blood flow re-establishment the fibrin network formation started to cover the wound surface; it was completed by the 3rd or 4th day. The endothelial recovery started on the 2nd day and continued to the base of the suture by the 6th day. Re-endothelialization from the wound edge, which was formed between intact and injured endothelium toward the suture-restrained site, was a two-fold process: initially, a single endothelial film covered the anastomosis site, then, the singled endothelial sheet proliferated and thickened to complete the endothelialization. A better understanding of the stages involved in microvascular repair is beneficial in evaluating vascular recovery and its relationship to patency rates in microvascular surgery.     

带监测皮岛的腓骨移植

目的 探索吻合血管腓骨移植术后腓骨血牮的监测方法。方法 设计一种与移植腓骨血供同源的小腿外侧小皮瓣－－监测皮岛进行移植。临床应用３０例。术后通过对监测皮岛的观察,达到监支腓骨血供的目的。结果 ３０例中,６例监测皮岛于术后监测过程中准确地提示了移植腓骨血管危象,均及时得到手术探查、复通血供。３０例移植腓骨均达到有性愈合。结论 监测皮岛是腓骨移植术后血供监测的可靠方法。     

Effect of nicotine on blood flow and patency of experimental microvascular anastomosis

Nicotine is known to have deleterious effects on the cardiovascular system, causing vasoconstriction and increased blood pressure. A drop in blood-flow velocity in humans, endothelial damage in rats, and inhibition of platelet aggregation in rabbits' blood have all been shown experimentally. In this article two studies are described that investigate the effects of nicotine on microvascular anastomotic patency. In experiment 1, electromagnetic blood-flow recordings were made in the saphenous artery of the saphenous flap after intraarterial installation of nicotine. Decreased blood flow was consistently recorded up to a maximum of 72% of normal flow. In experiment 2, rabbit femoral arteries were anastomosed and the patency rates at three weeks checked after various combinations of pre- and postoperative intraperitoneal nicotine had been injected. There was no significant increase in thrombosis between the groups treated with nicotine and the control. Although no thrombosis occurred in these experiments, decreased blood flow was noted in the saphenous flap in the dog. This slowing of flow should predispose to thrombosis, especially if other factors associated with the vascular repair were suboptimal. It is concluded in view of this study and the observed clinical effects in 2 patients with microvascular transfer that smoking in the perioperative period should be avoided.     

The value of the electromagnetic flow probe in experimental and clinical microvascular anastomosis.

The Gould Statham Blood Flowmeter Model SP 2204 has been used to assess microanastomosis in 25 superficial femoral arteries of rabbits. When a pulsatile wave form has been achieved this correlates with a satisfactory anastomosis and vice versa. The digital read out of estimated volume flow past the anastomosis made by this instrument will need further evaluation. We are persisting with the electromagnetic flow probe in the assessment of our clinical microvascular anastomoses at operation.     

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.     

Experimental laser-assisted end-to-side microvascular anastomosis

The authors present a new technique of end-to-side microvascular anastomosis in a rat carotid artery model, employing a milliwatt CO2 laser. Both carotid arteries were isolated and approximated in an end-to-side fashion by the placement of four 10-0 nylon stay sutures. The milliwatt CO2 laser was used to effect vessel anastomosis between the sutures, using 70-100 mW of power. Animals were killed 8 weeks postoperatively. Angiography of each anastomosis was performed in all animals. All anastomoses were then harvested, and submitted for histological analysis. Anastomotic patency was 100%, both intraoperatively and angiographically. There was no evidence of intravascular thrombus, anastomotic stenosis, or pseudoaneurysm formation. Early in the experiment, some anastomoses showed localized dilatation at the anastomotic site. The histologic changes at the anastomotic site are described. Laser-assisted microvascular anastomosis is a feasible technique, and a potential alternative to conventional suture techniques.     

Successful replantation of a bitten-off nose by microvascular anastomosis

A case is presented of a nose bitten off by a dog and successfully replanted by artery-to-artery and artery-to-vein anastomosis. In the absence of vein-to-vein anastomosis, the clinical course suggested that artery-to-vein anastomosis was useful for venous drainage, although the extent to which this contributed to the survival is not known.     

Use of the U-clip for microvascular anastomosis

Microvascular anastomosis is a demanding skill requiring technical excellence and a thorough knowledge of anatomy and physiology. Every suture placed in a microvascular anastomosis should be considered critical as each has the potential to compromise the delicate reconstruction. As such, any device that can facilitate microvascular suture placement deserves thorough evaluation. The U-clip (Coalescent Surgical, Sunnyvale, CA) is such a device in that it eliminates the often time consuming process of tying knots. We evaluated use of the U-clip in microvascular anastomosis of a 1.5 mm artery. We found the U-clip to offer some advantages including ease of use, traditional feel of directed suture placement (as compared to couplers), and elimination of time needed for knot tying. Its shortcomings include size (in diameter, the "pop-off" section of the device appears larger than standard 8-0 suture), the significant force required to "pop-off" the device and difficulty removing the device.     

Stasis-induced thrombosis of rat microvascular anastomosis

The rate of stasis-induced thrombosis in the rat femoral artery at varying times following microvascular anastomosis, was evaluated by direct inspection as well as by light and electron microscopy. The rate of thrombosis decreased with increasing postoperative time intervals. This decrease appears to coincide with histologic evidence of growth of the neo-intima at the anastomosis site.     

Heat-induced tissue fusion for microvascular anastomosis

Laser tissue welding was compared with a crude method of bipolar coagulator-generated heat application for achieving the same heat-induced welding effect in rat microarterial anastomoses. Rat femoral arteries were anastomosed with three triangulated stay sutures and subsequent laser welding or bipolar coagulator application between each pair of stitches. Control (non-welded) vessels received nine stitches placed circumferentially. Laser-welded vessel patency at 1 or more days postoperatively was 90% (65/72) for vessels treated with 0.1-second laser pulses, not significantly different from controls (100%; 16/16) or coagulator-welded anastomoses (88%; 14/16). Pseudoaneurysm rates were higher in the welded vessels (9% and 14% for laser- and coagulator-treated vessels, respectively) than in controls (0%). Histologic and electron microscopic evaluation revealed good healing with no apparent differences between laser- and coagulator-welded repairs. These findings suggest that laser application for microvascular tissue welding is similar to poorly controlled welding with a bipolar coagulator. © 1997 Wiley-Liss, Inc. MICROSURGERY 17:198–208 1996     

The double-barrelled end-to-end microvascular anastomosis.

We describe a simple alternative method of microvascular anastomosis to the internal jugular vein, which is useful when part of the internal jugular vein has been sacrificed and the free flap has two draining venae commitantes. In our hands, this method has proven to be quick, efficient and successful.     

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.