Microvascular anastomosis using carbon dioxide (CO2) laser: evaluation by SEM after corrosion cast

In order to compare the carbon dioxide laser-assisted microvascular anastomosis (CO2 LAMA) with conventional microvascular sutured anastomosis (CMSA), 40 microarterial anastomoses were performed in Wistar albino rats. At different time intervals from zero to four weeks after the procedure, the anastomoses were examined under the scanning electron microscope (SEM) after resin corrosion cast (Mercox). CO2 LAMA was easier and less time-consuming than CMSA, with the same patency rate. Healing of the lumen surface was similar in both procedures, suggesting that CO2 LAMA can be reliably used in microvascular anastomosis.     

Internal vessel occlusion: an improved technique for small vessel anastomosis

During infragenicular bypass, internal occlusion of the distal vessel avoids unnecessary dissection and potentially damaging use of external clamps or vessel loops while improving exposure and patency. This technique is especially useful in patients with small or calcific vessels in whom distal reconstruction is necessary for limb salvage.     

Spatulated versus end-to-end anastomosis for small vessel injury

Spatulated anastomosis (SA) was compared to end-to-end anastomosis (EEA) with small arteries (3-4 mm) in nine conditioned dogs (22-30 kg). A 1-cm segment of both common femoral arteries with an average of 3.5-mm external diameter was resected and reconstructed by EEA and by contralateral SA using a running suture of 5/0 proline. Pre- and postoperative flow rates, flow rates at 1 year in three dogs, arteriography at 1 year in six dogs, and gross examination at 1 year were done. The preoperative flow rates averaged 86 ml/min for the SA and 76 ml/min for the EEA; early postoperative flow rates averaged 100 ml/min and 92 ml/min, respectively, whereas 1-year flow rates averaged 63 ml/min and 57 ml/min, respectively. None of these differences is significant. Preoperative and 1-year external diameters averaged 3.54 mm and 3.39 mm in the SA group compared to 3.5 mm and 3.44 mm in the EEA group. Arteriograms showed good flow except for slight narrowing in one SA which, on postmortem exam, was seen to result from a fibrous band which extended from the spatulated segment to the opposite wall. These data show that SA and EEA yield comparable results both acutely and long term. The choice of EEA versus SA for primary repair of injured small vessels should be determined by surgical preference.     

Quantitative measure of small vessel anastomotic contour using corrosion resin cast models: an aid to surgical training.

A surgeon who had not previously carried out a small vessel anastomosis performed 20 consecutive anastomoses between human long saphenous vein and the left anterior descending artery of a pig's heart. Corrosion resin cast models were made of the anastomoses and subjected to a quantitative analysis of the anastomotic contour. A trend of improvement in contour parameters was found with increasing experience. This model may be useful for surgeons in training.     

An objective evaluation of an injured vessel wall using fluorescein sodium before microvascular anastomosis in an experimental rat model

The aim of this study was to establish an objective evaluation method for intraoperative detection of damaged vascular endothelium in avulsion injuries. Twenty male Fischer rats were randomly assigned to control or experimental groups ( N = 10, each). Crush-avulsion injury was performed on right femoral arteries. Resection of damaged segments was performed according to operative microscopic findings in the control group; fluorescein sodium was applied to the artery lumen before resection in the experimental group to help visualize the damaged endothelium. Microvascular repair was performed in five rats in each group. In the other animals, the whole length of the femoral arteries was resected to assess the actual extent of injury histologically. At the end of the follow-up period, patency of microvascular anastomoses was examined and the lengths of the resected segments were compared with the actual length of the injured segment measured histologically. The difference between these two measurements was statistically significant in the control group ( P < 0.05) but not in the experimental group ( P > 0.05). Anastomosis patency was significantly higher in the experimental group ( P < 0.0001). In conclusion, fluorescein sodium may help to accurately determine the length of the injured vascular segment in avulsion injuries.     

Microlymphography of spontaneous lymph vessel anastomosis in small bowel transplantation in the rat.

Following small bowel transplantation, new lymph vessel anastomoses form spontaneously. Surgical anastomoses of the lymphatic vessels are unnecessary. The formation occurs in three stages. To the second postoperative day, lymph stays within the lymphatic vessels of the transplant. Following the fourth postoperative day, lymph flows within preexistent adventitial lymphatic vessels along the transplanted mesenteric artery to the arterial anastomosis at the aorta and stops there. From the sixth postoperative day on, lymph crosses the arterial anastomosis for the first time and flows along the recipient's aorta. To the eighth postoperative day a new lymph anastomosis is formed between the adventitia of the aorta and the neighbouring major lymphatic vessels. In the experiments presented here, these are represented by the vasa lymphatica testicularia sinistra of the recipient. Thus, the new anastomosis between lymphatic vessels is complete on the eight postoperative day. These new vessels gradually dilate with time.     

Dissolvable supporting in small artery anastomosis: an experimental study

Intra-lumen supporting, made of biomaterial, non-toxic, tissue-compatible, and dissolvable, was used in anastomosing femoral artery on one side of 51 rabbits, while that on other side was anastomosed by conventional procedure for comparison. Results showed that suturing on the experiment group could be accomplished with better accuracy, less trauma and avoidance of puncturing the opposite wall, and with higher speed, shorter operation time than the contra. Better still, the intra-lumen supporting stabilized the vessel stumps and dilated the segments being handling, so that torsion and spasm were prevented. The intra-lumen supporting was then dissolved and no thrombosis developed in any of the experiment ones but some of the contra. Histological observation revealed that repair of tissue in each layer of the artery wall at the anastomosis site proceeded much quicker in the experiment ones than in the contra. We are impressed, through this survey, that the newly formed endothelial cells cover in the juncture area may arise from the uninjured endothelium nearby, and may also come from monocytes in the circulation.     

鼠带蒂肾上腺自体移植术的研究

目的 探讨临床肾上腺带蒂移植小血管吻合方法的改进。方法 采用显微外科技术，进行鼠肾上腺带蒂移植。经假手术组（６只），双侧肾上腺切除组（６只），肾上腺移植组（６只）的术后存活观察、内分泌检测及病理检查进行比较。结果 双侧肾上腺切除组血、尿醛固酮值明显下降，平均存活６．８ｄ。而肾上腺移植组术后１、１４ｄ尿醛固酮值分别达术前的２２０．６％和１０６．１％。术后能长期存活。结论 通过显微外科技术可以成功完成     

Minimally occlusive laser vascular anastomosis (MOLVA): experimental study

Background  Temporary occlusion of an intracranial artery during microvascular anastomosis is a major risk factor in cerebrovascular surgery. A new laser vascular welding technique that minimizes the occlusion time of the recipient vessel has been developed and is described in this report. Method  A new minimally occlusive technique of end-to-side microvascular anastomosis was developed employing a diode laser in association with the application of a chromophore in our experimental model of double end-to-side anastomosis. The implantation of a vein graft on the patent carotid artery was obtained through the application of three interrupted sutures at each anastomotic site; the carotid was then clamped, two arteriotomies were performed, followed by the application of a fourth suture and of the laser welding procedure on each anastomosis. Monitoring of the temperature at the site of the anastomosis was introduced in order to control the welding technique. Findings  The time of the clamping of the carotid artery was 12 min to perform two end-to-side anastomoses (i.e., 6 min for each anastomosis). All bypasses were patent after a follow-up of 90 days and histological study confirmed good preservation of the vascular wall. Conclusions  Our laser-assisted technique of vascular anastomosis reduces the duration of the clamping of the recipient artery down to 6 min. This technique can minimize the risk of cerebral ischemia associated with occlusion of a recipient artery in intracranial bypass procedures, promoting an improved vascular healing process with a lower risk of thrombosis and occlusion.     

Electromagnetic blood flowmetry in small vessel surgery. An experimental study.

The aim of this work was to study problems in microvascular flowmetry. Special emphasis was placed on the meticulous preparation of the vessel wall in order to improve zero-line stability and on the problems related to the calibration of small electromagnetic flow probes. Electromagnetic flow probes with an inner diameter of 2, 1.5 and 1 nm were used for studies on zero-line drifting and for calibration procedures in a series of rats and rabbits. Principles and tools derived from microvascular surgery, including the binocular microscope, were employed in the preparation of the vessel wall and in the application of the probes. The results obtained indicate an improvement in flow uptake and in zero-line stability following this procedure. Precalibration of small flow probes using laboratory animals should be considered if calibration is not feasible at the time of the flow measurement. Use of the microsurgical technique for vessel preparation is recommended.     

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.     

Left anterior small thoracotomy (LAST): mid-term results in single vessel disease

BACKGROUND: Left anterior descending artery grafting using the left internal mammary artery via a left anterior small thoracotomy (LAST) gained new popularity in 1994. We review our experience in 250 of 512 patients who underwent a LAST in single vessel left anterior descending artery disease from November 1994 to October 1997. METHODS: Left anterior descending artery stabilization was obtained pharmacologically and mechanically. Two patients (0.8%) had percutaneous transluminal coronary angioplasty at a mean of 23 +/- 5 days; 172 (68.8%) patients had early postoperative angiography. RESULTS: Eight conduits were occluded (patency rate 95.3%). There was only one late death. Cumulative angiography and Doppler flow evaluation showed that 96.8% of the anastomoses were patent and 95.6% were both patent and nonrestrictive. At a mean follow-up of 16.3 +/- 9.3 months, 9 (3.6%) patients had redo-surgery due to anastomotic/conduit failure and 249 (99.6%) patients were alive and asymptomatic. No patients had acute myocardial infarction. The 35-month actuarial survival rate was 99.6% +/- 0.4%, and the event-free survival rate for the entire experience was 93.7% +/- 1.3%. If only the last 157 patients are considered, at 18 months event-free survival was higher than in the entire group of patients (96.4% +/- 1.4% vs 93.7% +/- 1.3%, p = 0.05). CONCLUSIONS: New instrumentation has made the operation easier and has contributed to its spread, along with increased experience and the end of the learning curve. At the moment we consider the LAST a more anatomical and physiological surgical approach to single vessel coronary disease.