A comparison of para-anastomotic compliance profiles after vascular anastomosis: nonpenetrating clips versus standard sutures

PURPOSE: Anastomotic compliance is an important predictive factor for long-term patency of small diameter vascular reconstruction. In this experimental study we compare the compliance of continuous and interrupted sutured vascular anastomoses with those using nonpenetrating clips. METHODS: Both common carotid arteries in nine goats (average weight, 57 +/- 5.7 kg) were transected, and end-to-end anastomoses were constructed with nonpenetrating clips or polypropylene sutures. The latter were applied with both interrupted and continuous techniques. Intraluminal pressure was measured with a Millar Mikro-tip transducer, and vessel wall motion was determined with duplex ultrasound equipped with an echo-locked wall-tracking system. Diametrical compliance was determined. Environmental scanning electron microscopy was performed on explanted anastomoses. RESULTS: There was a reduction in anastomotic compliance and associated proximal and distal para-anastomotic hypercompliant zones with the use of all techniques. However, compliance loss was significantly less in those anastomoses with clips and interrupted sutures when compared with continuous suture (P <.001). Furthermore, the total compliance mismatch across anastomoses with continuous sutures was significantly greater than those with clips or interrupted sutures (P <.05). The mean time for constructing clipped anastomoses was 5.7 +/- 1.4 minutes, which was significantly less than either continuous (P <.0001) or interrupted sutures (P <.0001). Furthermore, environmental scanning electron microscopy demonstrated minimal intimal damage with good intimal apposition in the clip group. CONCLUSION: Anastomoses performed with nonpenetrating clips resulted in improved para-anastomotic compliance profiles and reduced intimal damage when compared with those with polypropylene sutures. These benefits may enhance long-term graft patency by reducing the risk of anastomotic intimal hyperplasia.     

In search of the "perfect" anastomosis

Forty-five end-to-side microvascular anastomoses were completed in rat carotid arteries of 0.7-0.8 mm diameter (anastomosing the distal end of the left common carotid to the side of the right common carotid). For comparison both 10-0 and 11-0 sutures were utilized in different anastomotic techniques: interrupted, direct-continuous, and diagonal-continuous sutures, plus total mural thickness vs. partial mural thickness (piercing only the adventitia and outer media, excluding the intima). Anastomoses were evaluated for patency and scanning electron microscopic appearance after 10 to 12 weeks. The results indicate complete patency in all anastomoses. Ultrastructural observations revealed nearly normal intimal appearance in the partial medial technique and only minimal evidence of intimal injury in the other techniques. It is concluded that 100% patency can be obtained regardless of suture size or anastomotic technique. The most important factor in anastomotic patency is the operator's technical skill.     

Clinical experience with non-penetrating vascular clips in free-flap reconstructions.

To date, the gold standard for performing a microvascular anastomosis has been the penetrating suture with attached needle. During the last two decades, non-penetrating techniques have been introduced, including the Unilink system for end-to-end anastomoses, and the VCS clip-applier system for both end-to-end and end-to-side anastomoses. The aim of this study was to compare the results of different techniques used to create microvascular anastomoses in free-flap reconstructions. Between January 1995 and October 1999, we performed 474 microvascular anastomoses in 216 consecutive free-tissue transfers. The anastomosis techniques included manual sutures (42%), Unilink rings (34%) and VCS clips (24%). Seven combined sutured-clipped anastomoses were excluded from further analysis. The mean anastomotic time when rings were applied was significantly shorter than when using clips (P 0.0001) or sutures (P 0.0001). Venous anastomoses using clips took less time than those using sutures (P 0.05). There were 19 anastomotic failures, all of which lead to early flap failure. Ten flaps were salvaged by early reoperation; nine flaps were lost. Three more flaps were lost as a result of other causes, bringing the flap survival rate down to 94.4%. Early flap failure was caused by failure of the arterial anastomosis in eight cases; all of them were sutured (these represented 5% of all arterial anastomoses with sutures). None of the clipped arterial anastomoses failed. Early flap failure was caused by failure of the venous anastomosis in 11 patients. Three of these anastomoses were sutured (representing 6% of all venous anastomoses with sutures), seven were anastomosed with rings (representing 5% of all venous anastomoses with rings) and one was clipped (representing 2% of all venous anastomoses with clips). Both the VCS clip-applier system and the Unilink system are easy to handle and allow fast microvascular anastomoses without intraluminal penetration. The patency rate of clipped vessels is at least as good as the patency rates of vessels anastomosed using sutures or rings.     

Nonpenetrating vascular clips for small-caliber anastomosis

In the search for better anastomosing techniques, an improved vascular stapler device (VCS clip applier system(R)) has been introduced. The system uses nonpenetrating clips to approximate everted vessel walls. The objective of this study was to determine the effects of nonpenetrating vascular clips on endothelial wound healing. Aortic end-to-end anastomoses were performed in male Wistar rats. A comparison was made between clipped (n = 12) and conventional hand-sewn (n = 6) anastomoses. Patency rates were verified at different time intervals (after 1, 4, and 8 weeks), after which the anastomotic sites were removed. Morphological evaluation was carried out using scanning electron microscopy. All rats survived the procedure. Closure with clips took less time than closure with conventional sutures, with decreasing aortic clamping times for the clipped procedures during the course of the experiments. Patency rates were 100% in both the "clipped" and "sutured" groups. Microscopic examination showed favorable endothelial healing at the clipped anastomotic sites, with less inflammatory reaction at 1 week, and a more complete endothelial regeneration at 4 and 8 weeks follow-up, as compared with the sutured anastomoses. The clip applier holds the promise of a useful device in anastomosing small-caliber vessels, since clip closure takes less time than suturing, while patency rates are identical, and morphological results are favorable. Training is mandatory to obtain technical skills and to achieve optimal results.     

Are mechanical microvascular anastomoses easier to learn than suture anastomoses?

Sutured anastomoses of small vessels are considered difficult to learn. Mechanical anastomosis systems allow a more rapidly performed anastomosis. In order to compare the process of learning to perform sutured and mechanical microvascular anastomoses, two surgeons, with limited microvascular experience, performed 30 aortic and 30 femoral vein anastomoses in 30 Wistar rats. The methods compared were conventional suture, vascular closure system (VCS) and microvascular anastomatic coupler system (MAC). There were no inter-surgeon differences regarding patency or time to perform anastomoses. The average time to perform a suture anastomosis was 39 min (patency 80%). Anastomoses with the VCS system took 24 min (patency 25%), whereas the MAC couplers took 13 min to perform (patency 95%). There was a significant learning effect with sutures, but no obvious reduction in time to perform MAC coupler or VCS clip anastomoses was seen. MAC couplers were easiest to use, and allowed us to perform rapid anastomoses with high patency.     

A new microvascular "sleeve" anastomosis

A new technique for performing a microvascular end-in-end or "sleeve" anastomosis is described. The new method utilizes two asymmetrically placed, looped sutures that do not enter the active lumen or breach the active intima. It has advantages over previous methods because it consistently saves time and because of the decrease in the number of possible technical complications. In 77 anastomoses performed in white rats by different surgeons, including a few inexperienced students of microsurgery, there was only one failure (24-hr patency). After eight practice anastomoses, the average time taken from vessel division to final clamp release in 30 procedures was 7 min 33 sec, with a standard deviation of 1 min 45 sec. The sleeve anastomosis performed by this method has shown itself to be as reliable as a conventional end-to-end suture method and has the advantages of significant time saving and minimization of intimal trauma. The anastomosis of vessels of differing sizes is facilitated by the conformation of this new method and the technique has clinical potential in the anastomoses of interposition vein grafts and in human intravenous anastomoses.     

An absorbable pinned-ring device for microvascular anastomosis of vein grafts: experimental studies

In the rabbit, posterior facial vein segments were grafted to the femoral arteries using either conventional suture technique or a mechanical absorbable pinned-ring device. The purpose of this study was to compare patency rates and anastomotic times for the two different methods. The anastomoses were evaluated macroscopically and using light and scanning electron microscopy. The grafts anastomosed with the absorbable rings exhibited 100% patency, while only 83% of the sutured grafts were patent. The mean anastomotic time using the mechanical pinned-ring device was 18.1 min (range 9.8-30 min). The conventionally sutured anastomoses were completed in a mean time of 60 min (range 50-75 min). The experiment has confirmed that the absorbable pinned-ring device provides a safe and fast way to perform microvascular anastomosis.     

Study of microvascular polyester prosthesis in rat carotid arteries

The implantation of a microvascular polyester prosthesis (MPP) (internal diameter 1 mm, length 10 mm) in the carotid arteries was studied in 48 Sprague-Dawley rats. The left carotid artery was resected to 7 mm in length and replaced with MPP by means of sleeve anastomoses. Postoperatively the patency was monitored with Doppler ultrasound at 24 and 72 hr, and at 1, 2, 3, 4, 8, and 12 weeks and was confirmed either by direct inspection intraoperatively or by angiography at the time of removal. At each monitoring time, all the throm-bosed and some selected patent grafts were removed and prepared for scanning electron microscopy (SEM) study. The early patency rate was 100% within 24 hr, and the cumulative long-term patency rate was 77.1% at 12 weeks. Rapid and complete endothelial lining (EL) restoration was demonstrated 3 weeks after operation, which provided a smooth and nonthrombogenic surface, and contributed to the long-term patency. Ten of the 11 failed grafts occurred within 3 weeks, that is, before EL, due to thrombosis. These observations indicate that MPP can be successfully used as arterial conduits in rats, and an enhanced patency rate may be expected with the use of anticoagulants or endothelial cell seeding for prevention of early thrombosis. © 1994 Wiley-Liss, Inc.     

A comparison of CO2 laser-assisted venous anastomoses and conventional suture techniques: patency, aneurysm formation, and histologic differences

The expected patency and the potential complications of CO2 laser-welded end-to-end venous anastomoses have not been well established despite increasing clinical interest in the subject. To further study this relatively new technique we used the internal jugular veins (1.0 to 1.4 mm diameter) of 15 New Zealand White rabbits weighing 2.5 to 3.5 kg. On one randomly selected side, a laser-welded end-to-end anastomosis was performed in all animals by placing three equidistant stay sutures followed by welding the vein edges with a CO2 laser (spot size of 0.27 mm, power of 100 mW, and power density of 175 W/cm2). On the contralateral side, the vein was anastomosed with interrupted 10-0 nylon sutures in 10 animals, and in the remaining five animals a continuous 10-0 nylon suture technique was used. All anastomoses were surgically assessed at 30 days after operation. A significantly lower 30-day patency rate (p less than 0.05, Fisher's Exact Test) was found in anastomoses constructed by use of the continuous technique (20%) compared with either interrupted (90%) or the laser-assisted technique (87%). No significant difference was observed in 30-day patency between laser-assisted and conventional interrupted anastomoses. Anastomoses performed with the continuous and the laser-assisted technique required 12.5 +/- 1.3 and 12.9 +/- 3.0 minutes, respectively, whereas those constructed with interrupted technique required 19.1 +/- 4.5 minutes (p less than 0.05, Student-Neuman-Keuls' Test). No evidence of false or true aneurysm was noted in any of the animals. Histologic evaluation of laser-assisted anastomoses demonstrated early full-thickness coagulation necrosis of the wall with reendothelialization by 7 days and complete healing by 30 days after the procedure. Conventional anastomoses showed reendothelialization and minimal necrosis near the sutures at 7 days, but healing was complete by 30 days after the procedure. The patency rate of vein anastomoses performed with the CO2 laser is excellent and superior to the one obtained with continuous sutures, and except for less operating time, the former technique does not appear to offer any significant advantage over the conventional interrupted suture technique for small vein anastomosis in this animal model up to 1 month of follow-up.     

Scintiscanning in the evaluation of biliary enteric anastomoses

The evaluation of symptomatic patients who have undergone biliary enteric anastomoses, particularly when the diversion was into the jejunum, is difficult. Conventional techniques for evaluation, such as oral cholecystography (OCG), intravenous cholangiography (IVC), ultrasonography (US), computer-assisted tomography scanning (CT scanning), or endoscopy are not adequate to provide definitive information on the patency of the anastomoses. Hepatobiliary scintiscanning using 99mTc-HIDA and BIDA (iminodiacetic acid derivatives) was performed on 12 patients. The patients were from 11 to 72 years of age and included ten men and two women. The scan results were correlated with US, CT scan, percutaneous transhepatic cholangiography (PTC), operative findings, and final diagnosis. Scanning was highly accurate in this group and could be performed successfully even in jaundiced patients (total serum bilirubin level up to 20.0 mg/dl). In patients in whom dilated bile ducts were demonstrated (by US, CT scan, or scintiscan), only the scintiscan revealed the true patency of the anastomoses. The advantages of the technique are that it is simple and noninvasive. Delayed transit of bile (scanning agent) to bowel is a very reliable indication of partial or complete obstruction. Scintiscanning is the only technique that demonstrated the functional state of biliary secretion and excretion into bowel in patients with previous biliary enteric anastomoses.     

Laser-assisted end-to-end BioWeld anastomosis in an ovine model

The BioWeld tube, an albumin-based exovascular stent, has been used for microsurgical anastomoses and compared to conventional sutures. The study presented investigated the potential of the BioWeld tube for vascular anastomosis in larger vessels. Laser-assisted BioWeld anastomoses were compared to conventional-sutured anatomoses of the carotid artery of Merino-x ewes. The BioWeld procedure resulted in 100% survival and 100% patency at 1 and 6 week post-operative periods, with no noticeable foreign body response. Sutured animals showed 100% survival and patency. The ischemic time for BioWeld anastomosis averaged 15 minutes compared with 10 minutes for sutures. This study indicates that the BioWeld tube is an easy to use anastomotic technique with equivalent success rates and comparable anastomotic times.     

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.     

End-to-end microvascular anastomosis in the rat carotid artery using continuous horizontal mattress sutures

This paper reports a continuous horizontal mattress suture technique with advantages such as decreased time for anastomosis, minimized anastomotic leakage, eversion around the vessel edges, and other advantages which the continuous anastomosis technique has. This technique was compared with the classical interrupted and classical continuous suture techniques on a total of 59 Sprague-Dawley rat common carotid arteries: Group 1 (n = 19), interrupted suture technique; Group 2 (n = 20), standard continuous technique, and Group 3 (n = 20), continuous horizontal mattress technique. Early (30 min) and late (21 days) patency rates, anastomosis time, leakage on clamp release, oozing duration, additional sutures needed, and total number of sutures placed were statistically compared between groups. Specimens were taken at the 21st day randomly, and light microscopy (LM), scanning electron microscopy (SEM), and angiographic studies were performed. Results revealed that the continuous mattress suture technique has the advantages of providing a water-tight anastomosis with less suture materials in a shorter time, and minimal intraluminal suture material which can incite thrombosis. On the other hand, a tendency to anastomotic stricture was found to be the sole disadvantage of this technique.     

A new technique for microvascular anastomosis: eversion with 3 horizontal mattress sutures

In our experimental study of a new microvascular anastomosis technique, we divided 30 Wistar albino rats into 2 groups. We performed the classic interrupted suture anastomosis technique in group 1 (n = 15) and our new technique, using 3 horizontal mattress sutures, in group 2 (n = 15). We checked patency immediately following anastomosis, at the end of the first hour, and at the end of the third week postanastomosis. While the patency rates for both techniques were 100% at the end of the first hour, the respective values were 100% and 93.4% by the end of the third week. Using light microscopy, lumen patency, intimal and medial damage, inflammation, and granulation were evaluated histopathologically. The mean anastomosis time for the experimental group (15 minutes) was shorter than that for the classic group (mean 21 minutes), and the difference was statistically significant (P < 0.01), while the difference between the patency rates was not significant (P = 0.05). Therefore, provided that the incisions are made correctly, our microvascular anastomosis technique using 3 horizontal mattress sutures can be used in experimental and clinical studies.     

Endothelialization of anastomoses in the aorta and inferior vena cava of the rat

Denuding endothelial damage at anastomoses may lead to thrombotic complications and failure of microvascular reconstructions. Confluent endothelial healing at anastomoses may reduce thrombotic and other complications. The progress of endothelial coverage of anastomotic structures in the aorta and inferior vena cava (IVC) of the rat was evaluated at 3,5,8,11, and 14 days after completion of the anastomoses, by means of scanning electron microscopy. Arterial anastomotic patency was 100%; venous patency was 84%. It was found that endothelial healing progressed towards thin confluent coverage first, thereafter thickening. Coverage was first achieved at the needle defect, then the anastomotic junction, and lastly the suture. The same stage of endothelial coverage of anastomotic structures was reached 5 to 8 days sooner at the IVC anastomosis than in the aorta. © 1994 Wiley-Liss, Inc.     

单边内翻套入缝合法吻合兔颈动脉的实验研究

目的：探寻一种新的安全、快捷的小血管吻合方法。方法成年新西兰白兔45只，一侧颈动脉行单边内翻套入缝合法为实验组，另一侧行常规对端缝合法为对照组，比较两组的血管吻合时间、血管通畅率，术后1周，2周行血管吻合口的大体观察、组织学及扫描电镜观察。结果血管吻合时间：实验组为（12±2） min，对照组（16±2） min，差异有显著性（P＜0.05），实验组明显低于对照组。术后两组的血管即刻通畅率均为100%，近期通畅率均为98%，两组间差异无显著性（P＞0.05）。组织学及扫描电镜观察示两组血管吻合口愈合过程及时间相似。结论单边内翻套入缝合法吻合小血管快捷、简单，效果可靠。     

Scanning electron microscopy in different techniques of microvascular anastomoses: categorization and factors affecting. A descriptive work

Many researchers have investigated microvascular anastomoses by scanning electron microscope (SEM); however, there are neither reports on classifying these anastomotic types according to the SEM results nor about studying the factors that affect these results. Sixty rat femoral arteries were anastomosed using four different techniques: simple interrupted, continuous, sleeve, and autogenous arterial cuff. The anastomotic sites of each group and other two intact femoral arteries were examined by SEM. Intimal disruption and rebuilding of the blood vessel endothelium after microvascular anastomoses depend upon anastomotic time; suture placement, either intra-luminal or extra-luminal; and mechanical factors. Accordingly, the simple interrupted suture technique has the highest degree of intimal disruption and the lowest degree of regeneration, the continuous and cuff anastomoses have better rebuilding with partial neo-endothelial coverage of the cut ends, whereas the sleeve anastomosis has the best regeneration with complete coverage of the cut ends by the new endothelial cells. Presented in the Fifth Congress of the World Society of Reconstructive Microsurgery (WSRM), Athens, Greece, June 2007.     

Use of continuous horizontal mattress suture techniques in microsurgery: an experimental study in rats

PURPOSE: The purpose of this study was to determine whether the continuous horizontal mattress suture technique can replace the continuous simple suture technique and to compare the results with other microvascular suture procedures. METHODS: Sixty-four femoral arteries of 32 Sprague-Dawley rats were used in this study. The animals were divided equally into 4 groups with 16 anastomoses in each group. The arteries (0.8-1.0 mm diameter) were anastomosed by using the continuous horizontal mattress suture technique in group I, interrupted horizontal mattress suture technique in group II, simple interrupted suture technique in group III, and simple continuous suture technique in group IV. At the end of the anastomosis time, leakage, and patency were assessed and graded in all groups. On the 14th day after surgery the rats were killed and 5 patent specimens from each group were examined under light microscopy for histology. One specimen from each group was prepared for scanning of the endothelial surface under electron scanning microscopy. RESULTS: Group I anastomoses were performed the most quickly. Groups I and III anastomoses had 100% patency rates. Under light microscopy the edge eversion was apparent consistently and under electron microscopy all endothelial surfaces were intact and no suture material was seen in groups I and II. In group III some suture material was covered by endothelial cells and lumen surfaces were torn; endothelization also was rough compared with groups I and II. In group IV suture material was seen in the lumen because of a loose suture knot. The endothelium also was not regular. CONCLUSIONS: The horizontal mattress suturing technique is the only technique in which the suture material never contacts the lumen. Continuous horizontal mattress suture technique is superior to the other microvascular procedures and is the safest and fastest procedure for microvascular anastomosis in rats.     

Continuous suture technique in microvascular end-to-end anastomosis

A refined technique for continuous suturing of end-to-end anastomoses is presented along with a study in which the continuous-suture technique was compared with the standard interrupted-suture technique in end-to-end anastomoses in the femoral arteries of 20 rats. The results of this comparative study demonstrate that the two techniques had equal patency rates, but that the continuous-suture technique required less than 50% of the time necessary to perform end-to-end anastomosis with interrupted sutures.     

Prosthetic microvenous grafting into the femoral vein of the rat; considerations concerning the anastomotic technique

The sequential thrombotic events which occur after implantation of microvenous prostheses prepared from a polyurethane-based material (I.D. 1 mm, length 5 mm, n = 36) into the rat femoral vein by means of the conventional end-to-end suture technique were evaluated by direct inspection and by scanning electron microscopy during the first 24 postoperative hours. Thrombus formation started at the anastomotic sites on the exposed collagenous vessel wall tissue and increased with increasing postoperative time intervals, leading to complete occlusion of the prostheses after 30 minutes of implantation. As a result of these findings, 8 more microvenous prosthetic implantations were performed with the sleeve anastomotic technique and evaluated after 24 hours. Six of these prostheses were patent with only minimal exposure of collagenous tissue at the anastomotic sites and subsequently minimal thrombus accumulation. Two prostheses left in situ and evaluated after 3 weeks were then still patent and completely endothelialised. Based upon the present study, we recommend the sleeve anastomotic technique for implanting synthetic microvenous prostheses because this technique prevents extensive exposure of collagenous vessel wall tissue at the anastomoses, thus leading to less thrombus accumulation and subsequently to a higher patency rate.