Arterial end-to-side anastomosis with the UNILINK system

Venous Repair with Vascular Clips and Conventional Suture: A Comparative Experimental Study

Objectives:

The non-penetrating Vascular Clip System (VCS) was tested experimentally and compared with the conventional suture method on the venous system.

Materials and Methods:

In five pigs, 30 transverse venotomies were carried out in the jugular and renal veins, and vena cava. Fifteen venotomies were reconstructed using autosuture clips and 15 using the standard needle and suture method. Eight weeks later, following phlebography, the specimens were examined macro- and microscopically.

Results:

For both methods, the veins remained patent; however, significant stenosis of 8.9% (95% CI: 0.6–17.1) for the renal vein and 8.5% (95% CI: 1.2–15.7) for the vena cava occurred when the suture technique was used. The intima to media height ratio remained the same. The anastomosis time with the clips was significantly shorter ( p<0.05), while the endothelium remained intact without any hyperplasia or inflammatory changes, which are usual findings of the suture technique.

Conclusion:

Early and mid-term results show that the VCS clipped anastomotic technique seems to be effective and acceptable for venous reconstructions.

Use of continuous horizontal mattress suture technique in end-to-side microsurgical anastomosis

PURPOSE

The aim of our study was to improve the new suturing method which increases the success rate of end to side microsurgical anastomosis.

METHODS

Thirty-six Sprague-Dawrey rats were randomly divided into three groups that consist of 12 rats in closed envelope method. The end-to-side microsurgical anastomosis procedures were applied by the same surgeon between left main carotid artey and left external jugular vein. The surgical evaluations were performed with anastomosis duration, leakage evaluation, vessels patency, aneurysm improvement and histological assesment.

RESULTS

End-to-side anastomosis, which was applied with Continuous Horizontal Mattress suture, gave significantly better results in terms of leakage, anastomosis openness, aneurysm and histologic assesment. Also anastomosis duration of Continuous Horizontal suture was significantly faster than Simple Intermittent suture.

DISCUSSION

Our study revealed that the Continuous Horizontal Mattress suture technique had the advantages of providing uninterrupted vessel flow in a shorter time, and minimal intraluminal suture material, which increase thrombosis risk. Also 'sac-mouth' effect of Continuous suture technique was prevented by Horizontal Mattress technique.

Nonsuture anastomosis of arteries and veins using the magnetic pinned-ring device: a histologic and scanning electron microscopic study

BACKGROUND

The goal of this study was to evaluate the performance of the magnetic pinned-ring device for nonsuture vascular anastomosis.

METHODS

The magnetic pinned-ring device consists of paired magnetic rings that are coated with titanium nitride and embedded in a polypropylene shell; the rings are equipped with alternately spaced holes and titanium pins. The vascular anastomosis procedure using the novel magnetic pinned-ring device was performed on 14 mongrel dogs, and the traditional hand-sewing technique was used on 14 additional dogs. In situ end-to-end anastomoses were performed in the femoral artery and the inferior vena cava. Patency was confirmed through ultrasonographic scans at different time points as late as 24 weeks after surgery. Gross observation, histological staining, and scanning electron microscopy were used to evaluate the results at 24 weeks postoperatively.

RESULTS

The time required to perform the vascular anastomosis was significantly shorter for the magnetic device than for hand sewing. A continuity of re-endothelialization was confirmed in all anastomotic stomas after 24 weeks, and neither formation of aneurysms nor thickening of the vascular wall was noted. The re-endothelialization was smooth at the anastomotic site of the magnetic device, whereas hand sewing resulted in rough and uneven re-endothelialization and the presence of visible sutures. Moreover, the endothelial cells were regularly arranged at the anastomotic site of the magnetic device, whereas different-sized and irregularly aligned endothelial cells were present at the hand-sewn anastomotic site. Use of the magnetic device was associated with significantly decreased deposition of fibrotic collagen and depressed infiltration of inflammatory cells compared with use of the hand-sewing technique.

CONCLUSIONS

The magnetic pinned-ring device offers a simple, fast, reliable, and efficacious technique for nonsuture vascular anastomosis. Use of this device shortens operation time, maintains a high patency rate, and improves the healing of vascular tissue.

Effect of Fibrin Adhesive Application in Microvascular Anastomosis: A Comparative Experimental Study

BACKGROUND

Microvascular anastomosis is the most critical step during free flap transfers or replantations. Although the conventional suture is still considered the standard technique, it is technically difficult, time consuming, and traumatic to the vessel wall. The aim of this study was to evaluate the effectiveness of fibrin adhesive to overcome these problems when applied in microvascular anastomosis.

METHODS

Sixty-eight Wistar rats were used in this study. Eight animals were used in a pilot study to determine the minimum amount of suture stitches required per anastomosis when the fibrin adhesive was applied. In the definitive study, we performed 30 anastomoses in the femoral artery and 30 anastomoses in the carotid artery. In each artery, half of the anastomoses were performed using interrupted sutures without fibrin adhesive (control groups), and the other half were performed using fibrin adhesive and fewer sutures (experimental groups).

RESULTS

The application of fibrin adhesive significantly reduced the number of sutures and the time taken to perform the anastomosis. The anastomotic bleeding was also significantly reduced in both experimental groups. The immediate and late patency rates were not compromised by fibrin glue application. No significant differences were observed in the histologic analysis of the anastomosed vessels between the two techniques.

CONCLUSIONS

The application of fibrin adhesive did not result in any harmful effects in the microvascular anastomosis. The authors encourage the clinical application of fibrin adhesive in more complex cases, when more than one microvascular anastomosis is required.

Arterial Anastomosis Without Sutures Using Ring Pin Stapler for Clinical Renal Transplantation: Comparison With Suture Anastomosis

PURPOSE

The metal ring pin stapler was initially developed for microvascular surgery and there has been little experience of their use in larger vessels. We determined if the titanium ring pin coupling system could be safely and rapidly applied for arterial reconstruction in clinical renal transplantation.

MATERIALS AND METHODS

The donor renal artery was end-to-end anastomosed to the internal iliac artery with titanium ring pin staplers in 36 patients. Anastomotic, clamp and total operative time and vascular problems were compared with those in the control group of sutured anastomosis in 39 transplant recipients.

RESULTS

The completion of mechanical anastomosis required half the time of suture anastomosis. Mean clamp time was 17.8 minutes in the nonsuture group and 28.1 minutes in the control group. There was no significant difference in total operative time between the 2 groups. A small anastomotic line leak was noted in each group, which was temporary and self-limited. There were no postoperative anastomotic failures, postoperative bleeding episodes or need to revise the anastomosis (100% patency rate) in the 2 groups. Of the patients 61 were followed for 2 to 5 years. Transplant renal artery stenosis was observed in 1 patient in the nonsuture group but 3 in the control group.

CONCLUSIONS

The anastomotic technique with the ring pin system is safe and simple, permitting an expeditious and everting anastomosis with a smooth intima-to-intima junction. Application of this technique may decrease warm ischemia time and the incidence of anastomotic artery stenosis, thus, improving outcomes.

Non-suture methods of vascular anastomosis

BACKGROUND

The main aim of performing a vascular anastomosis is to achieve maximal patency rates. An important factor to achieve that goal is to minimize damage to the vessel walls. Sutures inevitably induce vascular wall damage, which influences the healing of the anastomosis. Over time, several alternatives to sutures have become available.

METHODS

A Medline literature search was performed to locate English, German and French language articles pertinent to non-suture methods of vascular anastomosis. Manual cross-referencing was also performed and many historical articles were included.

RESULTS AND CONCLUSION

The non-suture techniques can be categorized into five groups based on the materials used: rings, clips, adhesives, stents and laser welding. With all these techniques a faster and less traumatic anastomosis can be made compared with sutures. However, each device is associated with technique-related complications. As a consequence, suturing continues to be the standard approach. The disadvantages of the non-suture techniques include: rigidity and a non-compliant anastomosis with rings; toxicity, leakage and aneurysm formation with adhesives; early occlusion with stents; cost, reduced strength in larger-sized vessels and demand for surgical skills with laser welding. Further refinement is needed before widespread adoption of these techniques can occur. Clips, however, may be particularly promising but long-term evaluation is required.

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.

Vascular anastomosis using a biodegradable device with a heat-shrinking sleeve: a preliminary report

PURPOSE

The objective of this study is to present a simple mechanical anastomosis system capable of uniting vessels of differing diameters and to evaluate its applicability.

MATERIALS AND METHODS

A new mechanical system for anastomosis of small vessels was used in 30 rabbits to join 100 sectioned carotid arteries and jugular veins. The system is resorbable and consists of a cuff and a shrinkable sleeve. To carry out the anastomosis, one vessel end is pulled through the cuff and everted over it. The second vessel end is then slipped over the everted vessel end and the cuff. A heat-shrinking sleeve is positioned over the site and shrunk to produce permanent fixation.

RESULTS

The overall patency rate of the anastomoses was 96.6% in the arteries and 93.3% in veins. Microscopically, the intima-to-intima contact sites were bridged by an endothelial layer in the first postoperative weeks.

CONCLUSION

Advantages of the system include a short insertion time, simple instrumentation, a high patency rate, and resorbability. However, the method requires additional vessel length for eversion, and it cannot be used for end-to-side anastomoses.

Intracranial vascular anastomosis using the microanastomotic system. Technical note

The authors describe the use of a microanastomotic device to perform intracranial end-to-end vascular anastomoses. Direct end-to-end anastomosis was performed between the superficial temporal artery and branches of the middle cerebral artery (MCA) in three patients. Two patients had moyamoya disease, with severe proximal MCA disease, and one suffered an internal carotid artery occlusion with poor collateral flow. All patients reported a history of recent ischemic symptoms. Each anastomosis was accomplished in less than 15 minutes with technically satisfactory results. Postoperative angiographic studies demonstrated patency of the bypasses in all patients.

Scanning electron microscopic analysis of the stapled microvascular anastomosis in the rabbit

BACKGROUND

Despite the high percentages of experimental and clinical patency rates achieved using so-called mechanical anastomotic devices (Unilink; 3M, St. Paul, MN; vascular staples) they remain little known and occasionally used.

METHODS

The VCS Auto Suture microstapler technique for microvascular anastomosis was tested experimentally and compared with the conventional "gold standard" 10/0 end-to-end microvascular technique. Thirty carotid arteries on one side of 30 rabbits were stapled using nonpenetrating 0.9-mm (small) VCS Auto Suture microclips, and the other 30 carotid arteries on the other side were sutured in a conventional way with 10/0 monofilament nylon. A 100% patency rate was achieved on both sides. Biopsy was performed in five groups of rabbits at different time intervals postoperatively, and the specimens were examined under scanning electron microscopy.

RESULTS

All 60 anastomoses were patent. Histomorphologic examination of the anastomotic site revealed no major differences between sutured and stapled groups.

CONCLUSIONS

Stapled microvascular anastomosis technique is fast and reliable.

Review of facilitated approaches to vascular anastomosis surgery

BACKGROUND

There is an increasing demand for an easier, quicker, less damaging, but reliable procedure to create a vascular anastomosis. This demand is not new but is revitalized by the movement of vascular procedures in various specialties, including cardiac surgery, toward minimally invasive procedures. This article reviews the most important representatives of devices or methods that have been developed in the last two centuries.

METHODS

A thorough literature search was performed. The outcome is presented and discussed in four parts: (1) stapling and clipping devices, (2) coupling devices, (3) glues, and (4) laser welding.

RESULTS

Stapling devices have not become the standard fashion to create an anastomosis because they are too complicated to use. In selected cases clips have potential in vascular surgery. There is a ring-pin coupling system available that is easy to use and especially suitable for creating an end-to-end anastomosis. The ideal glue is yet to be developed, and the currently available laser welding techniques have to become refined.

CONCLUSIONS

It is anticipated that the future lies in hybrid techniques that combine sutures or clips with glues or laser-welding techniques.

Clinical experience with a microvascular anastomotic device in head and neck reconstruction

BACKGROUND

Despite numerous refinements in microsurgical technique and instrumentation, the microvascular anastomosis remains one of the most technically sensitive aspects of free-tissue transfer reconstructions.

MATERIALS AND METHODS

Concurrent with the development of microsurgical techniques, various anastomotic coupling systems have been introduced in an effort to facilitate the performance and reliability of microvascular anastomoses. The microvascular anastomotic coupling device (MACD) studied here is a high-density, polyethylene ring-stainless steel pin system that has been found to be highly effective in laboratory animal studies. Despite its availability for human clinical use over the last 5 years, reported clinical series remain rare. Our clinical experience with this MACD in 29 head and neck free-tissue transfers is reported herein.

RESULTS

Thirty-five of 37 (95%) attempted anastomoses were completed with 100% flap survival with a variety of donor flaps, recipient vessels, and clinical contexts. Two anastomoses were converted to conventional suture technique intraoperatively, and one late postoperative venous thrombosis occurred after fistulization and vessel exposure.

CONCLUSIONS

We conclude that the MACD studied here is best suited for the end-to-end anastomosis of soft, pliable, minimally discrepant vessels. Previous radiation therapy does not appear to be a contraindication to its use. Interpositional vein grafts may also be well suited to anastomosis with the device. When carefully and selectively employed by experienced microvascular surgeons, this MACD can be a safe, fast, and reliable adjunct in head and neck free-tissue transfer reconstructions, greatly facilitating the efficiency and ease of application of these techniques.

Experimental evaluation and clinical use in the head and neck of a 3M/Precise microvascular anastomotic device

Microvascular reconstructions in the head and neck are usually long operating time procedures. Mechanical anastomotic devices help to reduce operating time and can reduce anastomotic failures avoiding foreign bodies in the lumen of the vessel. One of these systems is the 3M/Precise microvascular anastomotic device, it is a non-absorbable device, however, criticisms of this system have been directed to the fact that pulsation of the vessel wall against a rigid structure could lead to thinning of the vessel wall and aneurysm formation. No aneurysms have been found previously in other experimental models. Our experimental study on the aorta and vena cava of the rat comprises 25 arterial and 25 venous anastomoses. In the arteries, four proximal aneurysms were found, two of these were failures. In the venous anastomoses, no failures were found nor aneurysm formation. The system is very useful for performing clinical end to end venous anastomosis helping to reduce anastomotic failures. Aneurysms have been found in arteries although four different ring sizes were available. The device is less easy to use in them than in veins and sometimes can be difficult to apply, making manual suturing a better choice for clinical arterial anastomosis.

Clinical use of the 3M 2.5 mm mechanical microcoupling device in free tissue transfer

The long-term patency of the 2.5 mm mechanical microvascular anastomotic device (the Unilink system) was evaluated in 10 cases of free flap transfer in nine patients between July 1991 and July 1993. Flap survival indicated adequate patency to time of healing. All cases were considered critical end-to-end venous anastomoses, without a parallel conventional microvascular hand-sewn anastomosis associated with the coupling device. The types of flaps used were seven rectus abdominous and one each of serratus anterior and lateral arm muscles and a free jejunum. There were no postoperative complications requiring reexploration. The 2.5 mm device had a rate of 100% flap take with complete healing at an average of 15 months postoperatively. Selected Doppler flow studies depicted the coupler device in vivo with duplex scan verification of venous patency. The 2.5 mm coupler is a versatile anastomotic device for vessels with a diameter of 2.4-3.2 mm. This expands the applicability of the UNILINK system for use in larger diameter vessels.

Clinical experience with the Unilink/3M Precise microvascular anastomotic device

The Unilink/3M Precise anastomotic device for microvascular anastomoses has been evaluated in 38 critical anastomoses in 26 selected patients. The microvascular anastomosis was usually completed within three minutes by a single surgeon. There was only one failure, when an arterial anastomosis clotted because of a technical error. In all patients tissue survival was dependent on patent mechanical anastomoses (critical anastomoses) and the follow-up period was more than three years.

Long term evaluation of the unilink anastomotic system. A study with light and scanning electron microscopy

The long term effects of the Unilink mechanical microvascular anastomosis in terms of anastomotic patency and histological changes in the vessel wall were evaluated in 10 rabbits. Both carotid arteries and facial veins were divided and reanastomosed with the Unilink device. At death two years later all 40 anastomoses were fully patent, with histological changes similar to those described previously after 16 weeks, that is, normal endothelial lining, but almost total atrophy of the media at the anastomotic site. The thinning of the vessel wall at the anastomosis caused neither occlusions nor aneurysms during the observation period.