Eversion with four sutures: an easy, fast, and reliable technique for microvascular anastomosis

In this study, a microvascular anastomosing technique called "eversion with four sutures" is introduced. For microvascular anastomosis, this technique requires fishmouth incisions at both vessel ends and the completion of four sutures. In 120 Wistar-Albino rats, 120 eversion and 120 conventional anastomoses were done in 240 femoral arteries. Each rat received both treatments. Operating time, bleeding time, number of sutures used, patency rates, and pseudoaneurysm formation were analyzed statistically; healing was evaluated with both light and electron microscopy. When compared with the conventional technique using nine sutures, the eversion with four sutures technique was found to be a faster and easier method of anastomosis and as reliable as the conventional technique. Without compromising patency rates, bleeding time, or rates of pseudoaneurysm formation, anastomosis time and amount of suture material exposed to the lumen were significantly reduced when using this technique. In conclusion, the authors think that eversion with four sutures is a reliable alternative to the conventional suturing technique, especially for emergency cases that require multiple microvascular anastomoses.     

Testing of a new prototype surgical stapler that automates the rollover sleeve technique for venous anastomoses

The creation of successful vascular anastomoses is of primary importance in many surgical fields. Numerous attempts to automate this process have been made. These techniques have slowly gained acceptance, but their use is still limited. This report details feasibility testing of a new prototype stapler that automates the rollover sleeve technique for venous vascular anastomoses. Male and female mongrel dogs (n=7) (25-32 kg) were used. A segment of the right (n=5) or left (n=2) iliac vein was harvested for interposition grafts after the contra lateral side was transected. In each dog, two end-to-end venous anastomoses at the interposition grafts were performed. The standard anastomosis employed continuous mattress sutures. The experimental anastomosis was performed with a new prototype surgical stapler. The stapled anastomosis was proximal and the sutured was distal. In all experiments, it was possible to perform the experimental anastomosis with the stapler. Complications included two small leaks, one due to misfiring of a single pin in one experimental site. These leaks required suture reinforcement. One dog died of hemorrhage due to a slipped suture at the vein harvest site. One vein had thrombus seen at the sutured site although no technical abnormalities at either of the anastomoses could be found. After two weeks, grafts were inspected grossly and histologically. Healing appeared normal. There was a trend for less inflammatory cells infiltrating stapled sites; however, this was not statistically significant. The experiments demonstrate that this device can automate the rollover sleeve technique for venous anastomoses.     

Temporary assisting suspension suture technique for successful microvascular anastomosis of extremely small and thin walled vessels for mice transplantation surgery

Dissection and microsurgical anastomosis in small and thin-walled vessels is challenging. Temporary assisting suspension suture technique was developed to overcome those difficulties in establishing successful composite tissue allotransplantation in mice. The operations were performed in 12- to 16-week-old Balb/c mice weighing 25 to 30 grams as both donor and recipient animals. Extended vascularized groin cutaneous flaps based on the superficial epigastric vessels were used. A total of 10 groin cutaneous flaps were transplanted. Three temporary assisting suspension sutures of 11-0 nylon were placed at the 12-, 4-, and 8-o'clock positions to donor and recipient artery and vein before the anastomosis. This technique allowed atraumatic dissection of delicate and thin vessels, prevented vessel wall collapse, and facilitated adequate exposure of the lumen during placement of the permanent microvascular sutures. Thus, the microvascular anastomosis was performed in an unusual manner. The temporary assisting suspension sutures were removed just before the permanent suture was tied down. The mean operation time was 1 hour and 45 minutes with an ischemia time of 1 hour. Ninety-percent success in immediate and late-term patency rates was achieved, which was confirmed by transplant survival. This technique was proven to be useful for microvascular anastomosis in thin-walled vessels and is recommended.     

Sutureless microvascular anastomoses by a biodegradable laser-activated solid protein solder.

A new sutureless technique to successfully anastomose the abdominal aorta of rats (1.3 mm in diameter) by using a fully biodegradable, laser-activated protein solder is presented. A total of 90 rats were divided into two groups randomly. In group one, the anastomoses were performed by using conventional microsuturing technique, whereas in group two, the anastomoses were performed by using a new laser welding technique. In addition, each of the two groups were divided into five subgroups and evaluated at different follow-up periods (10 minutes, 1 hour, 1 day, 1 week, and 6 weeks). At these intervals, the anastomoses were evaluated for patency and tensile strength. Three anastomoses in each subgroup were processed for light and electron microscopy. All anastomoses were found to be patent. The mean clamp time of the anastomoses performed with conventional suturing was 20.6 minutes compared with 7.2 minutes for the laser-activated welded anastomoses (p < 0.001). The strain measurements showed a stronger mechanical bond of the sutured anastomoses in the initial phase. However, at 6 weeks the tensile strength of the laser-welded anastomoses was higher compared with the conventional suture technique. Histologic evaluations revealed a near complete resorption of the solder after 6 weeks. The junction site of the vessel ends cannot be determined on the luminal side of the artery. In conclusion, a resorbable protein used as a solder, activated by a diode laser, can provide a reliable, safe, and rapid arterial anastomosis, which could be performed by any microsurgeon faster than conventional suturing after a short learning curve.     

A new technique for microvascular anastomosis: external metallic circle

Vessel anastomosis is the most critical step in free tissue transfers and replantation surgery. We report on a new microvascular anastomosis technique that uses a metallic circle around the anastomotic circumference. Sutures are first passed inside the circle and tied outside and over the circle so as to stretch open the anastomotic site. By retraction of vessel ends, the circle is totally exteriorized and thus there is no contact with blood. In 48 rats, the external circle method was compared with the conventional technique for constructing end-to-end anastomosis between carotid arteries (1 to 1.2 mm) and femoral veins (1 to 1.5 mm). The external circle method proved to be superior to the conventional end-to-end technique in speed of execution for both arterial and venous anastomoses. Patency rates at the third week were significantly higher in the venous group using the metallic circle (100 percent versus 70.8 percent, p < 0.05). This new method may be applicable in clinical microvascular surgery.     

A triangular cutting arteriotomy scissors facilitating end-to-side anastomoses.

A new microsurgical triangular cutting scissors facilitating end-to-side anastomoses has been developed. The instrument removes oval pieces of tissue from the vascular wall with a single cut. This has several advantages over conventional double cuts with straight microscissors. Preferential use of end-to-side anastomoses has been advocated by several authors, one of the main reasons for this being preservation of the distal blood flow in the artery used in the recipient bed. It also has been reported that vascular occlusions are less frequent with this type of coupling. Another important indication for end-to-side anastomoses is a significant discrepancy in vessel size. One of the more demanding tasks in making an end-to-side anastomosis is the performance of a perfect arteriotomy. With the aim of facilitating the arteriotomy in end-to-side anastomoses, a new microsurgical instrument has been developed.     

Initial platelet deposition at the human microvascular anastomosis: effect on downstream platelet deposition to intact and injured vessels.

Initial platelet deposition (PD) in and around the region of a small-vessel anastomosis may set the stage for thrombosis and tissue loss. To study this problem, a human vessel model (human placental artery, HPA) has been designed to mimic the vascular injuries attendant on clinical microsurgery. To perform these studies, dissected lengths of human placental artery were treated to provide the following four types of injury: group I: control, dissected but otherwise uninjured (N = 5); group II: distal portion of vessel endothelium removed (N = 5); group III: central anastomosis, distal endothelium intact (N = 7); and group IV: central anastomosis, distal endothelium removed (N = 4). Vessels were perfused with 25 ml human whole blood for 17 +/- 5 s at an average shear rate of 536 s-1. Vessels in groups I to IV were segmented at 2-cm intervals, and the number of 111In-labeled platelets was measured. Data from the following groups of exposure zones were pooled and analyzed: endothelium intact, endothelium absent, anastomosis present, postanastomosis with endothelium intact, and postanastomosis with endothelium absent. Significant numbers of platelets were found to attach to intact endothelium, indicating that ischemia and microsurgical handling may augment platelet deposition to otherwise uninjured vessels. A similar degree of platelet deposition was measured after exposure of the subendothelium and perfusion, indicating that superficial subendothelial exposure in the absence of an additional prothrombotic stimulus may lead to no greater platelet deposition than occurs on slightly injured endothelium alone. Platelet deposition at anastomoses was strikingly elevated, although the anastomosis had no additive effect on platelet deposition to downstream endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)     

The use of prostacyclin analogue-containing suture for the prevention of postoperative venous thrombosis in the rat

The ability of prostacyclin analogue incorporated into a controlled-release suture to prevent postoperative venous thrombosis was investigated. Thirteen rats underwent bilateral transection and anastomosis of the common femoral vein. In each animal, polycaprolactone suture containing 0.25 micrograms/cm of the prostacyclin analogue Iloprost (Schering Ag, Berlin, West Germany) was used to perform the anastomosis on one vessel. Similar suture without prostacyclin analogue was used on the contralateral vessel, which served as a control. Functional patency and luminal surface morphology were assessed 24 hours postoperatively. All anastomoses performed using suture containing prostacyclin analogue were patent. Among controls, five anastomoses were patent and eight were occluded. This difference was highly significant (p less than 0.005). All anastomoses performed with prostacyclin analogue-containing suture exhibited a uniform absence of thrombosis. In contrast, eight control veins exhibited a dense, well-organized fibrinous clot that filled the entire lumen, effectively sealing off the vessel. These results suggest that the prostacyclin analogue released from the suture was highly effective in inhibiting thrombus formation without adversely affecting the vessel's ability to achieve hemostasis.     

Inhibition of microsurgical thrombosis by the platelet glycoprotein IIb/IIIa antagonist SR121566A

Despite major improvements in tools and significant refinements of techniques, microsurgical anastomosis still carries a significant risk of failure due to microvascular thrombosis. The key to improving the success of microvascular surgery may lie in the pharmacologic control of thrombus formation. Central to pathologic arterial thrombosis are platelets. Glycoprotein IIb/IIIa is a highly abundant platelet surface receptor that plays a major role in platelet aggregation by binding platelets to each other through the coagulation factor fibrinogen. To explore the ability of antithrombotic agents to prevent microvascular thrombosis, a rabbit ear artery model was used in which a standardized arterial injury results in predictable thrombus formation. This model was used to examine whether SR121566A, a specific and potent glycoprotein IIb/IIIa inhibitor, can successfully prevent microsurgical thrombosis.Using a coded, double-blind experimental design, 20 rabbits (40 arteries) were assigned to four treatment groups: (1) saline injection (n = 10), (2) acetylsalicylic acid 10 mg/kg (n = 10), (3) heparin 0.5 mg/kg bolus with subsequent intermittent boluses of 0.25 mg/kg every 30 minutes (n = 10), and (4) SR121566A 2 mg/kg bolus (n = 10). After vessel damage and clamp release, arteries were assessed for patency at 5, 30, and 120 minutes by the Acland refill test. Coagulation assays, in vivo bleeding times, and ex vivo platelet aggregation studies were also conducted. Scanning electron microscopy was used to examine mural thrombus composition.A significant, fourfold increase in vessel patency following administration of SR121566A over saline control (80 percent versus 20 percent patency, respectively, at 35 minutes after reperfusion, p < 0.01) was noted. This was correlated with marked inhibition of ex vivo platelet aggregation. This antiplatelet treatment did not prolong coagulation assays (mean international normalized ratio: saline, 0.66 +/- 0.04; SR121566A, 0.64 +/- 0.03; mean thromboplastin time: saline, 19.63 +/- 0.67; SR121566A, 17.87 +/- 3.27) and bleeding times (mean bleeding time: saline, 42 +/- 4; SR121566A, 48 +/- 6). Scanning electron microscopy demonstrated extensive platelet and fibrin deposition in control vessel thrombi. In contrast, thrombi from SR121566A-treated vessels demonstrated predominance of fibrin with few platelets when examined under scanning electron microscopy.Administration of SR121566A was associated with a significant increase in vessel patency, without deleterious effects on coagulation assays or bleeding times. The increase in vessel patency was correlated with inhibition of platelet aggregation and decreased platelet deposition, as demonstrated by scanning electron microscopy. Glycoprotein IIb/IIIa antagonists represent a new class of anti-platelet agents that may be suited for inhibiting microsurgical thrombosis. This study supports further investigation into the use of these agents in microsurgery.     

The laser-assisted end-to-side microvascular anastomosis

A simple method of performing the laser-assisted end-to-side microvascular anastomosis was devised. This technique was tested on 150 Sprague-Dawley rats in two separate series of experiments. In the first, end-to-side anastomoses were performed on the iliac artery under the normal tension due to the elastic recoil of severed vessels. Four stay sutures were placed 90 degrees apart, and the intervals were "spot welded" with a low-wattage CO2 microsurgical laser unit. The patency rate (96 percent) was equivalent to that found in a control group utilizing the conventional all-suture method (92 percent), but there was a significantly higher aneurysm rate (44 versus 11 percent). In a second model, an arterial bypass with very low anastomotic tension was performed around an obstruction created in the carotid artery. This model resulted in turbulent flow but low anastomotic tension. Here the laser-anastomosis patency rate was 98 percent, versus 42 percent for the conventional all-suture method. The placement of fewer sutures in association with turbulent flow in this model may account for the improved patency rate. The avoidance of excessive tension at the anastomotic site reduced the incidence of aneurysms to a negligible level.     

Microvascular anastomosis in an optical cavity: is it possible?

Microsurgery is one of the highly interesting surgical procedures that can be performed using different applications and in different specialties, including plastic surgery. The endoscope is a popular instrument used in many fields, including plastic surgery. Although the operating microscope is still a must for microsurgical performance, microsurgery could be performed, depending on the experiences and facilities, by using other visual-assisting equipment. From this point of view, the authors tried to find less costly and more widespread equipment suitable for performing microsurgery that can, furthermore, be applied in special situations and indications, such as operating in an optical cavity. The authors investigated this issue with the endoscope. In this experimental project, the authors performed vascular microsurgical anastomoses of the rats' femoral vessels to create an optical cavity in a prefabricated skin retraction model in the groin area of 10 Sprague-Dawley male rats. The microsurgical anastomoses of the femoral vessels and nerves were performed easily in a reasonable time, without recorded difficulties, and with maximum physical and visual comfort for the surgeon. The authors spent a mean time of 28.1, 27.3, and 19.2 minutes for the arterial, venous, and neural anastomoses, respectively. In this group of animals, 90 percent vascular patency and 100 percent accurate neural anastomoses were recorded. The advantage the authors noted was that this new technique of operating in the field of microsurgery, with its feasibility and difficulties, would be a point of research and application for the young generations of microsurgeons.     

Further technical considerations of the sleeve microanastomosis

In sleeve anastomoses, stenoses at the suture site have been the main concern. Mechanical dilatation is one way to prevent the stenosis, as suggested by Lauritzen. In the present study, 50 vessels (femoral and carotid) and 10 veins were used for sleeve anastomoses and the same numbers of vessels were used for conventional anastomoses (as control) to evaluate the effect of mechanical dilatation using resin corrosion cast (Mercox) because the Mercox cast facilitates three-dimensional stereoscopic views. Gradual dilatations around the suture sites were observed in seven carotid arteries, and three of seven resulted into aneurysm formation due to weakening of the inner vascular wall in the sleeve anastomosis. No dilatation or aneurysm was observed in the femoral arteries. Newly proliferating capillaries formed on the endothelial surfaces of the inner vascular walls around the suture sites after 4 weeks in the sleeve anastomoses. Operative time and endothelial trauma were markedly reduced with sleeve anastomoses. The gradual dilatation and aneurysm formation in the carotid arteries show that sleeve anastomoses should be used carefully for high-pressure arteries in clinical practice if mechanical dilatation is performed.     

Microvascular anastomosis: vascular cuff technique

A technique is described for reinforcing and sealing a microvascular anastomosis by using a detached vessel segment as a cuff around the anastomosis. This may allow fewer microvascular sutures to be used. This would allow a simpler, less traumatic, and more rapid repair and may allow "more vessels to be repaired by more people."     

Morphological evaluation of reconstructive operations on the bronchi using a microsurgical technic in an experiment

Morphological study of bronchial anastomoses repair made with or without microsurgical techniques has been performed in 30 mongrel dogs. Comparative analysis of bronchoscopy, microscopy and scanning electronic microscopy data shows earlier epithelialization, more regular conjunction of bronchial tube and less marked inflammation in anastomosis made with microsurgical techniques. The fact may be explained by a less pronounced traumatization of bronchial tissues with microinstruments and also by tight suture of mucosal layer which creates favourable conditions for repair of anastomosis per primam.     

Use of the vascular closure staple clip applier for microvascular anastomosis in free-flap surgery

We report our initial experience using the vascular closure staple clip applier (a nonpenetrating titanium clip applied in an interrupted, everting fashion) for microvascular anastomosis in free-flap surgery. In total, 153 anastomoses were performed in 87 free flaps (174 potential anastomoses) using the vascular closure stapler between October of 1997 and June of 1999. In 66 flaps, both the arterial and venous anastomosis were performed with the clip applier, whereas in 21 flaps only the venous anastomosis was performed using the clips. A total of 146 anastomoses were performed in an end-to-end fashion, and seven were performed end-to-side. Of the 87 flaps there were 53 TRAM flaps, seven bilateral TRAM, five latissimus dorsi, four gastrocnemius, three rectus abdominis, two radial forearm fibula, and four Rubens fat-pad flaps. Seventy flaps were used for breast reconstruction, seven flaps for lower limb reconstruction, four flaps for head and neck reconstruction, and six flaps for chest wall/trunk reconstruction. There were no postoperative anastomotic complications of bleeding, thrombosis, or need for revision (100 percent patency rate), with a significantly reduced time for completion of anastomoses. The clip applier is a safe, reliable method for performing microvascular anastomoses, allowing reduced operating time and possible cost savings in free-flap surgery.     

大鼠颈总动脉端-侧吻合模型的建立

目的建立大鼠颈总动脉端-侧吻合模型,以期对欲进行显微血管吻合训练或相关实验的同道提供帮助。方法成年SD大鼠10只,将左侧颈总动脉远端穿过颈前肌肉群和气管之间的隧道,与右侧颈总动脉行端-侧吻合。结果成功建立大鼠颈总动脉端-侧血管吻合动物模型,手术成功率约为100%,平均吻合所需8针,平均血管吻合所需时间(35±5)min。吻合3个月后观察通畅率100%,HE染色示吻合口愈合良好。结论吻合成功的关键是提高显微操作技术水平,同时注意保护术野中小的血管和神经。此模型可以较好的应用于显微血管缝合训练。     

Vascular anastomosis using controlled phase transitions in poloxamer gels

Vascular anastomosis is the cornerstone of vascular, cardiovascular and transplant surgery. Most anastomoses are performed with sutures, which are technically challenging and can lead to failure from intimal hyperplasia and foreign body reaction. Numerous alternatives to sutures have been proposed, but none has proven superior, particularly in small or atherosclerotic vessels. We have developed a new method of sutureless and atraumatic vascular anastomosis that uses US Food and Drug Administration (FDA)-approved thermoreversible tri-block polymers to temporarily maintain an open lumen for precise approximation with commercially available glues. We performed end-to-end anastomoses five times more rapidly than we performed hand-sewn controls, and vessels that were too small (<1.0 mm) to sew were successfully reconstructed with this sutureless approach. Imaging of reconstructed rat aorta confirmed equivalent patency, flow and burst strength, and histological analysis demonstrated decreased inflammation and fibrosis at up to 2 years after the procedure. This new technology has potential for improving efficiency and outcomes in the surgical treatment of cardiovascular disease.     

Experience using microvascular anastomotic rings for the transplantation of 20 free flaps

A new microvascular anastomosis technique was employed with success in 1985-1986 with the result of 18 free-flap survivals and 2 failures. The rate of success in microvascular anastomoses was 90.5 percent (38 of 42). The advantages of this technique are its simplicity, convenience, and safety, and it may shorten the duration of the operation. Our experience in using vascular anastomotic rings is presented.     

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice^1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates⁴.Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient⁵.Herein, we provide additional details of this technique to supplement the video.     

Present status and new perspectives in laser welding of vascular tissues

The laser welding of biological tissues is a particular use of lasers in surgery. The technique has been proposed since the 1970s for surgical applications, such as repairing blood vessels, nerves, tendons, bronchial fistulae, skin and ocular tissues. In vascular surgery, two procedures have been tested and optimized in animal models, both ex vivo and in vivo, in order to design different approaches for blood vessels anastomoses and for the repair of vascular lesions: the laser-assisted vascular anastomosis (LAVA) and the laser-assisted vessel repair (LAVR). Sealing tissues by laser may overcome the problems related to the use of conventional closuring methods that are generally associated with various degrees of vascular wall damage that can ultimately predispose to vessel thrombosis and occlusion. In fact, the use of a laser welding technique provides several advantages such as simplification of the surgical procedure, reduction of the operative time, suppression of bleeding, and may guarantee an optimal healing process of vascular structures, very similar to restitutio ad integrum. Despite the numerous preclinical studies performed by several research groups, the clinical applications of laser-assisted anastomosis or vessel repair are still far off. Substantial breakthrough in the laser welding of biological tissues may come from the advent of nanotechnologies. Herein we describe the present status and the future perspectives in laser welding of vascular structures.