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.     

Vascular Anastomosis—Sutures,Staples or Glue?

Different vascular suturing techniques were assessed in the experimental laboratory. Staples made of tantulum wire were employed for vascular anastomoses in normal dogs'' arteries and veins and in atherosclerotic rabbits'' aortas. The staples were driven with the NRC Vascular Suturing Instrument. In a similar series of experiments a plastic bonding agent (Eastman 910) was used. The anastomosed vessels were found to be patent and few complications were encountered. However, it is unlikely that the conventional suture technique with the currently available materials will be replaced by these methods except under special circumstances. Clinical application of the stapling method is envisaged in the anastomosis of small vessels and in situations when speed is essential, whereas the bonding agent promises to be useful as an ancillary method in combination with sutures or staples.     

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.     

Bipolar anastomosis technique with removable instruments: an easy, fast, and reliable technique for vascular anastomosis

The interrupted suture technique is most commonly used for microsurgical vascular anastomosis. For several reasons (e.g., exposure of suture material to blood, time needed), many attempts have been made to find other solutions. This article describes a new means of performing a microsurgical vascular anastomosis. The aim of this study was to show the feasibility and possible advantages of this new technique. The basic components at work here are a modified cuff and electrically generated heat used to unite the vessel walls. In this way, both endothelial layers are adapted without manipulating the inside of the vessel or leaving behind foreign matter. Various energy/coagulation time settings were used to perform arterial anastomoses (n = 42) in an isogeneic abdominal aorta interposition model in the rat. The quality of anastomosis was evaluated at days 1, 10, 21, and 120. Immediately after the welding process all anastomoses (n = 42) were patent. No stenosis was found at any observation time. Anastomosis time ranged from 3 to 18 minutes (average, 11 minutes). This new technique permits a vascular anastomosis to be performed easily and reliably with a high patency rate. With this technique, the authors are convinced that a skilled surgeon can create a high-quality anastomosis in a fraction of the time needed to sew an anastomosis.     

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.     

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.     

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.     

The relationship between the number of sutures and the strength of microvascular anastomoses.

The relative strengths of microvascular anastomoses in rat femoral arteries were measured, comparing controls (no anastomosis) to those with 4, 6, 8, 10, 12, and 14 stitches. The ones in which 8 sutures were used most closely paralleled the control state, whereas those with 4 or 6 sutures were clearly inferior. With a greater number of sutures the vessel behaves as a "shorter" vessel, with the anastomosis becoming the weakest part of the vessel.     

Patency of different arterial and venous end-to-side microanastomosis techniques in a rat model

Microvascular anastomotic patency is the most important factor in determining a successful outcome in free-flap transfers. End-to-end and end-to-side techniques have been shown to provide equivalent arterial patency rates in clinical and basic science studies, and end-to-side anastomoses have been used extensively in microsurgical reconstruction. Nevertheless, the effect of venotomy shape on the patency of venous end-to-side anastomoses has not been previously reported. The purpose of this study was to compare the patency rates of end-to-side anastomoses using different techniques in both arteries and veins. In total, 104 Sprague-Dawley rats were subdivided into four groups. The rats were anesthetized, and anastomosis was performed on either the femoral artery or vein on the right with the left used as control. Vesselotomy was varied between an end-to-side hole and an end-to-side slit with patency measured immediately following surgery and at 2 weeks. No significant difference in patency or histology between these techniques was demonstrated in any group. We conclude there is no difference in patency rate between the two techniques in arterial or venous vesselotomies; however, in small vessels < 1.5 mm, the slit technique is technically easier, and clinical recommendations are given.     

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.     

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.     

Mechanical anastomosis of small arteries and veins with the unilink apparatus: a histologic and scanning electron microscopic study

A new method for mechanical anastomosis of small vessels--the Unilink device--has been tested in 23 rabbits. A total of 81 arterial and venous anastomoses were performed. One of the arterial anastomoses were thrombotized, while the remaining 80 anastomoses were fully patent at 2 or 16 weeks. The repair process at the anastomotic site was very rapid both in arteries and veins. The endothelialization was complete at 2 weeks, but a marked atrophy of the media was noted in the arterial anastomoses. The same phenomenon was observed in the venous anastomosis, but to a much lesser degree. Thrombus formation was extremely rare, and the atrophy of the media did not seem to affect the patency rate. The experiment has confirmed that the Unilink method provides a very safe, fast, and simple way to perform microvascular anastomoses.     

Collateral arteries grow from preexisting anastomoses in the rat hindlimb

Previous findings have suggested that collateral arteries grow from preexisting arteriolar anastomoses ("arteriogenesis"). To investigate whether collateral growth occurs without preceding angiogenesis, we obtained vascular casts and postmortem angiographies 3, 7, and 21 days after unilateral femoral artery occlusion in the rat. Proliferation kinetics were determined after 5'-bromo-2'-desoxyuridin infusion. A preexisting anastomosis was identified. Proliferation of this vessel began 24 h after femoral artery occlusion, increased maximally during the first 3 days, and reached 60% at day 7. Cell division was restricted to preexisting anastomoses and occurred neither in directly neighboring arterial vessels nor in capillaries. Collateral vessels doubled their diameter within 7 days and assumed a typical corkscrew appearance (increase of length: 21%). After 7 days of occlusion, we measured a further increase of length (14%) but no proliferation or increase of diameter. We conclude that arteriogenesis is a biphasic process involving rapid proliferation of preexisting arteriolar shunts followed by pronounced remodeling processes. Arteriogenesis occurs independently of angiogenesis and denotes a separate entity of vascular proliferation.     

Characteristics of the reconstruction of collateral pathways after surgical decompression of the portal system

In 20 mongrel dogs after a preliminary stenosis of the portal vein, formation of the spleno-renal or mesenteric-caval anastomosis has been performed. For revealing the vessels vital portography, injection of roentgenopaque masses and morphometry have been carried out. The spleno-renal anastomosis ensures a selective outflow of blood from the esophago-gastro-splenic zone. The collaterals, developing as a result of the porto-caval anastomoses with the anterior vena cava, and the collaterals, developing as a results of the porto-portal anastomoses, disappear. The mesenteric-caval anastomoses favourably affects the intestinal hemodynamics. The bypasses of the blood stream, developed between the portal vein and posterior vena cava reduce predominantly. The decompressive angioanastomoses result in local hypertension in the posterior vena cava system.     

Experimental studies in animals on the use of a fibrin glue from the human plasma fraction Cohn I in nerve reconstruction

In order to compare the effects of suture and glue direct nerve connections and nerve transplantations in the sciatic nerve in rats were performed. 4, 6 and 12 weeks later, the nerve anastomosis were histologically studied. In the direct nerve connections, despite a single holding suture, dehiscences were frequently detected with the penetration of the adhesive between the nerve ends. Due to the exact adaptation with the aid of inserted nerve grafts, the anastomoses could be repaired sutureless successfully using a fibrin glue cuff. Since histologically, in comparison to suture, no foreign body granulomas were found, the findings in the literature could be confirmed. No cicatricial contractions of the anastomoses could be found. In the interfascicular nerve transplantation, comparatively good results may be obtained using the two-component adhesive on the Cohn I-fraction basis.     

Preferential use of end-to-side arterial anastomoses in free flap transfers.

In our early clinical experience with free flaps, we used end-to-end arterial anastomoses and in 9 our of 24 we had complete failures--7 of which were due to early arterial thrombosis. Contrarily, in 41 consecutive free flaps with end-to-side anastomoses we have not had a single failure. At the same time that we began using the end-to-side anastomoses, we also began using the latissimus dorsi free flap as our flap of first choice, and we agree that this was probably an additional reason for our improved success rate. The use of end-to-side anastomoses has the following advantages: (1) a high success rate; (2) preservation of all existing vessels in an injured extremity; (3) greater freedom of operative planning; and (4) technical simplicity in terms of access to the vessels. For us, these advantages have made end-to-side anastomosis the technique of choice in the transfer of free flaps.     

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。     

Microsurgery in the clinic and laboratory

Laboratory animals have been crucial to the development of modern microsurgical techniques which are now routinely used in many clinical departments worldwide. In return, microsurgical techniques are important in biomedical research as they allow many surgical procedures to be performed on rodents instead of dogs, pigs or primates. This has obvious advantages in terms of low cost, the use statistically valid numbers for comparison and the availability of genetically defined animals which are more likely to give valid answers to immunological questions. Microsurgical reconstruction is important in plastic, orthopaedic, urogenital, vascular and peripheral nerve surgery in man and it is likely that it will become part of every surgeon's training in the near future. In this review, the instrumentation essential to any microsurgical enterprise and the sutures available are described. Basic microsurgical techniques for end-to-end and end-to-side anastomosis of small vessels and for joining peripheral nerves, oviducts and other tubular structures are given in outline. Techniques for transplanting kidney, heart, heart and lung, liver, spleen, pancreas, small bowel, stomach, testicle, ovary and whole joint are only outlined but key references are given. Finally, some of the clinical indications for microsurgical reconstruction are reviewed.     

Radiation diagnosis of aortic aneurysmal ruptures with formation of anastomoses with the inferior cava and various organs

The results of radiation diagnostic techniques were analyzed in 29 patients with aortic aneurysmal ruptures with formation of aortic anastomoses. The examination and treatment of 362 patients with abdominal aortic aneurysmal ruptures revealed that 23 (6.35%) patients had anastomoses (aortocaval (n = 15), aortoduodenal (n = 6), aortogastric (n = 1), and aortoureteral (n = 1)). Six patients were observed to have secondary aortointestinal anastomoses occurring after reconstructive vascular surgery. In one patient, abdominal aortic aneurysmal rupture first led to the formation of a primary aortoduodenal anastomosis and some time after surgery a secondary aortointestinal fistula emerged. One out of 113 patients with aortic dissecting aortic aneurysms had an aortopulmonary fistula. Ultrasonography, computed tomography, and angiography were performed in 27, 19, and 14 patients, respectively. Radiation diagnostic techniques revealed fistulas in 9 (31%) out of the 29 patients. The diagnosis of aortic anastomoses presents challenges.