CO2-welded venous anastomosis: enhancement of weld strength with heterologous fibrin glue

The milliwatt CO2 laser was used to perform end-to-end anastomoses in canine jugular veins. There was a high disruption rate (50%) in laser-welded veins (n = 10). Fibrin glue (n = 17), formed from human fresh-frozen plasma, enhanced the weld strength decreasing the disruption rate (18%), resulting in an 82% patency which nearly equaled the contralateral sutured vein patency (93%). The bursting strength was improved with fibrin glue. Transmural necrosis was present initially in all groups but extended for a longer distance in the vessel wall in laser-welded anastomoses. Sutured anastomoses exhibited a greater inflammatory response. In laser-welded anastomoses endothelial cells were not as confluent as in sutured anastomoses by six weeks. Carbon dioxide laser-welded end-to-end vein anastomoses appear to be impractical because they disrupt too easily. However, the addition of heterologous fibrin glue to the weld results in a reasonably strong anastomosis with histologic properties that may be beneficial in vein bypass grafts.     

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.     

Laser-assisted microsurgical anastomosis

A low power carbon dioxide laser was used to perform 212 end-to-end laser-assisted microvascular anastomoses (LAMA) of femoral arteries (mean diameter, 1.2 mm) in Sprague-Dawley rats. Eighty-two conventional microvascular suture anastomoses (CMSA) utilizing 10-0 monofilament interrupted sutures were done for comparison of techniques and wound healing. The mean duration of each anastomosis procedure was 16 minutes for the LAMA repairs, compared to an average of 27 minutes for the CMSA repairs (P less than 0.05). All anastomoses were patent at the completion of the procedure. Each laser-assisted anastomosis required an average of seven intermittent laser exposures of 0.1 to 0.3 seconds each with approximately 80 mW of CO2 (wavelength = 10.6 micron) radiation at a spot size of 150 micron. A patency rate of 95% was obtained on the LAMA vessels (202 of 212) compared to 96% for the CMSA repairs (79 of 82). A total of 14 aneurysms were noted in the LAMA group (7%) compared to 11 in the CMSA (13%). All aneurysms were in patent vessels. Histological analysis indicates that the progression of wound healing of LAMA and CMSA anastomoses follows similar paths chronologically and morphologically with increased scar tissue formation around the suture. Scanning electron microscopy confirms the comparable luminal healing of the LAMA and CMSA vessels, with complete reendothelialization occurring by 3 weeks postoperatively. The tensile strength of the LAMA repair, although low immediately after operation, is comparable to that of the intact artery at 21 days. These findings suggest that a low energy carbon dioxide microsurgical laser has potential beneficial clinical application for anastomosis of small vessels.     

End-to-side and end-to-end vascular anastomoses with a carbon dioxide laser

This study was designed to compare anastomoses performed with a carbon dioxide laser and conventional anastomoses performed with 7-0 polypropylene suture. In each of 80 rabbits, the divided left carotid artery was anastomosed by a continuous suture technique and the right carotid was anastomosed with a carbon dioxide laser. In each of 40 additional rabbits, both end-to-end and end-to-side laser anastomoses were performed on the same carotid artery. The laser technique involved the placement of three stay sutures (end-to-end technique) or four stay sutures (end-to-side technique) of 7-0 polypropylene and an everting laser seal at a power level of 65 mW. The 1-year overall patency rate was 98% (78/80) in laser anastomoses, 79% (63/80) in suture anastomoses, and 95% (38/40) in combined end-to-end and end-to-side laser anastomoses. Microscopic findings in laser anastomoses demonstrated degeneration of collagen and protein in the adventitia and media, but much less intimal injury than in suture anastomoses, with reendothelialization beginning earlier (within 7 days after anastomosis as compared with 2 to 4 weeks). The tissue tensile strength at 1 hour was less in laser anastomoses than in suture anastomoses, but the laser anastomoses still withstood an intraluminal pressure load of 380 mm Hg. Laser anastomosis improved the microscopic and histologic appearance of the intimal layer, allowing for rapid early reendothelialization and resulting in excellent patency rates.     

Laser-assisted microvascular anastomoses: angiographic and anatomopathologic studies on growing microvascular anastomoses: preliminary report

A low-powered carbon dioxide laser was used to perform end-to-end anastomoses of growing femoral arteries (mean diameter 1.6 mm) in miniature swine. Five microvascular conventional anastomoses were performed with 10-0 monofilament interrupted sutures. Nine laser-assisted vascular anastomoses were performed. The mean duration of each anastomosis was 30 +/- 3 minutes for the conventional anastomosis and 20 +/- 2 minutes for the laser-assisted vascular anastomosis (p less than 0.05). All anastomoses were patent at the completion of the procedure. Each laser-assisted anastomosis required an average of eight laser pulses of 2 to 4 seconds. After 13 weeks the external diameters of the conventional anastomoses were 1.8 mm (+15%), while the laser-assisted anastomoses averaged 3.0 mm (+81%) (p less than 0.05). All nine laser-assisted anastomoses were patent, functional, and free of stenosis compared with one out of five conventional anastomoses. Histologically the laser induced minimal or no fibrosis, allowing normal physiologic healing and growth patterns. Electron microscopy confirmed that the integrity of the arterial layers had been restored. These findings suggest that a low-energy carbon dioxide laser has potential clinical application for anastomosis of small growing vessels.     

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.     

Patency of laser-assisted anastomoses in small vessels: one-year follow-up

Laser-assisted arterial anastomoses can now be performed with satisfactory short-term patency. This study was undertaken to evaluate patency and aneurysm formation with a 1-year follow-up. A microscopically guided CO2 laser was used to anastomose 1.5 to 2.0 mm carotid arteries in 24 rabbits. Under X6 to X40 magnification, 60 to 70 mW were delivered with a spot size of approximately 0.32 mm. One carotid artery underwent laser anastomosis; the opposite served as a sutured control (10-0 nylon sutures). The 48 end-to-end anastomoses were evaluated for patency and aneurysm formation at 3, 6, and 12 months. Aneurysms were defined as a 1.5 times increase in diameter at the anastomotic site. The vessels underwent microscopic examination. All laser-assisted and sutured anastomoses were patent up to 1 year. At 3 months, one of eight sutured and one of eight laser anastomoses were aneurysmal; stenosis was noted in one laser anastomosis. At 6 months, one of eight laser and 0 of eight sutured anastomoses were aneurysmal. At 12 months, one of eight rabbits had died; of the remaining seven, three of seven laser and zero of seven sutured anastomoses were aneurysmal. In total, five of 23 (21.7%) aneurysms developed with the laser technique and one of 23 (4.3%) with the suture technique (p less than 0.05). Laser-assisted anastomoses are technically feasible, and patency at 1 year is equal to those performed with the suture technique. Aneurysm formation is a consistent problem that demands further investigation.     

Growth of the aortic anastomosis in puppies--comparison of monofilament suture materials, whether absorbable or nonabsorbable, and of suture techniques, whether continuous or interrupted

This study compared the growth of vascular anastomoses performed with either polypropylene or polydioxanone sutures and with either continuous running suture or interrupted suture technique. Primary end-to-end anastomoses of the infrarenal aorta were performed in 38 puppies. Nineteen were performed with 5-0 polypropylene sutures; in ten all sutures were placed in continuous fashion, and in nine in interrupted fashion. The other nineteen were performed with 5-0 polydioxanone sutures; in ten the sutures were placed in continuous fashion, and in nine in interrupted fashion. The animals were subjected to the repeated aortograms at 2, 4, 8 weeks, 6 months and 1 year following operation. Each abdominal aorta was subjected to burst test, and pathological examination. All anastomoses were patent and tolerated burst-test (300 mmHg). Neither aneurysm nor dilatation of anastomotic site was observed. Anastomotic area was significantly smaller and more stenotic in the continuous polypropylene suture group than in other three groups at 8 weeks, 6 months and 1 year following operation. There was no significant difference among these three groups. No suture materials were observed in the polydioxanone suture groups after 6 months following operation. This study suggests that polydioxanone suture will be useful for the repair of cardiovascular anomalies where growth of the suture line is required.     

End-to-end versus end-to-side arterial anastomosis patency in microvascular surgery

The patency rates of microsurgical end-to-end and end-to-side anastomosis in the rat carotid artery were studied. Seventy end-to-end and seventy end-to-side arterial anastomoses, using 10-0 nylon interrupted sutures, were performed on 140 Sprague-Dawley rats. Findings indicated 100% patency in end-to-end as well as end-to-side immediately and 1 week post-anastomosis. This investigation suggests that there is no significant advantage between the methods studied based on vessel patency alone. The decision to perform an end-to-end vs. an end-to-side arterial anastomosis should be based upon the clinical circumstances encountered, since no significant difference in patency rates exists. © 1998 Wiley-Liss, Inc. MICROSURGERY 18:125-128 1998     

Low power CO2 laser-assisted microvascular anastomosis: an experimental study

Low power CO2 laser-assisted microvascular anastomosis (LAMA) was used for saphenous artery autotransplantation in 40 rabbits. Eighty end-to-end anastomoses were performed by three methods (conventional interrupted suture, stay suture + laser, laser without stay suture). The long term patency rate in the three types of anastomosis is 93%, 93%, and 100%, respectively. The time needed for the laser procedure is half to one-third of that required for the interrupted suture method. The tensile strength of the bonding site can withstand up to 250 mm Hg of arterial pressure. We have demonstrated that the CO2 laser can be used in microvascular anastomosis with or without stay sutures. Aneurysm formation is a potential risk of LAMA. Accurate coaptation of the transected vessel, precise control of laser energy, and minimal area exposed to the laser beam are the key points for further improving anastomotic quality.     

Microvascular surgery in experimental and clinical kidney transplantation

An improved microsurgical technique for orthotopic rat kidney transplantation is described in detail. (1) End-to-end anastomosis of renal arteries with 7-8 interrupted 10-0 sutures. (2) End-to-end anastomosis of renal veins with 2 continuous semicircular 10-0 sutures. (3) Non-splinted end-to-end ureteric anastomosis with 4 interrupted full-thickness 11-0 sutures. (4) Simultaneous bilateral nephrectomy. Seventy transplantations were analysed. No failure due to complications of the vascular anastomoses occurred. The ureteric anastomoses were complicated by stenosis in only 5 animals (7%). The operation times for vascular anastomoses were 20 (15-24) minutes and for complete transplantation 50 (45-60) minutes. This technique seems to be less time consuming than other methods. Our method has produced a success rate of 93% with well standardized and reproducible organ quality. Preliminary clinical experiences with extracorporeal microvascular reconstruction in 4 cases of injured small polar kidney allograft arteries support the continued application in appropriate situations to increase the number of suitable donor kidneys.     

Comparison of continuous and interrupted suture techniques in microvascular end-to-side anastomosis

To compare the speed and patency rates of the continuous and interrupted suture techniques in microvascular end-to-side anastomosis, 10 anastomoses utilizing each technique were performed using a femoral artery-superficial epigastric vein bypass model in Sprague-Dawley rats. The continuous suture technique was found to be almost twice as fast as the interrupted technique with no functional compromise. Patency for both techniques was 100 percent. These results are similar to those of several recent reports comparing the two techniques in end-to-end anastomosis and suggest that the continuous suture technique may be the most efficient technique for end-to-side anastomosis as well.     

Comparison of laser vascular welding,interrupted sutures,and continuous sutures in growing vascular anastomoses

Background and Objectives: The argon laser-assisted vascular anastomosis may solve the problems of conventional sutured anastomosis, such as vascular stenosis and arrest of growth owing to a foreign-body reaction to suture material. Study Design/Materials and Methods: Twelve argon laser-assisted vascular anastomoses, seven conventional anastomoses with interrupted sutures, and five conventional anastomoses with continuous sutures were performed in 12 young mongrel dogs. Results: Five months later, the external diameter at the anastomosis had increased 70.5% in the laser group, 67.0% in the interrupted suture group, and 22.9% in the continuous suture group. Histological examination of the laser-assisted anastomoses showed almost complete healing, with no granulomatous response around the anastomotic site. In the interrupted suture group, marked scaring and foreign body reactions were observed on the vessel wall at the site of the anastomosis. The continuous suture group showed more remarkable disorientation of the vascular layer and intimal hyperplasia than the interrupted suture group. Conclusion: Vascular anastomosis using the argon laser offers advantages over the conventional procedure in growing vessels.     

Bursting strength in CO2 laser-assisted microvascular anastomoses

Iliac artery end-to-end anastomoses were performed in 42 Sprague-Dawley rats, divided into seven groups, to determine the welding effects of CO2 laser radiation in microvascular anastomoses. Conventional suture techniques were performed on right iliac arteries, and left iliac arteries were anastomosed with a laser-assisted technique. Bursting strength and diameters of the anastomotic sites were measured at different intervals (from one day to five weeks) post surgery. The anastomotic patency rate was 100 percent in both groups, and the aneurysm rate was only 2 percent in the laser group. Bursting strength was low at one and three days post surgery in both groups; then, it increased gradually until both groups could withstand higher than physiologic pressures. Results of high patency rates, low aneurysm formation, and the ability to withstand pressures higher than physiologic, suggest that the laser-assisted anastomotic technique can play an important role in microvascular surgery.     

A new combined "interrupted-continuous" microvascular anastomotic technique. Experimental study and clinical application

A new combined interrupted-continuous microvascular anastomotic technique is introduced, using four interrupted stay stitches and continuous suturing in between. Its efficacy is compared with the simple interrupted and continuous techniques. Microanastomoses were performed in the femoral artery and vein of rats. The patency, anastomosis time, and blood loss from the suture line of all anastomoses were recorded. Also, the sites of all anastomoses were harvested and histologically examined for lumen stenosis, media regeneration, and endothelial lining. Experimentation findings showed 100% patency rate in all groups. The combined and the continuous techniques were significantly faster and watertight compared with the simple interrupted. The only difference in pathology findings was the development of significant lumen stenosis in vein anastomoses performed with the continuous technique, compared with the other two techniques. The combined technique was clinically used in 16 free flap transfers and ensured 100% patency in all arterial and vein anastomoses, as well as survival of all flaps. In conclusion, the combined technique was found to be fast and easy to perform and ensured the same patency rate as the simple interrupted and continuous techniques. It also diminished the lumen stenosis effect of the continuous technique in vein anastomoses. Therefore, we suggest its use in both experimental studies and clinical cases.     

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.     

Comparison of anastomotic suturing techniques in the rat esophagus.

BACKGROUND: Long-gap esophageal atresia continues to be a challenging pediatric thoracic surgical problem. Despite the use of various tension relieving procedures, the esophageal anastomosis is often performed under considerable tension. Excessive tension can cause anastomotic sutures to pull through the esophageal tissue, with resultant early esophageal anastomotic dehiscence. To test the hypothesis that interrupted horizontal mattress sutures would withstand the forces of tension better than interrupted simple sutures, an experimental study of rat esophageal anastomoses was done. METHODS: Twenty rats were killed and their esophagi were excised. The esophagi were divided in the mid portion and end-to-end anastomoses were done using interrupted 6-0 polypropylene sutures. Ten rats had anastomoses done with interrupted simple sutures and ten had interrupted horizontal mattress suturing. Anastomotic breaking strength was tested in a tensiometer. RESULTS: Anastomotic breaking strength was 3.22+/-0.56 N for the interrupted simple sutured anastomoses and 3.51+/-0.61 N for the interrupted horizontal mattress group (p=0.30). The difference was not significant. CONCLUSIONS: In this animal study interrupted simple and horizontal mattress suturing withstood the disruptive forces of anastomotic tension equally well.     

Growth of tracheal anastomoses in lambs. Comparison of PDS and Vicryl suture material and interrupted and continuous techniques

Tracheal anastomoses were performed in 19 lambs (mean age 4 weeks, mean weight 9.8 kg) to compare polydioxanone (PDS) and polyglactin 910 (Vicryl) suture material (Ethicon, Inc., Somerville, N.J.) and simple continuous and simple interrupted suture technique. Each animal had two anastomoses with full-thickness bites for both suture techniques. Animals were killed at 4 months (n = 6) or 8 months (n = 5). Eight animals died before they were scheduled to be put to death (mean 6 weeks postoperatively). Transverse sections of the trachea were taken at the level of the anastomoses and three tracheal rings above and below each anastomosis. The cross-sectional area of the tracheal lumen of these transverse sections was measured with a computerized digitizing tablet. A percent luminal area for each anastomosis was calculated relative to the mean tracheal area three rings above and three rings below the anastomosis. There was little difference between interrupted and continuous technique with either suture material (p = 0.94). In 10 animals that each served as its own control for suture material, PDS anastomotic area was 55.0% +/- 4.1% of mean tracheal luminal area compared with 45.4% +/- 7.1% for Vicryl anastomoses (p = 0.06). Histologic analysis revealed a more intense inflammatory reaction surrounding multifilament Vicryl sutures with more rapid resorption and greater subsequent fibrosis relative to the reaction seen with PDS sutures. A small clinical experience with seven infants has confirmed short-term satisfactory clinical performance of continuous PDS suture for tracheal anastomosis.     

Suture technique and para-anastomotic compliance

We previously described a para-anastomotic hypercompliant zone (PHZ), located 3 to 4 mm from end-to-end continuous anastomoses in canine femoral arteries, in which arterial compliance first increases approximately 50% above adjacent reference values before falling to a minimum at the anastomosis. To determine if PHZ is affected by suture technique, 16 interrupted and 21 continuous end-to-end anastomoses were studied. Pulsed ultrasound was used to obtain detailed longitudinal profiles of compliance and diameter vs. distance, at 1 mm intervals within a 2 cm region centered at the anastomoses. Both compliance and diameter at the anastomosis were lower in continuous compared with interrupted anastomoses (p less than 0.003). The PHZ was present in 86% of continuous but in only 50% of interrupted anastomoses (p less than 0.03). The site of peak compliance averaged 3.8 +/- 1.2 mm from the anastomosis and was independent of suture technique. The increase in peak compliance at the PHZ, when normalized to adjacent references values, was the same in continuous and interrupted anastomoses. PHZ augments any preexisting compliance mismatch between artery and graft, which may contribute to the development of para-anastomotic subintimal hyperplasia. Interrupted anastomoses, which create a smaller compliance mismatch than do continuous and have a lower incidence of PHZ, may be preferred in certain settings.     

Comparative study of microepineurial anastomoses with the use of CO2 laser and suture techniques in rat sciatic nerves: Part 1. Surgical technique, nerve action potentials, and morphological studies

The possibility of utilizing the CO2 laser for neural anastomoses was investigated in a rat sciatic nerve model. One nerve in each animal was acutely divided and anastomosed using 10-0 nylon epineurial sutures, while the opposite side was joined by "welding" the opposed nerve ends together with CO2 laser pulses. The surgical incisions were reexplored 60 days postoperatively, action potentials were recorded across the anastomoses, and the nerves were removed for light and electron microscopy. The operative patency rate in the suture group was 100%, compared to 87% in the laser group. Among those animals with bilaterally intact nerves, action potentials could be recorded across the anastomotic site in 78% of the sutured preparations and in 85% of nerves spot-welded with the CO2 laser. Morphological studies showed a greater degree of scar tissue formation and constriction in the anastomotic zone of the nerves joined by sutures than was present in laser-treated animals. We believe these preliminary observations suggest that the CO2 laser may have a role to play in peripheral nerve surgery. Further study of this technique is warranted.