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

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

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

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

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.     

Usefulness of combined continuous suture and interrupted tie technique in hindlimb composite tissue allotransplantation in rats

According to our experience of over 100 hindlimb transplantations, in rats, catching the posterior wall with an anterior wall suture is the most common cause of thrombosis and acute transplant failure. It is generally due to inadequate visibility of the lumen and consequent blind suture placement. With an intention to find a superior suture technique, a comparative study between standard end-to-end interrupted and combined continuous sutures and interrupted tie techniques was performed. Twenty hindlimb transplantations to rats' femoral vessels were performed in each group. Anastomosis time, patency, complications, and animal and transplant survivals were compared. In the interrupted suture group (group I), anastomosis failure was encountered in one vein, with 95% of immediate patency rate. A redo of the venous anastomosis was performed and successful. The combined suture technique (group II) had 100% patency rates without complications. The average time for arterial anastomosis in groups I and II was 8.5 and 8.9 min, and for venous anastomosis, 10.7 and 9.6 min, respectively. At 2 weeks, no differences were found between groups as related to transplant and animal survival.     

Classification and comparison of five techniques of end-to-end microarterial anastomoses in rats: A new proposed technique

We propose a new classification of five main techniques for microarterial anastomoses: interrupted, autogenous cuff, continuous, sleeve and partial sleeve. The last method was developed by the authors. A study was performed on 48 albino rats and comprised 20 anastomoses of each type (for a total of 100), performed on femoral and carotid arteries of average size 0.83 mm. These were compared with respect to patency, anastomosis time, leak, bleeding time, number of sutures (bites), microangiography, histopathology and scanning electron microscopy. The overall patency was 88%, and that of the partial sleeve technique was 100%, associated with 30% incidence of aneurysms. Clinical, histopathological and scanning electron microscopy findings showed better results for techniques with predominantly extraluminal sutures (sleeve and partial sleeve), which was particularly relevant in our situation, in which a larger sized needle (150 μm) had to be used. An overall aneurysm incidence of 17% was noted. © 1995 Wiley-Liss, Inc.     

In search of the "perfect" anastomosis

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

End-to-side-anastomosis in the dog using the 3M precise microvascular anastomotic system: a comparative study.

In this study, the patency rates, microscopic characteristics, and intraluminal dimensions of end-to-side anastomoses in the dog were compared with those of a conventional interrupted suturing technique, using the 3M precise microvascular anastomotic system. The anastomoses included end-to-side repairs of the saphenous artery to the femoral artery, as well as the saphenous vein to the femoral vein. The patency and microscopic characteristics of the two techniques were similar, but the mechanical coupling system required much less time than the suture technique to complete the vascular anastomosis.     

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.     

From simple interrupted to complex spiral: a systematic review of various suture techniques for microvascular anastomoses

Accomplishing successful microvascular anastomoses is undoubtedly one of the most critical steps in performing free tissue transfer. However, the ideal technique has often been a subject of debate. Therefore, our objective was to review the current literature in an attempt to find objective evidence supporting the superiority of one particular technique. A PubMed and OVID on-line search was performed in November 2007 using the following keywords: microvascular anastomoses, microsurgical anastomosis, continuous suture, interrupted suture, mattress suture, and sleeve anastomosis. Our literature review found no difference in short- and/or long-term patency rates between the six main published techniques, which includes continuous suture, interrupted suture, locking continuous, continuous horizontal, horizontal interrupted with eversion, and sleeve anastomoses. These findings were consistent for each technique as long as the microsurgeon maintained standard microsurgical principles and practice, including suture line eversion, minimized tension, and direct intima-to-intima contact. Current literature supports no overall statistical difference in short- and/or long-term patency rates between any of the various techniques. The choice to perform one suture technique over another ultimately depends on the plastic surgeon's preference and microsurgical experience. To date, there are no human randomized, controlled clinical trials comparing the efficacy and clinical outcomes of each of the various suture techniques, and therefore one's comfort and familiarity should dictate his or her microsurgical technique. However, "exposure to many and mastery of one" simply provides the plastic surgery resident, fellow, or staff the technical flexibility needed for less-complicated surgical planning when performing free tissue transfer.     

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.     

Comparison of the telescoping anastomotic technique with the end-to-end technique utilizing vein grafts for venous defects: Short- and long-term results

The telescoping anastomotic technique was used for both anastomoses of vein grafts placed in the rat left epigastric vein in an effort to make the anastomosis easier and faster. Vein grafting in the right epigastric vein was completed using the conventional technique. The 20 rats with 20 left and 13 right vein grafts, which were patent at 3 weeks, were seen again 3 months postoperatively to compare the two techniques with regard to long-term stenosis and histological changes. Patency of the grafts 2 hr postoperatively was also compared between the two techniques in another 25 rats to eliminate the influence of recanalization on patency. All the vein grafts, which had been patent 3 weeks postoperatively, remained patent after 3 months and no statistically significant difference was found between the telescoping and conventional technique in the degree of stenosis. The vein grafts 2 hr postoperatively were all patent in both groups. © 1995 Wiley-Liss, Inc.     

Absorbable polydioxanone suture for venous anastomoses: experimental studies using venography and transluminal angioscopy

Because of their increased tendency to stenosis and spasm and thrombosis, results after venous anastomoses are often unsatisfactory. Nonabsorbable sutures and a continuous suture technique have been suggested to have a negative effect on the compliance of vascular anastomoses. Eighty venous anastomoses were performed with either an interrupted or continuous suture technique, using polypropylene or polydioxanone (PDS) sutures, according to a randomised experimental model. The anastomoses were divided in four groups: (1) Nonabsorbable suture material, continuous suture technique; (2) Nonabsorbable suture material, interrupted suture technique; (3) Absorbable suture material, continuous suture technique; and (4) Absorbable suture material, interrupted suture technique. The morphology of the anastomoses was controlled by venography directly after closure of the wound and at weekly intervals for 2 months and monthly intervals thereafter until 2 years had passed. In 10 cases venography was followed by transluminal angioscopy in the early postoperative period and after 1, 2, 4, 8 and 12 weeks. In the first 2 months moderate and high degree stenoses were found in all 4 groups by venography. After 8 weeks there was a significant decrease in the incidence of stenosis in all groups with the exception of the group, in which continuous nonabsorbable suture had been used. Using angioscopy a marked swelling of the intima at the site of the anastomoses could be detected in the early postoperative period in all experimental groups. After 2 months no significant narrowing could be identified in groups 2, 3 and 4.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of suture technique on blood velocity waveforms in the microvascular anastomosis of autogenous vein graft

In using autogenous vein grafts in microvascular surgery, maintenance of compliance at the site of anastomosis is of importance in achieving patency. Using high-frequency, 20 MHz, pulsed Doppler ultrasonography to monitor blood flow velocity through the vein graft, we have evaluated the effects of continuous and interrupted suture technique on anastomotic compliance in vessels less than 1.5 mm in diameter. In 15 dogs, 15 procedures of each technique, using the continuous technique in one limb and the interrupted technique on the contralateral limb, patency rates for both techniques, documented by arteriography, are 100% at a mean follow-up of 11 weeks. There were no significant differences in the blood velocity profile and pulsatility proximally, distally, and at the graft site between continuous and interrupted technique. This study confirms the suggestion that autogenous vein graft has sufficient elasticity to maintain normal arterial blood velocity waveforms.     

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.     

Internal configuration of saphenous-coronary anastomoses as studied by the cast-injection technique.

A study of the internal configuration of saphenous vein--to--coronary artery anastomoses was undertaken to examine the effect of technical factors. One hundred fifty anastomoses were constructed in isolated swine hearts and epoxy-resin casts were made of the anastomoses by pressure-injection. The effects of interrupted sutures, continuous suture, vein tailoring, vein-to-artery size ratio, and end-to-side and side-to-side anastomoses were evaluated. We made several observations: (1) The external appearance of an anastomosis is not a reliable indicator of internal configuration. (2) Interrupted suturing consistently produces an internal configuration with minimal deformity. (3) Unless special precautions are taken with continuous suturing, severe deformities may occur. Very fine suture spacing and knotting distal corner sutures are recommended. (4) Proper vein-to-artery size ratio and "cobra-head" vein tailoring are desirable. (5) Side-to-side anastomoses are similarly significantly affected by suture techniques, vein graft size, venotomy size, and orientation. The study of the internal configuration of saphenous-coronary anastomoses is a simple and readily available method which should be useful to all coronary surgeons in assessing and perfecting their techniques.     

Improving the patency of vascular bypass grafts: the role of suture materials and surgical techniques on reducing anastomotic compliance mismatch.

BACKGROUND: compliance mismatch is an important factor in the development of myointimal hyperplasia in both coronary and vascular anastomoses. This mismatch may be reduced by the use of newer suture materials and techniques. This review discusses the current techniques and materials used to date in generating anastomoses in both coronary and vascular applications and to correlate these with the degree of inherent compliance achieved. METHODS: PubMed, ISIS, CAS and PAS database searches were performed. Other articles were cross-referenced. RESULTS AND CONCLUSION:continuous suture is still the most used technique in both cardiac and vascular surgery for the generation of anastomoses due to the reduced time and improved haemostasis. However, continuous suture results in a greater compliance mismatch than the interrupted technique. Vein cuffs and patches improve compliance and transmission of pulsatile blood flow and offer improvement of graft patency. Alternative to sutures are biological glue, clips and laser generated solders all of which have shown promising results, but further work is required before they become applicable for routine use.     

The interrupted-continuous microsurgical suture technique.

Interrupted microsurgical sutured anastomoses are the standard to which all new anastomotic techniques must be compared. In 1902, Alexis Carrel described a continuous suture technique for large vessels that initially triangulated the anastomosis with three stay sutures. Our technique is a modification of Carrel's original technique combined with other previously published microvascular methods. This is an attempt to address the inherent problems associated with the standard interrupted technique and previously described continuous suture techniques.     

Surveillance of in situ infrainguinal bypass grafts: conventional vs. color flow duplex ultrasonography

Surveillance of in situ saphenous vein bypass grafts with duplex scanning detects graft abnormalities which may lead to graft thrombosis. Correction of these defects, while grafts are still patent, potentially improves overall graft patency. In this study we compared color flow and conventional duplex to determine whether color flow provided additional information not obtainable by conventional duplex examination. The primary patency rate (patency maintained without intervention) for all 51 cases was 76% (39/51). The secondary patency rate (patency maintained by identification and correction of graft defects before failure) was 88% (45/51). Duplex scanning reduced the graft failure rate by 50%. Color flow and conventional duplex examination provided the same information regarding incipient graft failure. In 20 patients monitored with both techniques, the same number of proximal (100%) and distal (90%) anastomoses were imaged. The same number of graft defects (three vein graft stenoses, one proximal femoral artery stenosis) were identified. Velocity data obtained using the two techniques (peak systolic velocity in an area of stenosis and the duplex velocity ratio) were not always the same, making calculation of percent stenosis from this data inaccurate. Color flow duplex is useful in monitoring graft patency, but provides no additional information over that provided by conventional scanning.     

Combined microvascular anastomosis: experimental and clinical experience

A short operative time and a high successful rate of microvascular anastomosis are the goals of many plastic surgeons. The authors present their experimental and clinical experience in microvascular anastomoses with the use of a combination of continuous suture and interrupted tie. Twenty rats were divided into two groups. The aorta and inferior vena cava were used for microvascular anastomoses. The vessels of 10 rats were repaired with conventional interrupted suture, and the vessels of the other 10 rats were repaired with combined anastomoses. A total of 150 clinical microvascular surgeries during the past 2 years are also presented, all of which were performed using the combined method. Microvascular anastomoses with the combined method were completed faster than when using the conventional interrupted method in experimental studies. Clinically, no direct microvascular anastomosis failed with the use of combined method. Microvascular anastomosis with the use of the combined continuous suture and interrupted tie resulted in satisfactory outcomes. This technique has the advantages of both interrupted and continuous methods, but not their shortcomings.     

A new microvascular "sleeve" anastomosis

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