Microvascular Anastomosis Technique Research Articles

Experimental Study of L-shaped Silastic Stents for Microvascular Anastomosis.

Background: The stent technique of microvascular anastomosis, in which a stent is placed in the vessel before creating the anastomosis, is useful for accurate anastomosis formation, but the manipulation involved in stent insertion into the vessel and withdrawal from the anastomosis still poses problems. In this study, a silastic stent containing a copper wire-bent in an L-shape was designed and its utility in microvascular anastomosis was investigated in rats. Methods: Eighty end-to-end anastomosis procedures of the right femoral artery and vein were performed in rats. Anastomoses were conducted either by the conventional method (Method C) or using L-shaped silastic stents (Method L), with anastomosis condition assessed after one side had been sutured, at the completion of vascular anastomosis and on postoperative day 7. Results: After one side had been sutured, suture errors were observed in three veins with Method C. At the completion of vascular anastomosis, impaired blood flow was observed in two arteries and two veins with Method C, and in one artery with Method L. On postoperative day 7, impaired blood flow was observed in one artery and one vein with Method C and in one vein with Method L. Conclusions: The use of L-shaped silastic stents preserved the advantages of the stent technique while simplifying stent manipulation. This technique may help reduce the risk of intimal trauma.

Supermicrosurgery: past, present and future.

Supermicrosurgery was popularised in 1997 and is defined as a technique of microvascular anastomosis for single nerve fascicles and vessels 0.3-0.8 mm in diameter. It requires the use of powerful microscopes, ultradelicate microsurgical instruments and specialist dyes. The development of supermicrosurgery has vastly improved the ability of microsurgeons to create true perforator flaps with minimal donor site morbidity for reconstructive surgery and improved the precision of additional microsurgical techniques. This review outlines the origins and history of supermicrosurgery, its current applications in reconstructive surgery (including fingertip reconstructions, true perforator flap surgery, nerve flaps and lymphoedema surgery), supermicrosurgery training and future directions for the field.

The Impact of Venous Anastomosis Technique on Outcomes of Free Tissue Transfer to the Head and Neck.

Objectives: To evaluate the impact of different techniques of microvascular venous anastomosis on the outcome of free tissue transfer to the head and neck. Methods: Retrospective case series of patients undergoing microvascular free tissue transfer (MFTT) from January 2006 to September 2021. Chi-square tests and t-tests were utilized to identify differences in flap outcomes by technique, and log-binomial regression analyses were utilized to identify differences in flap outcomes by technique. Results: A total of 1055 consecutive MFTTs were analyzed. One hundred four cases required a return to the operating room for any reason, and 19 were attributed to venous compromise (18.0%). Ultimately, there were 22 FTT failures requiring complete revision (2.1%). In total, 1055 MFTTs involved 1352 venous anastomoses, ranging from 1 to 3 anastomoses in each case. End-to-end (ETE) was used 1040 times (76.9%) and end-to-side (ETS) 204 times (15.0%). The calculated risk ratio for venous complication for ETS compared with ETE was 1.17 (0.34-3.98). A microvascular coupler was used in 355 cases (33.6%). The calculated risk ratio for coupler compared with suture anastomoses was 0.92 (0.35-2.39). Conclusions: There were no significant difference in regard to outcomes of MFTT when comparing ETE with ETS, nor when comparing coupler with suture anastomoses.

The Multiple-U Technique: A Novel Microvascular Anastomosis Technique That Guarantees Everted Anastomosis Sites with Solid Intima-to-Intima Contact.

The key to successful microvascular anastomosis is achieving intima-to-intima contact, which is not always easy. In this article, the authors propose the multiple-U technique, which is a novel microvascular anastomosis technique that characterizes easy and reliable intima-to-intima contact. The technique was performed on patients who underwent free flap reconstruction for head and neck defects at the Kaohsiung Chang Gung Memorial Hospital from September 1, 2020, to November 30, 2020. The immediate patency test results for all vessel anastomoses were positive, and the postoperative recovery courses of the patients were without any vascular complications. In conclusion, the multiple-U technique is a widely available technique that guarantees everted anastomosis sites and solid intima-to-intima contact. This technique can be performed on both arterial and venous anastomoses regardless of vessel size and wall thickness.

Needle Parking Interrupted Suturing Technique for Microvascular Anastomosis: A Technical Note.

Interrupted and continuous suturing are 2 common techniques for microvascular anastomosis in cerebrovascular surgery. One of the technical complexities of interrupted suturing includes the risk of losing the needle in between interrupted sutures during knot tying, which may result in unnecessary movements and wasted time. To report a new needle parking technique for microvascular anastomosis that addresses a needle control problem during interrupted suturing. The needle parking technique involves puncturing both vessel walls at the site of the next provisional suture and leaving the needle parked in place while the knots at the first suture are being made. The thread is then cut, the needle is pulled through, and the process is repeated. Illustrative cases in which the needle parking technique was used are presented. We also compared time of anastomosis completion between the conventional interrupted, needle parking interrupted, and continuous suturing techniques during an in vitro study on standardized artificial vessels. This technique is being used successfully by the senior author for various cerebrovascular bypass surgeries. The in vitro study demonstrated that the needle parking technique can be significantly faster than the conventional interrupted suturing technique and may be as fast as continuous suturing. Needle parking technique is a modification of conventional interrupted suturing and solves the problem of losing the needle during knot tying. This technique is simple, prevents unnecessary movements, and may result in a faster anastomosis time.

Toe-First Technique for End to Side Microvascular Anastomosis

The use of the classic 2-ends anchoring technique is common in end-to side (ES) microvascular anastomosis. The literature on the toe-first (TF) technique is limited. In the current study we present the successful outcomes with the TF technique in ES anastomoses in rat femoral vessels model. ES microvascular anastomosis with the tf technique was performed in the femoral vessels of 10 Sprague Dawley rats. Two-throw reef knot interrupted sutures were used in all cases. Individual parameters during the procedure were recorded for analysis. The immediate and delayed (cut open technique after 2 weeks) patencies were confirmed. An illustrative case showing the use of this technique in superficial temporal artery to middle cerebral artery bypass in a pediatric moyamoya disease case is included. The average suturing time was 40.14 ± 5.30 minutes, the procedures were completed with an average of 14.57 ± 1.90 sutures. The average time per suture was 2.78 ± 0.43 minutes. The immediate patency was 100% (10 of 10 cases). Two rats died of unknown cause in the observation period. The delayed patency was 100% in the remaining 8 cases (average observation: 29.6 days). The TF interrupted suture technique of ES microvascular anastomosis with 2-throw reef knots is feasible with excellent immediate and delayed patency rates. The distinct advantages of the TF are the continuous visualization of the recipient lumen during anastomoses, avoiding back-wall bites, and the ability to correct any discrepancy in the recipient-donor lumens during the procedure.

Training model for the intraluminal continuous suturing technique for microvascular anastomosis

Microvascular anastomosis is a critical procedure in cerebral bypass surgeries. In some rare cases, the extraluminal interrupted technique is not optimal because the vessels are immobile and cannot be rotated, and anastomosis can be performed effectively through the intraluminal continuous suturing technique. The authors reported the application of the intraluminal continuous suturing technique in microanastomosis training with silicone tube, rat’s common iliac arteries and abdominal aorta. A silicone tube with a diameter of 1.5 mm was used to practice microanastomosis in intraluminal continuous suturing technique. Then the technique was applied in side-to-side, end-to-side anastomoses of common iliac arteries and the end-to-end abdominal aorta anastomoses of rat. The suturing time and patency rates were compared with an alternative intraluminal continuous suturing technique and one-way-up interrupted suturing technique in silicone tube and rat vessel anastomoses. The intraluminal continuous suturing technique could be gained through practicing with silicone tube, and the technique has also been demonstrated effective in side-to-side, end-to-side anastomoses of common iliac arteries of rat and the abdominal aorta end-to-end anastomoses. In all the animal experimental groups with different suturing techniques, there was no difference between the patency rates, all the immediate patency rate was 100%. There was no significant suturing time difference between the two intraluminal continuous suturing techniques, but the two intraluminal continuous suturing techniques were faster than the interrupted technique. The intraluminal continuous suturing technique described in the study could be used as an efficient method for side-to-side, end-to-side and end-to-end anastomosis, especially under the situation the posterior wall of the anastomosis could not be rotated. Proficiency of the technique could be achieved through practicing in laboratory with silicone tube and live animals.

Techniques Useful in Complex Microvascular Anastomosis

The video presents a useful technique for microvascular anastomosis in reconstructive surgery of the head and neck. It is advantageous to use this series of sutures when working with limited space, weak vessels (vessels irradiated, or with atheroclastic plaques), suturing in tension, or suturing smaller vessels (less than 0.8 cm in diameter).

How to Perform a Safe, Quick, and Easy Suture Technique for Microvascular Anastomosis, Where a Single Surgeon Works Alone: The Parachute Technique.

How to Perform a Safe, Quick, and Easy Suture Technique for Microvascular Anastomosis, Where a Single Surgeon Works Alone: The Parachute Technique.

A Novel Approach Using a Silicone Tube to Assist Microsurgical Anastomosis Training in Animal Models

Authors discuss a silicone tube that provides structural support to vessels throughout the entire precarious suturing process. This modification of the conventional microvascular anastomosis technique may facilitate initial skill acquisition using the rat model.

Who needs extra time? Amniotic membrane wrapped pauci-suture model for rapid anastomoses*

An ideal anastomosis method will obtain the highest post-anastomotic vessel patency and will repair the vessel anatomically with minimal thrombosis in an easier, faster and cheaper fashion. To achieve these goals an anastomosis model using an amniotic membrane is introduced. The study was performed on the femoral arteries of 22 Wistar Albino rats (11 control group, 11 experimental group). In the experiment group, the microvascular anastomosis was completed with three sutures and a patch of amniotic membrane which was wrapped around the anastomotic site. The conventional anastomosis technique with eight sutures was performed in the control group. The effects of the model on the patency and histological structure of the vessels were evaluated. As a result, normal patency was determined radiologically and macroscopically in all of the anastomoses. No thrombosis or aneurysm was detected in any of the anastomoses. In the angiographic study, vessel patency was detected in both the control and experimental groups. The average time to complete the arterial anastomosis was 18.14 (±2.84) and 10.39 (±2.45) minutes in the control and the experiment groups respectively. In the histological studies, anti-eNOS staining revealed that endothelin levels were significantly higher in the experimental group. This method describes a new anastomosis model in microvascular surgery with promising results that call for additional experimental studies and further clinical implementations. We believe that this experimental technique can be put into clinical practice as an alternative to the conventional microvascular anastomosis technique.

A simple and novel technique for training in microvascular suturing in a rat model

Though microvascular clamps are widely used for anastomosis training, there still have several shortcomings, including the bulging, expensiveness and unavailability due to sterilization. The aim of this study is to introduce a simple and novel microvascular training model without use of microvascular clamps. Femoral vessels of Sprague Dawley rats training model were used to evaluate the usefulness of 4-0 silk as a slipknot for performing arterio-arterial and veno-venous microvascular anastomoses. A total of 12 Sprague Dawley rats were randomly assigned to either slipknot group or vascular clamp group. We also assess other endpoints, including ischemic time, patency rate, and clinical features. An additional histological study was performed to compare their immediate traumatic effects on vessel wall. There was no ischemic change or congestive sign in the lower limb after microvascular anastomosis. The total warm ischemic time for the vascular anastomosis was not significantly different. We performed the patency test immediately after microvascular anastomosis and one week after surgery. No intraoperative vascular bleeding was found during these procedures and no thrombosis occurred postoperatively. The histologic damages to occluded area were not significantly different in both groups. We demonstrate a microsurgical suture technique performed without any vascular clamp on a rat model. This rat model was designed for training in the technique of microvascular anastomosis. Compared with microvascular clamps, silk slipknot is a cheap, easily available, less space-occupying technique while performing microvascular anastomoses training. This preliminary study provides a simple and effective alternative method for microvascular anastomosis training.

Sutureless microvascular anastomosis assisted by an expandable shape-memory alloy stent.

Vascular anastomosis is the highlight of cardiovascular, transplant, and reconstructive surgery, which has long been performed by hand using a needle and suture. However, anastomotic thrombosis occurs in approximately 0.5–10% of cases, which can cause serious complications. To improve the surgical outcomes, attempts to develop devices for vascular anastomosis have been made, but they have had limitations in handling, cost, patency rate, and strength at the anastomotic site. Recently, indwelling metal stents have been greatly improved with precise laser metalwork through programming technology. In the present study, we designed a bare metal stent, Microstent, that was constructed by laser machining of a shape-memory alloy, NiTi. An end-to-end microvascular anastomosis was performed in SD rats by placing the Microstent at the anastomotic site and gluing the junction. The operation time for the anastomosis was significantly shortened using Microstent. Thrombus formation, patency rate, and blood vessel strength in the Microstent anastomosis were superior or comparable to hand-sewn anastomosis. The results demonstrated the safety and effectiveness, as well as the operability, of the new method, suggesting its great benefit for surgeons by simplifying the technique for microvascular anastomosis.

Use of couplers for vascular anastomoses in 601 free flaps for reconstruction of defects of the head and neck: technique and two-year retrospective clinical study

We describe our experience with the use of 854 couplers for venous or arterial anastomoses, or both, in 601 free flaps for reconstruction of defects of the head and neck. We reviewed 601 patients who had had free flaps (with the microvascular anastomoses being made with couplers in 519) between July 2013 and December 2015. Personal details, and clinical data including the site of the defect, the tumour excised, the types of flaps, the size of the couplers, the method of anastomosis (venous or arterial) in which the coupler was used, and postoperative complications were recorded. There were 417 men (69%) and 184 women (31%), mean (range) age 53 (13–91) years. Four types of flaps were used: anterolateral thigh flap (n=232), radial forearm flap (n=223), fibula free flap (n=78), and iliac crest flap (n=68). The sizes of couplers ranged from 1–4mm, most being 2mm (n=158), followed by 1.5mm (n=122). The recipient vessels used included a single vein (n=348), two veins (n=406), and both vein and artery (n=100). The overall success rate was 99%, and eight patients required resuture, which was successful in each case. This retrospective study shows that a coupler is easy to use, and is a reliable and time-saving technique for microvascular anastomosis. However, the disadvantage is the cost of the instrument, which in less developed countries will limit its use.

A Comparison of the Minimal-Touch Technique and the Eversion Technique for Microvascular Anastomosis in a Rat Model

Background During microvascular anastomosis, needle placement is facilitated by inserting the tips of the forceps into the lumen of the vessel, rather than grasping and everting the luminal wall, to minimize trauma to the vessel. This study examines whether the vessel wall can be grasped and everted during microvascular anastomosis without compromising surgical outcomes. Methods A total of 20 Sprague-Dawley rats weighing between 252 and 483 g were used. Bilateral anastomoses of the animals' femoral arteries (mean size: 0.90 mm) were performed using two different techniques: the classic minimal-touch approach and the eversion technique. The first 10 animals were survived for 48 hours and the second 10 animals were survived for 2 weeks. Patency was assessed immediately after surgery and just before sacrifice. Hematoxylin and eosin stains were performed and each anastomosis scored according to a grading rubric assessing endothelial cell loss, neointimal proliferation, medial necrosis, adventitial inflammation, and inflammation thickness. Results The patency rates of both techniques were identical (100%). There was no difference in the patency rates of anastomoses evaluated 48 hours after surgery (100%) and 2 weeks after surgery (100%). Histological outcomes between the minimal-touch technique and the eversion method were similar. The thickness of adventitial inflammation at 2 weeks was the only outcome found to be statistically different (p = 0.046) between the two treatments and this difference favored the eversion technique (i.e., less inflammation thickness). Conclusion The eversion method of performing microvascular anastomosis provides comparable results to the classic minimal-touch approach in rat femoral artery anastomoses.

The microsurgical training programme in Gothenburg, Sweden: early experiences

Objective: Microsurgical techniques are increasingly used in routine surgical practice as well as in biomedical research. The training opportunities at standardised training courses are limited, and no microsurgical training facility or programme existed in Scandinavia before 2013.Methods: A microsurgery laboratory was set up and two different courses were started, aiming separately at biomedical researchers and surgeons. The course for biomedical researchers teaches basic microsurgical skills such as vessel isolation, cannulation, and arterial microvascular suture under magnification. The more advanced course for surgeons focuses on various techniques of microvascular and nerve anastomosis. Both courses use a combination of theory and practice, with emphasis on the practical part, the course for surgeons also includes clinically relevant information.Results: Twelve 5-day courses using both non-living models and exercises on laboratory animals have been conducted and attended by 49 researchers and 44 surgeons. The organisation and the programme of the training courses as well as ‘The 4E concept’ behind the course (educational curriculum, equipment, ergonomy, and evaluation) are further detailed.Conclusions: We have successfully established the first training laboratory and series of microsurgical training courses in Scandinavia at two different levels. The experience from the first 12 courses shows the need for this type of structured training, and confirms that the microsurgical education curriculums needs to be adapted to participants’ prerequisites and expectations, and various difficulty levels should be considered.

Effect of Microvascular Anastomosis Technique on End Product Outcome in Simulated Training: A Prospective Blinded Randomized Controlled Trial.

Background The aim of this article is to evaluate the difference in skills acquisition of two end-to-end microvascular anastomosis techniques-the triangulation and biangulation-in early microsurgery training. Method In this study, 32 candidates ranging from medical students to higher surgical trainees underwent a 5-day basic microsurgery course. On days 3 and 5 of the course, candidates performed two end-to-end anastomoses on cryopreserved rat aortas. One anastomosis was performed using the biangulation technique and the other using the triangulation technique. Candidates were randomized to the order of technique performed. Structural patency, errors performed, and suture distribution were evaluated randomly by a blinded reviewer using the anastomosis lapse index score and ImageJ (U.S. National Institutes of Health, Bethesda, MD) Software. Results A total of 128 anastomoses were evaluated during the study period. A total of six anastomoses performed with the biangulation technique, and four anastomoses with the triangulation technique, were physically occluded on day 3 of the course. On day 5, two biangulation technique anastomoses and one triangulation technique produced a nonpatent outcome. There was a statistically significant difference of patency rate between the 2 days of evaluation confirming evidence of skill acquisition but no statistically significant difference between the two techniques in relation to anastomotic patency, errors performed, or suture placement quality. Conclusion The biangulation and triangulation techniques of microvascular anastomosis produce similar outcomes in relation to vessel structural patency and quality of anastomosis when taught in early stages of microsurgery training. Our results suggest that both techniques are equally suitable in training novices, basic microsurgical skills.

A Secure Technique for Microvascular Anastomosis in Arteries with Intimal Dissection: Intimal Sleeve Fold-Over Technique.

Intimal dissection can cause an irregular internal surface with intimal flaps and subendothelial collagen exposure. This has been associated with a high risk of thrombosis. Trimming the artery to a healthy level is routinely recommended to avoid intimal dissection. However, this method is limited when there is inadequate vascular length to work with. We dealt with an artery exhibiting severe intimal dissection by using a new suture technique: the intimal sleeve fold-over technique. Severe arterial intimal dissections were observed in 9 (6.9%) of 130 arterial microvascular anastomoses in free flap reconstruction for oral cancer patients from January 2013 to December 2013. We used this technique in 6 of the 9 patients. All 6 patients were discharged as scheduled without perioperative problems and complications during follow-ups. The mean diameters of the recipient and pedicle arteries with intimal dissection were 2.13 and 2.20 mm. The mean time for performing sleeve fold-over procedure of on each artery was 5.1 minutes. A secure intima-to-intima contact can be achieved using this technique. This technique can provide an alternative method to intimal dissection when the length of the artery is limited.

The "Rolled-Up Sleeve" Technique for Microvascular Venous Anastomosis in Head and Neck Reconstruction: Animal Study and Clinical Series.

Venous anastomosis is challenging especially when encountering the thin recipient vein wall in the head and neck region. The authors developed the "rolled-up sleeve" technique to solve this scenario. An animal study was performed to access the safety and reliability of the "rolled-up sleeve" technique. This technique was performed in 53 consecutive patients during head and neck reconstruction. In the animal study, all anastomoses were patent. Histological analysis revealed neo-endothelialization over the anastomotic site. This technique was applied to 59 recipient veins: branch of internal jugular vein (27), external jugular vein (17), superficial temporal vein (9), retromandibular vein (4), facial vein (2), and internal mammary vein (2). No venous thrombosis occurred in these clinical series. The "rolled-up sleeve" technique is a useful procedure that can be performed safely to deal with thin vascular walls for venous anastomoses in head and neck reconstructions.

Microvascular stent anastomosis using N-fibroin stents: feasibility, ischemia time, and complications

To evaluate a novel microvascular anastomosis technique using N-fibroin stents. Cylinder stents of 1mm diameter and 5mm length were fabricated using N-fibroin from silkworms. In 22 rats, aortas were dissected, and the stent was inserted into the two ends of the aorta and fixed using methylmethacrylate. Stent anastomosis was successful in 21 (96%) rats. The mean ischemia time was 7.4minutes, significantly shorter than the 15.9minutes in the control group with conventional sutures (P<.0001). After 4months, anastomosis was functionally patent in all cases. However, elastic fibers remained interrupted in all stent anastomosis cases, and marked host rejection was evident at the stent anastomosis sites. Around the stents, thrombi were frequent (52%). Our study demonstrated the basic feasibility of stent anastomosis using N-fibroin stents and reduced ischemia time. However, thrombus formation, frequent and severe abdominal infections, and heavy host rejection remain critical issues.