Clinical experience with the Unilink/3M Precise microvascular anastomotic device

The Microvascular Anastomotic Coupler for Venous Anastomosis in Head and Neck Reconstruction: An Institutional Experience

Background This study aimed to identify outcome predictors with the GEM microvascular coupler system (GEM Coupler) in a series of patients undergoing free flap reconstruction for head and neck defects. Methodology In this retrospective chart review of 218 consecutive microvascular procedures performed on 204 patients at an academic tertiary care center, demographics, comorbidities, surgical data, and outcomes were retrieved. The endpoints for the analysis were microvascular revision surgery and flap survival. Results The study included 142 (70.2%) males and 62 (29.8%) females, with a mean age of 56 years, primarily treated for malignancy (76%). The anterolateral thigh and fibula were the most commonly used flaps (40.4% and 27.1%, respectively). In 21 (9.6%) cases, a double venous anastomosis was performed. There were nine flap failures requiring microvascular revision surgery; the flap was salvaged in four of these cases yielding an overall success rate of 97.7%. Factors associated with total flap loss included a history of a thrombotic or embolic event (p = 0.017), deep circumflex iliac artery flap (p < 0.001), and absence of monitoring skin paddle (p < 0.001). Conclusions Prothrombotic conditions, buried flaps, and flap type are outcome predictors in patients undergoing microvascular reconstruction with GEM Coupler.

Exploring the supremacy of microvascular coupling devices for arterial anastomosis in terms of added expeditiousness, safety concerns: A systematic review

Background

Arterial anastomoses are still most commonly performed using orthodox hand sewing technique. Various rationale such as non-pliable, atherosclerotic, thick-walled or irradiated vessels limit the competency of coupler devices for arterial micro-anastomosis. Microvascular coupling devices (MCD) are well known for venous anastomoses but arterial MCD have relatively been less navigated in reported literatures. This review outlines the current applications, troubleshooting, safety and efficiency of arterial MCD in free flaps.

Methods

Comprehensive search of electronic databases (PUBMED/MEDLINE) in accordance with PRISMA guideline was performed. Data were extracted and collected in four groups of standardised variables.

Results

Out of a total of 263 identified articles, 38 studies were analysed and 16 amidst these were included in final data synthesis. Included studies contained a combined total of 2416 patients who went through 521 arterial and 2460 venous anastomoses using 3 M/Synovis coupling devices. Among all coupled arterial anastomoses, 407 were conducted in head and neck free tissue transfer and 114 were performed in breast reconstruction. The aggregate coupled arterial micro-anastomosis success rate reported was 90.01 % (469/521). Only 9.98 % (52 out of 521) manifested pooled incidence of troubleshooting, thrombosis or flap failure.

Conclusion

Microsurgeons are resisting the frequent use of arterial coupling devices owing to inherent arterial characteristics, but with suitable vessel selection, arterial coupling may be a powerful tool and can be executed in safe, expeditious and reliable fashion. This study embellishes collaborative suggestions and troubleshooting issues related to arterial coupling, however further assessment would be required with controlled trials.

Applying the Microvascular Anastomotic Coupler Device to End-to-side Venous Anastomosis in Reconstructive Surgery

Background:

Microsurgical vascular anastomosis plays an important role in successful free-tissue transfer. The Microvascular Anastomotic Coupler Device (MACD) aims to simplify anastomosis and decrease the time spent on this step, thereby reducing surgeon stress and improving the overall quality of the surgery, especially when venous end-to-side anastomosis is required. Our comparative retrospective cohort study aimed to determine the effect of this widely used device on anastomosis times and complications in head and neck/esophageal reconstruction cases involving venous end-to-side anastomosis using the internal jugular vein as the recipient vessel.

Methods:

All consecutive patients who underwent head and neck/esophageal reconstruction with hand-sewn or MACD-mediated venous end-to-side anastomosis using the internal jugular vein by three experienced microsurgeons in our tertiary-care hospital in 2012–2020 were identified. Venous anastomosis times and venous trouble cases were recorded.

Results:

Of the 191 cases, 44 and 147 underwent hand-sewn and MACD-mediated anastomosis respectively. The average venous anastomosis times of these groups were 31 and 11 minutes, respectively. Venous trouble was observed in two hand-sewn (4.5%) and four MACD (2.7%) cases, respectively. Vein twisting and improper coupler placement were the causes in the latter four cases.

Conclusions:

This study confirmed that MACD simplifies end-to-side venous anastomosis and reduces the time spent on this procedure. Also, for safer anastomosis, it is necessary to pay attention to preventing twisting and improper coupler placement when using MACD. We believe the MACD can improve the quality of reconstructive surgery.

Meta-analysis of arterial anastomosis techniques in head and neck free tissue transfer

The present meta-analysis aimed to investigate the differences in the incidence of thrombosis and vascular compromise in arterial anastomosis between microvascular anastomotic devices and hand-sewn techniques during free tissue transfer in the head and neck. We searched for articles in PubMed/Medline, CNKI, WANFANG DATA, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Web of Science, from January 1, 1962 till April 1, 2020 that reported data of microvascular anastomosis during free tissue transfer in the head and neck. The incidence of arterial thrombosis or vascular compromise, or both was the primary outcome. The secondary outcome was anastomotic time. We also assessed the sensitivity and the risk of bias. This meta-analysis included 583 arterial anastomoses from six studies. The group using microvascular anastomotic devices tended to have an increased incidence of arterial thrombosis and vascular compromise (risk ratio (RR), 3.42; P = 0.38; 95% confidence interval (CI), 0.91–12.77). The hand-sewn technique took significantly longer to perform the anastomosis compared with that of the microvascular anastomotic devices (weighted mean difference, 15.26 min; P<0.01; 95% CI, 14.65–15.87). Microvascular anastomotic devices might increase the risk of arterial thrombosis and vascular compromise compared with the hand-sewn technique; however, further randomized controlled trials are needed to provide a more accurate estimate. The application of microvascular anastomotic devices will help to reduce anastomotic surgery time and achieve acceptable vessel opening, benefiting from the developments of arterial couplers and microsurgical techniques.

Microvascular anastomotic arterial coupling: A systematic review

INTRODUCTION

There are several reasons microsurgeons may not use a coupler device in arterial anastomosis: may be thick-walled, non-pliable due to atherosclerotic calcification or present vessel geometrical discrepancies. This review summarises the current applications, efficacy and troubleshooting of microvascular coupler devices in arterial end-to-end anastomosis.

METHODS

A systematic review of the literature was performed in November 2020 across 4 electronic databases and in accordance with the PRISMA guidelines. All studies comprised the data synthesis that reported the use of a microvascular coupler device for arterial end-to-end anastomosis. Data were extracted and collected in three groups of standardised variables: study, anastomosis-related and technical characteristics.

RESULTS

Out of the 7,690 articles identified, 20 were included in the final data synthesis. Included studies involved a total of 1639 patients, who underwent 670 arterial and 1,124 venous anastomoses. Out of all arterial anastomoses, 351 were performed in free tissue transfers in head and neck, 117 in breast, 4 in upper extremity and 5 in lower extremity reconstruction, whereas the remaining were not specified. The total arterial coupler anastomosis success rate reported was 92.1% (617/670). Fifty-three (8%) arterial anastomoses were reported to result in either troubleshooting events or intra- or post-operative failures, most being reported in extremity reconstructions.

CONCLUSIONS

Arterial coupling is not widespread with predominant use in head and neck and chest reconstructions, and total reported efficacy of 92.1%. Microsurgeons are reluctant to routinely use current widespread coupler devices as a result of inherent arterial characteristics. This study delivered collective recommendations, 'do's and don'ts' of microvascular arterial coupling.

Microvascular anastomotic coupler devices versus hand-sewn technique for arterial anastomosis: a systematic review

The use of microvascular anastomotic coupling devices (MACD) is an established technique for venous anastomosis. However, literature on arterial MACD is conflicting. We report, to our knowledge, the first registered systematic review of its kind to evaluate the safety and efficiency of arterial MACD in free flaps. We performed a PRISMA-guided systematic review (PROSPERO-registered) and identified reports using a search algorithm in MEDLINE/EMBASE. The rate of arterial thrombosis was set as the primary outcome. Secondary outcomes included flap survival, failure rates, and comparison of MACD and the conventional hand-sewn technique. From the 17 studies identified, 2672 free flap reconstructions were performed and 640 arterial anastomoses with MACD attempted (622 completed, 97.2%). The pooled incidence of arterial thrombosis was 2.1% (13/622), and overall flap failure rate 4.34% (116/2672). The total number of arterial MACD procedures performed first time, with no perioperative complications, revisions, or thrombosis, was 88.9% (569/640). Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality analysis revealed low quality and significant heterogeneity. The use of arterial MACD is a safe and efficient alternative to hand-sewn anastomosis, with more recent literature showing excellent results. However, further evaluation is required with controlled trials.

Systematic review of microvascular coupling devices for arterial anastomoses in free tissue transfer

BACKGROUND

Coupling devices have become commonplace in performing venous anastomoses during microvascular free tissue transfer (FTT). However, arterial anastomoses are still most commonly performed using traditional microvascular suture techniques.

OBJECTIVE

To describe the safety and feasibility of using microvascular coupling devices for free flap arterial anastomosis.

METHODS

A systematic review of English language literature was performed for studies that investigated the use of an arterial coupler for microvascular FTT in human patients. A comprehensive search of MEDLINE (January 1948 to August 2018), EMBASE (January 1974 to August 2018), and Web of Science was performed.

RESULTS

Fifteen studies were included. All studies were retrospective case series. A combined total of 395 arterial anastomoses were attempted with a coupling device. All studies except for one used the 3M Unilink/Synovis coupling device. One study used a novel absorbable coupling device. The coupling device was aborted and converted to a suture technique in 8.4% of attempted anastomoses. Rupture of the anastomotic device was reported in only 1 patient (0.3%). Thrombosis was also infrequent at 1.9%. The quality assessment showed a high risk of bias in all studies.

CONCLUSION

In selected patients, coupling devices for arterial anastomoses have a good success rate with low rates of thrombosis based on limited quality evidence.

Microvascular coupler device versus hand-sewn venous anastomosis: A systematic review of the literature and data meta-analysis

BACKGROUND

Successful vascular anastomosis is essential for the survival of free tissue transfer. The aim of the study is to review the current literature and perform a meta-analysis to assess the potential advantages of a mechanical anastomosis coupler device (MACD) over the hand-sewn (HS) technique for venous anastomoses.

METHODS

A systematic Medline search was performed to gather all reports of articles related to MACD from 1984 until now. The following data were extracted: first author and publication date, study design, number of patients and anastomosis, coupler size, site and type of reconstruction, venous anastomotic time, flap failure. A meta-analysis was performed on articles that met the following inclusion criteria: studies comparing MACD and HS technique in venous anastomosis, reporting anastomotic time, and postoperative complications.

RESULTS

Thirty-three studies were included for the analysis. Twenty-four were retrospective case series and nine were retrospective comparative studies. A total of 12,304 patients were enrolled with a mean age of 49.23 years (range 31-72). A total of 13,669 flaps were accomplished. The thrombosis rate recorded with MACD was 1.47%. The meta-analysis revealed that MACD significantly decreased anastomotic time (standard difference in means = -0.395 ± 0.105; Z = -3.776; p < .001) and postoperative flap failure risk (odds ratio [OR] = 0.362, 95% confidence interval [CI] = 0.218-0.603, Z = -3.908, p < .001), but it did not decrease postoperative venous thrombosis risk (OR = 0.504, 95% CI = 0.255-1.129, Z = -1.666, p = .096).

CONCLUSIONS

MACDs are a safe and effective alternative to traditional anastomosis. The anastomotic coupler is easier, much faster, and requires less technical skills than a HS microvascular anastomosis.

Utilization of microvascular couplers in salvage arterial anastomosis in head and neck free flap surgery: Case series and literature review

BACKGROUND

In microvascular reconstruction of ablative oncologic defects, coupler devices have traditionally been used for venous anastomosis, whereas the arterial anastomosis is hand-sewn. In the setting of repeated intraoperative arterial anastomotic thrombosis, a coupler device may be of use in reducing the risk of rethrombosis.

METHODS

Two patients were seen with advanced stage head and neck cancer and underwent oncologic resection. During microvascular reconstruction, a clot at the arterial anastomosis was encountered in both cases.

RESULTS

After starting therapeutic anticoagulation and attempting unsuccessful suture reanastomosis, coupler devices were used for arterial anastomosis, resulting in viable free-tissue transfer.

CONCLUSIONS

Although traditionally used for venous anastomosis, coupler devices may serve a purpose in the salvage setting when facing repeated intraoperative arterial thrombosis.

Mechanical venous anastomosis in head and neck microvascular reconstruction as an equivalent to the gold standard

To define the most successful and efficient manner to perform venous microvascular anastomoses, the effectiveness of mechanical venous anastomosis in head and neck microvascular reconstruction is reviewed. Head and neck reconstruction with free flap techniques has become the norm and gold standard for large defects. This retrospective, multicenter case series of a single microvascular surgeon's experience with mechanical venous anastomoses specifically assessed the effectiveness of head and neck reconstruction and the complications associated with it. Data were collected from two separate academic centers and are reported from a consecutive series of patients over the course of 10 years. All patients underwent microvascular reconstruction of the head and neck region using venous couplers and flap survival. Flap survival was greater than 98% using mechanical venous couplers as the primary means for venous outflow in this series of 402 consecutive patients and 431 total microvascular flaps. Venous couplers were performed in every instance. The study shows that mechanical venous anastomosis provides a highly effective and efficient means for venous outflow in head and neck microvascular reconstruction, and should be considered equivalent to the gold standard suture technique, even in the most difficult cases.

Salvage arterial anastomosis using a microvascular coupler in head and neck free flap reconstruction

Microvascular free tissue transfer is essential in complex head and neck reconstruction. The mainstay of microvascular anastomosis has classically been the suture technique, but the coupling device has emerged as a valuable alternative. Couplers are commonly used for venous anastomoses, but most head and neck reconstructive surgeons do not routinely couple arteries. However, coupling may afford reconstructive surgeons a unique tool for addressing difficult arterial anastomoses. In this case report, we describe the successful use of a microvascular coupler for salvage arterial anastomosis after recurrent thrombosis following multiple attempts at suture anastomosis in head and neck free flap reconstruction.

A comparison of microsurgical venous anastomosis techniques

BACKGROUND

Successful vascular anastomosis is essential for the survival of transferred free tissue. Arterial anastomosis is typically uncomplicated because the lumen is easily maintained and the vessel walls have elasticity. Venous anastomosis, however, is more time consuming because the vessel walls are thin and extensible. This article describes, reviews, and compares 3 currently used venous anastomosis techniques.

METHODS

From April 2012 through January 2014, free tissue transfer and supercharging pedicled tissue transfer were performed in 107 and 10 patients, respectively, at our hospital. According to the anastomotic technique used, patients (83 men and 34 women; mean age, 60.6 years) were divided into interrupted suture, continuous suture, and microvascular anastomotic coupling device (MACD) groups. Medical records were reviewed, and postoperative results were analyzed.

RESULTS

The diameter of anastomosed veins did not differ significantly among the groups. However, among the interrupted suture, continuous suture, and MACD groups, there were significant differences in vascular anastomosis time (51, 43.9, and 29.5 minutes, respectively) and transferred tissue ischemic time (151.9, 139.1, and 117.5 minutes, respectively). Surgical site infection occurred in 9 patients, and flap necrosis occurred in 2 patients. However, complication rates did not differ significantly among the 3 groups.

CONCLUSIONS

The venous anastomosis technique does not affect the complication rate but does affect anastomosis time and flap ischemia time. On the basis of these results, we believe that the continuous suture and MACD techniques are easier and safer for venous anastomosis than is the traditional interrupted suture technique.

Venous Thrombosis in Handsewn versus Coupled Venous Anastomoses in 857 Consecutive Breast Free Flaps

BACKGROUND

The anastomotic coupling device has demonstrated safety and efficacy; however, the coupler has never been compared directly to handsewn venous anastomoses exclusively in breast reconstruction. We hypothesized that rates of venous thrombosis would be lower using the coupler versus handsewn anastomoses in free flap breast reconstruction.

METHODS

We performed a retrospective review utilizing clinic records, hospital records, and operative reports for 857 consecutive breast free flaps at a single institution from 1997 to 2012. Data were collected on reconstruction type, recipient vessels, timing, laterality, preoperative radiation, chemotherapy, venous thrombosis, and flap outcome. We compared rates of venous thrombosis between handsewn and coupled anastomoses for breast free flaps. Chi-square test was used to calculate statistical significance.

RESULTS

A total of 857 consecutive free flaps were performed for breast reconstruction in 647 patients over 16 years. The venous anastomosis was handsewn in 303 flaps, and the anastomotic coupler was used in 554 flaps. The rate of venous thrombosis requiring anastomotic revision in the handsewn group was 0.04% (12/303), compared with 0.01% in the coupled group (8/554; p = 0.02).

CONCLUSION

The anastomotic coupler was more effective in preventing venous thrombosis than handsewn anastomoses in our series. While our study demonstrates improved patency rates using the venous coupler in breast reconstruction, we were unable to definitively separate this finding from potential confounding variables due to the low rates of thrombosis in both the groups. Our data are consistent with current literature, which suggests that the coupler is a safe and effective alternative to hand sutured anastomoses.

The utility of the microvascular anastomotic coupler in free tissue transfer

BACKGROUND

The microvascular anastomosis remains a technically sensitive and critical determinant of success in free tissue transfer. The microvascular anastomotic coupling device is an elegant, friction-fit ring pin device that is becoming more widely used.

OBJECTIVE

To systematically review the literature to examine the utility of the microvascular coupler in free tissue transfer.

METHODS

A comprehensive database search was performed to identify eligible publications. Inclusion criteria were anastomotic coupler utilization and free-tissue transfer. Recorded information from eligible studies included patient age, follow-up, radiation history, number of free-flaps and failure rates, reconstruction subsites, number of coupled venous and arterial anastomoses, coupling time, conversion to sutured anastomosis, coupler size and thrombosis rates.

RESULTS

Twenty-five studies reporting on 3207 patients were included in the analysis. A total of 3576 free-flaps were performed within the following subsites: 1103 head and neck, 2094 breast, 300 limb or body, and 79 nonspecified. There were only 26 reported flap failures (0.7%). A total of 3497 venous and 342 arterial coupled anastomoses were performed. The primary outcome measure was thrombosis rates, and there were 61 venous (1.7%) and 12 arterial (3.6%) thromboses reported. Mean coupling time was 5 min, and 30 anastomoses (0.8%) were converted to suture.

CONCLUSION

Flap survival and revision-free application of the microvascular coupler occurred in more than 99% of cases. There is a substantial time savings with coupler use. Venous and arterial thrombosis rates are comparable with the best results achieved by sutured anastomosis and, when used by experienced surgeons, the coupler achieves superior results.

Arterial coupling for microvascular free tissue transfer

OBJECTIVE

The purpose of this study was to demonstrate the efficacy of arterial coupling.

STUDY DESIGN

Retrospective data were collected in a consecutive series of 124 patients undergoing surgical resection of head and neck tumors followed by free tissue transfer (FTT).

METHODS AND MEASURES

The Unilink coupling device was used to perform arterial and venous anastomosis. Flap survival and thrombosis of the arterial anastomoses were determined.

RESULTS

A total of 124 consecutive patients underwent a total of 127 microvascular FTTs. Reconstruction included 90 radial forearm, 26 fibula, 9 rectus abdominis, and 2 iliac crest myocutaneous free flaps. There were four (3.2%) complications related to arterial insufficiency in our series, three of which were salvageable. There were three (2.4%) flap failures, resulting in an overall free flap survival rate of 97.6 percent.

CONCLUSION

The flap survival with the Unilink Microvascular Anastomotic System is similar to that of standard suture techniques. Use of a coupler device is the preferred method in performing microvascular FTT at our institution.

Venous Thrombosis in Coupled Versus Sutured Microvascular Anastomoses

BACKGROUND

The anastomotic coupling device (ACD) is currently used for microsurgical venous anastomoses as an alternative to sutures and can reduce anastomotic time.

METHODS

We reviewed the microsurgical procedures performed at the University of Texas M. D. Anderson Cancer Center over a 40-month period. Procedures were performed for elective reconstruction of the breast, head or neck, or extremities after tumor excision. Thrombosis and ultimate flap salvage rates were compared between cases using ACDs and those using sutures for the venous anastomoses.

RESULTS

Seven hundred twenty-three free flaps were included in the study. There were no intraoperative technical complications using the ACD. Overall, the venous thrombosis rates were not significantly different between the ACD (1.4%, 2/139 cases) and sutured (3.3%, 19/584 cases) groups. Salvage rates following venous thrombosis were not significantly different for venous anastomoses performed with an ACD (50%, 1 of 2 cases salvaged) compared with venous anastomoses performed with sutures (68.4%, 13 of 19 cases salvaged).

CONCLUSION

The ACD is a useful alternative to sutured venous anastomoses that can reduce anastomotic time while achieving similar patency rates.

Arterial Anastomosis Without Sutures Using Ring Pin Stapler for Clinical Renal Transplantation: Comparison With Suture Anastomosis

PURPOSE

The metal ring pin stapler was initially developed for microvascular surgery and there has been little experience of their use in larger vessels. We determined if the titanium ring pin coupling system could be safely and rapidly applied for arterial reconstruction in clinical renal transplantation.

MATERIALS AND METHODS

The donor renal artery was end-to-end anastomosed to the internal iliac artery with titanium ring pin staplers in 36 patients. Anastomotic, clamp and total operative time and vascular problems were compared with those in the control group of sutured anastomosis in 39 transplant recipients.

RESULTS

The completion of mechanical anastomosis required half the time of suture anastomosis. Mean clamp time was 17.8 minutes in the nonsuture group and 28.1 minutes in the control group. There was no significant difference in total operative time between the 2 groups. A small anastomotic line leak was noted in each group, which was temporary and self-limited. There were no postoperative anastomotic failures, postoperative bleeding episodes or need to revise the anastomosis (100% patency rate) in the 2 groups. Of the patients 61 were followed for 2 to 5 years. Transplant renal artery stenosis was observed in 1 patient in the nonsuture group but 3 in the control group.

CONCLUSIONS

The anastomotic technique with the ring pin system is safe and simple, permitting an expeditious and everting anastomosis with a smooth intima-to-intima junction. Application of this technique may decrease warm ischemia time and the incidence of anastomotic artery stenosis, thus, improving outcomes.

Morphological and functional evaluation of leg-muscle reinnervation after coupler coaptation of the divided rat sciatic nerve

Mechanical couplers are successfully used for microvascular venous anastomoses. The advantages include a simple and fast technique and a high patency rate. Couplers offer a secluded coaptation site, and might also be of use in peripheral nerve repair. The present study was designed to investigate coupler coaptation of the rat sciatic nerve, evaluating the number and locations of motor and sensory neurons projecting to the selected muscles as well as stimulation-induced muscle contraction force. Adult rats underwent either suture or coupler repair after left sciatic nerve transection. In all rats, the experimental side was compared to the healthy right side. Evaluation after 20 weeks included retrograde labeling of motoneurons and dorsal root ganglion neurons projecting to the tibial anterior muscle and to the tibial posterior muscle, histology, muscle contraction force (tibial anterior muscle and gastrocnemius muscle), and a pinch reflex test. The results show that the suture and the coupler groups did not differ significantly regarding the examined parameters, except for discrete signs of nerve compression at the coaptation site after coupler repair due to fibrous tissue ingrowth. However, this did not impair axonal regeneration. Importantly, axonal outgrowth from the repair site to the surrounding tissue was not observed after coupler coaptation, but it was observed after suture repair. These results suggest that couplers may be of value for repair of nerves in adjacency to avoid axonal crisscrossing between nerves during regeneration.

[The ring-pin anastomosis technique. Long-term clinical experiences with the mechanical ring-pin system for microvascular anastomoses in reconstructive head and neck surgery ]

BACKGROUND

Microvascular anastomosis remains one of the most critical aspects of free tissue transfer. Since microsurgical suture techniques are complicated and time-consuming, other techniques of anastomosis have been created. One of these is the ring-pin system.

METHODS

Between January 1996 and October 2001, 48 patients underwent reconstruction with a free radial forearm flap. In 20 patients the venous anastomosis was carried out using a ring-pin system with end-to-end technique. The clinical results were compared to the other 28 patients in whom the anastomosis was sutured with 9-0 prolene.

RESULTS

In the group using ring-pin anastomosis ( n=20), two flaps showed venous congestion within 24 h postoperatively. After revision the flaps were well perfused. In the other group with sutured vessels ( n=28), a transplant became ischemic in one patient due to venous thrombosis and had to be partly removed. The time of anastomosis was considerably shortened by the use of the ring-pin system.

CONCLUSIONS

The venous end-to-end-anastomosis using the ring-pin system can be carried out relatively easily and rapidly after a comparatively short period of training. Long-term results have shown good tissue tolerance of the material and sufficient blood circulation of the grafts.

Experimental study of mechanical microvascular anastomosis with new biodegradable ring device

The commercially available mechanical vascular anastomotic device with ring-pin technique employs polyethylene rings and stainless steel pins, but even after healing of the anastomotic site, the ring remains. To resolve this disadvantage, the ring material was replaced by biodegradable material, and a ring coupling device was fabricated. This new ring was used to anastomose the femoral vein of rabbits, and morphological observations were made macroscopically and by light and scanning electron microscopy. Of the 58 anastomosed veins, 54 were patent, giving a patency rate of 92.9%. The ring was largely absorbed 15 weeks after anastomosis and completely after 30 weeks. Histologically, re-endothelialisation was observed in 1 week. Infiltration of inflammatory cells was significant around the ring at 3 weeks, but inflammation subsided within 6 weeks. There were no findings indicating adverse effects of the stainless steel pins remaining outside the vascular wall.

Experimental evaluation and clinical use in the head and neck of a 3M/Precise microvascular anastomotic device

Microvascular reconstructions in the head and neck are usually long operating time procedures. Mechanical anastomotic devices help to reduce operating time and can reduce anastomotic failures avoiding foreign bodies in the lumen of the vessel. One of these systems is the 3M/Precise microvascular anastomotic device, it is a non-absorbable device, however, criticisms of this system have been directed to the fact that pulsation of the vessel wall against a rigid structure could lead to thinning of the vessel wall and aneurysm formation. No aneurysms have been found previously in other experimental models. Our experimental study on the aorta and vena cava of the rat comprises 25 arterial and 25 venous anastomoses. In the arteries, four proximal aneurysms were found, two of these were failures. In the venous anastomoses, no failures were found nor aneurysm formation. The system is very useful for performing clinical end to end venous anastomosis helping to reduce anastomotic failures. Aneurysms have been found in arteries although four different ring sizes were available. The device is less easy to use in them than in veins and sometimes can be difficult to apply, making manual suturing a better choice for clinical arterial anastomosis.

Use of the 3M precise microvascular anastomotic system in hand surgery

The results of a two-center clinical study on the use of the 3M Precise Microvascular Anastomotic System in microvascular procedures for hand trauma are presented. Since November 1992, 17 patients (age range, 18-76 years) have received an end-to-end vascular anastomosis using this device. All patients had vascular trauma or amputation requiring replantation or revascularization procedures. The diameter of the anastomosed vessels varied between 1 and 2 mm. Sixteen of the 17 anastomoses were at the level of or distal to the superficial arterial arch of the hand, with 5 anastomoses as distal as the distal interphalangeal joints. No early thromboses were observed in the postoperative period, and all operations were successful with regard to tissue survival and wound healing. Patency and quality of the blood flow at the site of repair were evaluated by means of Doppler ultrasound investigations. In a few cases, angiography was used to confirm patency of the device.

Clinical use of microvascular PTFE grafts

This paper reports on the first clinical case where a polytetrafluoroethylene (PTFE) graft of less than 3 mm in diameter was implanted in the arterial system of a patient to bridge a vascular defect. A 1.5 cm long, 1.5 mm diameter prosthesis was interposed in the superficial palmar arch of a man who sustained a laceration of the palm of his dominant hand. The graft was implanted by means of the 3M Precise Microvascular Anastomotic System on one end, and by conventional microsurgical technique on the other end. There were no postoperative complications. The patient resumed his pre-injury activities 9 weeks after trauma. Serial Doppler ultrasound examinations showed normal blood flow and complete patency of the graft. An angiogram performed 12 weeks postoperatively confirmed the patency of the prosthesis. Twelve months post-operatively the patient is free from complications. The use of small diameter PTFE prostheses may be considered when planning grafting procedures for microvascular defects.