Simplifying Arterial Coupling in Microsurgery-A Preclinical Assessment of an Everter Device to Aid with Arterial Anastomosis

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.

60 Years of Michigan Plastic Surgery

In 1964, the Section of Plastic and Reconstructive Surgery at the University of Michigan opened its doors to future surgeons and leaders in the field. Today, we are celebrating the 60-year history of the program and its significant contributions to the field. Beginning under the leadership of Reed O. Dingman, MD, DDS, the program began with three faculty members and two independent surgical residents. Since that time, it has expanded dramatically to include 24 faculty members and 28 integrated plastic surgery residents. The goals of the program have always been to achieve excellence in all three of our academic missions including clinical care, teaching, and research. Annually, the program sees an average of 35,000 outpatient clinic visits, 4,000 major operations, 200 peer-reviewed publications, $5,000,000 in research spending, and residents who are well trained and highly competitive for fellowships of their choosing every single year. Through scientific collaborations, academic exchanges, and medical missions, the program's influence has spread beyond Michigan, reaching the entire world. In addition to training world-renowned surgeons, Michigan's faculty and graduates have assumed leadership roles in prestigious professional organizations, scientific journals, and research foundations. In this article, we explore the roots of the program and reflect on six decades of impact, innovation, and inspiration.

A Novel Method of End-to-Side Microvascular Anastomosis Using T-Shaped Metal Stents: A Porcine Study

ABSTRACT

End-to-side anastomosis requires highly specialized techniques. An easy end-to-side anastomosis technique enables anastomosis of vessels with different diameters and under various situations. We invented T-shaped metal stents and evaluated novel methods of end-to-side sutureless anastomosis, confirming their safety, effectiveness, and operability. We performed 8 end-to-side sutureless anastomoses in 4 7- to 11-month-old, male Mexican hairless piglets. After induction of anesthesia, the left femoral artery was resected by approximately 8 cm, and the superior and posterior stumps of the resected femoral artery underwent an end-to-side anastomosis with the right femoral artery by the placement of the metal stents with subsequent use of adhesive for the circumferential area. The patency of blood vessels and the presence of thrombosis were evaluated by ultrasonography or contrast-enhanced computed tomography and histology 4 weeks postoperatively. All the animals survived the procedure; no thrombosis was identified in any of the 8 anastomosis sites according to imaging studies performed 4 weeks postoperatively. Histological examination confirmed the probe patency of blood vessels and neointimal cell proliferation around stent branches. End-to-side anastomosis is possible with T-shaped metal stents. In the future, we aim for the practical application of these stents by improving their operability.

Compression of the vascular wall to create a friction fit in a vascular anastomotic coupler

A previously reported microvascular coupler was shown to effectively create vascular anastomoses, but was too large for practical clinical use. To safely reduce coupler size, certain failure modes needed to be better understood. The coupler functions, in part, by compressing the vessel wall between two concentric rings, creating a friction fit that anchors the device to the vessel. This work investigates the relationship between vessel wall compression and resulting friction fit strength to ensure reducing coupler size will not unduly increase the risk that this friction fit might fail. Vascular walls were compressed to a specified strain and the tensile force required to overcome the resulting friction was measured. Experiments were conducted with various vessel types (Porcine common carotid artery, splenic artery, and jugular vein), across a range of compressive strains (55-95%), and by using either PEEK or HDPE to compress the vessel. Tensile force was increased at a rate of 5 g/min or held constant for 24 h. For experiments with incrementally increasing force, the force at failure varied with compressive strain via a power function. At 70% compression, PEEK produced 4.6 times stronger friction fits than HDPE, and common carotid arteries and splenic arteries produced 1.8 and 1.3 times stronger fits than jugular veins respectively. For experiments where tensile force was applied for 24 h, much lower forces were required to overcome friction. These results were compared to friction fit failure in a coupler prototype and it was found that the prototypes failed at just 30% of the force required to cause vessel slip under the other test conditions. These results were used to develop a model that predicts the probability of device failure via vessel slipping (one design, smaller than previously reported, was estimated to fail at maximum in vivo axial stress once in 500 anastomoses, a potentially safe level of risk).

Microvascular anastomosis techniques using the medical adhesive VIVO and expandable micro-stents in a rat carotid artery model

BACKGROUND

Sutured anastomosis remains the gold standard in microvascular surgery. The procedure is not free of complications and is a time-consuming operation requiring a high level of experience. The aim of this study was to develop new methods for a stable, faster, and safer anastomosis using a novel biodegradable adhesive, VIVO, and a custom-made microvascular stent.

METHODS

The VIVO medical adhesive was used for a total of 30 anastomoses in rats in the right carotid artery: 15 anastomoses were performed with a temporary intraluminal catheter, VIVO, and reduced sutures (VIVO + TC). A further 15 anastomoses were performed with nitinol stents, VIVO, and reduced sutures (VIVO + SM). Sutured anastomoses served as controls (C) and were performed on the left carotid arteries of the 30 rats. Operation and bleeding times were assessed, and patency was evaluated by Doppler flowmetry and indocyanine green (ICG) angiography. Subsequently, the anastomoses were evaluated histopathological.

RESULTS

The overall patency was recorded as 100% in all groups. No thrombosis or circulatory disturbance was found. Compared to C and VIVO + SM, VIVO + TC proved to be significantly less traumatic, less demanding, and time-saving. The sealing properties of VIVO lead to shorter bleeding times and less oozing. In contrast, VIVO + SM proved to be the most technically demanding and time-consuming procedure.

CONCLUSION

The success of a microvascular sutured anastomosis is determined by a short ischemic interval. Compared to sutured anastomosis, VIVO + TC showed ease of use as well as shorter time taken for anastomosis, less trauma, and lower blood loss. More long-term studies on the functions, biological interactions, and survival rates of glue-based anastomoses need to be initiated.

Microsurgery in the era of COVID-19

The COVID-19 pandemic has presented new challenges to microsurgeons. The virus is highly transmissible, with increased risk during operations that involve the aerodigestive tract. It is important to be able to identify high-risk operations and scenarios to guide management decisions and selection of personal protective equipment. Preoperative testing is a key element in identifying high-risk scenarios, and preoperative testing protocols are essential to maintaining safety in the COVID-19 era. Because COVID-19 can be transmitted via the conjunctiva, adaptations to loupes and microscopes are necessary to safely perform microsurgery in high-risk scenarios. We outline a potential risk stratification algorithm, as well as precautions for each scenario. Potential areas for innovation are also discussed.

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.

A Protocol for Safe Head and Neck Reconstructive Surgery in the COVID-19 Pandemic

The COVID-19 pandemic has had significant implications for citizens globally and for the healthcare system, including plastic surgeons. Operations of the upper aerodigestive tract, including head and neck reconstruction and craniomaxillofacial procedures, are of particularly high risk because they may aerosolize the virus and lead to severe surgeon and surgical team illness. Until the virus is eradicated or widespread vaccination occurs, we recommend certain precautions to safely perform these operations. We propose evolving algorithms for head and neck reconstruction and facial trauma surgeries to maintain provider safety. Central to these guidelines are preoperative COVID-19 testing, appropriate personal protective equipment, and operative techniques/principles that minimize operative time and aerosolization of the virus. We aim to provide efficient care to our patients throughout this pandemic, while maintaining the safety of plastic surgeons and other healthcare providers.

Safety of Coupled Arterial Anastomosis in Autologous Breast Reconstruction

BACKGROUND

 This study compares the outcomes of coupled versus hand-sewn arterial anastomosis in microvascular breast reconstruction.

METHODS

 Retrospective chart review of breast reconstruction free flaps performed between 2013 and 2018 was conducted. Primary end points included flap loss, intraoperative arterial anastomosis revision, and operating room takeback. The decision to couple the arterial anastomosis was based on patient's age, surgeon's preference, history of radiation, and vessel quality. All anastomoses were performed under ×3.5 loupe magnification to internal mammary or thoracodorsal vessels.

RESULTS

 Authors reviewed 104 free flaps; two were lost in hand-sewn group; no flaps were lost in coupled group. There was no significant difference in anastomotic revision rate between coupled and hand-sewn arterial anastomosis (p = 0.186) or return to operating room (OR) between coupled and hand-sewn flaps (p = 1.000). Reasons for takeback included venous congestion and hematoma.

CONCLUSION

 This study reflects that coupled arterial anastomosis in breast reconstruction may be safely performed without increased risk in anastomotic revision, takeback, or flap loss. Decision to couple should be based on surgeon skill, patient age and history, and assessment of flap and recipient site vasculature.

Review and update on the use of the microanastomotic coupler device for arterial anastomosis in free tissue transfer

While a simple interrupted sutured anastomosis remains the gold standard in microsurgery, the introduction of the microanastomotic coupler device (MACD) has decreased procedure time and thrombosis risk, and improved the patency of venous anastomoses. The aim of this review is to update the evidence-based advantages of the MACD on arteries, based on clinical and experimental data, and to compare them to the hand-sewn approach in free flap transfer. All relevant articles that appeared in the PubMed and Medline/Ovid databases during the past three decades were reviewed. After exclusions, 11 studies were retained and discussed. The MACD had a generally shorter arterial anastomosis time, with improved flap survival and reduced ischaemia compared with the hand-sewn approach. The use of the MACD in arterial anastomosis is an efficient and less time-consuming alternative to the hand-sewn technique, provided that the selection of vessels is appropriate and the vessel diameter is large enough to do the anastomosis.

Use of venous couplers in microsurgical lower extremity reconstruction: A systematic review and meta-analysis

BACKGROUND

Free tissue transfer for lower limb reconstruction has become a workhorse procedure for limb-salvage. Compared with other recipient sites, the lower extremity has a higher risk of microvascular complications, in particular with venous anastomosis. The study's objective is to evaluate the evidence, safety, and efficacy of venous coupler use in microsurgical anastomosis in lower limb reconstruction to provide objective appraisal of the surgical techniques.

METHODS

A systematic review (SR) and meta-analysis (MA) were performed analyzing articles from PubMed, Cochrane, Embase, and Web of Science from January 1990, to August 2018. Abstracts and titles were screened and assessed for eligibility by independent reviewers. Following full-text review, articles were included in the SR and MA. Case reports were excluded. Cochrane Collaboration and the Quality of Reporting of Meta-analyses (QUOROM) guidelines were followed.

RESULTS

Out of 15 included studies that met the inclusion criteria for the SR, 9 were included in MA. Patients treated with venous couplers did not experience more surgical complications (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.48-1.33; p = .38), total failure (RR 0.61; 95% CI 0.22-1.70; p = .34), venous compromise (RR 0.72; 95% CI 0.23-2.27; p = .57), arterial compromise (RR 0.85; 95% CI 0.25-2.88; p = .80), partial failure (RR 0.77; 95% CI 0.33-1.77; p = .54), or reoperation (RR 11.79; 95% CI 0.49-286.55; p = .13) in comparison with hand-sewn anastomosis.

CONCLUSIONS

Outcomes of venous couplers in lower limb reconstruction are comparable to those of hand-sewn anastomosis. However, this study was limited by the quality of the available literature. Additional prospective studies should aim to directly compare both techniques and potential further benefits in clinical trials.