Patency of different arterial and venous end-to-side microanastomosis techniques in a rat model

Prophylaxis of microvascular thrombosis using direct oral anticoagulants (DOAC) in microvascular free tissue transplantation - a pilot study

INTRODUCTION

We conducted this pilot study to assess direct oral anticoagulants (DOACs) in the prevention of microvascular thrombosis.

MATERIALS AND METHODS

Five patients undergoing microvascular free tissue transplantation received rivaroxaban or apixaban (depending on their home medication). We compared this group to 19 patients who received enoxaparin subcutaneously. We evaluated the rate of graft loss due to microvascular thrombosis and the number of transfusions administered intra- and postoperatively.

RESULTS

There was no graft loss due to microvascular thrombosis in either of the groups. There was no significant difference in the number of intraoperative (study group mean 1.00 (SE 0.32) vs. control group mean 1.11 (SE 0.59); p = 0.876) and postoperative (study group mean 1.2 (SE 0.37) vs. control group mean 1.74 (SE 0.34); p = 0.310) red blood cell transfusions.

CONCLUSION

Based on our results in this pilot study, DOACs can be used with microvascular flaps. Further studies with larger sample sizes should be performed to find an optimal medication regimen both for patients already taking DOACs and perhaps even for those not taking DOACs.

Validation of Novel Microsurgical Vessel Anastomosis Techniques: A Systematic Review

INTRODUCTION

 Thorough validation of novel microsurgical techniques is deemed essential before their integration into clinical practice. To achieve proper validation, the design of randomized controlled trials (RCTs) should be undertaken, accompanied by the execution of comprehensive statistical analyses, including confounder adjustment and power analysis. This systematic review aims to provide an encompassing overview of the validation methodologies employed in microsurgical studies, with a specific focus on innovative vessel anastomosis techniques.

METHODS

 A literature search was conducted in PubMed for articles describing the validation of novel microsurgical vessel anastomosis techniques in animal or human subjects.

RESULTS

 The literature search yielded 6,658 articles. A total of 6,564 articles were excluded based on title and abstract. Ninety-four articles were assessed for full-text eligibility. Forty-eight articles were included in this systematic review. Out of 30 comparative studies, 9 studies validated novel modified interrupted suture techniques, 6 studies modified continuous techniques, 6 studies modified sleeve anastomosis techniques, 1 study a modified vesselotomy technique, 7 studies sutureless techniques, and 1 study a modified lymphaticovenular anastomosis technique. Twenty-eight studies contained animals (n = 1,998). Fifteen animal studies were RCTs. Two studies contained human/cadaveric subjects (n = 29). Statistical power analysis and confounder adjustment were performed in one animal study. Out of 18 noncomparative studies, 5 studies validated novel modified interrupted suture techniques, 1 study a modified continuous technique, 2 studies modified sleeve anastomosis techniques, 4 studies modified vesselotomy techniques, 4 studies sutureless techniques, and 2 studies modified lymphaticovenular anastomosis techniques. Ten studies contained animal subjects (n = 320), with two RCTs. Eight studies contained human subjects (n = 173). Statistical power analysis and confounder adjustment were performed in none of the animal or human studies.

CONCLUSION

 The current methods of microsurgical technique validation should be reconsidered due to poor study design. Statistical analysis including confounder adjustment and power analysis should be performed as a standard method of novel technique validation.

Microsurgical robotic system enables the performance of microvascular anastomoses: a randomized in vivo preclinical trial

Technical advances in microsurgery have enabled complex oncological reconstructions by performing free tissue transfers, nerve and lymphatic reconstructions. However, the manual abilities required to perform microsurgery can be affected by human fatigue and physiological tremor resulting in tissue damage and compromised outcomes. Robotic assistance has the potential to overcome issues of manual microsurgery by improving clinical value and anastomoses' outcomes. The Symani Surgical System, a robotic platform designed for microsurgery, was used in this in-vivo preclinical study using a rat animal model. The tests included anastomoses on veins and arteries performed by microsurgeons manually and robotically, with the latter approach using Symani. The anastomoses were assessed for patency, histopathology, and execution time. Patency results confirmed that the robotic and manual techniques for venous and arterial anastomoses were equivalent after anastomosis, however, the time to perform the anastomosis was longer with the use of the robot (p < 0.0001). Histological analysis showed less total average host reaction score at the anastomotic site in robotic anastomosis for both veins and arteries. This study demonstrates the equivalence of vessel patency after microsurgical anastomoses with the robotic system and with manual technique. Furthermore, robotic anastomosis has proven to be slightly superior to manual anastomosis in terms of decreased tissue damage, as shown by histological analysis.

Submerged vascular anastomosis. A technique for vascular suturing in experimental microsurgery

PURPOSE

To evaluate the impact of submersion of the microsurgical anastomosis suture area using saline (0.9% NaCl) in an experimental laboratory during the training of medical students and resident physicians.

METHODS

Wistar rats (n = 10) were selected to have the two femoral arteries sectioned and anastomosed end-to-end under optical magnification. They were randomly divided, so that on one side suturing was performed under submersion with saline, and the contralateral side was kept dry during the procedure. The surgical times, as well as the patency within 30 min and 72 h of the procedure, were evaluated.

RESULTS

Six male Wistar rats survived the surgical anesthetic procedure, with the average initial weight of 243.3 g and the average artery diameter of 0.86 mm, with average time of 15.67 min for the submerged technique and 20.50 min for the dry technique (p = 0.03). The failure rates were 17 and 50% for the submerged group and the dry one, respectively (p = 0.62).

CONCLUSIONS

Submerged microvascular suture does not compromise the patency of the vessel or increase the time of anastomosis. Therefore, it is a strategy that can be applied by the surgeon according to his/her technical preferences.

Blood flow distribution after end-to-side anastomosis with wide arteriotomy in extremity free flap surgery

PURPOSE

Although many studies have investigated the optimal anastomotic procedure for the end-to-side (ETS) procedure with a free flap, no study has focused on the size of the arteriotomy. Some surgeons have recently described the effectiveness of ETS with wide arteriotomy, but the postoperative haemodynamics remains unclear for free flaps created using this technique. The aim of this study was to use ultrasonography to evaluate the postoperative blood flow distribution after ETS with a wide arteriotomy in extremity free flap surgery.

METHODS

We evaluated 20 free flaps in 18 consecutive patients who received an ultrasonographic examination after free flap surgery using the ETS technique with wide arteriotomy for arterial anastomosis. All flaps were examined after surgery and blood flow was calculated for the flap and recipient vessels.

RESULTS

All 20 flaps survived, but one flap developed asymptomatic arterial thrombosis and 19 flaps were analysed. For the ETS technique with wide arteriotomy, peripheral circulation was well preserved in all flaps. Comparison of flap types showed that blood flow was significantly higher in myocutaneous flaps than in fasciocutaneous flaps, but there was no significant difference according to the size of the arteriotomy.

CONCLUSIONS

Given the range of arteriotomy performed using the ETS with a wide arteriotomy technique, the blood flow volume in the flap depended on the type of flap but not on the size of the arteriotomy. A steal phenomenon related to the creation of a wide window in the receipt artery was not found in the analysed retrospective cohort.

The effect of ticagrelor on microarterial thrombosis in an experimental model

Thromboses that form in the pedicle after free flap and/or replantation may result in the loss of the flap and/or limb. Ticagrelor is an adenosine diphosphate (ADP) receptor antagonist antithrombotic that can inhibit ADP-dependent platelet activation and aggregation. It is clinically used in acute coronary syndrome and unstable angina. However, its effect on microarterial anastomoses has not been investigated in the literature. An experimental thrombosis model was developed in both femoral arteries of a total of 40 rats. Twenty rats were randomly selected as the drug-free control group, and 20 rats were randomly selected as the ticagrelor group. The rats in the ticagrelor group were administered a 20 mg/kg loading dose orally by gavage 24 h before the experiment, and a maintenance dose of 2x10 mg/kg ticagrelor for 14 days after surgery. After the experiment, the femoral artery was evaluated for macroscopic and microscopic thrombosis, inflammation, edema, and endothelialization. Macroscopically and microscopically, thrombosis was observed at rates of 73.3% and 33.3% in the control group and the ticagrelor group, respectively. Inflammation in the vessel wall was found as 56.7% in the control group and 16.7% in the ticagrelor group. Edema in the vessel wall was found in 63.3% of the control group and 20% of the ticagrelor group. A statistical difference was found between the two groups in terms of thrombosis, inflammation, and edema. Both groups had similar characteristics in terms of endothelialization. Ticagrelor has a reducing effect on thrombosis in the microarterial tuck model.

Single Artery Upper Extremity Salvage with Two Free Flap End-to-Side Brachial Artery Anastomoses

Background A 36-year-old male was involved in a motor vehicle accident, presenting with a Guistillo's IIIB crush injury to the upper extremity. A severely comminuted ulnar fracture resulted in a 10-cm bone defect with significant overlying soft tissue injury.

Methods The injury resulted in a wide zone of injury with inadequate collateral vascularity at the level of the elbow and distal viability dependent on the brachial artery. An osteocutaneous free fibular flap and fasciocutaneous anterolateral thigh flap were used to reconstruct the defect with both flaps anastomosed in an end-to-side fashion to the brachial artery.

Results The upper extremity was successfully salvaged, and the patient discharged from hospital at postoperative day 10. Both free flaps survived with no donor or recipient site complications at a follow-up period of 2 years.

Conclusion The case illustrates the challenges inherent to significant Guistillo's IIIB injuries with insufficient recipient vessels over a large zone of injury. While performing anastomoses outside the zone of injury is preferred, this case demonstrates the success of performing multiple anastomoses to the brachial artery in an end-to-side fashion within the zone of injury.

Large-to-Small End-to-Side Venous Anastomosis in Free Flap Transfer

BACKGROUND

Vessel size discrepancy is one of the major risk factors for anastomotic failure in free flap transfer. The situation becomes challenging for reconstructive microsurgeons when the recipient vein is much smaller than the flap vein. We investigated the feasibility of large-to-small end-to-side venous anastomosis for such cases.

MATERIALS AND METHODS

The subjects were 16 consecutive patients who underwent a free flap transfer for oncologic defects with a large-to-small end-to-side venous anastomosis. The larger flap vein was anastomosed to the side slit of the smaller recipient vein under an operating microscope. Surgical details and postoperative outcome were investigated retrospectively.

RESULTS

An anterolateral thigh flap was used in five patients, a superficial inferior epigastric artery flap in four, a thoracodorsal artery perforator flap in three, and a latissimus dorsi musculocutaneous flap and a fibular osteocutaneous flap in two patients each. The internal mammary vein and the anterior tibial vein were most frequently used as a recipient vein (four patients each), followed by the deep inferior epigastric vein (three patients). The extent of vessel size discrepancy ranged from 1.3- to 3.3-fold, and the mean discrepancy was 1.9-fold. No anastomotic failure occurred postoperatively, and the flap survived in all patients.

CONCLUSIONS

Large-to-small end-to-side venous anastomosis can be a versatile option when only a small vein is available as a recipient vein. Internal mammary, deep inferior epigastric, and anterior tibial veins are good candidates for this technique.

Antithrombotic efficacy of direct oral anticoagulants on patency rate following microsurgical anastomosis in crushed rat arteries

BACKGROUND

During the last decade direct oral anticoagulants (DOAC) have been established in various fields of medicine.Their use in microsurgery has not been evaluated yet though. This study aims to evaluate their efficacy in microsurgery and additionally compare them with a well established antithrombotic agent.

MATERIALS AND METHODS

The right femoral artery of 101 rats divided into 4 groups, was crushed and anastomosed. Group A (20 rats) received placebo therapy (1 ml NaCl 0.9%, orally), while Group B (27 rats), Group C (27 rats) and Group D (27 rats) received rivaroxaban (3 mg/kg, orally), dabigatran (30 mg/kg, orally) and enoxaparin (30 mg/kg, subcutaneously) respectively. All drugs were administered 3 h preoperatively and once daily for the following postoperative days until the sacrifice of the animals. Patency was evaluated at 1st, 7th and 20th postoperative day. Following patency evaluation the rats were sacrificed and the vessels were harvested for histological examination.

RESULTS

None of the rats died postoperatively. Patency rates of rivaroxaban group (78%), dabigatran group (70%) and enoxaparin group (63%) were statistically similar, but significantly higher than the placebo-treated control group (p < 0.05). Cells with morphologic features of endothelial cells were evident 7 days after the injury.

CONCLUSION

The results of this study demonstrate the following: (1) rivaroxaban and dabigatran through inhibition of thrombus formation significantly enhanced the patency rate compared to placebo treatment (2) the antithrombotic efficacy of rivaroxaban and dabigatran in compromised microvessels was similar to that of enoxaparin, the most widely used antithrombotic agent.

The rat choledochojejunostomy model for microsurgical training

Purpose

The feasibility of a rat choledochojejunostomy (CJ) training model was investigated, as an introductory model to microsurgery for general surgeons.

Methods

Roux-en-Y CJ was performed on 20 rats. Interrupted 10-0 prolene sutures were used to perform CJ. The animals were observed for 7 days and sacrificed and examined.

Results

The rats were divided into 2 groups of 10 based on surgical order. The CJ time showed a significant decrease from 36.2 ± 5.6 minutes in group 1 to 29.4 ± 5.7 minutes in group 2 (P = 0.015). The bile leakage rate was 40% in group 1 and 10% in group 2. The survival time was 5.4 ± 2.2 days in group 1 and 7 days in group 2 (P = 0.049).

Conclusion

The rat CJ training model is a feasible introductory model for general surgeons with no previous experience in microsurgery.

Tips and tricks for end-to-side anastomosis arteriotomies

Arteriotomy is a critical step during end-to-side anastomosis procedures. However, it is challenging to carry out because of the concentric lamellar structure of blood vessels and the need for clean margins. We performed a review of the literature to identify the advantages and disadvantages of the available arteriotomy methods. The techniques were classified into (1) single-cut or slit arteriotomy (longitudinal and transverse) or (2) excision arteriotomy. The latter techniques can be performed from either outside-in (excision with straight microscissors, curved microscissors, Acland-Banis arteriotomy clamp, micro-arteriotomy scissors, or triangular cutting scissors, and vaporization with Excimer(®) laser) or inside-out (excision with punch/micropunch). Microsurgeons have multiple arteriotomy methods at their disposal. By being familiar with these methods, they can select the most appropriate one for the situation at hand.

Modified uterine allotransplantation and immunosuppression procedure in the sheep model

Objective

To develop an orthotopic, allogeneic, uterine transplantation technique and an effective immunosuppressive protocol in the sheep model.

Methods

In this pilot study, 10 sexually mature ewes were subjected to laparotomy and total abdominal hysterectomy with oophorectomy to procure uterus allografts. The cold ischemic time was 60 min. End-to-end vascular anastomosis was performed using continuous, non-interlocking sutures. Complete tissue reperfusion was achieved in all animals within 30 s after the vascular re-anastomosis, without any evidence of arterial or venous thrombosis. The immunosuppressive protocol consisted of tacrolimus, mycophenolate mofetil and methylprednisolone tablets. Graft viability was assessed by transrectal ultrasonography and second-look laparotomy at 2 and 4 weeks, respectively.

Results

Viable uterine tissue and vascular patency were observed on transrectal ultrasonography and second-look laparotomy. Histological analysis of the graft tissue (performed in one ewe) revealed normal tissue architecture with a very subtle inflammatory reaction but no edema or stasis.

Conclusion

We have developed a modified procedure that allowed us to successfully perform orthotopic, allogeneic, uterine transplantation in sheep, whose uterine and vascular anatomy (apart from the bicornuate uterus) is similar to the human anatomy, making the ovine model excellent for human uterine transplant research.

Opened end-to-side technique for end-to-side anastomosis and analyses by an elastic true-to-scale silicone rubber model

The end-to-side anastomosis is frequently used in microvascular free flap transfer, but detailed rheological analyses are not available. The purpose of this study was to introduce a new modified end-to-side (Opened End-to-Side, OES-) technique and compare the resulting flow pattern to a conventional technique. The new technique was based on a bi-triangulated preparation of the branching-vessel end, resulting in a "fish-mouthed" opening. We performed two different types of end-to-side anastomoses in forty pig coronary arteries and produced one elastic, true-to-scale silicone rubber model of each anastomosis. Then we installed the transparent models in a circulatory experimental setup that simulated the physiological human blood flow. Flow velocity was measured with the one-component Laser-Doppler-Anemometer system, recording flow axial and perpendicular to the model at four defined cross-sections for seven heart cycles in each model. Maximal and minimal axial velocities ranged in the conventional model between 0.269 and -0.122 m/s and in the experimental model between 0.313 and -0.153 m/s. A less disturbed flow velocity distribution was seen in the experimental model distal to the anastomosis. The OES-technique showed superior flow profiles distal to the anastomosis with minor tendencies of flow separation and represents a new alternative for end-to-side anastomosis.

Use of the slit arteriotomy for end-to-side arterial anastomosis in free-tissue transfers to the extremities

INTRODUCTION

The purpose of this study was to demonstrate the reliability and advantages of the slit arteriotomy for end-to-side arterial anastomosis.

MATERIALS AND METHODS

Sixty free flaps for reconstruction of the upper and lower extremities were re-vascularised using this technique. Flaps used were: gracilis (20), latissimus dorsi (18), rectus abdominis (6), lateral arm (6), fibula (3), radial forearm (4), scapular (1) and anterolateral thigh (2).

TECHNIQUE

A double microclamp is applied. Using a 30 degrees microknife, a longitudinal slit is made on the recipient vessel. The clamps are then approximated slightly. This slackens the segment bearing the slit and opens up the slit to facilitate placement of sutures. Beginning at the heel, interrupted sutures are placed in such a way as to feed the redundancy of the donor artery wall towards the toe of the anastomosis. A slightly oversized slit is used to stretch the donor vessel, which due to its inherent elastic recoil keeps the anastomosis patent. Once the tourniquet is released, blood flow resumes and the slit forms an elliptical opening. A video is available for viewing at our website: www.microflap.com.

RESULTS

The arterial patency rate was 98%. The mechanical advantage of the slit arteriotomy construct was demonstrated through computer simulation on a finite-element analysis model.

CONCLUSION

The slit arteriotomy is simple, reliable, and can be consistently used in the transfer of free flaps to the extremities. As no portion of the recipient vessel wall is excised, the anastomotic diameter is increased. This promotes blood flow through the anastomosis.

Prevention of Microsurgical Anastomotic Thrombosis Using Aspirin, Heparin, and the Glycoprotein IIb/IIIa Inhibitor Tirofiban

BACKGROUND

Recent clinical trials involving patients with acute coronary syndromes have demonstrated significant reduction in the progression of coronary artery thrombosis using a regimen of aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban. Acute coronary syndromes and free tissue transfer are similar pathophysiologically in that they both involve endothelial injury, thrombosis, and ischemia. In this study, the authors investigate tirofiban, combined with aspirin and heparin, for the prevention of microsurgical anastomotic thrombosis in a thrombogenic rat model.

METHODS

Using a randomized, controlled, double-blind experimental design, 80 thrombogenic anastomoses were performed on rat femoral arteries (n = 40) and veins (n = 40). Preoperatively, each rat received one of four treatment regimens: aspirin and heparin (regimen 1), aspirin and heparin plus tirofiban (regimen 2), tirofiban alone (regimen 3), or isotonic saline (control) (regimen 4). Vessels were assessed for patency at 5, 15, 30, and 120 minutes after reperfusion and then harvested for microscopic analysis.

RESULTS

At 120 minutes after reperfusion, regimen 1 had an arterial and venous patency rate of 80 percent and 70 percent, respectively, whereas the vessel patency rate for regimen 2 was 100 percent. The difference between regimens 1 and 2 was not statistically significant. Regimens 3 and 4 had vessel patency rates of 40 percent or less. The aspirin/heparin and aspirin/heparin/tirofiban groups both demonstrated significantly improved vessel patency and significantly less thrombotic occlusion compared with controls.

CONCLUSIONS

Combination therapy with aspirin, heparin, and tirofiban significantly increases arterial and venous patency and decreases anastomotic thrombus formation in thrombogenic anastomoses in rats. The role of glycoprotein IIb/IIIa inhibitors in microsurgery warrants further investigation.

Femoral nerve palsy after mandibular reconstruction with microvascular iliac flap: a complication under anticoagulation therapy

Pharmacological prophylaxis and intervention are used extensively in head and neck reconstructions with microvascular flaps. There is no universally accepted protocol, but the microvascular surgery literature recommends intraoperative anticoagulation with heparin. Here is reported a case of iliacus haematoma with subsequent femoral nerve palsy after the harvest of a microvascular iliac flap for mandibular reconstruction in a patient who had been treated with heparin. The association between femoral nerve palsy and anticoagulant therapy has been well described. It remains unclear as to why the iliacus muscle is particularly vulnerable to intramuscular haemorrhage. Femoral nerve neuropathy is also an uncommon but recognized complication after abdominopelvic surgery. Iliacus haematoma secondary to microvascular surgery has not been previously reported. This case illustrates the need to be aware of this type of complication and its clinical manifestations for patients under anticoagulant therapy in the perioperative period during microvascular reconstructions.

Anticoagulation therapy in microsurgery: a review

The advent of microsurgical tissue transfer including replantation greatly has expanded the scope of reconstructive surgery. There are few recent innovations in anticoagulation therapies for microsurgery, however, and anastomotic thrombosis remains an occasional cause of surgical failure. No consensus exists on the ideal anticoagulation protocol for microsurgery. This article reviews major pharmacologic modalities of anticoagulation, delineates the mechanism of action and study of efficacy of each agent, and compares the risks and benefits of popular anticoagulation therapies. Finally, it examines available human outcomes-based data and attempts to provide a glimpse of the future direction of microsurgical anticoagulation research.

Simple and reliable procedure for end-to-side microvascular anastomosis: The diamond technique

In the last few decades, microsurgery has become a reliable technique in reconstructive surgery due to numerous technical and conceptual advances. End-to-side anastomosis is currently preferred by many microsurgeons. Many recent clinical and experimental studies showed no significant difference between the slit and hole techniques for end-to-side anastomosis. We propose a different technique, based on geometrical planning of arteriotomies on both the recipient and pedicle artery. The diamond technique is easy to execute, simple, and reliable, with many advantages, and should be kept in mind in selected patients.

End-to-side venous anastomoses....a patency test

A hitherto unpublished means of testing the patency across an end-to-side venous anastomosis is described. It relies on the elasticity of the venous walls to produce ballooning when the appropriate segments of the veins are occluded and blood is flowing unimpeded across the end-to-side anastomosis. It is foolproof, easy to perform and has no ambiguity in its interpretation.

O retalho hipogástrico cutâneo no cão: modelo para o aprendizado experimental de microcirurgia

O treinamento em microcirurgia constitui-se de diversas etapas, uma delas é a prática em animais. Retalhos microcirúrgicos cutâneos no cão são pouco descritos na literatura médica. Objetivo: O presente trabalho propõe um modelo de retalho hipogástrico cutâneo no cão centrado nos vasos circunflexos laterais. Métodos: Foram utilizados nove cães de raças e idades desconhecidas e peso variando entre 8 e 15kg. Descrevem-se com detalhes todos os passos seguidos no procedimento. O fluxo das anastomoses foi comprovado por observação direta, teste de enchimento (empty-and-refill test) imediatamente após as microanastomoses, por doppler após uma hora do procedimento e por avaliação clínica (coloração do retalho e sangramento após furo com agulha). Resultados: Todos os retalhos mostraram-se viáveis pelos critérios acima descritos. Conclusão: Este é um instrumento valioso para os que desejam aprender microcirurgia de forma autodidata, pois o modelo é dotado de todos os requisitos necessários para o aprendizado de microcirurgia experimental.

Different venous end-to-side microanastomotic techniques: comparative study in a new rat model

End-to-side venous anastomosis is sometimes necessary when there is the lack of a suitable vein, when there is a size discrepancy in the veins to be repaired, or when the anastomosis of multiple veins is required. The effects of elliptical vs. slit venotomy on vessel patency have not been investigated in a flap model. A new, simple, reliable, and reproducible model is described in which the femoral vein of the groin flap is anastomosed to the side of the deep dorsal penile vein. Elliptical hole and slit venotomies were tested in 26 Sprague-Dawley rats, and the anastomoses were 100% patent. The type of venotomy was not found to affect patency. Either technique is equally valid in end-to-side venous anastomosis, and the model itself is convenient for training.

Pharmacologic optimization of microsurgery in the new millennium

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the mechanisms by which the three most common antithrombotic agents work. 2. Be familiar with accepted dosing levels for the three agents. 3. Understand the rationale for their use and formulate an algorithmic approach to microvascular thrombosis. Microsurgical anastomoses are largely technically dependent; however, there exists a finite rate of failure, with often devastating consequences. Pharmacologic prophylaxis and intervention are used extensively in microsurgical cases, yet a unified algorithm does not exist among the various basic science and clinical studies in the literature. This results in a confusing and nonstandardized practice based on anecdotal experiences. The purpose of this article is to review the literature on this topic and synthesize a practical clinical management algorithm for pharmacologic therapy in microsurgery.

Coronary anastomotic devices: theory and patented ideas on micromechanical fastening

Coronary anastomotic devices are being designed to reduce the laborious, complex suturing approach to endoscopic coronary surgery. An anastomotic device should be safe and reliable, it should allow full view of the vessel parts to be bonded, it must provide a simple and rapid deployment, and should be hemodynamically adequate. Three anastomotic device categories found in the (patent) literature are discussed that use micromechanical fastening techniques. First, devices using individual bonding elements; second, devices using bonding elements anchored to extra-luminal frames; third, devices using an internal frame, often a stent-like structure. Anastomotic devices described in the (patent) literature to date fail to meet all requirements for endoscopic coronary application.