2-Octylcynanoacrylate-assisted microvascular anastomosis in a rat model: long-term biomechanical properties and histological changes

Evaluation of fibrin, cyanoacrylate, and polyurethane-based tissue adhesives in sutureless vascular anastomosis: a comparative mechanical ex vivo study

The stability of a microvascular anastomosis is an important prerequisite for successful tissue transfer. Advances in tissue adhesives are potentially opening new avenues for their use in sutureless microsurgical anastomosis, however they have not yet gained clinical acceptance. In this ex vivo study, a novel polyurethane-based adhesive (PA) was used in sutureless anastomoses and its stability compared with that of sutureless anastomoses performed with fibrin glue (FG) and a cyanoacrylate (CA). Stability was assessed using hydrostatic (15 per group) and mechanical tests (13 per group). A total of 84 chicken femoral arteries were used in this study. The time taken to create the PA and CA anastomoses was significantly faster when compared to the FG anastomoses (P < 0.001): 1.55 ± 0.14 min and 1.39 ± 0.06 min, respectively, compared to 2.03 ± 0.35 min. Both sustained significantly higher pressures (289.3 mmHg and 292.7 mmHg, respectively) than anastomoses using FG (137.3 mmHg) (P < 0.001). CA anastomoses (0.99 N; P < 0.001) and PA anastomoses (0.38 N; P = 0.009) could both withstand significantly higher longitudinal tensile forces compared to FG anastomoses (0.10 N). Considering the background of an in vitro study, the PA and CA anastomosis techniques were shown to be similar to each other and superior to FG, due to their stability and faster handling. These findings need to be validated and confirmed in further in vivo studies.

Reduction of Anastomotic Time Through the Use of Cyanoacrylate in Microvascular Procedures

Background: Ever since the description of the first microvascular anastomosis, numerous alternative methods have been described to the classical approach. Tissue adhesive has shown promising result in previous studies and can be a fast and efficient alternative which still requires more studies to allow its clinical implementation. Methods: A randomized comparative experimental study was conducted on rats' femoral arteries and an end-to-end anastomosis was performed in order to compare 2 anastomosis techniques. In one group, a simple interrupted suture was utilized, whereas in the second group a combination between fewer sutures and tissue adhesive was used. The anastomotic time, total operative time, blood flow velocity before, immediately after and 48 hours after the procedure, as well as an independent grading of the anastomosis immediately after the procedure were performed. Magnetic resonance imaging (MRI) was performed in order to assess the degree of stenosis. After euthanasia, histology and scanning electron microscopy (SEM) were performed on the vessels in order to assess possible complications. Results: A total of 24 anastomoses were performed, of which 12 with a classic technique and 12 with an adhesive technique. All the anastomoses were patent with a significant reduction of anastomotic and total operative time. The grading of the anastomoses showed better results in the classic suture group. The blood flow velocities were not statistically significant between the 2 groups. On MRI there was one stenotic anastomosis, whereas histology and SEM showed more complications on the adhesive group. Conclusion: Anastomotic times were significantly lower with a non-significant trend toward more thrombotic complications in the adhesive group. Further improvement of the glue properties and refinement of the technique will likely make it a viable alternative to interrupted suturing in the future.

Sutureless venous microanastomosis using thermosensitive poloxamer and cyanoacrylate: experimental study on a rat model

INTRODUCTION

Sutureless microvascular anastomoses could simplify the microvascular field, shortening operative time and improving the final outcome. The use of thermosensitive poloxamers (TP407) together with the application of cyanoacrylate as an alternative method for conventional sutures was well-documented for arteries, but not for veins. The purpose of our study was to prove the feasibility of this technique for venous anastomoses and compare it with the traditional hand-sewn technique on a rat model.

MATERIALS AND METHODS

Twenty male Sprague-Dawley rats that weighed between 265 and 310 g were used. In the sutureless group (SG), 20 left external jugular veins (LEJV) end-to-end anastomoses were performed using a T704 and cyanoacrylate glue. They were compared to 20 right external jugular veins (REJV) anastomoses sutured with conventional 10-0 stitches (control group - CG). Diameters of veins, anastomosis time, and patency rate at 15 days were reported. Foreign body reaction was assessed histologically.

RESULTS

The mean diameter of the LEJV was 0.94 ± 0.1 mm and 0.95 ± 0.09 mm for the REJV. The mean anastomosis time was 11.9 ± 1.37 min for the SG and 27.75 ± 3.31 min for the CG. In the latter group, the immediate patency rate was 95% and 90% at 15 days. For the SG group, 90% of the anastomoses were patent immediately and 85% at 15 days.

CONCLUSION

TP407 and cyanoacrylate could offer a fast and reliable technique for sutureless venous anastomoses. Before human application, effectiveness of this method remains to be confirmed in larger animals in a long-term follow-up.

N-butyl cyanoacrylate- and alpha-cyanoacrylate induced hepatotoxicity and venous sclerosis in a rabbit model

BACKGROUND AND STUDY AIMS

Tissue adhesives are commonly used. The aim of this study was to assess the efficacy and hepatotoxicity of intravenous injection of N-butyl cyanoacrylate versus alpha-cyanoacrylate in a rabbit model.

MATERIALS AND METHODS

A total of 20 rabbits were divided into three groups: group I included four rabbits injected with lipiodol in the dorsal vein of a pinna (control group); group II included eight rabbits injected with N-butyl cyanoacrylate/lipiodol; and group III included eight rabbits injected with alpha-cyanoacrylate/lipiodol. All animals were left under normal living conditions for 1week, and then euthanised. Specimens of ear and liver were taken and fixed in 10% formalin saline for histological examination. Secondary fixation was performed using Bouin solution. Specimens of ear were decalcified in ethylenediaminetetraacetic acid (EDTA) at room temperature for 3months. Then, all specimens were processed, embedded in paraffin, sectioned, and stained with haematoxylin and eosin stains for microscopic examination.

RESULTS

Microscopic examination of all specimens of the control group revealed normal structure of pinna and liver tissue. Both test groups demonstrated a wide variability of structural changes ranging from oedema and congestion to necrosis and marked cellular inflammatory infiltration. The two groups were compared using a self-designed inflammatory score. This revealed that alpha-cyanoacrylate caused more venous sclerosis with extensive perivenous reaction and hepatotoxicity than both N-butyl cyanoacrylate and control (p<0.05 and p<0.05). N-butyl cyanoacrylate was also found to cause more venous sclerosis and hepatotoxicity than control (p<0.05).

CONCLUSION

This study suggested that injection of Krazy Glue, either the clinically usable N-butyl cyanoacrylate or the commercially available alpha-cyanoacrylate, caused comparable venous sclerosis. Unfortunately, both induced significant hepatotoxicity. Therefore, neither of them should be used unless all other safe options are absent. Larger studies have to be conducted and effects of these components on other organs should be investigated; however, caution must be exercised in their clinical use.

Non-suture technique for rabbit oviduct anastomosis with 2-octyl cyanoacrylate: a histopathologic and biomechanical analysis

AIM

The aim of this study was to investigate histological and biomechanical properties of oviduct anastomosis with 2-octyl cyanoacrylate (OCA) in the rabbit.

MATERIAL AND METHODS

Sixty female rabbits were randomly divided equally into three groups: A (control), B (traditional catgut suture), and C (non-suture technique using OCA). After suture or OCA anastomosis, gross examination (adhesion formation) and histopathology (hematoxylin-eosin), ultrastructure (transmission electron microscopy), and biomechanics (bursting pressure) on para-anastomotic site were investigated on oviduct taken at 1 (A1, B1, C1) and 4 (A2, B2, C2) weeks, respectively.

RESULTS

Adhesion score in group B was more severe than that in groups A and C at 1 and 4 weeks. Histopathology showed that acute endosalpingitis in group B was the most intense at 1 week, followed by significantly more tissue stimulation induced by catgut and foreign-body giant cells in group B than in group C at 4 weeks. Ultrastructural damage of ciliated cells was reversed partly (B2) and completely (C2) at 4 weeks. Bursting pressure in C1 was weaker than that in B1, followed by no significant difference at 4 weeks.

CONCLUSION

Non-suture using OCA for oviduct anastomosis can be accepted as a new-perspective technique.

Technology-assisted and sutureless microvascular anastomoses: evidence for current techniques

BACKGROUND

Since the birth of reconstructive microvascular surgery, attempts have been made to shorten the operative time while maintaining patency and efficacy. Several devices have been developed to aid microsurgical anastomoses. This article investigates each of the currently available technologies and attempts to provide objective evidence supporting their use.

METHODS

Techniques of microvascular anastomosis were investigated by performing searches of the online databases Medline and Pubmed. Returned results were assessed according to the criteria for ranking medical evidence advocated by the Oxford Centre for Evidence Based Medicine. Emphasis was placed on publications with quantifiable endpoints such as unplanned return to theatre, flap salvage, and complication rates.

RESULTS

There is a relative paucity of high-level evidence supporting any form of assisted microvascular anastomosis. Specifically, there are no randomized prospective trials comparing outcomes using one method versus any other. However, comparative retrospective cohort studies do exist and have demonstrated convincing advantages of certain techniques. In particular, the Unilink™/3M™ coupler and the Autosuture™ Vessel Closure System® (VCS®) clip applicator have been shown to have level 2b evidence supporting their use, meaning that the body of evidence achieves a level of comparative cohort studies.

CONCLUSION

Of the available forms of assisted microvascular anastomoses, there is level 2b evidence suggesting a positive outcome with the use of the Unilink™/3M™ coupler and the Autosuture™ VCS® clip applicator. Other techniques such as cyanoacrylates, fibrin glues, the Medtronic™ U-Clip®, and laser bonding have low levels of evidence supporting their use. Further research is required to establish any role for these techniques.

The use of cyanoacrylate in surgical anastomosis: an alternative to microsurgery

To present anastomosis with cyanoacrylate as a cheap, simple, fast, and available technique for anastomosis in urological, vascular, gynecological, and general surgical procedures. This method may in the future be a good alternative to microsurgery, particularly in centers where facilities are unavailable and the financial implication is unbearable for the patient. Cyanoacrylate is an adhesive or glue that is available in different chemical forms ranging from ethylcyanoacrylate (superglue) to Isobutylcyanoacrylate and octylcyanoacrylate (dermerbond), which is in clinical use. Anastomosis with cyanoacrylate requires the application of stay sutures, a luminal stent and the subsequent application of the adhesive. The adhesives with lower molecular weights produce a rigid and patent region of anastomosis, while the higher molecular compounds produce a consistency close to the normal tissue. This technique presents a surgical method that is socially, culturally, and ethically acceptable, which is affordable to a larger majority of patients in our subregion. Cyanoacrylate anastomosis may in the future present a fast, convenient, simple, and affordable option in the treatment of patients requiring anastomosis. In our subregion where the socio-cultural, psychological, and economic burden of failed anastomosis is high, associated with the low per capital income, this may be a novel option for the management of urogynecological, vascular, neurosurgical, and general surgical procedures requiring either microscopic or macroscopic anastomosis.

Vascular anastomosis using controlled phase transitions in poloxamer gels

Vascular anastomosis is the cornerstone of vascular, cardiovascular and transplant surgery. Most anastomoses are performed with sutures, which are technically challenging and can lead to failure from intimal hyperplasia and foreign body reaction. Numerous alternatives to sutures have been proposed, but none has proven superior, particularly in small or atherosclerotic vessels. We have developed a new method of sutureless and atraumatic vascular anastomosis that uses US Food and Drug Administration (FDA)-approved thermoreversible tri-block polymers to temporarily maintain an open lumen for precise approximation with commercially available glues. We performed end-to-end anastomoses five times more rapidly than we performed hand-sewn controls, and vessels that were too small (<1.0 mm) to sew were successfully reconstructed with this sutureless approach. Imaging of reconstructed rat aorta confirmed equivalent patency, flow and burst strength, and histological analysis demonstrated decreased inflammation and fibrosis at up to 2 years after the procedure. This new technology has potential for improving efficiency and outcomes in the surgical treatment of cardiovascular disease.

BioWeld® Tube and surgical glue for experimental sutureless venous microanastomosis

Background

The medial wall of mammalian veins is generally thin and fragile compared with the thick muscle seen in arteries. This makes venous microanastomoses time consuming and challenging. This study aimed to determine the feasibility and effectiveness of using the BioWeld® Tube in conjunction with a surgical glue (butyl-2-cyanoacrylate) in performing sutureless venous microanastomoses.

Methods

The feasibility and effectiveness of microvascular anastomoses in a rabbit jugular vein model were investigated in six animals, using the BioWeld® Tube in conjunction with butyl-2-cyanoacrylate surgical glue. Patency and tissue repair mechanisms at the anastomotic site were assessed 1 week after the procedure.

Results

All anastomoses remained patent at 1 week. Muscle necrosis occurred only in areas where the tissue was subject to the fold-and-bond procedure.

Conclusion

The study showed the feasibility and short-term effectiveness of the BioWeld® Tube in facilitating venous anastomoses.

Tissue adhesives and the pancreas: biocompatibility and adhesive properties of 6 preparations

OBJECTIVES

The aim of this study was to investigate biocompatibility and adhesive properties of 6 tissue adhesives available, when applied between the pancreas and jejunum in an experimental model.

METHODS

Portion of jejunum was glued on the pancreas in rats with 3 cyanoacrylate derivatives (Histoacryl, Dermabond, and Glubran 2), 2 human fibrin sealants (Tisseel Duo Quick and Quixil), and 1 albuminglutaraldehyde sealant (BioGlue). Pancreatic tissue specimens and blood samples were harvested 1, 3, 7, and 21 days after gluing for histological determination and amylase activity measurement. Pancreaticojejunal attachment created with adhesives underwent tensile strength measurement at each time point. Samples were also taken from unoperated rats and sham-operated rats.

RESULTS

Exposure and sham groups both induced a similar increase in amylase activity on day 1 with normalization by day 3. Sham operation induced mild changes in the pancreas. Each tissue adhesive induced changes in pancreatic histology to the entire gland. Injurious effect was more severe with the 3 cyanoacrylates than with the 3 fibrin/semisynthetic glues. Histoacryl and Quixil induced lower tensile strength than the other adhesives.

CONCLUSIONS

All of the tissue adhesives studied induced histological changes in the pancreas of which at least part might be considered harmful. The potentially harmful tissue effects of the preparations tested might compromise the use of these substances in pancreatic surgery.

Enhancing the strength of the tendon-suture interface using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and cyanoacrylate

PURPOSE

Preventing gap or rupture is important to achieving a successful outcome after tendon repair. Weak sutures break; strong sutures fail by pull-out at the tendon-suture interface. In this study, we investigated the use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and cyanoacrylate to enhance the strength of the tendon-suture interface.

METHODS

Twenty-four canine flexor digitorum profundus tendons were used to test EDC and cyanoacrylate reinforcement methods, with 12 tendons in each group. A single-loop suture technique was used to test the tendon-suture interface strength.

RESULTS

The mean ultimate strengths of the EDC group and the cyanoacrylate group were significantly higher than those of their respective control groups. The stiffness of the group with cyanoacrylate-augmented loops was significantly higher than that of its respective control group. There was no significant difference in stiffness between the 2 reinforcement methods.

CONCLUSIONS

Our results suggest that tendon-suture interface reinforcement may improve the pull-out failure strength of a suture construct and thereby increase the effectiveness of stronger suture materials. Future studies might address the effects of different kinds and methods of reinforcement with various suture materials and constructs and in different tissues.