Absorbable cyanoacrylate surgical sealant in kidney transplantation

A prospective, randomized, pilot trial of a polyethylene glycol (PEG)-coated collagen patch (Hemopatch®) for intraoperative hemostasis during deceased donor renal transplant

INTRODUCTION

The objective of this study was to evaluate the safety and feasibility of using a polyethylene glycol (PEG)-coated collagen patch (Hemopatch^®) in patients undergoing deceased donor renal transplant. The primary outcome was the amount of intraoperative estimated blood loss in those patients receiving the patch compared to without. Secondary outcomes were the subjective achievement of hemostasis, perigraft collection, and drop in hemoglobin 48 hours postoperatively.

METHODS

We performed a single-center, prospective, randomized trial. Patients scheduled to undergo deceased donor renal transplant surgery were randomized to receive the PEG-coated patch or standard hemostasis (i.e., electrocautery and clips).

RESULTS

A total of 30 patients were enrolled over 15 months and randomized to receive the PEG-coated patch (n=15) or standard hemostasis (n=15). The mean age was 62.5 years. As determined by the operating surgeon, hemostasis was successfully achieved in all 15 cases using the PEG-coated patch. In the PEG-coated patch group, there was a trend towards less estimated blood loss (237 cc vs. 327 cc; p=0.11) and a lower drop in hemoglobin 48 hours postoperatively (22.27 g/L vs. 29.53 g/L; p=0.09) compared to the standard hemostasis group. Perigraft collection was similar between groups (27% vs. 40%; p=0.43). Subgroup analysis on patients who received anticoagulation therapy revealed no significant difference in blood loss between groups.

CONCLUSIONS

Based on our single-center experience, the PEG-coated patch (Hemopatch^®) is a safe and feasible option to aid hemostasis during deceased donor renal transplant surgery. Hemostasis was successfully achieved in all cases using the PEG-coated patch.

Behaviour of the Biological Adhesives TachoSil®, GelitaSpon®, and a New Elastic Cyanoacrylate (Adhflex®) in Experimental Renal Trauma and Wound Healing

BACKGROUND

Renal injuries are relatively frequent in abdominal trauma. In some cases, adhesives and sealants can be used to repair and preserve injured organs. This paper describes the behaviour of three biomaterials - TachoSil®, GelitaSpon®, and a new elastic cyanoacrylate (CyA), Adhflex® - in standardized experimental renal injuries.

METHODS

Ninety male Wistar rats (300-350 g) were used. A Stiefel Biopsy Punch (8 mm diameter, 3 mm depth) was used to create injuries to the anterior kidney to evaluate wound healing. The animals were divided into five groups: (1) sham (n = 3); (2) control (n = 6), untreated, standard punch injury created on the anterior left kidney; (3) TachoSil® (n = 27), punch injury treated with TachoSil®; (4) GelitaSpon® (n = 27), punch injury treated with GelitaSpon®, and (5) Adhflex® (n = 27), punch injury treated with the new elastic CyA adhesive. The parameters studied were bleeding time, peritoneal adhesions, and histopathological evaluation of wound healing on days 2, 6, and 18, including measurements of the gap between wound edges, inflammatory reaction (CD68), and vascular neoformation (CD31).

RESULTS

The bleeding time was significantly shorter (27.7 ± 12.9 s) in the Adhflex® group than in the control (135.8 ± 11.6 s; p < 0.01), TachoSil® (77.5 ± 7.4 s; p < 0.05), and GelitaSpon® (82.5 ± 14.4 s; p < 0.05) groups. The incidence of intraperitoneal adhesions in the animals treated with Adhflex® was 3.6 times higher than in the non-treated group. It was also higher (p < 0.04) than in the groups treated with TachoSil® and GelitaSpon®. The time point with the largest gap between the wound edges and most abundant granulation tissue was at day 6. The largest gap after 18 days was reported for the Adhflex® adhesive. With regard to the markers CD31 and CD68, Adhflex® showed the largest areas 2 days after surgery, but no differences were found after 6 and 18 days versus the other treatments. The expression of the immunomarkers on the renal samples treated with Adhflex® was consistent with a normal healing process.

CONCLUSIONS

In this experimental model of renal injuries, the new elastic CyA (Adhflex®) resulted in the shortest bleeding time. It offers rapid sealing of the bleeding produced by renal injuries, fixation to adjacent tissues, and reduced occurrences of relapse. The evolution of the scarring is similar to other procedures. Given that traumatic renal injuries are always an emergency due to haemorrhage, Adhflex® might offer additional benefits over conventional treatment methods in human clinical practice.

Adhesive and sealant interfaces for general surgery applications

The main functions of biological adhesives and sealants are to repair injured tissues, reinforce surgical wounds, or even replace common suturing techniques. In general surgery, adhesives must match several requirements taking into account clinical needs, biological effects, and material features; these requirements can be fulfilled by specific polymers. Natural or synthetic polymeric materials can be employed to generate three-dimensional networks that physically or chemically bind to the target tissues and act as hemostats, sealants, or adhesives. Among them, fibrin, gelatin, dextran, chitosan, cyanoacrylates, polyethylene glycol, and polyurethanes are the most important components of these interfaces; various aspects regarding their adhesion mechanisms, mechanical performance, and resistance to body fluids should be taken into account to choose the most suitable formulation for the target application. This review aims to describe the main adhesives and sealant materials for general surgery applications developed in the past decades and to highlight the most important aspects for the development of future formulations.

Surgical Materials: Current Challenges and Nano-enabled Solutions

Surgical adhesive biomaterials have emerged as substitutes to sutures and staples in many clinical applications. Nano-enabled materials containing nanoparticles or having a distinct nanotopography have been utilized for generation of a new class of surgical materials with enhanced functionality. In this review, the state of the art in the development of conventional surgical adhesive biomaterials is critically reviewed and their shortcomings are outlined. Recent advancements in generation of nano-enabled surgical materials with their potential future applications are discussed. This review will open new avenues for the innovative development of the next generation of tissue adhesives, hemostats, and sealants with enhanced functionality for various surgical applications.