Comparison of 2-octyl cyanoacrylate adhesive, fibrin glue, and suturing for wound closure in the porcine urinary tract

Effects of cyanoacrylate on leakage pressures of cooled canine cadaveric jejunal enterotomies

OBJECTIVE

To compare the intraluminal initial and maximal pressures of enterotomies closed using three different techniques (single-layer appositional continuous closure; closure with cyanoacrylate; a single-layer appositional closure augmented with cyanoacrylate) in a cooled canine cadaveric jejunal model and to report the initial leak location in all samples.

STUDY DESIGN

Experimental, ex-vivo study.

SAMPLE POPULATION

Grossly normal chilled small intestine segments from three canine cadavers.

METHODS

A total of 45 chilled jejunal segments (n = 15 segments/group) were assigned to a handsewn group (HSE), a cyanoacrylate only group (CE) and a handsewn and cyanoacrylate group (HS + CE). A 2 cm antimesenteric enterotomy was performed and closure with one of the above techniques. Initial leakage pressures (ILP), maximal intraluminal pressures (MIP) and initial leakage location were recorded by a single observer.

RESULTS

Handsewn enterotomies leaked at higher ILP when augmented with cyanoacrylate (83.3 ± 4.6 mmHg, p < .001) compared to both the HSE group (43.8 ± 5.3 mmHg) and the CE group (18.6 ± 3.5 mmHg). Those sealed with cyanoacrylate only leaked at a lower MIP compared with the other groups (p < .001). Maximal intraluminal pressures did not differ between handsewn enterotomies, whether augmented or not (p = .19).

CONCLUSION

Reinforcement of a sutured enterotomy closure with cyanoacrylate was easy to perform and resulted in significantly increased initial leak pressures in cadaveric jejunum.

CLINICAL SIGNIFICANCE

The increased leakage pressures achieved by reinforcing enterotomies with cyanoacrylate could consequently reduce the incidence of postoperative intestinal leakage following an enterotomy and may result in reduced patient morbidity or mortality.

Preclinical evaluation of a regenerative immiscible bioglue for vesico-vaginal fistula

Currently, there are no clinically available tissue adhesives that work effectively in the fluid-rich and highly dynamic environments of the human body, such as the urinary system. This is especially relevant to the management of vesico-vaginal fistula, and developing a high-performance tissue adhesive for this purpose could vastly expand urologists' surgical repertoire and dramatically reduce patient discomfort. Herein, we developed a water-immiscible mussel protein-based bioadhesive (imWIMBA) with significantly improved properties in all clinical respects, allowing it to achieve rapid and strong underwater adhesion with tunable rheological properties. We evaluated in vivo potential of imWIMBA for sealing thermally injured fistula tracts between the bladder and vagina. Importantly, the use of imWIMBA in the presence of prolonged bladder drainage resulted in perfect closure of the vesico-vaginal fistula in operated pigs. Thus, imWIMBA could be successfully used for many surgical applications and improve treatment efficacy when combined with conventional surgical methods. STATEMENT OF SIGNIFICANCE: Vesico-vaginal fistula (VVF) is an abnormal opening between the bladder and the vagina, which is a stigmatized disease in many developing countries. Leakage of urine into internal organs can induce serious complications and delay wound repair. Conventional VVF treatment requires skillful suturing to provide a tension-free and watertight closure. In addition, there is no clinically approved surgical glue that works in wet and highly dynamic environments such as the urinary system. In this work, for potential clinical VVF closure and regeneration, we developed an advanced immiscible mussel protein-based bioglue with fast, strong, wet adhesion and tunable rheological properties. This regenerative immiscible bioglue could be successfully used for sealing fistulas and further diverse surgical applications as an adjuvant for conventional suture methods.

Histopathological Comparison of 2-Octyl Cyanoacrylate and Primary Suturing for Tongue Lacerations

OBJECTIVE

To enable tongue incisions to be repaired more easily, rapidly, and practically, particularly in pediatric patients by using 2-octyl cyanoacrylate (OCA) tissue adhesive.

METHODS

A single linear incision was made on the midline dorsal part of the tongue. Twenty-four rats were randomly divided into the four groups: Group 1 (n = 6), OCA healing at day 5; group 2 (n = 6), OCA healing at day 21; group 3 (n = 6), Vicryl healing at day 5; group 4 (n = 6), Vicryl healing at day 21. In groups 1 and 2, OCA was applied to the incision site. The incisions of the rats in groups 3 and 4 were closed using Vicryl sutures. Histopathological examination was compared between and within the groups at day 5 and 21.

RESULTS

The operation duration was significantly shorter with OCA than with Vicryl sutures(P < 0.001). Regarding the histopathological results, there were no differences between group 1 and group 3 in epithelial regeneration, inflammation, fibroblastic activity, edema, presence of giant cells, fibrin deposition, ulceration, abscess formation, and granulation tissue. However, moderate infiltration of acute inflammatory cells was significantly more frequent in group 1 than in group 3. At day 5, the incidence of moderate foreign body residue was significantly higher in group 1 than in group 3. No difference was observed between group 2 and group 4 at day 21 (P > 0.05).

CONCLUSION

OCA is a practical, rapid, and effective method for repairing tongue lacerations. Although infiltration by inflammatory cells and foreign bodies increased in the early period, the long-term results of OCA were indistinguishable from those of suturing.

From poly(alkyl cyanoacrylate) to squalene as core material for the design of nanomedicines

This review article covers the most important steps of the pioneering work of Patrick Couvreur and tries to shed light on his outstanding career that has been a source of inspiration for many decades. His discovery of biodegradable poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs) has opened large perspectives in nanomedicine. Indeed, NPs made from various types of alkyl cyanoacrylate monomers have been used in different applications, such as the treatment of intracellular infections or the treatment of multidrug resistant hepatocarcinoma. This latest application led to the Phase III clinical trial of Livatag^®, a PACA nanoparticulate formulation of doxorubicin. Despite the success of PACA NPs, the development of a novel type of NP with higher drug loadings and lower burst release was tackled by the discovery of squalene-based nanomedicines where the drug is covalently linked to the lipid derivative and the resulting conjugate is self-assembled into NPs. This pioneering work was accompanied by a wide range of novel applications which mainly dealt with the management of unmet medical needs (e.g. pancreatic cancer, brain ischaemia and spinal cord injury).

Surface modification of polypropylene surgical meshes for improving adhesion with poloxamine hydrogel adhesive

Tissue adhesive has notable clinical benefits in hernia repair fixation. A novel poloxamine tissue adhesive was previously shown to successfully bond collagen tissue with adequate adhesive strength. In application related to attachment of polypropylene (PP) mesh, the adhesive strength between the mesh and poloxamine hydrogel adhesive is limited by the hydrophobicity of PP monofilaments and lack of covalent bond formation. The purpose of this study was to compare two different surface modifications [bovine serum albumin (BSA) adsorption and poly-glycidyl methacrylate/human serum albumin (PGMA/HSA) grafting] of PP mesh for improving the adhesive strength between poloxamine hydrogel adhesive and PP mesh. The PGMA/HSA surface modification significantly improved the adhesive strength for meshes attached with poloxamine hydrogel tissue adhesive compared with unmodified meshes and meshes modified by BSA adsorption. An area of 1 cm² adhesive provided for a maximum adhesive strength of 65-70 kPa for meshes modified by PGMA/HSA, 4-13 kPa for meshes modified by BSA, and 22-45 kPa for unmodified meshes. Optical microscopy and infrared spectroscopy (FTIR) confirmed the improved adhesive strength was achieved through mechanical interlock of the hydrogel tissue adhesive into the PP mesh pores and chemical bonding of the albumin after successful PGMA/HSA grafting onto the PP monofilaments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1047-1055, 2019.

Biocompatible alkyl cyanoacrylates and their derivatives as bio-adhesives

Cyanoacrylate adhesives and their homologues have elicited interest over the past few decades owing to their applications in the biomedical sector, extending from tissue adhesives to scaffolds to implants to dental material and adhesives, because of their inherent biocompatibility and ability to polymerize solely with moisture, thanks to which they adhere to any substrate containing moisture such as the skin.

Development and characterization of novel highly-loaded itraconazole poly(butyl cyanoacrylate) polymeric nanoparticles

Treatment of cryptococcal meningitis with antifungals such as itraconazol is difficult due their low concentration in the brain. Therefore, drug carriers with high payload are highly desired. But, generation of itraconazole loaded poly(butyl cyanoacrylate) nanoparticles with higher drug load, for instance more than 20% drug, is challenging. In present study we were able to generate novel highly loaded itraconazole poly(butyl cyanoacrylate) nanocapsules containing up to 99% (w/w) itraconazole and 1% polymer (w/w). Moreover, a controllable manufacturing procedure using a one-step emulsion solvent evaporation technique was established in order to discriminate between itraconazole loaded nanocapsules and nanospheres. Furthermore, it could be demonstrated that our novel nanocapsules can be decorated with targeting molecules such as apolipoprotein E. More precisely, apolipoprotein E was covalently bound to a maleimide linker, which was integrated within the surface of polymeric nanoparticle. This covalent binding of apolipoproteinE to the surface of a drug delivery system enables targeting of low density lipoprotein receptor (LDLR) expressed on endothelial brain capillary cell membranes, making our novel highly loaded itraconazole poly(butyl cyanoacrylate) nanocapsules a promising drug delivery system for treatment of cryptococcal meningitis.

Introduction of 2-octyl cyanoacrylate (Dermabond®) for incisional hernia mesh repair

PURPOSE

We developed a new technique, sutureless mesh fixation, using 2-octyl cyanoacrylate (Dermabond^®, a surgical tissue adhesive) for incisional hernia repair. The objective of this article is to introduce the new technique and to examine whether the technique provides sufficient resistance to abdominal pressure.

METHODS

We conducted two tests using a porcine model, a traction experiment and artificial pneumoperitoneum test. In the traction experiment, the adherence properties of Dermabond^® with mesh and peritoneum were examined using a tissue fragment from a pig. In the artificial pneumoperitoneum test, which used an incisional hernia porcine model, mesh was implanted on the peritoneum in the abdominal cavity with Dermabond^®. It was then determined whether sutureless mesh fixation could bear artificial abdominal air pressure.

RESULTS

In the traction experiment, Dermabond^®, which bonded the mesh to the peritoneum, tolerated pressure up to 2.45 × 10³ mmHg. In the artificial pneumoperitoneum test, the mesh was strongly fastened to the peritoneum by means of only Dermabond^®, and there was little air circulation even without closing the wound over the mesh.

CONCLUSIONS

Sutureless mesh fixation with Dermabond^® is technically feasible and promises to provide sufficient resistance to abdominal pressure.

Pharmacokinetics on a microscale: visualizing Cy5-labeled oligonucleotide release from poly(n-butylcyanoacrylate) nanocapsules in cells

For successful design of a nanoparticulate drug delivery system, the fate of the carrier and cargo need to be followed. In this work, we fluorescently labeled poly(n-butylcyanoacrylate) (PBCA) nanocapsules as a shell and separately an oligonucleotide (20 mer) as a payload. The nanocapsules were formed by interfacial anionic polymerization on aqueous droplets generated by an inverse miniemulsion process. After uptake, the PBCA capsules were shown to be round-shaped, endosomal structures and the payload was successfully released. Cy5-labeled oligonucleotides accumulated at the mitochondrial membrane due to a combination of the high mitochondrial membrane potential and the specific molecular structure of Cy5. The specificity of this accumulation at the mitochondria was shown as the uncoupler dinitrophenol rapidly diminished the accumulation of the Cy5-labeled oligonucleotide. Importantly, a fluorescence resonance energy transfer investigation showed that the dye-labeled cargo (Cy3/Cy5-labeled oligonucleotides) reached its target site without degradation during escape from an endosomal compartment to the cytoplasm. The time course of accumulation of fluorescent signals at the mitochondria was determined by evaluating the colocalization of Cy5-labeled oligonucleotides and mitochondrial markers for up to 48 hours. As oligonucleotides are an ideal model system for small interfering RNA PBCA nanocapsules demonstrate to be a versatile delivery platform for small interfering RNA to treat a variety of diseases.

Mechanical characterization of a bifunctional Tetronic hydrogel adhesive for soft tissues

Although a number of tissue adhesives and sealants for surgical use are currently available, attaining a useful balance in high strength, high compliance, and low swelling has proven difficult. Recent studies have demonstrated that a four-arm poly(propylene oxide)-poly(ethylene oxide) block copolymer, Tetronic, can be chemically modified to form a hydrogel tissue adhesive (Cho et al., Acta Biomater 2012;8:2223-2232; Barrett et al., Adv Health Mater 2012;1-11; Balakrishnan, Evaluating mechanical performance of hydrogel-based adhesives for soft tissue applications. Clemson University, All Theses, Paper 1574: Tiger Prints; 2013). Building on the success of these studies, this study explored bifunctionalization of Tetronic with acrylates for chemical crosslinking of the hydrogel and N-hydroxysuccinimide (NHS) for reaction with tissue amines. The adhesive bond strengths of various uni and bifunctional Tetronic blends (T1107 ACR: T1107 ACR/NHS) determined by lap shear testing ranged between 8 and 74 kPa, with the 75:25 (T1107 ACR: T1107 ACR/NHS) blend displaying the highest value. These results indicated that addition of NHS led to improvement of tissue bond strength over acrylation alone. Furthermore, ex vivo pressure tests using the rat bladder demonstrated that the bifunctional Tetronic adhesive exhibited high compliance and maintained pressures under hundreds of filling and emptying cycles. Together, the results of this study provided evidence that the bifunctional Tetronic adhesive with a proper blend ratio may be used to achieve an accurate balance in bulk and tissue bond strengths, as well as the compliance and durability for soft tissue such as the bladder.

Silk fibroin and polyethylene glycol-based biocompatible tissue adhesives

Tissue sealants have emerged in recent years as strong candidates for hemostasis. A variety of formulations are currently commercially available and though they satisfy many of the markets' needs there are still key aspects of each that need improvement. Here we present a new class of blends, based on silk fibroin and chemically active polyethylene glycols (PEGs) with strong adhesive properties. These materials are cytocompatible, crosslink within seconds via chemical reaction between thiols and maleimides present on the constituent PEGs and have the potential to further stabilize through β-sheet formation by silk. Based on the silk concentration in the final formulation, the adhesive properties of these materials are comparable or better than the current leading PEG-based sealant. In addition, the silk-PEG based materials show decreased swelling and longer degradation times. Such properties would make them suitable for applications for which the current sealants are contraindicated.

Suture-free anastomosis of the colon. Experimental comparison of two cyanoacrylate adhesives

BACKGROUND

We explored the potential of two cyanoacrylate tissue adhesives for constructing colonic anastomoses.

METHOD

The study involved 12 female domestic pigs. The animals were divided into two equal groups. In both groups, the sigmoid colon was transected. An intestinal anastomosis was constructed with a modified circular stapler (all staples were withdrawn) and cyanoacrylate tissue adhesives. Glubran 2 was used in group A and Dermabond was applied in group B. Fourteen days after the first operation, a follow-up surgery was performed in both groups. The glued section of the colon was resected, processed with the standard paraffin technique and stained with haematoxylin-eosin. The finished specimens were examined under light microscopy. Assessments were made for the presence of fibroblasts, neutrophils, giant polynuclear cells, neovascularisation and collagen deposits. Adhesions, anastomotic dehiscence, peri-anastomotic inflammation and intestinal healing were assessed peri-operatively.

RESULTS

All anastomoses in group A healed with no signs of pathology. In group B, fibrotic adhesions and stenoses tended to occur in areas surrounding the anastomoses. Histological examinations confirmed increased fibrosis.

CONCLUSION

The tissue adhesive Glubran 2 appears to be (under experimental conditions) a promising synthetic adhesive for colonic anastomosis construction; conversely, the tissue adhesive Dermabond was unsuitable for suture-free anastomosis construction.

Advances in bioadhesives, tissue sealants, and hemostatic agents

The use of bioadhesives, tissue sealants, and hemostatic agents has allowed for increased use of minimally invasive techniques for complex reconstructive urologic procedures. Hemostatic agents can facilitate clot formation through enzymatic reactions with host factors, mechanical compression, or a combination of the two. Tissue sealants and bioadhesives act through polymerization between themselves and adjacent tissues. This article reviews the unique features, mechanism of action, safety profile, and prototypical applications of the agents most commonly used in urologic surgery.

Is the use of cyanoacrylate in intestinal anastomosis a good and reliable alternative?

PURPOSE

The present study aims to compare strength, healing, and operation time of experimental intestinal anastomoses performed by polyglactin 910 (Vicryl; Ethicon, Edinburgh, United Kingdom) sutures with ethyl-2-cyanoacrylate glue (Pattex; Henkel, Dusseldorf, Germany).

MATERIAL AND METHODS

Ninety-six Sprague-Dawley rats were divided into 2 (groups E and L). Each group was further subdivided into 6 subgroups (EA1, EA2, EA3, EB1, EB2, EB3, LA1, LA2, LA3, LB1, LB2, LB3), each containing 8 rats. Intestinal anastomosis was performed by polyglactin 910 sutures in A subgroups and with ethyl-2-cyanoacrylate in B subgroups. The anastomosis was end to end in A1 and B1, side to side in A2 and B2, and end to side in A3 and B3. Time for anastomosis performance (AT) was recorded. In group E, bursting pressures and hydroxyproline levels were determined on the second postoperative day, whereas in group L, the same measurements were made on the sixth postoperative day. One-way analysis of variance was used for analyses of variance in the groups. Quantitative data were analyzed with Student's t test. P value was considered significant at less than .05.

RESULTS

There was no significant difference between bursting pressures of subgroup pairs on both postoperative days 2 and 6. Hydroxyproline levels and AT were significantly better in B subgroups.

CONCLUSION

Better healing, shorter AT, and equal strength were achieved with ethyl-2-cyanoacrylate compared with polyglactin 910 sutures in intestinal anastomosis in the experimental setting.

Comparison of healing after cystotomy and repair with fibrin glue and sutured closure in the porcine model

PURPOSE

We compared healing after laparoscopic cystotomy using fibrin glue, sutures, or a combination to determine whether fibrin glue can obviate the need for sutures and whether there is any detriment when glue is used in the presence of sutures.

MATERIALS AND METHODS

In 24 Yorkshire pigs, a 3.5 cm vertical cystotomy was created laparoscopically and repaired as follows: Group 1--no closure; group 2--fibrin glue closure; group 3--suture repair; group 4--combined fibrin glue and suture repair. All animals had a Foley catheter for 1 week. In each group, three animals were harvested at 1 week (acute) and three animals were harvested at 6 weeks (chronic).

RESULTS

Acute: Group 1--all pigs had an unhealed defect that leaked when evaluated by cystography. Groups 2, 3, 4--mean leak pressures were 80, 97, and 60 cm H(2)O (P = 0.36), respectively. Mean bladder capacity was not significantly different between groups. Chronic: No leakage seen on a cystogram at 1 week; at 6 weeks, bladders were filled at > or =95 to 100 cm H(2)O without leakage. Histologically, there was more inflammation in the acute group v chronic group pigs. In the acute group pigs repaired with glue or suture + glue, there was more inflammation and less epithelial continuity than in the suture alone group. At 6 weeks, there was no difference between groups.

CONCLUSION

Fibrin glue provoked an intense inflammatory response that might have delayed healing acutely, resulting in a lower burst pressure in both scenarios in which it was used (i.e., alone or in combination with sutures). However, by 6 weeks, there did not seem to be any difference between groups either clinically or histopathologically.

Enhancing the tolerance of poly(isobutylcyanoacrylate) nanoparticles with a modular surface design

Polymer nanoparticles are designed as nanovehicles to carry drugs in the body in a controlled manner increasing the concentration of the biologically active substance in the diseased organs and cells. The safety and biocompatibility of these nanosystems are those of the many properties that nanoparticles must meet to be used in vivo. Here we show that the cytotoxicity profile of poly(isobutylcyanoacrylate) (PIBCA) nanoparticles is affected by the way the nanosystems were produced and by the design of their surface. It was found that the tolerance of PIBCA nanoparticles by cells could be improved up to 100-fold by coating their surface with polysaccharides and haemoglobin.

The Use of Hemostatic Agents and Sealants in Urology

PURPOSE

While hemostatic agents and sealants have long been used in the fields of surgery and urology, confusion persists about their indications for use and the optimal agent choice. We comprehensively defined and evaluated the scientific basis for hemostatic agent and sealant use in urology, and provide a conceptual framework for future research and discussion.

MATERIALS AND METHODS

A MEDLINE search of all available literature concerning hemostatic agents in urology was performed, including topical hemostats, anti-fibrinolytics, fibrin sealants and matrix hemostats. Select references were also chosen from the broader surgical literature. Animal studies, case reports, retrospective and prospective studies, and opinion articles were reviewed.

RESULTS

Hemostatic agents include a wide range of components. Recent literature has focused on fibrin sealants and matrix agents. Two main indications exist for hemostatic agents, including 1) hemostasis and 2) sealant. The best evidence for efficacy and safety exists for hemostasis, especially for nephrectomy and trauma. Newer data highlight urinary tract reconstruction, fistula and percutaneous tract closure, suture line strengthening and infertility as potential uses. Novel drug delivery and tissue engineering are areas with large clinical potential.

CONCLUSIONS

Hemostatic agent use is promising and yet unproven for most conditions currently treated in urology. Hemostasis continues to be the main indication, which is well established. Few trials have examined comparative efficacy among hemostatic agents and further prospective studies are needed to justify additional indications as well as determine the optimal mode of use. Minimally invasive surgery will further drive the use of hemostatic agents and sealants. Cost-effective, evidence based hemostatic agent use will continue to challenge all urologists.

Estudo da cicatrização nas lesões traumáticas esplênicas utilizando octil-2-cianoacrilato e fio de poliglecaprone 25

OBJETIVO: Estudar comparativamente a cicatrização e a formação de aderências em baço de ratos submetidos à trauma operatório e corrigidos utilizando octil-2-cianoacrilato (DE) e fio de poliglecaprone 25 (CA). MÉTODO: 30 ratos machos Wistar foram separados em três grupos de 10 animais, anestesiados de acordo com as normas do COBEA, submetidos à laparotomia xifopúbica e com uma tesoura Metzenbaum, foi realizada uma lesão esplênica com 4mm de profundidade, na borda anti-hilar do pólo inferior do baço. No Grupo CA, suturou-se a lesão com pontos contínuos de poliglecaprone 25; no Grupo DE, com octil-2-cianoacrilato e no Grupo CO, não houve sutura. Após 14 dias, os ratos foram submetidos à eutanásia e as aderências anotadas em protocolo próprio. O estudo anatomopatológico foi realizado nas colorações hematoxilina-eosina e Picro-Sirius, sendo do tipo fechado, duplo-cego. RESULTADOS: O Grupo DE apresentou menos aderências e menor reação de cicatrização tipo corpo estranho que o CA. Ambos mostram quantidade semelhante de colágeno jovem e maduro. CONCLUSÕES: O octil-2-cianoacrilato provocou menos aderências macroscópicas que o fio de poliglecaprone corado e não induziu cicatrização com reação de corpo estranho, mostrando-se efetivo no reparo das lesões traumáticas esplênicas, em ratos.

Evaluation of Hydrogel Tissue Sealant in Porcine Laparoscopic Partial-Nephrectomy Model

BACKGROUND AND PURPOSE

Laparoscopic partial nephrectomy (LPN) is technically challenging with a steep learning curve, primarily because techniques used to control bleeding on the cut surface of the kidney can be ineffective, inconsistent, or challenging. Hemostatic techniques can include intracorporeal suturing, vascular coagulation (argon-beam coagulator, bipolar cautery, laser), and application of various tissue sealants. There is no uniformity of opinion regarding which hemostatic technique is optimal for this application. CoSeal, a hydrogel (Baxter Healthcare Corp, Deerfield, IL), has been effective following vascular surgery but has not been applied to a partial-nephrectomy model. We evaluated the effectiveness of this hydrogel in controlling bleeding and sealing the collecting system by comparing it with intracorporeal suturing and fibrin sealant (Tisseel; Baxter) in a porcine laparoscopic partial-nephrectomy model.

MATERIALS AND METHODS

Bilateral synchronous upper-pole partial nephrectomies were performed in two groups of 18 farm pigs, and the three hemostatic techniques (suturing, Tisseel, CoSeal) were applied. In the first group, partial nephrectomies were performed and the pigs sacrificed 3 days postoperatively (acute group). In the second group, the pigs were euthanized 6 weeks postoperatively (chronic group). In both groups, weight, blood pressure, estimated blood loss, weight of the partial and completion nephrectomy specimen, presence/ absence of urinary leak on retrograde study, histopathologic findings, and complications were recorded.

RESULTS

The mean weight, blood pressure, estimated blood loss, histopathology findings, and weight of the partial and completion nephrectomy specimens were similar in the three groups. CoSeal did not adhere well to the renal parenchyma compared with Tisseel. All three animals in the acute CoSeal group and three of the six pigs in the sutured group had small urinary leaks during retrograde ureteral study, whereas none of the pigs in the fibrin-glue cohort had urinary leaks. There was one complication (urinary leak) in the CoSeal group, necessitating sacrifice of the animal on postoperative day 8 because of sepsis.

CONCLUSIONS

CoSeal is not as effective as fibrin glue in adhering to the cut renal surface and sealing the collecting system during laparoscopic partial nephrectomy.

What Happens to Hemostatic Agents in Contact with Urine? An in Vitro Study

BACKGROUND AND PURPOSE

As the indications for topical hemostatic agents increase in urology, the question arises: what happens to these agents when they enter the urinary collecting system? To answer this question, we performed a series of in-vitro experiments mixing three hemostatic agents with normal and sanguineous urine.

MATERIALS AND METHODS

Four commercially available topical hemostatic products: oxidized regenerated cellulose (Surgicel; Ethicon, Somerville, NJ), fibrin sealant (Tisseel VH Kit; Baxter Health Care Corporation, Irvine, CA), gelatin matrix hemostatic sealant (FloSeal; Baxter Health Care), and polyethylene glycol (CoSeal; Cohesion Technologies, Palo Alto, CA) were studied. Human urine (10 mL) was added to samples of each substance; this was done in triplicate. The 12 sample tubes were then capped and placed on a tube shaker at slow speed and 37 degrees C. Observations regarding consistency of the material were made at 6, 12, 24, 48, 72, 96, and 120 hours (5 days). Gelatin matrix hemostatic sealant was further tested in urine with various amounts of blood or blood clot; observations were again recorded out to 5 days.

RESULTS

Surgicel maintained its solid form when it initially came in contact with urine, but over a period of 5 days, it transformed into a mucoid substance with visible free-floating fibers. It did not dissolve completely in urine within 5 days. Gelatin matrix was immediately transformed by urine into a fine colloidal suspension that did not change over the 5 days of the study. Fibrin glue, after mixing of the two components (fibrinogen and thrombin) directly in the urine, and polyethylene glycol immediately formed a solid clot at the bottom of the test tube on contact with the urine. When the mixture of fibrin sealant was allowed to form for 15 minutes and then added to urine, it again maintained a solid form. After 72 hours, the fibrin glue became a semisolid gelatinous plug. On analysis at 5 days, the fibrin sealant clot had transformed into a cohesive mucoid gel, and the polyethylene glycol clot had not changed. The gelatin matrix hemostatic sealant, when in contact with blood or blood clot, appeared to either become part of a clot or to remain in a colloidal suspension. At 5 days, all clots had dissolved to fine particulate suspensions, and the gelatin matrix appeared as a fine suspension.

CONCLUSION

Fibrin glue and oxidized regenerated cellulose maintain a solid form when initially placed in direct contact with urine and then assume a semisolid gelatinous state, which is still present at 5 days. Polyethylene glycol forms a solid clot initially and does not change after 5 days. Only hemostatic gelatin matrix remained as a fine particulate suspension in both normal and sanguineous urine. The implications of these findings with regard to sealing the renal parenchyma or small violations of the collecting system after percutaneous or laparoscopic surgery await in-vivo testing.

Investigating the effects of bone cement, cyanoacrylate glue and marine mussel adhesive protein from Mytilus edulis on human osteoblasts and fibroblasts in vitro

Bone cement is a widely used standard fixation substance in Orthopaedic Surgery. Cyanoacrylate glue is available for wound closure to supplement suturing. The mussel adhesive protein extracted from Mytilus edulis (Cell-Tak, BD Biosciences, Heidelberg, Germany) is an experimental fixation device used for in vitro purposes of cell adhesion. The aim of this study is to introduce a cell culture model investigating the effects of commonly applied and experimental glues on human fibroblasts and osteoblasts in vitro. Cells cultured without additives served as a control group. Microscopic examination was performed to evaluate the morphologic changes. An apoptosis test (Apo-Tag, Chemicon International, Temecula, CA, U. S. A.) was applied to determine the rate of natural cell death at the end of the study. It could be demonstrated that morphological changes in bone cement are different in fibroblasts and osteoblasts. Osteoblasts seem to grow on bone cement and develop an orderly formation. Fibroblasts grow in a confluent monolayer around bone cement but do not adhere to the cement itself. This is a desirable effect since most Orthopaedic applications aim at osteointegration as opposed to fibrous tissue overgrowth. Apoptosis attributed to bone cement is comparable to the respective natural rate of apoptosis. Cyanoacrylate glue and the mussel adhesive protein lead to an almost complete apoptosis in the investigated cells. Their routine application should be avoided. The developed cell culture model seems appropriate for performing further investigations.

Poly(alkylcyanoacrylates) as biodegradable materials for biomedical applications

This review considers the use of poly(alkylcyanoacrylates) (PACAs) as biomedical materials. We first present the different aspects of the polymerization of alkylcyanoacrylate monomers and briefly discuss their applications as skin adhesives, surgical glues and embolitic materials. An extensive review of the developments and applications of PACAs as nanoparticles for the delivery of drugs is then given. The methods of preparation of the nanoparticles are presented and considerations concerning the degradation, in vivo distribution, toxicity and cytotoxicity of the nanoparticles are discussed. The different therapeutic applications are presented according to the route of administration of the nanoparticles and include the most recent developments in the field.

Vesicourethral anastomosis with 2-octyl cyanoacrylate adhesive in an in vivo canine model

OBJECTIVES

To evaluate the effectiveness of 2-octyl cyanoacrylate adhesive (OCA) in the formation of vesicourethral anastomoses.

METHODS

Open total prostatectomy was performed on 12 mongrel hounds. Of these, 8 had a vesicourethral anastomosis formed using OCA (4 with suture support and 4 sutureless). The remaining four anastomoses were conventionally formed using eight interrupted sutures. Acute leakage was tested intraoperatively. Before killing the hounds, the anastomosis of 1 animal in each group was assessed on postoperative days 3, 5, 7, and 14 by radiography. Each anastomotic specimen was then tested for leak pressure and examined histologically.

RESULTS

At intraoperative testing, one small leak was found in the sutureless OCA group. All other anastomoses were watertight intraoperatively. Radiographically, two leaks occurred in the OCA group with suture support, three leaks in the sutureless OCA group, and only one small localized leak in the control group. Only one of the eight anastomoses using OCA achieved a physiologic leak pressure greater than 70 mm Hg (one of these, however, could not be tested because of injury at the time the specimen was retrieved). The leak pressures of all four control-group anastomoses were 70 mm Hg or greater. Histologically, no significant differences were found in healing between the control and OCA anastomoses.

CONCLUSIONS

With or without suture support, OCA appears to be unsuitable for use in forming the large-diameter vesicourethral anastomosis required in radical prostatectomy.