2-Octyl cyanoacrylate to prevent salivary fistula formation following oral cavity microvascular reconstruction: A prospective trial.

BACKGROUND: Salivary fistulas remain a significant problem in patients undergoing major head and neck reconstructive surgery. Surgical sealants have become increasingly used in cutaneous and non-cutaneous wound closure, providing a barrier to fluids/gases and promoting healing. The purpose of this study was to determine the efficacy of a common surgical sealant, 2-Octyl Cyanoacrylate (2-OCA, Dermabond®), in the prevention of salivary fistulas following free flap reconstruction of the oral cavity. METHODS: In this non-randomized, single arm prospective trial, patients undergoing free flap reconstruction of gravity-dependent oral cavity defects were recruited. Application of 2-OCA was performed along flap inset suture lines at the time of surgery. Prospectively collected trial data were propensity score matched to a control cohort to compare outcomes. Data collected include demographics, medical co-morbidities, previous treatments, primary tumor site, and subsites reconstructed. The primary outcome measure was rate of salivary fistula formation. Secondary outcomes were time to development of leak and percentage of patients tolerating oral feeding at one month post-operatively. RESULTS: In the 46 propensity score matched pairs, eight (17.4%) out of 46 patients in the 2-OCA prospective cohort and seven (15.2%) out of 46 patients in the control cohort developed postoperative salivary fistulas within the one-month study interval (p = 1.00). The average time to postoperative leak in the 2-OCA group was 12.5 days versus 7.1 days in the control cohort (p = 0.10). In the 2-OCA group, 30 (65.2%) patients were tolerating regular diet at one month post-operatively compared to 33 (71.7%) in the control cohort (p = 0.65). CONCLUSION: Salivary fistula rates after application of a 2-OCA surgical sealant were not improved compared to a control cohort in this single institutional trial. There are several surgical sealants available, each with varying elasticity and adhesiveness. Future studies are needed to identify surgical sealants that are able to provide sufficient strength and adhesion to seal closures and combat corrosive saliva, but elastic enough to handle motion related tension during swallowing and post-operative movements in the head and neck.

[Application of adhesive compositions in surgery (in Russian only)]. / Primenenie kleevykh kompozitsii v khirurgii.

New adhesive compositions will almost completely prevent leakage of surgical sutures and undue tissue damage, improve healing and postoperative rehabilitation. At present time there is no universal type of bioadhesives that is suitable for all tissues and types of sutures because of various surgeries and their specificity. The article describes the advantages and disadvantages of all common types of bioadhesives, as well as the ways to overcome their disadvantages.

Effectiveness of Tachosil(®) in the prevention of postoperative pancreatic fistula after distal pancreatectomy: a systematic review and meta-analysis.

PURPOSE: Postoperative pancreatic fistula (POPF) is a frequent and clinically relevant problem after distal pancreatectomy. A variety of methods have been tested in the attempt to prevent POPF, most of them without convincing results. METHODS: A systematic literature search was conducted in PubMed, Embase and the Cochrane Library to identify clinical studies comparing pancreatic stump closure with the addition of Tachosil(®) to conventional stump closure. The identified studies were critically appraised, and meta-analyses were performed using a random-effects model. Dichotomous data were pooled using odds ratios, and weighted mean differences were calculated for continuous outcomes, together with the corresponding 95 % confidence intervals. RESULTS: Four studies (two randomised controlled trials and two retrospective clinical studies) reporting data from 738 patients were included in the meta-analysis. Overall POPF, clinically-relevant POPF, mortality, reoperations, intraoperative blood loss and length of hospital stay did not differ significantly between conventional closure and additional covering of the pancreatic stump with Tachosil(®). A sensitivity analysis of only randomised controlled trials confirmed the results. CONCLUSIONS: The application of Tachosil(®) to the pancreatic stump after distal pancreatectomy is a safe procedure but provides no relevant benefit in terms of POPF, mortality, reoperation rate, blood loss or length of hospital stay. Future research should concentrate on novel methods of pancreatic stump closure to prevent POPF after distal pancreatectomy.

Sprayable Hydrogel for Instant Sealing of Vascular Anastomosis.

Bleeding-related complications following vascular surgeries occur in up to half of the patients-500 000 cases annually in the United States alone. This results in additional procedures, increased mortality rate, and prolonged hospitalization, posing a burden on the healthcare system. Commercially available materials rely, in large, on forming covalent bonds between the tissue and the biomaterial to achieve adhesion. Here, it is shown that a biomaterial based on oxidized alginate and oxidized dextran together with polyamidoamine (PAMAM) dendrimer amine provides simultaneous electrostatic and covalent interactions between the biomaterial and the tissue, maximizing adhesion. This study finds that the material withstands supraphysiological pressures (≈300 mmHg) and prevents bleeding in a rabbit aortic puncture model and in a pig carotid bilateral poly(tetrafluoroethylene) graft model-achieving superior performance to commercially available materials such as Tisseel and BioGlue. Material biocompatibility is validated in comprehensive in vitro and in vivo studies in accordance with the US Food and Drug Administration (FDA) guidelines, including in vitro neutral red uptake test, subcutaneous implantation in rabbits, ames genotoxicity, and guinea pig maximization test. This material has the potential to provide with adequate seal and reduced complications following complex vascular surgeries, including hard-to-seal tissue-graft interfaces.

An adhesive and injectable nanocomposite hydrogel of thiolated gelatin/gelatin methacrylate/Laponite® as a potential surgical sealant.

Hemostatic adhesive hydrogels as sealants for surgical operations are one of the focus of the researches in the field of injectable materials. Herein, we evaluated the potential application of a mechanically robust nanocomposite hydrogel with significant adhesion strength and shorter blood clotting time. This hydrogel was composed of thiolated gelatin (Gel-SH) and gelatin methacrylate (GelMA) as the main matrix to support cell viability and proliferation, while polydopamine functionalized Laponite® (PD-LAP) were introduced to the structure to improve the mechanical properties, adhesion strength, and blood clotting. This hydrogel formed via Michael reaction between Gel-SH and GelMA, and covalent interaction between PD-LAP and hydrogel. Results revealed that presence of PD-LAP significantly controlled the swelling ratio, biodegradability, and mechanical properties of nanocomposite hydrogels. Tensile and compressive strength of nanocomposite hydrogels were measured in the range of 22-84 kPa and 54-153 kPa, respectively. Furthermore, nanocomposite hydrogels revealed excellent recovery ability, strong tissue adhesiveness and significantly less blood clotting time than Gel-SH/GelMA hydrogel (2.25 min). In the culture with L929 fibroblasts cells, viability more than 97% and high proliferation after 5 days of culture was estimated. The simplicity, low-cost, tunable mechanical properties, short blood clotting time, and cytocompatibility of the hydrogels composed of Gel-SH, GelMA, and PD-LAP highlight its potential as hemostat sealants.

Recent developments and clinical applications of surgical glues: An overview.

Novel developments in surgical glues for sealing wounds, surgical incision and tissue healing was inspired by limitations related to other surgical techniques. Sealants or bioadhesives are considered as a promising candidate over sutures, staples for sealing of air and gas leakages with minimal scarring in different surgeries. Their physical, biological properties and adhesive strength have encouraged many surgeons for employing them in clinical practice. Commonly, various natural biopolymers such as fibrin, collagen, gelatin, albumin, chitosan are used for the preparation of surgical glues. These biopolymers mimic the mechanism of physiological interaction such as blood clotting process. Besides natural polymers, synthetic polymers are also incorporated in surgical glues. Several sealants or adhesives are available commercially and have been used for neurosurgery, orthopaedic, periodontal, ophthalmic, cardiovascular, pneumothoracic, gastrointestinal, plastic and reconstructive surgery. This article focuses on providing a comprehensive review on the development of surgical glues, their unique features and application in clinical practice. In addition to the advantages of these sealants, the insights on their limitations, especially biocompatibility and tissue elasticity have been covered. Although the use of surgical glues is increasing gradually, the next generation of products should be marketed after extensive clinical studies and adequate safety and efficacy data.

Surgical sealants with tunable swelling, burst pressures, and biodegradation rates.

We developed two types of polyethylene glycol (PEG)-based surgical sealants, which we have termed the PER and PRO series. In one, the PRO series, an 8-arm PEG containing activated carbonyl end-groups was reacted with a 4-armed amino-PEG. In the second, the PER series, a 4-arm PEG containing bi-functional end groups with four azides and four activated esters was reacted by strain-promoted alkyne-azide cycloaddition with a 4-arm cyclooctyne-PEG to give a near-ideal Tetra-PEG hydrogel. The sealants showed predictably tunable strength, swelling, adhesion, and gelation properties. The gels were compared to commercially available PEG-based sealants and exhibit physical properties equivalent to or better than the standards. Variants of each gel-format were prepared that contained a ß-eliminative cleavable linker in the crosslinks to control degradation rate. Linkers of this type self-cleave with half-lives spanning from hours to years, and offer the unique ability to precisely tune the degradation to match the healing process. In addition, these linkers could serve as cleavable tethers for controlled drug release. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1602-1611, 2017.

Biodegradable-Polymer-Blend-Based Surgical Sealant with Body-Temperature-Mediated Adhesion.

The development of practical and efficient surgical sealants has the propensity to improve operational outcomes. A biodegradable polymer blend is fabricated as a nonwoven fiber mat in situ. After direct deposition onto the tissue of interest, the material transitions from a fiber mat to a film. This transition promotes polymer-substrate interfacial interactions leading to improved adhesion and surgical sealant performance.

Elastic sealants for surgical applications.

Sealants have emerged as promising candidates for replacing sutures and staples to prevent air and liquid leakages during and after the surgeries. Their physical properties and adhesion strength to seal the wound area without limiting the tissue movement and function are key factors in their successful implementation in clinical practice. In this contribution, the advances in the development of elastic sealants formed from synthetic and natural materials are critically reviewed and their shortcomings are pointed out. In addition, we highlight the applications in which elasticity of the sealant is critical and outline the limitations of the currently available sealants. This review will provide insights for the development of novel bioadhesives with advanced functionality for surgical applications.