A Biodegradable Tissue Adhesive for Post-Extraction Alveolar Bone Regeneration under Ongoing Anticoagulation-A Microstructural Volumetric Analysis in a Rodent Model

In addition to post-extraction bleeding, pronounced alveolar bone resorption is a very common complication after tooth extraction in patients undergoing anticoagulation therapy. The novel, biodegenerative, polyurethane adhesive VIVO has shown a positive effect on soft tissue regeneration and hemostasis. However, the regenerative potential of VIVO in terms of bone regeneration has not yet been explored. The present rodent study compared the post-extraction bone healing of a collagen sponge (COSP) and VIVO in the context of ongoing anticoagulation therapy. According to a split-mouth design, a total of 178 extraction sockets were generated under rivaroxaban treatment, of which 89 extraction sockets were treated with VIVO and 89 with COSP. Post-extraction bone analysis was conducted via in vivo micro-computed tomography (µCT), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) after 5, 10, and 90 days. During the observation time of 90 days, µCT analysis revealed that VIVO and COSP led to significant increases in both bone volume and bone density (p ≤ 0.001). SEM images of the extraction sockets treated with either VIVO or COSP showed bone regeneration in the form of lamellar bone mass. Ratios of Ca/C and Ca/P observed via EDX indicated newly formed bone matrixes in both treatments after 90 days. There were no statistical differences between treatment with VIVO or COSP. The hemostatic agents VIVO and COSP were both able to prevent pronounced bone loss, and both demonstrated a strong positive influence on the bone regeneration of the alveolar ridge post-extraction.

Enhanced Dural Repair Using Biodegradable Sealants Based on Photocurable Hyaluronic Acid

Cerebrospinal fluid (CSF) leakage is a common complication of intradural surgery or incidental durotomy in neurosurgery. Dural suturing is a common method for durotomy repair, but this technique requires a long operation time and includes the risk of CSF leakage by incomplete sealing. Glue-type sealants are effective for watertight dural closure. However, unresolved shortcomings include insufficient sealing performance, poor biocompatibility, and excessive swelling. Here, a dural sealant using light-activated hyaluronic acid (HA) with multi-networks (HA photosealant) that provides fast sealing performance and high biocompatibility is reported. The HA photosealants form a watertight hydrogel barrier with multilength networks under low-energy visible light exposure (405 nm, <1 J cm-2) for 5 s and allow firm tissue adhesion on the wet dural surface. In a rabbit model of craniectomy and durotomy, HA photosealants exhibit the faster sealing performance of dural tears and enhance dural repair with accelerated bone formation compared to commercial surgical glues, with no degenerative changes, such as inflammation or necrosis, in histopathological evaluation. This biocompatible HA photosealant can be applied in a variety of clinical settings that require fast wound closure as a promising potential.

Comparison of 2-octyl cyanoacrylate with polyester mesh with standard suture and staples in total knee and hip arthroplasty

OBJECTIVE

The use of 2-octyl cyanoacrylate with polyester mesh (OCA-M) has become common in total hip and knee arthroplasty (THA, TKA). We aimed to compare the safety and cosmetic outcomes between OCA-M and standard suture techniques and staples, and determine whether OCA-M can safely be used for TKA.

METHOD

Inclusion criteria were patients who underwent THA or TKA from January 2010 to October 2011 (Suture group), November 2011 to August 2013 (Staple group), March 2017 to September 2018 (OCA-M group). Exclusion criteria was loss of imaging data. Complications during hospitalisation (early complication) and after discharge (late complication) were compared in groups. Plastic and orthopaedic surgeons performed cosmetic evaluations with the modified Vancouver Scar Scale (VSS) and Likert scale at three and six months postoperatively and compared in groups.

RESULTS

A total of 249 arthroplasties (suture group=88 patients; staple group=94 patients; OCA-M group=67 patients) were included in the study. The OCA-M group had a significantly lower early complication rate than the suture group (p=0.015). For THA, the OCA-M group had a significantly lower total complication rate than the suture group (p=0.048). For TKA, there was no significant difference among the three groups. The complication rate in the OCA-M group showed no significant difference between THA/TKA. With regards to the VSS, the OCA-M group was significantly better for cosmetic qualities than the suture group (p=<0.001, p=0.021 at three and six months, respectively). For the Likert scale, the OCA-M group was also significantly better for cosmetic qualities than the suture group and staple group (suture-OCA-M, p=0.003 (three months), p=<0.001 (six months); staple-OCA-M, p=0.027 (three months)).

CONCLUSION

In this study, the OCA-M complication rate was low compared to suturing and similar to stapling. Moreover, better cosmetic outcomes were achieved compared to suturing and stapling.

Sprayable Multifunctional Black Phosphorus Hydrogel with On-Demand Removability for Joint Skin Wound Healing

Wound healing remains a critical challenge in regenerative engineering. Great efforts are devoted to develop functional patches for wound healing. Herein, a novel sprayable black phosphorus (BP)-based multifunctional hydrogel with on-demand removability is presented as a joints' skin wound dressing. The hydrogel is facilely prepared by mixing dopamine-modified oxidized hyaluronic acid, cyanoacetategroup-functionalized dextran containing black phosphorus, and the catalyst histidine. The catechol-containing dopamine can not only enhance tissue adhesiveness, but also endow the hydrogel with antioxidant capacity. In addition, benefiting from the photothermal conversion ability of the BP and thermally reversible performance of the formed C═C double bonds between aldehyde groups and cyanoacetate groups, the resulting hydrogel displays excellent antibacterial performance and on-demand dissolving ability under NIR irradiation. Moreover, by loading vascular endothelial growth factor into the hydrogel, the promoted migration and angiogenesis effects of endothelial cells can also be achieved. Based on these features, it is demonstrated that such sprayable BP hydrogels can effectively facilitate joint wounds healing by accelerating angiogenesis, alleviating inflammation, and improving wound microenvironment. Thus, it is believed that this NIR-responsive removable BP hydrogel dressing will put forward an innovative concept in designing wound dressings.

Bio-Inspired Self-Healing, Shear-Thinning, and Adhesive Gallic Acid-Conjugated Chitosan/Carbon Black Composite Hydrogels as Suture Support Materials

The occurrence of leakage from anastomotic sites is a significant issue given its potential undesirable complications. The management of anastomotic leakage after gastrointestinal surgery is particularly crucial because it is directly associated with mortality and morbidity in patients. If adhesive materials could be used to support suturing in surgical procedures, many complications caused by leakage from the anastomosis sites could be prevented. In this study, we have developed self-healing, shear-thinning, tissue-adhesive, carbon-black-containing, gallic acid-conjugated chitosan (CB/Chi-gallol) hydrogels as sealing materials to be used with suturing. The addition of CB into Chi-gallol solution resulted in the formation of a crosslinked hydrogel with instantaneous solidification. In addition, these CB/Chi-gallol hydrogels showed enhancement of the elastic modulus (G') values with increased CB concentration. Furthermore, these hydrogels exhibited excellent self-healing, shear-thinning, and tissue-adhesive properties. Notably, the hydrogels successfully sealed the incision site with suturing, resulting in a significant increase in the bursting pressure. The proposed self-healing and adhesive hydrogels are potentially useful in versatile biomedical applications, particularly as suture support materials for surgical procedures.

Highly Tough and Biodegradable Poly(ethylene glycol)-Based Bioadhesives for Large-Scaled Liver Injury Hemostasis and Tissue Regeneration

Conventional tissue adhesives face challenges for hemostasis and tissue regeneration in large-scaled hemorrhage and capillary hypobaric bleeding due to weak adhesion, and inability to degrade at specific sites. Herein, convenient and injectable poly(ethylene glycol) (PEG)-based adhesives are developed to address the issues for liver hemostasis. The PEG-bioadhesives are composed of tetra-armed PEG succinimide glutarate (PEG-SG), tetra-armed PEG amine (PEG-NH2 ), and tri-lysine. By mixing the components, the PEG-bioadhesives can be rapidly formulated for use of liver bleeding closure in hepatectomy. The PEG-bioadhesives also possess mechanical compliance to native tissues (elastic modulus ≈40 kPa) and tough tissue adhesion (≈28 kPa), which enables sufficient adhering to the injured tissues and promotes liver regeneration with the PEG-bioadhesive degradation. In both rats of liver injury and pigs of large-scaled hepatic hemorrhage, the PEG-bioadhesives show effective hemostasis with superior blood loss than conventional tissue adhesives. Due to biocompatibility and degradability, the PEG-bioadhesive is advantageous for liver regeneration, while commercial adhesives (e.g., N-octyl cyanoacrylate) display adhesion failure and limited liver reconstructions. These PEG-bioadhesive components are FDA-approved, and demonstrate excellent adhesion to various tissues not only for liver hemostasis, it is a promising candidate in biomedical translations and clinical applications.

A Mechanically Resilient and Tissue-Conformable Hydrogel with Hemostatic and Antibacterial Capabilities for Wound Care

Hydrogels are used in wound dressings because of their tissue-like softness and biocompatibility. However, the clinical translation of hydrogels remains challenging because of their long-term stability, water swellability, and poor tissue adhesiveness. Here, tannic acid (TA) is introduced into a double network (DN) hydrogel consisting of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) to realize a tough, self-healable, nonswellable, conformally tissue-adhesive, hemostatic, and antibacterial hydrogel. The TA within the DN hydrogel forms a dynamic network, enabling rapid self-healing (within 5 min) and offering effective energy dissipation for toughness and viscoelasticity. Furthermore, the hydrophobic moieties of TA provide a water-shielding effect, rendering the hydrogel nonswellable. A simple chemical modification to the hydrogel further strengthens its interfacial adhesion with tissues (shear strength of ≈31 kPa). Interestingly, the TA also can serve as an effective hemostatic (blood-clotting index of 58.40 ± 1.5) and antibacterial component, which are required for a successful wound dressing. The antibacterial effects of the hydrogel are tested against Escherichia coli and Staphylococcus aureus. Finally, the hydrogel is prepared in patch form and applied to a mouse model to test in vivo biocompatibility and hemostatic performances.

Comparative Evaluation of Tissue Adhesives and Sutures in the Management of Facial Laceration Wounds in Children

BACKGROUND

This study evaluated tissue adhesives in comparison to sutures for treating facial lacerations in children.

METHODS

We retrospectively analyzed data from September 2017 to August 2022 involving pediatric facial lacerations managed with either tissue adhesives or sutures.

RESULTS

Among 50 children, 20 received tissue adhesives, and 30 received sutures. Both methods showed comparable outcomes in terms of wound complications such as dehiscence (adjusted odds ratio = 1.56, 95% CI = 0.08-31.25) and infection (adjusted odds ratio = 2.17, 95% CI = 0.08-58.80). The cosmetic outcomes, assessed using the Hollander Wound Evaluation Score, were also consistent between groups (adjusted beta = -0.55, 95% CI = -1.15-0.05). Notably, those treated with tissue adhesives reported greater satisfaction (adjusted beta = 1.13, 95% CI = 0.63 -1.63) and experienced significantly less pain (adjusted beta = -3.03, 95% CI = -4.15--1.90).

CONCLUSIONS

Both techniques displayed similar rates of infection, dehiscence, and cosmetic outcomes. However, tissue adhesives were associated with increased patient comfort, especially in terms of reduced pain and greater satisfaction.

Initial experience of coaxial percutaneous liver biopsy with tract embolization using N-Butyl cyanoacrylate

OBJECTIVE

Bleeding occurs after liver biopsy in up to 10.9% cases, and patients with impaired hemostasis or ascites are considered to have absolute or relative contraindications. N-butyl cyanoacrylate enables immediate hemostasis, even in lethal situations. Therefore, percutaneous liver biopsy combined with tract embolization using N-butyl cyanoacrylate is expected to enable safe biopsy, even in patients for whom conventional biopsy is contraindicated. Here we describe our initial experience with coaxial percutaneous biopsy with tract embolization using N-butyl cyanoacrylate.

MATERIALS AND METHODS

Eighty-six patients who underwent tract embolization using N-butyl cyanoacrylate between October 2014 and July 2020, including 21 patients who had absolute or relative contraindications for liver biopsy, were retrospectively analyzed. Tract embolization using N-butyl cyanoacrylate comprised two steps: (1) liver biopsy with a biopsy needle inserted via a coaxial introducer needle and (2) embolization of the puncture route by injecting N-butyl cyanoacrylate via the coaxial needle.

RESULTS

No complications occurred in any patient. The mean number of biopsies per patient was 3.30 (range, 1-7). Histologically adequate samples were acquired in all cases, and pathological diagnoses were obtained. The mean time required for tract embolization was 52.8 s (range, 6-132 s). The mean peak skin dose was 9.97 mGy (range, 2-68 mGy), which is far below the 3-Gy threshold dose for temporary erythema.

CONCLUSIONS

This proposed technique may be a promising and straightforward alternative to improve the management of patients with severe liver disease by allowing safer biopsy, including patients for whom conventional liver biopsy is contraindicated.

Evaluation of the Hemostatic Effect of an Innovative Tissue Adhesive during Extraction Therapy under Rivaroxaban in a Rodent Model

An increase in rivaroxaban therapies is associated with increased numbers of postoperative bleeding despite the use of hemostatic sponges, which are currently the gold standard treatment. VIVO has shown promising hemostatic results, favorable tissue properties, and ease of application, although it has not yet been used in the oral cavity. The aim of this study was to evaluate the hemostatic properties of VIVO in the extraction sockets of 31 rodents and compare this to gelatin sponge (GSP) therapy. At rivaroxaban concentrations of 264.10 ± 250.10 ng/mL, 62 extraction sockets were generated, of which 31 were treated with VIVO and 31 with GSP. The duration time, early and late bleeding events, and wound healing score were determined. Histologic examinations of the tissues were performed after 5 days. VIVO presented a longer procedure, 1.26 ± 0.06 min, but a significantly shorter bleeding time, 0.14 ± 0.03 min. There was no difference between the two groups in terms of the severity and timing of bleeding. More minor early bleeding events were observed for GSP. VIVO showed a significantly better healing score, with favorable histological results. In an animal study, VIVO showed promising hemostatic properties after tooth extraction under ongoing anticoagulative therapy.

Tough Adhesive Hydrogel for Intraoral Adhesion and Drug Delivery

Oral lichen planus (OLP) and recurrent aphthous stomatitis (RAS) are common chronic inflammatory conditions, manifesting as painful oral lesions that negatively affect patients' quality of life. Current treatment approaches are mainly palliative and often ineffective due to inadequate contact time of the therapeutic agent with the lesions. Here, we developed the Dental Tough Adhesive (DenTAl), a bioinspired adhesive patch with robust mechanical properties, capable of strong adhesion against diverse wet and dynamically moving intraoral tissues, and extended drug delivery of clobetasol-17-propionate, a first-line drug for treating OLP and RAS. DenTAl was found to have superior physical and adhesive properties compared to existing oral technologies, with ~2 to 100× adhesion to porcine keratinized gingiva and ~3 to 15× stretchability. Clobetasol-17-propionate incorporated into the DenTAl was released in a tunable sustained manner for at least 3 wk and demonstrated immunomodulatory capabilities in vitro, evidenced by reductions in several cytokines, including TNF-α, IL-6, IL-10, MCP-5, MIP-2, and TIMP-1. Our findings suggest that DenTAl may be a promising device for intraoral delivery of small-molecule drugs applicable to the management of painful oral lesions associated with chronic inflammatory conditions.

Intrinsically Nonswellable Multifunctional Hydrogel with Dynamic Nanoconfinement Networks for Robust Tissue-Adaptable Bioelectronics

Developing bioelectronics that retains their long-term functionalities in the human body during daily activities is a current critical issue. To accomplish this, robust tissue adaptability and biointerfacing of bioelectronics should be achieved. Hydrogels have emerged as promising materials for bioelectronics that can softly adapt to and interface with tissues. However, hydrogels lack toughness, requisite electrical properties, and fabrication methodologies. Additionally, the water-swellable property of hydrogels weakens their mechanical properties. In this work, an intrinsically nonswellable multifunctional hydrogel exhibiting tissue-like moduli ranging from 10 to 100 kPa, toughness (400-873 J m^-3 ), stretchability (≈1000% strain), and rapid self-healing ability (within 5 min), is developed. The incorporation of carboxyl- and hydroxyl-functionalized carbon nanotubes (fCNTs) ensures high conductivity of the hydrogel (≈40 S m^-1 ), which can be maintained and recovered even after stretching or rupture. After a simple chemical modification, the hydrogel shows tissue-adhesive properties (≈50 kPa) against the target tissues. Moreover, the hydrogel can be 3D printed with a high resolution (≈100 µm) through heat treatment owing to its shear-thinning capacity, endowing it with fabrication versatility. The hydrogel is successfully applied to underwater electromyography (EMG) detection and ex vivo bladder expansion monitoring, demonstrating its potential for practical bioelectronics.

Circumcision wound dressing with octylcyanoacrylate tissue adhesive

OBJECTIVE

Circumcision wounds are commonly dressed with paraffin gauze dressings. Octylcyanoacrylate tissue adhesive (Dermabond; Ethicon, US) is increasingly being used for wound closure, as well as wound dressing. This study compared the outcomes of tissue adhesive dressing versus paraffin gauze dressing for circumcision wounds.

METHOD

Adult male patients undergoing circumcision were randomised into two groups: tissue adhesive dressing (study group) or paraffin gauze dressing (control group). They were followed up at two weeks and at two months after surgery. The primary objective of this study was to determine the difference in patient-reported dressing satisfaction at two week follow-up. Our secondary outcomes included operation time, postoperative pain, postoperative complications, patient-reported cosmetic satisfaction, surgeon-reported cosmetic satisfaction, and surgeon-reported objective measure of cosmetic outcome using a validated scale.

RESULTS

A cohort of 40 patients was randomised into two equal groups, study and control. Tissue adhesive dressing was associated with a significantly better patient-reported dressing satisfaction, with a mean Likert scale score of 4.53±0.51 for the study group versus 3.20±1.24 for the control group (p<0.001). It was also associated with a significantly better patient-reported cosmetic satisfaction of 4.58±0.51 versus 4.00±1.12 (p<0.05), respectively. There was no difference in operation time, postoperative pain, postoperative complications or surgeon-reported cosmetic outcomes.

CONCLUSION

Tissue adhesive dressing is an acceptable alternative to paraffin gauze dressing for circumcision wounds. This option should be offered to all patients undergoing circumcision.

An Instant Underwater Tissue Adhesive Composed of Catechin-Chondroitin Sulfate and Cholesterol-Polyethyleneimine

Due to the safety issue and poor underwater adhesion of current commercially available bioadhesives, they are hard to apply to in vivo physiological environments and more diverse medical use conditions. In this study, a novel and facile bioadhesive for underwater medical applications are designed based on the coacervation of electrostatic interactions and hydrophobic interactions, with the introduction of catechin as a provider of catechol moieties for adhesion to surrounding tissues. The orange-colored bio-adhesive, named PcC, is generated within seconds by mixing catechin-modified chondroitin sulfate and cholesterol chloroformate-modified polyethyleneimine with agitation. In vitro mechanical measurements prove that this novel PcC bio-adhesive is superior in underwater adhesion performance when applied to cartilage. Animal experiments in a rat mastectomy model and rat cartilage graft implantation model demonstrate its potential for diverse medical purposes, such as closing surgical incisions, reducing the formation of seroma, and tissue adhesive applied in orthopedic or cartilage surgery.

Tissue Adhesives for the Management of Corneal Perforations and Challenging Corneal Conditions

Corneal perforations are ophthalmological emergencies which can have serious and detrimental consequences, if not managed timely and appropriately. These are a significant cause of ocular morbidity and can result in decreased vision, blindness, and even loss of the eye. Corneal perforations can be managed using a range of treatment approaches, including temporary solutions such as the application of corneal glue and bandage contact lens, as well as definitive treatment such as corneal transplantation. Tissue glues/adhesives were developed as substitutes for sutures in ophthalmic surgery. Unlike sutures, these glues are associated with shorter overall surgical times and reduced inflammation, thus improving postoperative comfort without compromising wound strength. The available tissue adhesives can be broadly classified into two types: synthetic (eg, cyanoacrylate derivatives) and biological (eg, fibrin glue). Cyanoacrylate glue is chiefly used as a corneal patch to manage acute corneal perforations and improve visual outcomes. Fibrin glue can be used instead of cyanoacrylate glue in many conditions with the benefits of reduced conjunctival and corneal inflammation and reaction. Apart from this, each type of adhesive is distinct in terms of its benefits as well as limitations and is accordingly used for different indications. The present review focuses on the two main types of tissue adhesives, their applications in the management of corneal perforations, the associated complications, safety and efficacy data related to their use available in the literature and the need for newer adhesives in this field.

Patient-reported outcomes of palatal donor site healing using four different wound dressing modalities following free epithelialized mucosal grafts: A four-arm randomized controlled clinical trial

BACKGROUND

The aim of this study was to compare the effects of four different commonly used wound dressings in improving patient reported outcomes (PROMS) after free epithelialized mucosal grafts (FEGs) harvesting.

METHODS

Following 72 FEGs harvesting from 72 patients, patients were assigned into four groups.

CONTROL

collagen plug + sutures (CPS); test: collagen plug with cyano-acrylate (CPC), platelet rich fibrin (PRF) + sutures, or palatal stent only (PS). Patients were observed for 14 days, with evaluation of pain level utilizing the visual analog scale, number of analgesics consumed, need for additional analgesics, amount of swelling, amount of bleeding, activity tolerance, and willingness for retreatment.

RESULTS

Compared to the control group all test groups indicated significant lower pain perception (P < 0.0001), lower analgesic consumption (P < 0.0001), and higher willingness for retreatment (P < 0.0001), while no statistically significant differences among test groups were observed. There were no statistically significant differences in amount of day-by-day swelling, bleeding, and activity tolerance among four groups. Compared to other groups, the PS had the lowest overall pain scores (over the 14-day period). Palatal thickness, graft length, graft width, and graft thickness did not appear to affect patient morbidity (P > 0.05).

CONCLUSIONS

All interventions significantly decreased pain perception compared to a hemostatic collagen sponge alone over the palatal donor site after FEG surgery. In the first few days after surgery, the use of a palatal stent seemed to be associated with less overall pain, pain pills consumed, and higher willingness of doing the same procedure again.

Comparing large-volume band ligators and cyanoacrylate injection for gastric variceal eradication: A prospective study

BACKGROUND

The role of endoscopy in the ligation of gastric varices (GV) remains controversial. This study aimed to evaluate the efficacy of endoscopic band ligation (EBL) using large-volume ligators for the management of non-bleeding GV in patients with cirrhosis.

METHODS

One hundred fifty-eight patients with non-bleeding GV due to cirrhosis were divided randomly into 2 groups: the EBL group and the endoscopic variceal obturation (EVO) group. The EBL group underwent EBL with large-volume ligators and the EVO group underwent tissue glue injection for the treatment of GV. Follow-up endoscopy was performed 3 to 4 weeks after endoscopic treatment. Patients were followed up for ≥6 months after treatment. Eradication, complication, and recurrence rates were evaluated and compared between groups.

RESULTS

The type and size of GV were similar in both groups. No significant difference was found in the mean number of treatment sessions or eradication and recurrence rates after 6 months. Ulcer bleeding occurred in 2 EBL patients (2.50%) after ligation, whereas 8 EVO patients (10.25%) experienced bleeding due to glue extrusion. The bleeding rate after endoscopic treatment significantly differed between the groups. In the EVO group, 1 patient developed renal embolism after injection and 2 patients developed sepsis. The prevalence of postoperative fever was significantly higher in the EVO group than in the EBL group.

CONCLUSION SUBSECTIONS

Large-volume band ligators have similar efficacy to tissue glue for eradicating GV, however, the former is safer. Nevertheless, multicenter studies are needed to further confirm these results.

Natural Deep Eutectic Solvents Based on Choline Chloride and Phenolic Compounds as Efficient Bioadhesives and Corrosion Protectors

Natural deep eutectics solvents (NADES), owing to their high solvation capacity and nontoxicity, are actively being sought for many technological applications. Herein, we report a series of novel NADES based on choline chloride and plant-derived polyphenols. Most of the obtained phenolic NADES have a wide liquid range and high thermal stability above 150 °C. Among them, small-sized polyphenols, like pyrogallol, vanillyl alcohol, or gentisic acid, lead to low-viscosity liquids with ionic conductivities in the order of 10^-3 S cm^-1 at room temperature. Interestingly, polyphenols possess valuable properties as therapeutic agents, antioxidants, adhesives, or redox-active compounds, among others. Thus, we evaluated the potential of these novel NADES for two applications: bioadhesives and corrosion protection. The mixture of choline chloride-vanillyl alcohol (2:3 mol ratio) and gelatin resulted in a highly adhesive viscoelastic liquid (adhesive stress ≈ 135 kPa), affording shear thinning behavior. Furthermore, choline chloride-tannic acid (20:1) showed an extraordinary ability to coordinate iron ions, reaching excellent corrosion inhibitive efficiencies in mild steel protection.

A Dual-Bioinspired Tissue Adhesive Based on Peptide Dendrimer with Fast and Strong Wet Adhesion

Although tissue adhesives have potential advantages over traditional sutures, existing ones suffer from several limitations: slow adhesion kinetic, low mechanical strength, and poor interfacial bonding with wet biological tissues. Herein, a cooperative mussel/slug double-bioinspired hydrogel adhesive (DBHA) composed of a robust adhesive interface and a stretchable dissipative matrix is developed. The DBHA is formed by a cationic polysaccharide (chitosan), an anionic polysaccharide (carboxymethyl cellulose), and a barbell-like dendritic lysine grafted with catechol groups (G3KPCA). Compared to various commercial bio-glues and traditional adhesives, the DBHA has significantly stronger tissue adhesion and enhanced toughness both ex vivo and in vivo. Meanwhile, the DBHA exhibits fast, strong, tough, and durable adhesion to diverse ex vivo tissue surfaces with blood. The adhesion energy between the adhesive and porcine skin can reach 200-900 J m^-2 . Additionally, in vivo studies prove that DBHA has good hemostasis of rabbit artery trauma and achieves better wound healing of tissue incision than commercial bio-glues. This study provides a novel strategy for fabricating fast and strong wet adhesives, which can be used in many applications, such as soft robots, tissue adhesives and hemostats.

A Biodegradable Multifunctional Film as a Tissue Adhesive for Instant Hemostasis and Wound Closure

Here, a multifunctional film (MFF) as an alternative tissue adhesive in the form of an interpenetrating network consisting of self-crosslinked aldehyde-functionalized chitosan (AC) and crosslinked poly(acrylic acid) (PAA) further coordinated with Ag⁺ is reported. The MFF combines enhanced toughness and stretchability, which is attributed to the synergistic effects of the double-network design. Covalent crosslinking maintains the overall integrity of the MFF matrix, while noncovalent crosslinking dissipates energy under deformation. Upon contact, the MFF quickly dries the tissue surface followed by instant physical crosslinking to the tissue. Subsequent covalent crosslinking between the aldehyde groups of the MFF and the primary amine groups on the surface of the tissue further stabilizes the adhesion. Meanwhile, Ag⁺ provides strong antibacterial properties to the MFF. Notably, in vivo studies demonstrate that the MFF allows facile and tough attachment to the wet and dynamic surface of rabbit liver and presents superior hemostasis and sealing properties. Furthermore, the MFF can be safely degraded without causing abnormal defects in vivo. The outstanding physicochemical properties of the MFF can potentially be a good alternative to existing sutures or staples and has potential for use in clinical practice.

No Additional Benefits of Tissue Adhesives for Skin Closure in Total Joint Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

This systematic review is aimed to compare the performance of tissue adhesives (TA) as an adjunct or closure method with traditional wound closure methods for cutaneous closure in arthroplasty and evaluate whether they have any added benefits in terms of decreasing wound complications and increasing postoperative patient satisfaction.

METHODS

Cochrane Library, PubMed, and EMBASE were searched until February 2021. Randomized controlled trials (RCTs) comparing outcomes of TA with emphasis on skin closure time, in-hospital stay, complication rates, cosmetic scoring systems, and patient satisfaction scores (PSS) compared to subcuticular sutures (SCS) and skin staples (ST) in arthroplasty. The quality of RCTs was assessed using the National Institutes of Health quality assessment tool.

RESULTS

Ten RCTs were included. The pooled and the subgroup analysis revealed no significant difference in the wound infection rates, discharge rates, dehiscence rates, and PSS between TA (as an adjunct or closure method) and SCS or ST. TA (as an adjunct or closure method) was significantly (P < .00001) associated with a longer time to closure compared to ST and a shorter time compared to SCS as a closure method. Length of stay was comparable in all groups.

CONCLUSION

Using TA in combination with subcuticular sutures or ST or as a cutaneous method of closure does not provide additional benefits in terms of decreased hospital stay, decreased infection rates, or wound discharge rates. The PSS and pain scores of the scars also appear to be comparable to standard wound closure methods. No clear conclusion could be drawn regarding cosmetic scoring systems, because of the paucity of data.

LEVEL OF EVIDENCE

Level I (Meta-analysis of RCTs).

Promoting Oral Mucosal Wound Healing with a Hydrogel Adhesive Based on a Phototriggered S-Nitrosylation Coupling Reaction

The wet and highly dynamic environment of the mouth makes local treatment of oral mucosal diseases challenging. To overcome this, a photo-crosslinking hydrogel adhesive is developed inspired by the success of light-curing techniques in dentistry. The adhesive operates on a fast (within 5 s) phototriggered S-nitrosylation coupling reaction and employs imine anchoring to connect to host tissues. Unlike other often-used clinical agents that adhere weakly and for short durations, this thin, elastic, adhesive, and degradable cyclic o-nitrobenzyl-modified hyaluronic acid gel protects mucosal wounds from disturbance by liquid rinsing, oral movement, and friction for more than 24 h. The results from both rat and pig oral mucosa repair models demonstrate that this new gel adhesive creates a favorable microenvironment for tissue repair and can shorten tissue healing time. This study thus illustrates a therapeutic strategy with the potential to advance the treatment of oral mucosal defects in the clinic.

Effect of tissue adhesives in repairing perineal trauma during childbirth: A systematic review and meta-analysis

AIMS AND OBJECTIVES

To investigate the effect of tissue adhesives on perineal wound healing and pain relief in women with perineal trauma during childbirth.

BACKGROUND

Due to the high incidence and severe consequences of perineal trauma during childbirth, tissue adhesives are recommended as an alternative to conventional sutures to repair perineal trauma. Although many original studies have explored the effect of tissue adhesives on perineal wound healing and pain relief in women with perineal trauma during childbirth, these studies have differed in participants, interventions and outcomes. Therefore, the effect of tissue adhesives on wound healing and pain relief in perineal trauma during childbirth is inconclusive.

DESIGN

A systematic review and meta-analysis based on PRISMA 2020.

METHODS

A systematic and comprehensive literature search was conducted. Eight electronic databases, three clinical trial registers, and grey literature were searched from inception to 28th April 2021 and reference lists were also retrieved. Randomised controlled trials (RCTs) involving women with first- or second-degree perineal lacerations or women who underwent episiotomy were included. The intervention was the use of tissue adhesives alone or in combination with sutures. For the outcome indicators of perineal wound healing and pain relief, subgroup analyses based on the extent of perineal trauma and measurement time points were conducted, respectively.

RESULTS

A total of 14 RCTs involving 2264 participants were included in this research. The results indicated that for first-degree lacerations, the incidence of wound complications was significantly higher in the tissue adhesives group. In contrast, for episiotomy, the effect of the combination of tissue adhesives and sutures was comparable to that of sutures exclusively. The pooled results revealed that tissue adhesives exerted a positive effect on relieving immediate and short-term perineal pain, but no significant difference was found in the effect of long-term pain relief. Moreover, this review also supported the effect of tissue adhesives in shortening intraoperative repair time and improving clinician-maternal satisfaction.

CONCLUSIONS

The existing evidence illustrates that tissue adhesives effectively promote perineal wound healing and relieve immediate and short-term pain. However, for first-degree lacerations, the increased occurrence of wound complications must be prudently considered when applying tissue adhesives alone, whereas, for episiotomy, the combination of tissue adhesives and sutures may be a promising repair alternative. Future studies are encouraged to adopt long-term effect, adverse effect, and cost-effect analysis as important outcome indicators to comprehensively validate the applicability and generalisability of tissue adhesives.

RELEVANCE TO CLINICAL PRACTICE

For first-degree perineal lacerations, we do not recommend using tissue adhesives alone to repair the wound, given the increased wound complications. While for episiotomy, the combination of tissue adhesives and sutures may be a promising alternative to the use of sutures exclusively. Additionally, the adverse effect and long-term effect of using tissue adhesives alone to repair perineal trauma should be further clarified.

Rational engineering and applications of functional bioadhesives in biomedical engineering

For the past decades, several bioadhesives have been developed to replace conventional wound closure medical tools such as sutures, staples, and clips. The bioadhesives are easy to use and can minimize tissue damage. They are designed to provide strong adhesion with stable mechanical support on tissue surfaces. However, this monofunctionality of the bioadhesives hinders their practical applications. In particular, a bioadhesive can lose its intended function under harsh tissue environments or delay tissue regeneration during wound healing. Based on several natural and synthetic biomaterials, functional bioadhesives have been developed to overcome the aforementioned limitations. The functional bioadhesives are designed to have specific characteristics such as antimicrobial, cell infiltrative, stimuli-responsive, electrically conductive, and self-healing to ensure stability under harsh tissue conditions, facilitate tissue regeneration, and effectively monitor biosignals. Herein, we thoroughly review the functional bioadhesives from their fundamental background to recent progress with their practical applications for the enhancement of tissue healing and effective biosignal sensing. Furthermore, the future perspectives on the applications of functional bioadhesives and current challenges in their commercialization are also discussed.

Multifaceted Design and Emerging Applications of Tissue Adhesives

Tissue adhesives can form appreciable adhesion with tissues and have found clinical use in a variety of medical settings such as wound closure, surgical sealants, regenerative medicine, and device attachment. The advantages of tissue adhesives include ease of implementation, rapid application, mitigation of tissue damage, and compatibility with minimally invasive procedures. The field of tissue adhesives is rapidly evolving, leading to tissue adhesives with superior mechanical properties and advanced functionality. Such adhesives enable new applications ranging from mobile health to cancer treatment. To provide guidelines for the rational design of tissue adhesives, here, existing strategies for tissue adhesives are synthesized into a multifaceted design, which comprises three design elements: the tissue, the adhesive surface, and the adhesive matrix. The mechanical, chemical, and biological considerations associated with each design element are reviewed. Throughout the report, the limitations of existing tissue adhesives and immediate opportunities for improvement are discussed. The recent progress of tissue adhesives in topical and implantable applications is highlighted, and then future directions toward next-generation tissue adhesives are outlined. The development of tissue adhesives will fuse disciplines and make broad impacts in engineering and medicine.

Comparing the Treatment Outcomes of Absorbable Sutures, Nonabsorbable Sutures, and Tissue Adhesives in Cleft Lip Repair: A Systematic Review

OBJECTIVES

To examine the literature and synthesize the available reports for the best possible option between absorbable, nonabsorbable, and tissue adhesives in cleft lip skin closure.

DESIGN

We conducted systematic searches for randomized controlled trials and controlled clinical trials in PubMed, Cochrane, Ovid Medline, and OpenGrey databases. Identified studies were retrieved and assessed for eligibility. All statistical analyses were done with Revman, version 5.4.

INTERVENTIONS

The intervention considered in this systematic review were techniques of cleft lip repair using resorbable sutures, nonabsorbable sutures, medical adhesives, or any combination of these.

OUTCOME MEASURES

The primary outcomes assessed in the trials had to include any combination of the following: wound healing cosmesis and wound healing complications. While secondary outcomes considered were quality of life, direct and indirect costs to patients and health services, and participant satisfaction.

RESULTS

Only 6 studies met all inclusion criteria and were selected for qualitative analysis. A more favorable wound healing cosmesis was seen when nonabsorbable suture was used in cleft lip repair compared to absorbable sutures and tissue adhesives (CI, 0.65-4.35). This advantage was overshadowed by the significantly higher prevalence of postoperative complications when nonabsorbable sutures are used.

CONCLUSION

Although the results point to more favorable cosmesis with nonabsorbable sutures and an overall more favorable outcome with either absorbable sutures or tissue adhesives, the 6 selected studies were assessed at an unclear risk of bias; therefore, the results of this study should be interpreted with caution and regarded as low-certainty evidence.

Long-term function of Hydrofit as hemostatic sealant: abridged republication

The newly-designed hemostatic sealant, Hydrofit, was developed in Japan and consists of a urethane-based polymer without blood products. By applying Hydrofit gel to an anastomosis site on the aorta, water contact initiates a chemical change in the forming elastomer which adheres rapidly and tightly. We experienced an extirpation of Hydrofit gel that had been applied 4 years and 8 months previously in a 42-year-old female who underwent aortic valve replacement and graft replacement of the ascending aorta. The Hydrofit left around the aortic graft suture line was without infection and functioned very well as an elastic sealant for a long period.

Surgical alternatives to keratoplasty in microbial keratitis

Penetrating keratoplasty is often required in microbial keratitis not responding to the standard treatments available or the development of complications like corneal perforation. Performing keratoplasty in microbial keratitis has several challenges, the major ones being the availability of donor corneal tissue and the poor success of the corneal graft performed in such a setting. For overcoming these challenges, several alternatives to keratoplasty have been described. Broadly, these options could be categorized into autologous tissues such as conjunctival and tenon tissue, synthetic products like tissue adhesives and therapeutic contact lenses, or biological tissues like amniotic membrane graft. These alternative modalities are not universal. They have their specific indications in microbial keratitis. Most of these alternatives are useful only for small corneal perforations. While autologous tissues are cost-effective and readily available, lack of tectonic support is a significant limitation. Tissue adhesives are excellent alternatives in terms of tectonic support, but surface irregularity and tissue reaction are their potential limitations. The amniotic membrane is useful for small corneal perforations, but availability, cost, and poor tectonic support restrict its use. Herein, we discuss these various alternatives to keratoplasty in microbial keratitis, their indications, advantages, disadvantages, and the various techniques of performing these procedures.

Umbilical closure using 2-octyl cyanoacrylate in transumbilical laparoscopic adrenalectomy: A randomized controlled trial

OBJECTIVES

To evaluate postoperative pain and esthetic outcomes in patients undergoing transumbilical laparoscopic adrenalectomy with wound closure using 2-octyl cyanoacrylate.

METHODS

A total of 26 patients who underwent laparoscopic adrenalectomy with the transumbilical approach and agreed to participate in this study were included. Patients were randomly divided into two groups: the 2-octyl cyanoacrylate group (Glue group) or the non-use group (non-Glue group). A single surgeon (AM) carried out all procedures between 2014 and 2017.

RESULTS

There were no significant differences in the clinical background of the Glue and non-Glue groups. The number of patients with moderate or high levels of pain in the resting/moving period on postoperative days 1, 2 and 3 was 6/10 (46%/77%), 6/9 (46%/69%) and 3/5 (23%/38%) in the non-Glue group, and 5/7 (38%/54%), 2/7 (15%/54%) and 1/3 (8%/23%) in the Glue group. These differences were not significant. In the subgroup analysis of patients aged <50 years, the numbers were 4/6 (57%/86%), 5/7 (71%/100%) and 3/5 (43%/71%) in the non-Glue group, and 3/4 (33%/44%), 1/4 (11%/44%) and 0/1 (0%/11%) in the Glue group in the resting/moving period. On postoperative days 2 and 3, these differences were significant (P = 0.035 and 0.037 in the resting period, and P = 0.017 and 0.013 in the moving period).

CONCLUSIONS

2-octyl cyanoacrylate can be used safely for laparoscopic adrenalectomy with the transumbilical approach, and might be useful for reducing postoperative pain in patients aged <50 years.

Dopamine-Modified Hyaluronic Acid Hydrogel Adhesives with Fast-Forming and High Tissue Adhesion

Commercial or clinical tissue adhesives are currently limited due to their weak bonding strength on wet biological tissue surface, low biological compatibility, and slow adhesion formation. Although catechol-modified hyaluronic acid (HA) adhesives are developed, they suffer from limitations: insufficient adhesiveness and overfast degradation, attributed to low substitution of catechol groups. In this study, we demonstrate a simple and efficient strategy to prepare mussel-inspired HA hydrogel adhesives with improved degree of substitution of catechol groups. Because of the significantly increased grafting ratio of catechol groups, dopamine-conjugated dialdehyde-HA (DAHA) hydrogels exhibit excellent tissue adhesion performance (i.e., adhesive strength of 90.0 ± 6.7 kPa), which are significantly higher than those found in dopamine-conjugated HA hydrogels (∼10 kPa), photo-cross-linkable HA hydrogels (∼13 kPa), or commercially available fibrin glues (2-40 kPa). At the same time, their maximum adhesion energy is 384.6 ± 26.0 J m^-2, which also is 40-400-fold, 2-40-fold, and ∼8-fold higher than those of the mussel-based adhesive, cyanoacrylate, and fibrin glues, respectively. Moreover, the hydrogels can gel rapidly within 60 s and have a tunable degradation suitable for tissue regeneration. Together with their cytocompatibility and good cell adhesion, they are promising materials as new biological adhesives.

Recent Advances in Tissue Adhesives for Clinical Medicine

Tissue adhesives have attracted more attention to the applications of non-invasive wound closure. The purpose of this review article is to summarize the recent progress of developing tissue adhesives, which may inspire researchers to develop more outstanding tissue adhesives. It begins with a brief introduction to the emerging potential use of tissue adhesives in the clinic. Next, several critical mechanisms for adhesion are discussed, including van der Waals forces, capillary forces, hydrogen bonding, static electric forces, and chemical bonds. This article further details the measurement methods of adhesion and highlights the different types of adhesive, including natural or biological, synthetic and semisynthetic, and biomimetic adhesives. Finally, this review article concludes with remarks on the challenges and future directions for design, fabrication, and application of tissue adhesives in the clinic. This review article has promising potential to provide novel creative design principles for the generation of future tissue adhesives.

A randomised clinical trial to compare octyl cyanoacrylate with absorbable monofilament sutures for the closure of laparoscopic cholecystectomy port incisions

Tissue adhesives have gained increasing use as a possible method of wound closure. We compared the use of 2-octyl cyanoacrylate (OCA) or subcuticular suture in incisions sutures for the closure of laparoscopic cholecystectomy port incisions. A prospective randomised controlled trial was performed. Patients were randomised to have closure of laparoscopic port sites using either OCA or sutures. Patients were reviewed at 24 hours and returned for follow-up 1 week and 1 month after postoperatively. At these times, different wound characteristics were documented: Two tools were used to measure the cosmetic result using Hollander wound evaluation scale (HWES) and the patient and observer scar assessment scale (POSAS). A total of 70 patients, 35 in each group were enrolled. The wounds were closed significantly faster in the OCA group (mean 229.16 [±43.7] seconds versus 258.82 [±51.7] seconds, P = .01). Statistically significant difference in favour of using OCA was found for dehiscence (17.1% versus none in the suture group, P = .025) after 1 week. However, no difference was found for wound dehiscence after 1 month. OCA and suture groups did not differ significantly on patient satisfaction. There were no differences in the percentage of wounds achieving optimal scores on the HWES (suture 85.7% versus OCA 74.2%, P = .169). Nerveless, wound evolution was judged to be significantly better in the OCA group using POSAS. Patients' median POSAS was 9.45 (6-11) and 11.43 (10-13) in the OCA and suture groups, respectively (P = .005), and surgeon's median POSAS was 9.42 (6-11) and 11.48 (10-13) in the OCA and suture groups, respectively (P = .006). N-butyl-cyanoacrylate tissue adhesive is an acceptable technique for the closure of laparoscopic wounds with less operative time, and cosmetic results are comparable to suturing.

Entanglement-Driven Adhesion, Self-Healing, and High Stretchability of Double-Network PEG-Based Hydrogels

Hydrogels that are capable of wet adhesion and self-healing can enable major advances in a variety of biomedical applications such as tissue regeneration, wound dressings, wearable/implantable devices, and drug delivery. We hereby developed an innovative but simple strategy to achieve adhesive, self-healing, and highly stretchable double-network hydrogels, which were composed of a primary covalent polyethylene glycol diacrylate (PEGDA) network in combination with a noncovalent network of highly diffusive, giant PEG chains. The adhesion to substrates including tissue matrices was instant and repeatable due to the diffusive PEG chains that can spontaneously penetrate and entangle with the substrate network. Combining the intrinsic biocompatibility of PEG and rational design for tuning the hydrogel network properties, we exemplarily demonstrated that this hydrogel can be used as a three-dimensional matrix for cell culture or as a tissue adhesive for wound healing. The in vivo study showed that the hydrogel is capable of effectively triggering skin wound healing with a significantly lower immune response in comparison to commercial tissue adhesives currently used in clinics. Therefore, our study provides new and critical insights into the design strategy to achieve adhesion and rehealability by taking advantages of the entanglement effect from double-network hydrogels and opens up a new avenue for the application of entanglement-driven hydrogels in regenerative medicine.

Patch and glue repair for extensive left ventricular laceration

Laceration of the left ventricular wall is a rare but potentially life-threatening complication of electrophysiological studies. We describe emergency surgery on a 64-year-old man who suffered cardiac tamponade after an electrophysiological study, which revealed an extensive laceration in the inferior left ventricular wall, requiring repair by a patch and glue technique, with a good clinical outcome.

Endoscopic Cyanoacrylate Injection with Lauromacrogol for Gastric Varices: Long-Term Outcomes and Predictors in a Retrospective Cohort Study

Introduction: The first-line treatment for gastric variceal rebleeding in cirrhotic patients is endoscopic cyanoacrylate injection. We focused on the efficacy and prognosis of cyanoacrylate combined with Lauromacrogol^® for gastric varices (GV) in a retrospective study of long-term follow-up. Materials and Methods: One hundred thirty patients with cirrhosis and GV from March 2011 to February 2013 were included. Sixty-eight patients underwent endoscopic cyanoacrylate injection with Lauromacrogol and 62 patients without Lauromacrogol. The median follow-up was 40.1 and 38.8 months, respectively. Results: The volumes of cyanoacrylate used for the GV eradication in the Lauromacrogol group were significantly lower than those in the Ethiodol^® group (1.6 ± 0.8 versus 2.1 ± 1.2 mL, P = .029). No ectopic embolisms were observed during follow-up. The 1- and 3-year rebleeding-free rate did not differ between groups (83.7% and 59.2% versus 75.8% and 62.5%; P = .797). The same was observed for mortality (86.6% and 83.5% versus 85.5% and 83.7%; P = .955). New portal venous thrombosis (PVT) and progression of previous partial PVT were independently associated with rebleeding (hazard ratio [HR] 5.127, 95% confidence interval [CI], 2.430-10.817, P = .000) and death (HR 10.093, 95% CI, 3.988-25.548, P = .000). Conclusions: Endoscopic cyanoacrylate injection with Lauromacrogol might minimize the required dosage of cyanoacrylate, but it did not improve rebleeding rate or survival. Exacerbation of PVT was associated with rebleeding and death.

Using tissue glues for decreasing alveolar air leak in thoracic surgery

Background

Prolonged air leak is one of the most annoying complications after pulmonary surgery. Studies have shown that patients with more intraoperative air leaks are at higher risk of developing prolonged postoperative air leak. Various types of sealants have been used effectively for decreasing intraoperative alveolar air leak. We decided to compare 3 sealants to determine which was best.

Methods

This was a prospective nonrandomized study that included 120 patients undergoing pulmonary surgical procedures associated with intraoperative air leak. They were divided into 4 equal groups. In the first group, no sealant was used. Glubran 2 sealant was used in the second group, BioGlue in the third, and TachoSil in the fourth.

Results

Preoperative and intraoperative data showed no significant differences among groups, except age which was significantly older in the BioGlue group. Air leak duration and tube duration were significantly shorter in the sealant groups, separately and collectively. No significant difference was found among groups regarding total tube drainage. Also, no significant difference was found between the no-sealant and sealant groups collectively regarding the incidence of postoperative complications, but the BioGlue group had a significantly lower incidence of postoperative complications compared to the no-sealant group. Postoperative hospital stay was significantly shorter in the sealant groups, separately and collectively.

Conclusion

Our results support the use of sealants for decreasing alveolar air leak. They were easily used in a short time with no significant superiority of one sealant over the others, except for a lower incidence of postoperative complications with BioGlue.

Histological analysis of biocompatibility of different surgical adhesives in subcutaneous tissue

The focus of this study was to test the hypothesis that there would be no difference between the biocompatibility of cyanoacrylate-based adhesives in rat subcutaneous tissues. In total, 60 male Wistar rats were used, and divided into four groups (n = 15): Group C (control, PVA-polyvinyl alcohol sponge), Group NO (N-butyl-2-octylcyanoacrylate), Group NH (n-hexyl-cyanoacrylate), and Group EC (Ethyl-cyanoacrylate). The animals were sacrificed after time intervals of 7, 15, and 30 days and tissues were analyzed under optical microscope as regards the events of inflammatory infiltrate, edema, necrosis, granulation tissue, giant cells, young fibroblasts, and collagen formation. The results were statistically analyzed by the Kruskal-Wallis and Dunn tests (p < .05). Significant inflammatory infiltrate was shown for all the adhesives in the time intervals of 7 (p = .004) and 15 days (p = .003). In the time interval of 30 days, moderate inflammatory infiltrate was observed in Groups NH and EC, with significant difference from Control (p = .001). The quantity of collagen fibers in all the experimental groups showed significant difference compared with Control in the time intervals of 7 (p = .002) and 15 days (p = .001), at 30 days only Group EC showed a smaller quantity of collagen fibers in comparison with Control (p = .001). The hypothesis was rejected. The adhesive N-butyl-2-octylcyanoacrylate had less influence on the inflammatory intensity of multinucleated giant cells. Ethyl-cyanoacrylate demonstrated the lowest level of biocompatibility among the adhesives, but its use in clinical practice may be promising for coaptation of smaller edges of superficial tissue. Surgical adhesives were shown to be feasible for clinical use in substitution of conventional suturing. Ethyl-cyanoacrylate should be used with caution due to its greater influence on tissues.

Update on surgical management of corneal ulceration and perforation

Corneal ulcerations are a medical emergency, and in recalcitrant cases, leading to perforation, a surgical ophthalmological emergency. The urgency of the treatment is dictated by the necessity of preventing complications that can lead to serious ocular morbidities. Medical treatment represents the first therapeutic approach and is a defining step in the further management of a patient with corneal ulceration. Multiple surgical strategies are available, but the option depends on the etiology and parameters of the ulceration: size, depth, and location.

Endoscopic management of tracheoesophageal fistulas

Tracheoesophageal fistulas (TEF) are pathologic communications between the trachea and esophagus. TEF can lead to significant respiratory distress that may result in lethal respiratory compromise, often due to recurrent and intractable infections. Through the use of endoscopy, some TEF can be successfully repaired using different approaches depending on the size, location, availability, and experience of the treating endoscopist. The aim of this manuscript is to provide an up-to-date review of the endoscopic management of TEF for gastroenterologists.

Tunable Adhesion for Bio-Integrated Devices

With the rapid development of bio-integrated devices and tissue adhesives, tunable adhesion to soft biological tissues started gaining momentum. Strong adhesion is desirable when used to efficiently transfer vital signals or as wound dressing and tissue repair, whereas weak adhesion is needed for easy removal, and it is also the essential step for enabling repeatable use. Both the physical and chemical properties (e.g., moisture level, surface roughness, compliance, and surface chemistry) vary drastically from the skin to internal organ surfaces. Therefore, it is important to strategically design the adhesive for specific applications. Inspired largely by the remarkable adhesion properties found in several animal species, effective strategies such as structural design and novel material synthesis were explored to yield adhesives to match or even outperform their natural counterparts. In this mini-review, we provide a brief overview of the recent development of tunable adhesives, with a focus on their applications toward bio-integrated devices and tissue adhesives.

Fibrin sealants for the prevention of postoperative pancreatic fistula following pancreatic surgery

BACKGROUND

Postoperative pancreatic fistula is one of the most frequent and potentially life-threatening complications following pancreatic resections. Fibrin sealants are introduced to reduce postoperative pancreatic fistula by some surgeons. However, the use of fibrin sealants during pancreatic surgery is controversial. This is an update of a Cochrane Review last published in 2016.

OBJECTIVES

To assess the safety, effectiveness, and potential adverse effects of fibrin sealants for the prevention of postoperative pancreatic fistula following pancreatic surgery.

SEARCH METHODS

We searched trial registers and the following biomedical databases: the Cochrane Library (2018, Issue 4), MEDLINE (1946 to 12 April 2018), Embase (1980 to 12 April 2018), Science Citation Index Expanded (1900 to 12 April 2018), and Chinese Biomedical Literature Database (CBM) (1978 to 12 April 2018).

SELECTION CRITERIA

We included all randomized controlled trials that compared fibrin sealant (fibrin glue or fibrin sealant patch) versus control (no fibrin sealant or placebo) in people undergoing pancreatic surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified the trials for inclusion, collected the data, and assessed the risk of bias. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes (or a Peto odds ratio (OR) for very rare outcomes), and the mean difference (MD) for continuous outcomes, with 95% confidence intervals (CIs).

MAIN RESULTS

We included 11 studies involving 1462 participants in the review.Application of fibrin sealants to pancreatic stump closure reinforcement after distal pancreatectomyWe included seven studies involving 860 participants: 428 were randomized to the fibrin sealant group and 432 to the control group after distal pancreatectomy. Fibrin sealants may lead to little or no difference in postoperative pancreatic fistula (fibrin sealant 19.3%; control 20.1%; RR 0.96, 95% CI 0.68 to 1.35; 755 participants; four studies; low-quality evidence). Fibrin sealants may also lead to little or no difference in postoperative mortality (0.3% versus 0.5%; Peto OR 0.52, 95% CI 0.05 to 5.03; 804 participants; six studies; low-quality evidence), or overall postoperative morbidity (28.5% versus 23.2%; RR 1.23, 95% CI 0.97 to 1.58; 646 participants; three studies; low-quality evidence). We are uncertain whether fibrin sealants reduce reoperation rate (2.0% versus 3.8%; RR 0.51, 95% CI 0.15 to 1.71; 376 participants; two studies; very low-quality evidence). There is probably little or no difference in length of hospital stay between the groups (12.1 days versus 11.4 days; MD 0.32 days, 95% CI -1.06 to 1.70; 755 participants; four studies; moderate-quality evidence). The studies did not report serious adverse events, quality of life, or cost effectiveness.Application of fibrin sealants to pancreatic anastomosis reinforcement after pancreaticoduodenectomyWe included three studies involving 251 participants: 115 were randomized to the fibrin sealant group and 136 to the control group after pancreaticoduodenectomy. We are uncertain whether fibrin sealants reduce postoperative pancreatic fistula (1.6% versus 6.2%; RR 0.25, 95% CI 0.01 to 5.06; 57 participants; one study; very low-quality evidence). Fibrin sealants may lead to little or no difference in postoperative mortality (0.1% versus 0.7%; Peto OR 0.15, 95% CI 0.00 to 7.76; 251 participants; three studies; low-quality evidence) or length of hospital stay (12.8 days versus 14.8 days; MD -1.58 days, 95% CI -3.96 to 0.81; 181 participants; two studies; low-quality evidence). We are uncertain whether fibrin sealants reduce overall postoperative morbidity (33.7% versus 34.7%; RR 0.97, 95% CI 0.65 to 1.45; 181 participants; two studies; very low-quality evidence), or reoperation rate (7.6% versus 9.2%; RR 0.83, 95% CI 0.33 to 2.11; 181 participants; two studies, very low-quality evidence). The studies did not report serious adverse events, quality of life, or cost effectiveness.Application of fibrin sealants to pancreatic duct occlusion after pancreaticoduodenectomyWe included two studies involving 351 participants: 188 were randomized to the fibrin sealant group and 163 to the control group after pancreaticoduodenectomy. Fibrin sealants may lead to little or no difference in postoperative mortality (8.4% versus 6.1%; Peto OR 1.41, 95% CI 0.63 to 3.13; 351 participants; two studies; low-quality evidence) or length of hospital stay (17.0 days versus 16.5 days; MD 0.58 days, 95% CI -5.74 to 6.89; 351 participants; two studies; low-quality evidence). We are uncertain whether fibrin sealants reduce overall postoperative morbidity (32.0% versus 27.6%; RR 1.16, 95% CI 0.67 to 2.02; 351 participants; two studies; very low-quality evidence), or reoperation rate (13.6% versus 16.0%; RR 0.85, 95% CI 0.52 to 1.41; 351 participants; two studies; very low-quality evidence). Serious adverse events were reported in one study: more participants developed diabetes mellitus when fibrin sealants were applied to pancreatic duct occlusion, both at three months' follow-up (33.7% fibrin sealant group versus 10.8% control group; 29 participants versus 9 participants) and 12 months' follow-up (33.7% fibrin sealant group versus 14.5% control group; 29 participants versus 12 participants). The studies did not report postoperative pancreatic fistula, quality of life, or cost effectiveness.

AUTHORS' CONCLUSIONS

Based on the current available evidence, fibrin sealants may have little or no effect on postoperative pancreatic fistula in people undergoing distal pancreatectomy. The effects of fibrin sealants on the prevention of postoperative pancreatic fistula are uncertain in people undergoing pancreaticoduodenectomy.

Recent Developments in Tough Hydrogels for Biomedical Applications

A hydrogel is a three-dimensional polymer network with high water content and has been attractive for many biomedical applications due to its excellent biocompatibility. However, classic hydrogels are mechanically weak and unsuitable for most physiological load-bearing situations. Thus, the development of tough hydrogels used in the biomedical field becomes critical. This work reviews various strategies to fabricate tough hydrogels with the introduction of non-covalent bonds and the construction of stretchable polymer networks and interpenetrated networks, such as the so-called double-network hydrogel. Additionally, the design of tough hydrogels for tissue adhesive, tissue engineering, and soft actuators is reviewed.

Inorganic Nanomaterials for Soft Tissue Repair and Regeneration

Inorganic nanomaterials have witnessed significant advances in areas of medicine including cancer therapy, imaging, and drug delivery, but their use in soft tissue repair and regeneration is in its infancy. Metallic, ceramic, and carbon allotrope nanoparticles have shown promise in facilitating tissue repair and regeneration. Inorganic nanomaterials have been employed to improve stem cell engraftment in cellular therapy, material mechanical stability in tissue repair, electrical conductivity in nerve and cardiac regeneration, adhesion strength in tissue approximation, and antibacterial capacity in wound dressings. These nanomaterials have also been used to improve or replace common surgical materials and restore functionality to damaged tissue. We provide a comprehensive overview of inorganic nanomaterials in tissue repair and regeneration, and discuss their promise and limitations for eventual translation to the clinic.

Local and systemic effects of fibrin and cyanoacrylate adhesives on lung lesions in rabbits

OBJECTIVES

Tissue adhesives can be used to prevent pulmonary air leaks, which frequently occur after lung interventions. The objective of this study is to evaluate local and systemic effects of fibrin and cyanoacrylate tissue adhesives on lung lesions in rabbits.

METHODS

Eighteen rabbits were submitted to videothoracoscopy + lung incision alone (control) or videothoracoscopy + lung incision + local application of fibrin or cyanoacrylate adhesive. Blood samples were collected and assessed for leukocyte, neutrophil and lymphocyte counts and interleukin-8 levels preoperatively and at 48 hours and 28 days post-operatively. After 28 days, the animals were euthanized for gross examination of the lung surface, and lung fragments were excised for histopathological analysis.

RESULTS

Fibrin and cyanoacrylate produced similar adhesion scores of the lung to the parietal pleura. Microscopic analysis revealed uniform low-cellular tissue infiltration in the fibrin group and an intense tissue reaction characterized by dense inflammatory infiltration of granulocytes, giant cells and necrosis in the cyanoacrylate group. No changes were detected in the leukocyte, neutrophil or lymphocyte count at any time-point, while the interleukin-8 levels were increased in the fibrin and cyanoacrylate groups after 48 hours compared with the pre-operative control levels (p<0.01).

CONCLUSION

Both adhesive agents promoted normal tissue healing, with a more pronounced local inflammatory reaction observed for cyanoacrylate. Among the serum markers of inflammation, only the interleukin-8 levels changed post-operatively, increasing after 48 hours and decreasing after 28 days to levels similar to those of the control group in both the fibrin and cyanoacrylate groups.

Endoscopic cyanoacrylate injection with or without lauromacrogol for gastric varices: A randomized pilot study

BACKGROUND AND AIM

Current guidelines recommend injection of cyanoacrylate as first-line therapy to prevent gastric variceal rebleeding. The method still poses a risk of ectopic embolism, which possibly correlates with the volume of cyanoacrylate used. In this trial, we evaluated the short-term efficacy and safety of tissue adhesive injection combined with lauromacrogol for treating gastric varices.

METHODS

Patients admitted to our hospital for variceal hemorrhage were enrolled and blindly randomized into two treatment groups: lauromacrogol group (lauromacrogol-cyanoacrylate-lauromacrogol) and lipiodol group (lipiodol-cyanoacrylate-lipiodol). Patient follow-up was 6 months. Primary outcome was rebleeds, and secondary outcomes were mortality, gastric varices eradication, and treatment-related adverse events.

RESULTS

Between March 6, 2013 and October 16, 2013, 96 patients met the criteria. Two cases were lost to follow-up, and all treated cases were successful. No procedural-related adverse events were observed in either group. Cyanoacrylate volumes used in the lauromacrogol group were significantly less than those of the lipiodol group (0.9 ± 0.5 vs 2.0 ± 1.2 mL, P = 0.000). Eleven patients developed upper gastrointestinal rebleeding, which did not show significant difference between groups. On multivaritate analysis, portal venous thrombosis and fever were potential risk factors of rebleeding. Treatment failure, complications, gastric varices obturation, and survival did not differ between the two groups.

CONCLUSION

Tissue adhesives combined with lauromacrogol is a safe therapeutic option for gastric varices, with comparably less cyanoacrylate volume used. Because of the small number of study patients, it cannot be proven to have better efficacy than without lauromacrogol. Multicenter studies with larger patient groups are necessary.

Evaluation of novel biodegradable three-armed- and hyper-branched tissue adhesives in a meniscus explant model

Current treatment methods to repair meniscal tears do not bring fully satisfactory results. Tissue adhesives are considered promising alternatives, since they are easy to apply and cause minimal tissue trauma. The first aim of this study was to analyze the adhesive properties of and tissue response to two recently developed biodegradable block copolymeric three-armed- and hyper-branched tissue adhesives. The second aim was to investigate if tissue surface modification with collagenase improves the attachment of the adhesives and increases the healing potential of the tissue. Cylindrical explants were harvested from bovine menisci. The central core of the explants was removed and glued back into the defect, with or without incubation in collagenase solution prior to gluing, using one of the novel glues, Dermabond® or fibrin glue. The repair constructs were cultured in vitro for 1 and 28 days. Adhesion tests and histology were performed to analyze the effects of the glue in combination with the additional treatment. The adhesive strength of the novel glues was 40-50 kPa, which was significantly higher than that of fibrin glue (15 kPa). Cells were present in direct contact with the glues, and the tissue remained vital during the whole culture period. Increased cellularity around the tear in the collagenase treated explants was observed after 1 day. The two newly developed tissue adhesives are attractive materials to be used for repair of meniscal tears. The beneficial influence of collagenase treatment in treating meniscal tears with glues still needs to be confirmed in more clinical relevant studies. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1405-1411, 2017.

Fibrin glue for pilonidal sinus disease

BACKGROUND

Pilonidal sinus disease is a common condition that mainly affects young adults. This condition can cause significant pain and impairment of normal activities. No consensus currently exists on the optimum treatment for pilonidal sinus and current therapies have various advantages and disadvantages. Fibrin glue has emerged as a potential treatment as both monotherapy and an adjunct to surgery.

OBJECTIVES

To assess the effects of fibrin glue alone or in combination with surgery compared with surgery alone in the treatment of pilonidal sinus disease.

SEARCH METHODS

In December 2016 we searched: the Cochrane Wounds Specialised Register; CENTRAL; MEDLINE; Embase and CINAHL Plus. We also searched clinical trials registries and conference proceedings for ongoing and unpublished studies and scanned reference lists to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) only. We included studies involving participants of all ages and studies conducted in any setting. We considered studies involving people with both new and recurrent pilonidal sinus. We included studies which evaluated fibrin glue monotherapy or as an adjunct to surgery.

DATA COLLECTION AND ANALYSIS

Two study authors independently extracted data and assessed risk of bias. We used standard methods expected by Cochrane.

MAIN RESULTS

We included four RCTs with 253 participants, all were at risk of bias. One unpublished study evaluated fibrin glue monotherapy compared with Bascom's procedure, two studies evaluated fibrin glue as an adjunct to Limberg flap and one study evaluated fibrin glue as an adjunct to Karydakis flap.For fibrin glue monotherapy compared with Bascom's procedure, there were no data available for the primary outcomes of time to healing and adverse events. There was low-quality evidence of less pain on day one after the procedure with fibrin glue monotherapy compared with Bascom's procedure (mean difference (MD) -2.50, 95% confidence interval (CI) -4.03 to -0.97) (evidence downgraded twice for risk of performance and detection bias). Fibrin glue may reduce the time taken to return to normal activities compared with Bascom's procedure (mean time 42 days with surgery and 7 days with glue, MD -34.80 days, 95% CI -66.82 days to -2.78 days) (very low-quality evidence, downgraded as above and for imprecision).Fibrin glue as an adjunct to the Limberg flap may reduce the healing time from 22 to 8 days compared with the Limberg flap alone (MD -13.95 days, 95% CI -16.76 days to -11.14 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). It is uncertain whether use of fibrin glue affects the incidence of postoperative seroma (an adverse event) (risk ratio (RR) 0.27, 95% CI 0.05 to 1.61; very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). There was low-quality evidence that fibrin glue, as an adjunct to Limberg flap, may reduce postoperative pain (median 2 versus 4; P < 0.001) and time to return to normal activities (median 8 days versus 17 days; P < 0.001). The addition of fibrin glue to the Limberg flap may reduce the length of hospital stay (MD -1.69 days, 95% CI -2.08 days to -1.29 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for unexplained heterogeneity).A single RCT evaluating fibrin glue as an adjunct to the Karydakis flap did not report data for the primary outcome of time to healing. It is uncertain whether fibrin glue with the Karydakis flap affects the incidence of postoperative seroma (adverse event) (RR 3.00, 95% CI 0.67 to 13.46) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for imprecision). Fibrin glue as an adjunct to Karydakis flap may reduce length of stay but this is highly uncertain (mean 2 days versus 3.7 days; P < 0.001, low-quality evidence downgraded twice for risk of selection, performance and detection bias).

AUTHORS' CONCLUSIONS

Current evidence is uncertain regarding any benefits associated with fibrin glue either as monotherapy or as an adjunct to surgery for people with pilonidal sinus disease. We identified only four RCTs and each was small and at risk of bias resulting in very low-quality evidence for the primary outcomes of time to healing and adverse events. Future studies should enrol many more participants, ensure adequate randomisation and blinding, whilst measuring clinically relevant outcomes.

Supramolecular Metallo-Bioadhesive for Minimally Invasive Use

A novel metallo-bioadhesive to be used as tissue sealant in minimally invasive procedures is reported. Metal complexation can be used to render gelatin derivatives adhesive, which occurs in minutes, is efficient, and fully biodegradable within weeks.

Polyglycolic acid mesh occlusion for postoperative bronchopleural fistula

BACKGROUND

Postoperative bronchopleural fistula is one of the most life-threatening complications after anatomical pulmonary resection. Bronchopleural fistula may cause empyema and aspiration pneumonia with subsequent acute respiratory distress syndrome. Surgical interventions for bronchopleural fistula can prolong hospitalization and impair postoperative quality of life. Postoperative care requires minimally invasive endoscopic occlusion.

METHODS

We retrospectively reviewed the records of 7 patients who developed bronchopleural fistula among 689 patients who underwent segmentectomy or lobectomy without sleeve resection for lung cancer in Jichi Medical University from 2009 to 2013. Bronchopleural fistula occurred in the right lower bronchial stump in 3 patients, in the superior segmental bronchus of the right lower lobe in 2, in the superior segmental bronchus of the left lower lobe in one, and in the right intermediate bronchus in one. Flexible bronchoscopy was used to occlude 3-mm fistulas with polyglycolic acid mesh in 2 patients. Larger fistulas in 5 patients were occluded with polyglycolic acid mesh plus fibrin glue to secure the mesh. The median procedure was 37 min. Procedures were considered complete upon resolution of air leakage from the chest drainage system.

RESULTS

Bronchoscopic interventions for bronchopleural fistula were repeated an average of 2 times. No procedure-related complications or death occurred. Bronchoscopic interventions were successful in all patients.

CONCLUSIONS

Bronchoscopic occlusion with polyglycolic acid mesh with or without fibrin glue is easy and feasible as the first step in postoperative management of bronchopleural fistula.

Bronchopleural fistula closed with cellulose patch and fibrin glue

We describe a bronchoscopic technique for closing small postoperative bronchopleural fistulas, using an oxidized regenerated cellulose patch and fibrin glue. The patch is mounted on the end of endoscopic forceps and introduced into the fistula to cover it. Intracavitary and submucosal injections of fibrin glue fill the bronchial stump and achieve apposition of the fistula edges. Closure was obtained in 3 of 4 patients; the 4th had complete bronchial dehiscence and empyema.