Comparison of tensile strength of fibrin glue and suture in microflap closure

Andrias Davidianus Mucus-Based Bioadhesive with Enhanced Adhesion and Wound Healing Properties

The skin secretion of Andrias davidianus (SSAD) is a novel biological adhesive raw material under development. This material exhibits robust adhesion while maintaining the flexibility of the wound. It also has the potential for large-scale production, making it promising for practical application explore. Hence, in-depth research on methods to fine-tune SSAD properties is of great importance to promote its practical applications. Herein, we aim to enhance the adhesive and healing properties of SSAD by incorporating functional components. To achieve this goal, we selected 3,4-dihydroxy-l-phenylalanine and vaccarin as the functional components and mixed them with SSAD, resulting in a new bioadhesive, namely, a formulation termed "enhanced SSAD" (ESSAD). We found that the ESSAD exhibited superior adhesive properties, and its adhesive strength was improved compared with the SSAD. Moreover, ESSAD demonstrated a remarkable ability to promote wound healing. This study presents an SSAD-based bioadhesive formulation with enhanced properties, affirming the feasibility of developing SSAD-based adhesive materials with excellent performance and providing new evidence for the application of SSAD. This study also aims to show that SSAD can be mixed with other substances, and addition of effective components to SSAD can be studied to further adjust or improve its performance.

Sutureless Transplantation of Amniotic Membrane Using a Visible Light-Curable Protein Bioadhesive for Ocular Surface Reconstruction

The conjunctiva is a thin mucous membrane of the eye. Pterygium, a commonly appearing disease on the ocular surface, requires surgery to excise the conjunctiva to prevent visual deterioration. Recently, transplantation of the amniotic membrane (AM), which is the innermost membrane of the placenta, has been highlighted as an efficient method to cure conjunctiva defects because of its advantages of no side effects compared to mitomycin C treatment and not leaving additional scars on donor site compared to conjunctival autografting. However, to minimize additional damage to the ocular surface by suturing, AM transplantation (AMT) needs to be simplified by using a less invasive, time-saving method. In this work, a visible light-curable protein bioadhesive (named FixLight) for efficient sutureless AMT is applied. FixLight, which is based on bioengineered mussel adhesive protein (MAP), is easily applied between damaged ocular surfaces and transplanted AM, and rapidly cured by harmless blue light activation. Through in vivo evaluation using a rabbit model, the authors demonstrated that FixLight enabled facile, fast, and strong attachment of AM on sclera and promoted ocular surface reconstruction with good biocompatibility. Thus, FixLight can be successfully used as a promising clinical bioadhesive in opthalmological surgeries that require sutureless and rapid operation.

Full- versus partial-thickness sutures: experimental models of corneal injury repair

PURPOSE

To evaluate the performance of full-thickness (FT) versus partial-thickness (PT) sutures in a full-thickness corneal wound in an animal model.

METHODS

This is a prospective, experimental, comparative, longitudinal study. A 6-mm linear, full-thickness corneal incision was performed on the right eye of eight domestic pigs. Eyes were randomly assigned for repair with interrupted PT (80-90% depth) sutures or FT 10-0 nylon sutures. Anterior segment OCT, corneal pachymetry and clinical photographs were obtained 1, 4 and 8 weeks postoperatively. Corneal thickness, depth of suture placement, perilesional edema, coaptation of wound edges and complications were noted. Histopathologic examination was performed at 8 weeks.

RESULTS

100% of the eyes with FT sutures developed a linear, less opaque scar. 100% of the eyes with PT developed a dense, opaque stromal scar (p = 0.02). Vascularization of the cornea was present in 75% of PT group and 25% in the FT group (p = 0.50). As the corneas healed, there was a marked trend toward thicker corneas in the PT group versus FT group with a median difference of - 63 µm at week 1 [median 788 µm vs. 725 µm, (p = 0.11)], - 38 µm at week 4, (724 µm vs. 686 µm, (p = 0.63)) and - 47 µm median difference at week 8 with (670 µm vs. 623 µm, (p = 0.06)). Histopathology showed disorganization of the collagen fibers and the formation of a retrocorneal fibrous membrane in the PT group.

CONCLUSIONS

The FT group presented less corneal edema at week 8 with a more linear and less opaque scar. Histopathology showed a better-organized scar and endothelialization without the formation of a fibrous membrane.

Mussel-inspired antimicrobial gelatin/chitosan tissue adhesive rapidly activated in situ by H2O2/ascorbic acid for infected wound closure

The development of minimally invasive surgery has created a demand for ideal medical adhesives exhibiting biocompatibility, biodegradability, antimicrobial activity, and strong adhesion to tissues in wet environments. However, as clinically approved surgical tissue glues suffer from poor adhesion activation, limited adhesion strength, and toxicity, novel tissue glues are highly sought after. Herein, a mussel-inspired injectable hydrogel was prepared from catechol- and methacrylate-modified chitosan/gelatin and shown to exhibit biocompatibility, inherent antimicrobial activity, and good adhesion to wet tissues. Moreover, as this gel could be applied onto tissue surfaces and cured in situ within seconds of body contact by a biocompatible and multifunctional redox initiator (H₂O₂-ascorbic acid), it was concluded to be a promising surgical sealant and wound dressing (even for infected wounds) accelerating wound healing.

Two-handed tying technique in vocal fold mucosa microsuture for the treatment of Reinke's edema

BACKGROUND

Removal of Reinke's edema may result in moderate to large-sized mucosal defect on the vocal fold, which heals by secondary intention. Microsuturing this defect may lead to primary wound healing with fastened recovery and less scar, but costs extra time and effort. Exploring methods that can shorten microsuture time is helpful for the wider application of this technology.

STUDY DESIGN

Retrospective.

METHODS

57 patients with Reinke's edema, who were admitted from November 2010 to June 2018, were enrolled as research subjects for the retrospective analysis. 27 patients were the knot pusher group (from November 2010 to March 2015), and 30 patients were the two-handed tying group (from April 2015 to June 2018). Evaluation indicators include the number of knots, the average time for suturing and tying the knot for each patient, and the occurrence of complications, subjective and objective voice assessments.

RESULTS

All patients underwent successful operation. The average time for making knots in the knot pusher group and two-handed tying group was 668.40 ± 173.73 s and 328.73 ± 121.0 s, respectively, and there was a statistically significant difference between the two groups (p < 0.001). No significant difference was noted in the mucosal avulsion, overall incidence of complications between the groups, and no significant difference was found between the two groups in terms of the preoperative and 3-month postoperative subjective and objective indicators.

CONCLUSION

Microsuturing of Reinke's edema microflaps using the two-handed tying technique can achieve the similar effect with the knot pusher method, and save operation time while the surgeon is well trained.

LEVEL OF EVIDENCE

4.

Investigation of surgical adhesives for vocal fold wound closure

OBJECTIVES

Surgical adhesives are increasingly used for vocal fold microsurgery to assist wound closure and reduce the risks of scar formation. Currently used vocal fold adhesives such as fibrin glue, however, have thus far not been found to promote wound closure or reduce scarring. The objectives of this study were to investigate the mechanical strength and the cytotoxicity of three commercially available adhesives (Glubran 2, GEM, Viareggio, Italy; BioGlue, CryoLife, Kennesaw, GA; and Tisseel, Baxter Healthcare, Deerfield, IL) for vocal fold wound closure.

METHODS

Shear and tension tests were performed on 150 porcine larynges. The cytotoxicity of the adhesives to immortalized human vocal fold fibroblasts was investigated using neutral red uptake assays.

RESULTS

The average shear adhesive strength for Tisseel, BioGlue, and Glubran 2 was 13.86 ± 5.03 kilopascal (kPa), 40.92 ± 17.94 kPa, and 68.79 ± 13.29 kPa, respectively. The tensile adhesive strength for Tisseel, BioGlue, and Glubran 2 was 10.70 ± 6.42 kPa, 34.27 ± 12.59 kPa, and 46.67 ± 12.13 kPa, respectively. The vocal fold cell viabilities in extracts of Tisseel, BioGlue, and Glubran 2 were 99.27%, 43.05%, and 1.79%, respectively.

CONCLUSION

There was a clear tradeoff between adhesive strength and toxicity. The maximum failure strength in shear or tension of the three surgical adhesives ranked from strongest to the weakest was: 1) Glubran 2, 2) BioGlue, and 3) Tisseel. Tisseel was found to be the least toxic of the three adhesives, whereas Glubran 2 was the most toxic.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2139-2146, 2019.

Comparison of Fixation Techniques of 3D-Woven Poly(ϵ-Caprolactone) Scaffolds for Cartilage Repair in a Weightbearing Porcine Large Animal Model

Objective To test different fixation methods of a 3-dimensionally woven poly(ϵ-caprolactone) (PCL) scaffold within chondral defects of a weightbearing large animal model. Methods Full thickness chondral defects were made in the femoral condyles of 15 adult male Yucatan mini-pigs. Two surgical approaches were compared including total arthrotomy (traditional) and a retinaculum-sparing, minimally invasive surgery (MIS) approach. Following microfracture (MFX), scaffolds were placed without fixation or were fixed with fibrin glue, suture, or subchondral anchor. Experimental endpoints were between 1 and 6 weeks. Micro-computed tomography and histology were used to assess samples. Results The MIS approach was superior as the traditional approach caused medial condyle cartilage wear. One of 13 (7.7%) of scaffolds without fixation, 4 of 11 (36.3%) fibrin scaffolds, 1 of 4 (25%) of sutured scaffolds, and 9 of 9 (100%) of anchor-fixed scaffolds remained in place. Histology demonstrated tissue filling with some overgrowth of PCL scaffolds. Conclusions Of the methods tested, the MIS approach coupled with subchondral anchor fixation provided the best scaffold retention in a mini-pig chondral defect model. This finding has implications for fixation strategies in future animal studies and potential future human use.

Fixation of split-thickness skin graft using fast-clotting fibrin glue containing undiluted high-concentration thrombin or sutures: a comparison study

Objective

For skin defects caused by full-thickness burns, trauma, or tumor tissue excision, skin grafting is one of the most convenient and useful treatment methods. In this situation, graft fixation is important in skin grafting. This study was performed to compare the effectiveness of skin graft fixation between high-concentration fibrin sealant and sutures. There have been numerous studies using fibrin sealant for graft fixation, but they utilized slow-clotting fibrin sealant containing less than 10 IU/mL thrombin.

Method

Twenty-five patients underwent split-thickness skin grafting using fast-clotting fibrin sealant containing 400 IU/mL thrombin, while 30 patients underwent grafting using sutures. Rates of hematoma/seroma formation, graft dislocation, graft necrosis, and graft take were investigated postoperatively. The graft surface area was calculated using Image J software (National Institutes of Health, Bethesda, MD, USA).

Result

After 5 days, rates of hematoma/seroma formation and graft dislocation were 7.84 and 1.29% in group I, and 9.55 and 1.45% in group II, respectively. After 30 days, rates of graft necrosis and graft take were 1.86 and 98.14% in group I, and 4.65 and 95.35% in group II. Undiluted fibrin sealant showed significantly superior results for all rates (p < 0.05) except graft dislocation.

Conclusion

When high-concentration fast-clotting fibrin sealant was applied to skin grafts without dilution, no difficulty was experienced during surgery. Sealant showed superior results compared with sutures and had an excellent graft take rate.

Level of evidence

II.