2-octyl cyanoacrylate adhesive for conjunctival wound closure in rabbits

Comparison of the effects of preservation methods on structural, biological, and mechanical properties of the human amniotic membrane for medical applications

Amniotic membrane (AM), the innermost layer of the placenta, is an exceptionally effective biomaterial with divers applications in clinical medicine. It possesses various biological functions, including scar reduction, anti-inflammatory properties, support for epithelialization, as well as anti-microbial, anti-fibrotic and angio-modulatory effects. Furthermore, its abundant availability, cost-effectiveness, and ethical acceptability make it a compelling biomaterial in the field of medicine. Given the potential unavailability of fresh tissue when needed, the preservation of AM is crucial to ensure a readily accessible and continuous supply for clinical use. However, preserving the properties of AM presents a significant challenge. Therefore, the establishment of standardized protocols for the collection and preservation of AM is vital to ensure optimal tissue quality and enhance patient safety. Various preservation methods, such as cryopreservation, lyophilization, and air-drying, have been employed over the years. However, identifying a preservation method that effectively safeguards AM properties remains an ongoing endeavor. This article aims to review and discuss different sterilization and preservation procedures for AM, as well as their impacts on its histological, physical, and biochemical characteristics.

Clinical-pathological study of the healing of wounds provoked on the dorso-lingual mucosa in 186 albino rats

OBJECTIVE: To evaluate wound healing of incisions created in the upper aerodigestive tract.

STUDY DESIGN AND SETTING: In this prospective and blind study, 186 adult rats were assigned to six groups to create incisions in the tongue. In the first three groups, the wounds were made with a steel scalpel; no substance was applied to the wound in the first group, but N-butyl-2-cyanoacrylate was applied in the second group, and trichloroacetic acid at 50 percent in the third group. In the fourth, fifth, and sixth groups, the wounds were caused by cryosurgery, electrocautery, and CO2 laser. Hemostasis, postoperative oral intake, and wound healing were measured. Statistical analysis was performed with analysis of variance.

RESULTS: The wounds to which N-butyl-2-cyanoacrylate was applied showed no hemorrhaging and faster reepithelialization and resolution of the inflammatory response.

CONCLUSIONS: N-butyl-2-cyanoacrylate is a good hemo-static for managing wounds in the oral mucosa provoked by steel scalpel.

© 2007 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

A comparison of 2-octyl cyanoacrylate adhesives versus conventional suture materials for eyelid wound closure in rabbits

Purpose

To evaluate the clinical efficacy and histopathological tolerance of 2-octyl cyanoacrylate versus conventional suture materials for eyelid wound closure in rabbits.

Methods

We performed an experimental study on 16 eyes of eight New Zealand albino rabbits. Eyelid incisions of 15 mm were done 4mm from the upper eyelid margin in both eyes. The eyes of the rabbits were divided into two groups: eyelid incisions of the right eye were closed by a 2-octyl cyanoacrylate adhesive (group A) and eyelid incisions of the left eye were closed by 7-0 nylon sutures (group B). At 1, 2, 4, and 8 weeks after surgery, the rabbits were macroscopically examined and then sacrificed. The specimens of their eyelid tissues were stained by a hematoxylin and eosin stain and Masson-trichrome stain, and were observed under microscope.

Results

Both eyelid surgical closure methods were found to be equally efficacious in fixing the eyelids of groups A and B, and their clinical efficacy was similar. Histopathological findings of the hematoxylin and eosin stain of group A showed less inflammatory infiltration than group B at 2 weeks. There were no significant histopathological differences between the two groups at 1, 4, and 8 weeks. The degree of fibrosis of the Masson-trichrome stain was similar between the two groups at 8 weeks.

Conclusions

The 2-octyl cyanoacrylate adhesive proved to be an effective eyelid closure method and was very well tolerated by the skin surface. 2-Octyl cyanoacrylate could be used as an alternative tissue adhesive for eyelid wound closure along with conventional suture materials.

Use of a hyperdried cross-linked amniotic membrane as initial therapy for corneal perforations

PURPOSE

To report the use of hyperdried cross-linked (HDCL) amniotic membrane (AM) patching with tissue adhesive as an initial therapy for corneal perforations.

METHODS

Cryopreserved AM was cross-linked with 0.1% glutaraldehyde and then dried using far-infrared rays and microwaves (hyperdry method). Three eyes of three patients with corneal perforations of up to 3 mm in diameter were included in this study. They were treated with a single-layer patch of HDCL-AM applied with a tissue adhesive (2-octyl-cyanoacrylate). We also evaluated the resistance of HDCL-AM to collagenases during in vitro digestion testing.

RESULTS

In all three cases, the corneal perforations were repaired within 28 days (range, 17-28 days). No recurrence occurred during the follow-up period (3-6 months). In the collagenase digestion testing, the HDCL-AM did not dissolve until 48 h, whereas the cryopreserved AM completely dissolved within 60 min.

CONCLUSIONS

Three cases of corneal perforations were successfully managed using HDCL-AM patching with tissue adhesive. The HDCL-AM was resistant to collagenases during in vitro digestion testing. The HDCL-AM was a useful substrate for corneal perforations. This simple surgical technique may be one of the initial therapeutic options for corneal perforations.

Extraocular muscle fixation to porous polyethylene orbital implants using 2-octyl-cyanoacrylate

PURPOSE

To evaluate the efficacy of bioadhesive in attaching the extraocular muscles to porous polyethylene spheres in rabbit enucleated cavities.

METHODS

A prospective, experimental study was performed. Eight adult New Zealand white rabbits underwent right enucleation with insertion of an unwrapped 12 mm porous polyethylene sphere. The superior and inferior rectus muscles were attached to the implant with 2-octyl cyanoacrylate placed to the underside of the muscles and application of pressure for 5 seconds. Ninety days after surgery, the orbits were exenterated and four animals underwent histologic evaluation and the other four animals tensile strength testing of the muscle-sphere attachment.

RESULTS

There were no exposures or infections of the implants and the muscles remained attached in all cases. Histologic examination showed fibrous tissue reaction at the muscle-sphere attachment with minimal inflammation of the surrounding tissues; a pseudocapsule formation around the spheres and full vascularization of the implant was also observed. There was no evidence of residual glue on histologic examination. Tensile strength testing showed that rupture force was similar between bonded muscle and the porous polyethylene sphere.

CONCLUSIONS

The 2-octyl-cyanoacrylate did not cause deleterious effects in orbital tissues and provided strong adhesion between muscles and spheres. Bioadhesive may be an option for attaching the extraocular muscles to orbital implants in anophthalmic cavity reconstruction.

A hyperdry amniotic membrane patch using a tissue adhesive for corneal perforations and bleb leaks

PURPOSE

To evaluate the efficacy of hyperdry amniotic membrane (AM) patching attached using a tissue adhesive for corneal perforations and glaucoma filtering bleb leaks.

DESIGN

Prospective, noncomparative, interventional case series.

METHODS

Five eyes of 5 patients (glaucoma bleb leaks, 2 eyes; corneal perforations, 3 eyes) were treated with a single-layer patch of dried AM using a biological tissue adhesive. The dried AM was prepared with consecutive far-infrared rays and microwaves (hyperdry method) and was sterilized by gamma-ray irradiation. The dried AM was cut to the desired size and shape, and the tissue adhesive was applied to the amniotic epithelial side of the dried membrane. After applying the tissue adhesive, the dried membrane with glue applied then was positioned to cover the conjunctival bleb leak site or corneal perforation lesion using forceps. A therapeutic hydrogel contact lens then was installed as a bandage.

RESULTS

Bleb leaks or corneal perforations were repaired successfully within 21 days in all 5 cases. There were no remarkable adverse effects, and there was no recurrence of bleb leak or corneal perforation.

CONCLUSIONS

The hyperdry AM is a useful substrate, and this surgical procedure is a promising method to treat glaucoma filtering bleb leak or corneal perforation, which may result in serious vision-threatening ocular complications.

Evaluation of biochemical the two cyanoacrylates: an experimental study in rats

The objective of this work is to study the biochemical effect in liver and kidney 2, 14, and 28 days after applying different tissue adhesives. In a prospective longitudinal study, 20 adult rats are assigned to two groups. After making incisions in the buccal mucosa, n-butyl-2-cyanoacrylate is applied to the first group and 2-octyl-cyanoacrylate (OCA) to the second. The biochemical parameters studied are: albumin (ALB), alanine aminotransferase (ALT), amylase (AMY), total bilirubin (TBI), blood urea nitrogen (BUN), creatinine (CRE), glucose, globulin, total proteins (TP), and the ions calcium, phosphorus, sodium, and potassium. The group treated with n-butyl-2-cyanoacrylate shows no statistically significant differences with respect to the control, but OCA produces statistically significant alterations in BUN, ALT, TP, TBI, and AMY. The application of n-butyl-2-cyanoacrylate to wounds in the buccal mucosa produces no significant alterations in the hepatic and renal profile of the animals studied, while OCA produces greater changes in the biochemical profile.

Capacity and tolerance of a new device for ocular drug delivery

A new method to increase the drug-capacity of the OphthaCoil, a flexible and tubular device for delivery of drugs to the tear film of the eye, was explored. Poly(2-hydroxyethyl methacrylate)- and poly(2-hydroxyethyl methacrylate-co-1-vinyl-2-pyrrolidone)-microspheres were prepared by suspension polymerization. The resultant particles were swollen in a highly concentrated solution of either the dye fluorescein sodium or the antibiotic chloramphenicol. The loaded particles were placed in the central cavity of the ocular device. In vitro release profiles showed a six-fold increase of the capacity for the dye fluorescein sodium, but not for the antibiotic chloramphenicol. Flexibility measurements revealed that by introducing microspheres in the central cavity of the device, flexibility did not decrease. Finally, a preliminary in vivo evaluation of the device (n=5) was done for a 2h-period to assess the tolerance of the device in the human eye. Ophthalmologic examinations and photographs of the eye indicated no signs of irritation. Volunteers reported that the presence of the device in the eye could be noticed, but no irritation was reported.

Preliminary in vitro evaluation of 2-octyl cyanoacrylate (Dermabond) to seal corneal incisions

OBJECTIVE

To compare the efficacy of Dermabond with conventional nylon sutures for sealing linear corneal incisions.

METHODS

A keratome knife was used to create a 4-mm full-thickness linear corneal incision anterior to the limbal arcade in 20 fresh pig eyes. The incision was sealed with Dermabond tissue adhesive or closed with 10-0 nylon sutures. A 27-gauge needle connected via tubing to a bottle containing balanced salt solution (BSS) was inserted into the anterior chamber. Infusion pressure was controlled by varying the height of the column of BSS. The tensile strength of the incisions was measured by increasing the infusion pressure to the point where leakage was noted.

RESULTS

The mean height at which leakage was detected was 100.20 +/- 31.19 cm H(2)O (equivalent to a pressure of 73.70 +/- 22.99 mm Hg) for the nylon suture group (n = 10 eyes) and 113.80 +/- 31.20 cm H(2)O (equivalent to a pressure of 83.71 +/- 22.95 mm Hg) for the Dermabond group (n = 10 eyes). The difference was not significant (P = 0.343).

CONCLUSIONS

The mean leakage pressures were comparable for the 2 groups. Either method of closure should be able to withstand any postoperative increases in intraocular pressure. Dermabond adhesive may be considered as an alternative to conventional sutures in corneal wound closure.

Effects of scalpel (with and without tissue adhesive) and cryosurgery on wound healing in rat tongues

OBJECTIVE

To evaluate wound healing of incisions created by steel scalpel (with and without the application of N-butyl-2-cyanoacrylate) and cryosurgery.

STUDY DESIGN

Prospective blinded and randomized study. Adult albino rats (N = 93) were randomly assigned to 3 groups (31 animals per group) before making incisions on oral mucosa by steel scalpel (2 groups) or cryosurgical techniques (remaining group). No product was applied to the resulting wound in the first group, while N-butyl-2-cyanoacrylate was applied to the wounds made in the tongues of the second group. Hemostasis, postoperative oral intake, and wound healing were measured. Statistical analysis was performed using analysis of variance.

RESULTS

The wounds to which N-butyl-2-cyanoacrylate had been applied showed no hemorrhaging and faster reepithelialization and resolution of the inflammatory response, and the animals gained weight more rapidly.

CONCLUSIONS

N-butyl-2-cyanoacrylate is a good hemostatic for managing wounds in the oral mucosa provoked by steel scalpel.

Advances in the use of adhesives in ophthalmology

PURPOSE OF REVIEW

To summarize the known uses of available medical tissue adhesives in the management of diseases of the anterior segment, highlighting recent developments in the field.

RECENT FINDINGS

Human fibrin glues may be used in place of cyanoacrylate tissue adhesives in the treatment of progressive corneal thinning and small perforations, potentially resulting in less corneal and conjunctival inflammatory reaction. Additional currently proposed uses of fibrin glues in ophthalmic surgery include minimizing sutures in recurrent pterygium surgery, forniceal reconstruction, amniotic membrane transplantation, and lamellar corneal grafting.

SUMMARY

After reviewing the literature pertaining to the current use of tissue adhesives in ophthalmic surgery, the authors conclude that the main indication for cyanoacrylate tissue adhesives is for the treatment of progressive corneal thinning and small, uncomplicated corneal perforations. Human fibrin glues appear to be equally effective in such cases and have the advantage of biocompatibility, allowing application over a larger surface area and the use of a superficial covering layer such as amniotic membrane or conjunctiva for further reinforcement and promotion of rapid re-epithelialization. Other applications of human fibrin glues in ophthalmic surgery are evolving, but their widespread use is limited by concern over the theoretic risk of viral transmission and the complexity of their preparation and application in comparison with traditional sutures.