[Fibrin glue for closing conjunctival wounds in ophthalmic surgery]

BACKGROUND

Tissue adhesives offer the attractive prospect of sutureless surgery and provide a mechanism for repairing potentially difficult surgical wounds. We examined the ability of fibrin glue--instead of sutures--to close conjunctival wounds at the end of different ophthalmic surgeries.

METHODS AND PATIENTS

Between 2002 and 2003 the fibrin glue Beriplast was used in our department to close the conjunctival wound in 100 eye muscle surgeries, 10 scleral buckling procedures in retinal detachment, and 20 pars plana vitrectomies.

RESULTS

No patient showed postoperative adverse or allergic reactions, bacterial infections, inflammation, or delayed healing. The healing process of the conjunctiva takes a similar time course as in suture closure, but without disturbing suture ends and knots. In children with extensive Tenon's fascia, adaptation of the conjunctiva is safer using sutures. The necessary time using fibrin glue is reduced to one-fourth of the usual 4-8 min necessary for suturing the conjunctiva. The costs for fibrin glue are the same as for Vicryl 9/0, i.e., approximately 18-20 Euros per patient.

CONCLUSIONS

Fibrin glue for closing conjunctival wounds results in good adaptation, is time saving, effective, and not more expensive than a suture with a high-end needle. Especially the thin atrophic conjunctiva in adults will tear using sutures in contrast to the very fast and effective adaptation with fibrin glue. Application of fibrin glue is limited in children with extensive Tenon's fascia: in these patients a suture is superior for good adaptation of the conjunctiva.

IgG antibodies against bovine serum albumin in humans--their prevalence and response to exposure to bovine serum albumin

Human exposure to bovine serum albumin (BSA) is very common and occurs through dietary and medicinal routes. Although great effort has been made to reduce exposure to BSA in pharmaceuticals to eliminate the threat of bovine spongiform encephalopathy, less attention has been given to assessing the human immune response after exposure to BSA. A sensitive quantitative radioimmunoassay was therefore developed to measure anti-BSA IgG antibodies in healthy subjects and in cancer patients participating in a randomized, placebo controlled clinical trial where they were exposed to BSA as an intrathoracic surgical sealant during pneumonectomy. Anti-BSA antibodies were detected in 55% of 60 healthy blood donors and 51% of 83 patients before lung cancer resection. The median antibody levels were the same in both cohorts; 0.086 microg/mL (range 0.016-19.5 microg/mL) for health blood donors and 0.062 microg/mL (range 0.009-44 microg/mL) for cancer patients. Six months after exposure of the cancer patients to BSA, the percentage of patients with anti-BSA antibody rose to 96% and the median antibody level rose to 19 microg/mL (range 0.009-258 microg/mL). Placebo-treated cancer patients showed no significant increase in the percentage of patients with anti-BSA antibody (41%) or the median antibody level (0.047 microg/mL; range 0.008-1.58) over 6 months. Western blot analysis confirmed the presence of anti-BSA antibody. Elevated levels of anti-BSA antibody were not associated with any detectable clinical events in either the healthy blood donors or the cancer patients.

Evaluation of a water-soluble bioadhesive patch for photodynamic therapy of vulval lesions

An innovative bioadhesive patch intended primarily as a vulval drug delivery system and, specifically, as a means to deliver photosensitisers, or their prodrugs, for photodynamic purposes is described. The patch was formulated with a copolymer of methyl vinyl ether and maleic anhydride (PMVE/MA) as a bioadhesive matrix and poly(vinyl chloride) as a drug-impervious backing layer. Adhesive strength to neonate porcine skin, as a model substrate, was evaluated using peel and tensile testing measurements. Acceptabilities of non-drug loaded patches were appraised using human volunteers and visual-analogue scoring devices. An optimal formulation, with water uptake and peel strengths appropriate for vulval drug delivery, was cast from a 20% (w/w) PMVE/MA solution and adhered with a strength of approximately 1.7 Ncm(-2). Patient evaluation demonstrated comfort and firm attachment for up to 4h in mobile patients. Aminolevulinic acid, a commonly used photosensitiser, was formulated into the candidate formulation and applied to vulval intraepithelial neoplastic lesions. Fluorescence under ultraviolet illumination revealed protoporphyrin synthesis. The patch achieves the extended application times obligatory in topical photodynamic therapy of vulval lesions, thereby contributing to potential methods for the eradication of neoplastic lesions in the lower female reproductive tract.

Postoperative bronchial stump fistula responding well to occlusion with metallic coils and fibrin glue via a tracheostomy: a case report

An 80-year-old man underwent middle and lower lobectomy of the right lung to treat squamous cell carcinoma (SCC) (4 cm in diameter) originating from the right B4 bronchus. On the 4th postoperative day, a massive air leak from the thoracic drain was noted. At that time, a diagnosis of bronchial stump fistula was made on the basis of the bronchoscopic findings. Continuous thoracic drainage, aspiration of sputum via a tracheostomy and intravenous administration of antibiotics were performed immediately after the diagnosis. However, the patient's condition was complicated by aspiration pneumonia. On the 11th postoperative day, bronchoscopic procedure to close the bronchial fistula was performed via the tracheostomy. During this procedure, metallic coils were first inserted into the fistula to serve as the core for occlusion. Then, instead of directly infusing fibrin glue, several small beans-sized pieces of Surgicell cotton (Johnson & Johnson Co., Cincinnati, OH) soaked in fluid A (concentrated fibrinogen) and the same number of Surgicell cotton pieces soaked in fluid B (thrombin) were alternately inserted into the fistula, to allow closure of the bronchial fistula. After this procedure, the embolus created remained in place without being expectorated, and the aspiration pneumonia entered remission, allowing the patient to be discharged from the hospital on the 24th postoperative day. At preset, 14 months after surgery, the patient is in good condition. This technique allows simple and reliable closure of a fistula if a tracheostomy is available. It should be selected as a therapy of first choice when dealing with patients with a postoperative bronchial stump fistula in poor general condition. Patients undergoing right pneumonectomy or middle and lower lobectomy of the right lung should be considered as belonging to a high risk group for bronchial fistula and as requiring preventable measures (e.g., covering the stump with an intercostal muscle flap).

Influence of Gelatin-Resorcin-Formalin Glue on Mid-Term Redissection After Aortic Repair

PURPOSE

To determine whether the development of mid-term redissection after surgery for acute type A aortic dissection using gelatin-resorcin-formalin (GRF) glue could be prevented by applying less formalin.

METHODS

Between 1995 and 1999, 59 patients underwent surgery with GRF glue to repair acute type A aortic dissection. Forty-one patients underwent surgery before October 1998, and 18 patients underwent surgery after November 1998. An excessive amount of formalin was used in the former period and less was used in the latter period.

RESULTS

Follow-up computed tomography was done for 34 patients in the former period (Former group) and for 16 patients in the latter period (Latter group). This showed redissection in 19 of the 34 patients in the Former group and in 6 of the 16 patients in the Latter group. There was no significant difference in the frequency of mid-term redissection between the two groups.

CONCLUSION

The development of mid-term redissection of the aortic root was not prevented by applying less formalin in the GRF glue. Thus, we conclude that the cause of redissection is not entirely the result of too much formalin.

Using Dermabond for Wound Closure in Lumbar and Cervical Neurosurgical Procedures

OBJECTIVE:

2-Octylcyanoacrylate (Dermabond; Ethicon, Inc., Somerville, NJ) is a liquid adhesive being used with increasing frequency for the closure of lacerations and surgical incisions. Dermabond provides excellent cosmetic closure, and recent studies have demonstrated very low infection risks when it is properly applied. There are no published studies using Dermabond on lumbar or cervical procedures. This study was undertaken to determine whether Dermabond is safe and efficacious to use in these common neurosurgical procedures.

METHODS:

Records of 200 consecutive patients with Dermabond closure after anterior cervical discectomy, microlumbar discectomy, or lumbar laminectomy by the senior author (JEB) with a mean follow-up time of 5.42 months were retrospectively reviewed. Suspected infections with or without confirmatory cultures, erythema, and incisional drainage were documented.

RESULTS:

Of 200 patients, 85 underwent microlumbar discectomy, 22 lumbar laminectomy, and 93 anterior cervical discectomy. There was only 1 definitive infection, which was a culture-proven discitis in a microlumbar discectomy patient. Of the remaining 85 microlumbar discectomies, there was 1 transient incisional erythema. Of the 22 lumbar laminectomies, there was 1 patient with clinical superficial wound infection with negative cultures and 4 patients with transient incisional drainage without infection. Of the 93 anterior cervical discectomies, 2 had transient incisional drainage without infection.

CONCLUSION:

This study demonstrates that Dermabond is safe to use in neurosurgery patients undergoing lumbar or cervical procedures, with only 1 patient of 200 having a proven infection. Patients are able to shower and do not have sutures or staples to remove. Patient responses are overwhelmingly positive.

Cellular, histomorphologic, and clinical characteristics of a new octyl-2-cyanoacrylate skin adhesive

Short-chained cyanoacrylates have been used for many years for topical skin closure. Toxic effects in cell culture of a new long-chained octyl-2-cyanoacrylate tissue adhesive are compared with those of short-chained ethyl-2- and butyl-2-cyanoacrylates. Two cellular tests were used: the agar overlay test and the MTT test. An in vitro test using copper plates coated with the three types of cyanoacrylates serves for evaluating the stability of polymerized skin adhesives. Bilateral neck skin incisions in Goettingen miniature pigs were glued on one side with Dermabond. On the other side, conventional sutures were applied. After the pigs were killed, the resulting skin samples were tested for the tensile strength of their wound stability. Samples of pig dermis were exemplarily and histomorphologically characterized. A clinical examination after submandibular lymph node dissection should examine the application in humans. Cell culture tests were used to show the toxic effects of the three cyanoacrylates. In a copper test, octyl-2-cyanoacrylate was more stabile than ethyl- and butyl-cyanoacrylates. Breaking strength was 30% lower 28 days after operation with the new product than with sutures. In electron microscopy, octyl-2-cyanoacrylate showed no disadvantages with regard to tissue regeneration and no histotoxicity. For plastic surgery, this new topical skin adhesive is a real alternative with attractive results, as compared with conventional suture.

[The use of N-butyl-2-cyanoacrylate (Histoacryl) in primary tendon repair: a biomechanical study with sheep flexor tendons]

OBJECTIVES

In this study, the biomechanical properties of peripheral tendon repair with the use of epitendinous suture technique and N-butyl-2-cyanoacrylate (Histoacryl) (NBSA), a biodegradable glue, were compared.

METHODS

Twenty-four flexor tendons were harvested from sheep hind limbs. Following transection of the tendons, 12 tendons (group 1) were repaired with modified Kessler core sutures using no 2 prolene and epitendinous running sutures with 3/0 prolene. In the other 12 tendons (group 2), NBSA was applied between the cut surfaces before placing modified Kessler core sutures. Placed on an hydrolic test machine, half of the tendons from each group were subjected to load to failure with a tensile force of 20 mm/min and the other half to cyclic loading with a tensile loading between 1-15 N at a rate of 20 cycles/min. Observation of a gap of 1 mm between the tendon ends in each test was regarded as repair failure.

RESULTS

The mean load to failure was 27.3 N (range 25 to 32 N) for group 1 and 50.4 N (range 32 to 63 N) for group 2 (p=0.022). The mean number of cycles at failure was 140 (range 45 to 250) in group 1 and 350 (range 150 to 600) in group 2 (p=0.032).

CONCLUSION

Our results showed that peripheral tendon repair with the use of NBSA has biomechanical advantages over repair with the epitendinous running suture technique.

Retinal function after subconjunctival injection of carboplatin in fibrin sealant

PURPOSE

To evaluate retinal function in a rabbit model after subconjunctival delivery of carboplatin in balanced saline solution (BSS) or fibrin sealant to determine possible retinal toxicity.

METHODS

One group of rabbits (n = 5) received a unilateral subconjunctival injection of 12.2 +/- 1.0 mg/mL of carboplatin (Paraplatin) in BSS. Another group of rabbits (n = 5) received 25.1 +/- 7.7 mg/mL of carboplatin in fibrin sealant (Hemaseel APR). Rabbits injected with fibrin sealant only (n = 2) and BSS only (n = 2) were used as control groups. Electroretinographic recordings consisted of a series of intensities presented under dark- and light-adapted conditions. Electroretinograms were recorded before the injection (baseline) and 2 days, 1, 2, and 3 weeks after the injection. After 3 weeks, all rabbit eyes were obtained for histopathologic examination.

RESULTS

Transient reductions in the dark-adapted b-wave amplitudes were noted 2 days after treatment for eyes injected with carboplatin compared with the vehicle-only treatment groups. Other treatment groups and postinjection time points showed no significant changes from baseline. Retinal structure and thickness were normal 3 weeks after treatment for all treatment groups.

CONCLUSION

Subconjunctival delivery of carboplatin in fibrin sealant or BSS does not have a toxic effect on retinal function or structure in a non-tumor-bearing rabbit model at the doses used in this study at 3 weeks' follow-up.

Laparoscopic injection of dermabond tissue adhesive for the repair of inguinal hernia: short- and long-term follow-up

PURPOSE

Is laparoscopic injection of 2-octyl-cyanoacrylate tissue adhesive (Dermabond: Db) into the inguinal hernia sac (IHS) effective for inguinal hernia repair?

METHODS

Thirty male 4-week-old Lewis rats were used as subjects for this study. In the right Db (R-Db) group (n = 10), a fine catheter was passed through an 18-guage indwelling intravenous cannula inserted in the right lower quadrant, and 0.2 mL Db was injected into the right IHS under laparoscopic control. The left side was not treated. Both IHSs were treated in the bilateral Db (B-Db) group (n = 10). In the no Db (N-Db or control) group (n = 10), only laparoscope insertion was performed. Herniography was performed before death. B-Db and N-Db rats were mated 50 days after treatment. Half of all rats were killed 2 months after treatment and the remaining half 12 months after treatment.

RESULTS

All rats survived until killing. Macroscopic findings postdeath confirmed herniography results; treated IHS were closed, and untreated IHS were patent. There were minor adhesions in 3 of 20 treated rats. Sperm were identified in the vaginas of all mated rats.

CONCLUSIONS

These results suggest that our new technique is simple, safe, and reliable as an alternative to standard operative repair for inguinal hernia.

Treatment of pilonidal sinus disease using fibrin glue as a sealant

BACKGROUND

Complete excision is the preferred treatment for pilonidal sinus disease. We describe a new technique of excision and tension-free primary closure of pilonidal sinus disease, combined with application of fibrin glue in order to obliterate the dead space and to promote wound healing.

METHODS

A curved incision of the carried out, 2-3 cm lateral to the opening of the sinus, done under general or spinal anesthesia, and a thick flap was created by undercutting the medial edge and advancing it across the midline. The sinus was completely excised with all of its extensions. The flap was then sutured back to its original place by several interrupted monofilament mattress sutures. Then, 2-4 ml of fibrin glue was injected through the original pilonidal sinus opening to the sinus bed in order to obliterate the dead space.

RESULTS

Thirty patients with pilonidal sinus disease were treated by this technique. In four patients, there was a temporary purulent discharge through the opening of the sinus, and there were no other complications. The mean period for returning to daily activities and to work for patients was 11 days (SD=6 days). No infection or recurrent disease was noticed during the follow-up period (23+/-3 months).

CONCLUSIONS

Complete excision with tension free closure with fibrin glue application may be a useful technique for the treatment of pilonidal sinus disease.

Does fibrin glue sealant decrease the rate of pancreatic fistula after pancreaticoduodenectomy? Results of a prospective randomized trial

Despite substantial improvements in perioperative mortality, complications, and specifically the development of a pancreatic fistula, remain a common occurrence after pancreaticoduodenectomy. It was the objective of this study to evaluate the role of fibrin glue sealant as an adjunct to decrease the rate of pancreatic fistula after pancreaticoduodenectomy. One hundred twenty-five patients were randomized after pancreaticoduodenal resection only if, in the opinion of the surgeon, the pancreaticojejunal anastomosis was at high risk for development of a pancreatic anastomotic leak. After completion of the pancreaticojejunal anastomosis, the patients were randomized to topical application of fibrin glue sealant to the surface of the anastomosis or no such application. The primary postoperative end points in this study were pancreatic fistula, total complications, death, and length of hospital stay. A total of 59 patients were randomized to the fibrin glue arm, whereas 66 patients were randomized to the control arm and did not receive fibrin glue application. The pancreatic fistula rate in the fibrin glue arm of the study was 26% vs. 30% in the control group (p = not significant [NS]). The mean length of postoperative stay for all patients randomized was similar (fibrin glue = 12.2 days, control = 13.6 days) and the mean length of stay for patients in whom pancreatic fistula developed was also not different (fibrin glue = 18.9 days, control = 21.7 days). There were no differences with respect to total complications or specific complications such as postoperative bleeding, infection, or delayed gastric emptying. These data demonstrate that the topical application of fibrin glue sealant to the surface of the pancreatic anastomosis in this patient population undergoing high-risk pancreaticojejunal anastomosis did not reduce the incidence of pancreatic fistula or total complications after pancreaticodudodenectomy. There seems to be no benefit regarding the use of this substance in this setting.

Closure of long surgical incisions with a new formulation of 2-octylcyanoacrylate tissue adhesive versus commercially available methods

BACKGROUND

Topical 2-octylcyanoacrylate tissue adhesive is an alternative to traditional devices for closing short surgical incisions.

METHODS

An open-label, randomized study compared a new high-viscosity formulation of 2-octylcyanoacrylate with commercially available devices, including low-viscosity 2-octylcyanoacrylate, for epidermal closure of incisions > or = 4 cm requiring subcutaneous and/or deep-dermal suturing.

RESULTS

Of patients with 1 to 3 wounds, 106 were treated with high-viscosity 2-octylcyanoacrylate and 103 with commercially available devices. The day-10 rates of healing by wound were 96% and 97% for study versus control treatment and 97% and 95% for new and old 2-octylcyanoacrylate formulations versus other controls, respectively. Day-10 infection rates by wound were 4 of 145 versus 7 of 131 for study versus control treatment and 6 of 207 and 5 of 69 for new and old 2-octylcyanoacrylate versus other controls, respectively.

CONCLUSIONS

The new tissue adhesive formulation provides epidermal wound closure equivalent to commercially available devices with a trend to decreased incidence of wound infection.

Temporary closure of the abdomen using a new composite prosthesis (PL-PU99)

BACKGROUND

Temporary abdominal wound closure is sometimes desirable when tension-free approximation of the wound edges is impractical or when reexploration is planned.

METHODS

The behavior of a composite prosthesis (PL-PU99) designed by our group was evaluated as a method of temporary abdominal closure in white New Zealand rabbits. After a 7 cm long midline laparotomy, a spindle-shaped 4 cm (maximum width) by 7 cm (length) fragment of PL-PU99 was sutured to the edges of the peritoneal, muscular, and fascial abdominal tissues, so that the biomaterial remained in contact with the exterior. The PL-PU99 composite is composed of a polypropylene mesh adhered to a sheet of polyurethane with an acrylic cement. At 7 and 14 days after implant, animals were sacrificed and specimens taken for morphological, ultrastructural, morphometry of the neoperitoneum, and immunohistochemical (macrophage reaction, RAM-11) analysis.

RESULTS

No death or signs of infection or rejection of the prostheses were recorded. No adhesions could be macroscopically observed between the composite and the intestinal loops. The biomaterial achieved a good seal, no leakage of fluids being detected. Fourteen days after implant, the neoperitoneum formed on the prosthesis was of an even structure and was made up of organized, vascularized connective tissue covered by an uninterrupted mesothelium.

CONCLUSIONS

The PL-PU99 prosthesis shows optimal behavior at the prosthesis/visceral peritoneum interface, making it ideal for its use in the temporary closure of the abdomen. The implanted composite may also prove useful for the permanent repair of the abdominal wall.

Sellar repair with fibrin sealant and collagen fleece after endoscopic endonasal transsphenoidal surgery

OBJECTIVE

To determine, in patients undergoing sellar repair after endoscopic endonasal transsphenoidal surgery, the clinical efficacy of a combination of fibrin sealant/collagen fleece compared to the use of fibrin sealant or collagen fleece alone, in preventing CSF-related (cerebrospinal fluid) postoperative complications.

METHODS

From a retrospective analysis of our series of 242 consecutive endoscopic transsphenoidal procedures, in 56 out of the 90 cases in which the sella had been repaired, fibrin sealant and/or collagen fleece was employed, both in combination with one or multiple layers of other materials. The incidence of postoperative CSF leaks and the need for a postoperative lumbar drainage in the groups of fibrin sealant or collagen fleece treated patients were compared to the group of patients treated with the fibrin sealant/collagen fleece combination.

RESULTS

In 2 out of 16 fibrin sealant treated patients a postoperative CSF leak presented, and in 6 out of these 16 subjects a postoperative lumbar drainage was necessary; patients who received a fibrin sealant/collagen fleece combination exhibited no detectable postoperative CSF leak, and no postoperative lumbar drainage was used.

CONCLUSIONS

Closure of the sella turcica with fibrin sealant in combination with a collagen fleece is a safe and effective method to prevent CSF fistulas. When used in combination, the collagen fleece enhances the sealing and tissue regeneration properties of the fibrin sealant, thus reducing the incidence of postoperative CSF leaks, obviating the need for a lumbar drain placement.

Ultrasound-Guided Glue Injection as Alternative Treatment of Femoral Pseudoaneurysms

The interventional angiographic techniques using the percutaneous femoral approach for endovascular revascularization are becoming increasingly more popular. These methods usually require larger sheaths, and most patients need postprocedural anticoagulation or antiplatelet therapy. As a consequence, the interventional procedure is associated with a higher rate of complications at the arterial entry site compared to diagnostic angiography. The reported incidence of iatrogenic pseudoaneurysm formation after coronary artery interventions ranges from 3.2% to 7.7%, and the rates noted after diagnostic angiography range from 0.2% to 1%.

Injectable fibrin scaffold improves cell transplant survival, reduces infarct expansion, and induces neovasculature formation in ischemic myocardium

OBJECTIVES

In this study, we determined whether fibrin glue improves cell transplant retention and survival, reduces infarct expansion, and induces neovasculature formation.

BACKGROUND

Current efforts in restoring the myocardium after myocardial infarction (MI) include the delivery of viable cells to replace necrotic cardiomyocytes. Cellular transplantation techniques are, however, limited by transplanted cell retention and survival within the ischemic tissue.

METHODS

The left coronary artery of rats was occluded for 17 min followed by reperfusion. One week later, bovine serum albumin (BSA), fibrin glue, skeletal myoblasts in BSA, or skeletal myoblasts in fibrin glue were injected into the infarcted area of the left ventricle. The animals were euthanized five weeks after injection, and their hearts were excised, fresh frozen, and sectioned for histology and immunohistochemistry.

RESULTS

After five weeks, the mean area covered by skeletal myoblasts in fibrin glue was significantly greater than the area covered by myoblasts injected in BSA. Myoblasts within the infarct were often concentrated around arterioles. The infarct scar size and myoblasts in the fibrin group were significantly smaller than those in the control and BSA groups. Fibrin glue also significantly increased the arteriole density in the infarct scar as compared with the control group.

CONCLUSIONS

This study indicates that fibrin glue increases cell transplant survival, decreases infarct size, and increases blood flow to ischemic myocardium. Therefore, fibrin glue may have potential as a biomaterial scaffold to improve cellular cardiomyoplasty treat and MIs.

Improved Esthetic Results With Fine-Tip Dermabond Application Technique

Tissue glues and adhesives have achieved increasing popularity as alternatives to small wound closure. When applying these substances, it is often difficult to avoid contact with the surrounding skin and foreign objects such as surgical gloves. A technique for the application of Dermabond is described in this report. Twenty wounds less than 10 cm in length were reapproximated using a fine-tip tuberculin syringe applicator. The wounds were evaluated immediately after the application, and 2, 4, and 6 weeks after surgery. Use of the tuberculin fine-tip technique allowed reapproximation of the wound edges with no clinical evidence of surrounding tissue damage. There were no apparent decreases in wound strength or associated discoloration or fuzziness onto the skin. Esthetic results were considered good to excellent by patients. Dermabond can be accurately applied with a tuberculin syringe, avoiding the surrounding tissue damage and foreign object adhesion reported in the literature.

N-butylcyanoacrylate embolization of a middle meningeal artery aneurysm in a patient with neurofibromatosis type 2

Aneurysms of the middle meningeal artery are rare, with no documented association with neurofibromatosis type 2 (NF2). Middle meningeal artery aneurysm embolization with N-butylcyanoacrylate has not been described, and altogether, few accounts exist regarding the endovascular management of these unusual aneurysms. In this case report of a patient with NF2, an unruptured middle meningeal artery aneurysm was prophylactically embolized in a previously unreported fashion by using N-butylcyanoacrylate acrylic glue.

Clinical experience with butyl-2-cyanoacrylate adhesive in the management of canine and feline corneal disease

PURPOSE

To examine and evaluate clinical indications and postoperative outcome in a series of small animal patients in which corneal disease was managed by the application of butyl 2-cyanoacrylate adhesive.

MATERIALS AND METHODS

In this retrospective study all small animal patients were identified that presented to the Royal Veterinary College, University of London over a 2-year period, in which corneal disease was managed by the application of butyl 2-cyanoacrylate. Indications for application, complicating factors prior to gluing, glue retention time, postoperative comfort, and extent of subsequent corneal reaction and scarring were noted for each case. Long-term follow-up data concerning visual and cosmetic outcome were obtained from owners and referring veterinarians.

RESULTS

Thirty-seven patients (28 dogs and 9 cats), in which 39 eyes were treated, were identified. Indications for corneal gluing in this series included stromal ulceration (26/39 eyes); descemetocele (4/39 eyes); corneal laceration/foreign body (5/39 eyes); lamellar keratectomy (3/39 eyes) and superficial ulceration (1/39 eyes). At least one factor responsible for initiation, persistence or progression of the ulcer was identified in 66.7% of eyes prior to corneal gluing. These included keratomalacia; confirmed bacterial keratitis; corneal edema related to endothelial disease and keratoconjunctivitis sicca. Cyanoacrylate was generally well tolerated by patients with only 8/34 eyes demonstrating transient blepharospasm and increased lacrimation postoperatively. Retention time of cyanoacrylate varied widely from < 1 week to approximately 6 months, but was < 2 months in the majority (89%) of eyes. Exaggerated corneal vascularization was an infrequent postoperative complication, noted in only six canine eyes, and did not appear to be related to initial corneal disease, glue retention time or breed.

CONCLUSIONS

Butyl 2-cyanoacrylate offers a convenient, economical and effective alternative to other treatment modalities, such as conjunctival grafts, in the management of corneal defects in canine and feline patients.

Perivascular delivery of losartan with surgical fibrin glue prevents neointimal hyperplasia after arterial injury

OBJECTIVE

Long-term success of revascularization procedures is limited by recurrent stenosis, a reduction in vascular lumen area that results from neointimal hyperplasia. Inhibitors of the renin-angiotensin system, such as losartan, have potential to prevent recurrent stenosis; however, to date, efficacy has not been demonstrated in either animal models or human beings. While we have previously reported that treatment with a satisfactory dose may be an important element in obtaining efficacy, oral delivery cannot achieve the required concentration. We therefore tested the ability of losartan to restrict neointimal hyperplasia after local delivery of an elevated dose in a fibrin glue.

METHODS

The porcine saphenous artery was subjected to balloon angioplasty. Losartan (25 micromol/mL) was applied directly to the adventitial surface of the injured vessel after mixing with 1.0 mL of Tisseel. Neointimal formation was quantified after 14 days with morphometry, and immunologic staining was used to monitor expression of proteins associated with cell proliferation, migration, and phenotypic modulation.

RESULTS

A statistically significant decrease of 82% (n = 5) in neointimal area was obtained with losartan, and cell proliferation, as defined by proliferating cell nuclear antigen (PCNA) expression, was inhibited by 97%. Reduced cyclin A expression in losartan-treated vessels confirmed that cell cycle progression was blocked; however, the presence of cytokeratin 8 and tenascin in the media and neointima of injured vessels, regardless of treatment, suggested that losartan does not restrict phenotypic modulation. Inhibition of MT1-MMP (MMP-14) expression by losartan indicated that this inhibitor likely suppresses cell migration as well.

CONCLUSIONS

These data demonstrate that losartan can effectively prevent recurrent stenosis when delivered locally with a fibrin glue such as Tisseel. Our results also indicate that losartan may operate by interfering with the expression of proteins required for cell cycle progression and migration.

CLINICAL RELEVANCE

Release of angiotensin II in response to vascular injury may promote neointimal hyperplasia, because this hormone can stimulate smooth muscle cell proliferation and migration. This study demonstrates that local application of an angiotensin receptor antagonist, losartan, to the site of injury can effectively prevent neointimal hyperplasia after balloon angioplasty. Application of losartan to the perivascular surface of the injured vessel in a surgical fibrin glue enabled delivery of a dose that exceeds the maximum attainable, via a systemic delivery route. The glue also served as a depot from which the drug was slowly released over time. Treatment with losartan may be a viable approach for controlling neointimal hyperplasia at locations (eg, grafts) that are accessible during a surgical procedure.