Surgical Tissue Adhesives In Otolaryngology-Head And Neck Surgery

Recent Advances in Hemostasis at the Nanoscale

Rapid and effective hemostatic materials have received wide attention not only in the battlefield but also in hospitals and clinics. Traditional hemostasis relies on materials with little designability which has many limitations. Nanohemostasis has been proposed since the use of peptides in hemostasis. Nanomaterials exhibit excellent adhesion, versatility, and designability compared to traditional materials, laying a good foundation for future hemostatic materials. This review first summarizes current hemostatic methods and materials, and then introduces several cutting-edge designs and applications of nanohemostatic materials such as polypeptide assembly, electrospinning of cyanoacrylate, and nanochitosan. Particularly, their advantages and working mechanisms are introduced. Finally, the challenges and prospects of nanohemostasis are discussed.

Fibrin as a Tissue Adhesive and Scaffold with an Angiogenic Agent (FGF-1) to Enhance Burn Graft Healing In Vivo and Clinically

There is a need for a strategy to reduce scarring in meshed skin graft healing leading to a better cosmetic result without a significant increase in cost. The strategy in this paper is to increase the closure rate of a meshed skin graft to reduce scarring, which should also decrease the infection rate. Specifically, we used fibrin glue to attach all parts of the graft to the wound bed and added in an angiogenic growth factor and made the fibrin porous to further help the growth of blood vessels from the wound bed into the graft. There was a 10-day animal study and a one-month clinical study. Neither making the fibrin porous or adding an angiogenic agent (i.e., fibroblast growth factor-1 (FGF-1)) seemed to make a significant improvement in vivo or clinically. The use of fibrin on a meshed skin graft appears to speed up the regenerative healing rate leading to less scarring in the holes in the mesh. It appears to shorten the healing time by five days and keep the tissue stiffness close to normal levels vs. the doubling of the stiffness by the controls. A larger clinical study, however, is needed to definitively prove this benefit as well as the mechanism for this improvement.

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 N-butyl cyanoacrylate in nasal septoplasty: histopathological evaluation using rabbit nasal septum model

OBJECTIVES

This study was designed to investigate the effects of the tissue adhesive N-butyl cyanoacrylate on nasal septal tissues after septal surgery in a rabbit model.

METHODS

Forty-two adult New Zealand rabbits were randomly divided into three groups (14 in each group): septoplasty alone, septoplasty plus N-butyl cyanoacrylate, and controls. The open approach was used to explore the nasal septum. After raising mucoperichondrial and mucoperiosteal flaps on both sides of the septum, the septum was detached from the nasal floor in the septoplasty alone and septoplasty plus N-butyl cyanoacrylate groups. In the septoplasty plus N-butyl cyanoacrylate group, the mucoperichondrial and mucoperiosteal flaps were fixed to the septum and the septum was fixed lateral to the nasal spine using N-butyl cyanoacrylate; in the septoplasty alone group, the septum was packed with Merocel. In the control group, no further septal surgery was performed after flap elevation. Animals were observed for bleeding and haematoma formation over the first 24 hours. Seven animals in each group were used to evaluate early histopathological effects on the septal tissues, at four weeks post-operatively; the other seven in each group were used to evaluate late effects, at 12 weeks.

RESULTS

Haematoma formation was observed in 10 animals in the septoplasty alone group, in four animals in the control group, and in only one animal in the septoplasty plus N-butyl cyanoacrylate group. The difference in haematoma incidence between the septoplasty alone and the septoplasty plus N-butyl cyanoacrylate groups was significant (p = 0.000). Histopathological evaluation revealed no significant difference between the groups as regards granulation tissue formation at week four versus week 12; however, there was a significant difference between the septoplasty plus N-butyl cyanoacrylate group and the control groups as regards inflammation at week 12 (p = 0.038). There was a significant difference between the septoplasty plus N-butyl cyanoacrylate group and the septoplasty alone group as regards the composition of the bone-cartilage junction zone at week four (p = 0.001). There was also a significant difference between the septoplasty plus N-butyl cyanoacrylate group and the control group as regards the cellular structure of new cartilage formation at week 12 (p = 0.004).

CONCLUSIONS

In this rabbit septoplasty model, N-butyl cyanoacrylate appeared to be an effective nasal tissue adhesive, with a low complication rate.

[Adjuvants in operative laryngology: corticosteroids, fibrin adhesives, Mitomycin C]

Medicinal adjuvants are often used in operative laryngology but their value is judged very differently. The scientific evidence is unsatisfactory for most of these substances. For corticosteroids it is proven that in pediatric intensive care they reduce stridor following extubation. Routine prophylactic use for intubation does not seem to be justified and methylprednisolone and dexamethasone are the preferred preparations. Fibrin adhesives are well tolerated and low in side-effects. The indications for their use should be primarily limited due to the cost factor. Their use in laryngology remains a decision on an individual case-to-case basis. Mitomycin C is used because of its antiproliferative effect on fibroblasts in order to reduce scar tissue formation. Many positive effects have been attributed to the topical application but there are large differences in dosage and exposure time.

Effect of cyanoacrylic glue on penile fracture: an experimental study

PURPOSE

We investigated the effect of Glubran(R)2 cyanoacrylic glue on rat cavernous tissue after forming penile fractures experimentally as well as the histopathological effect. We also investigated its clinical use.

MATERIALS AND METHODS

Experimental penile fracture was formed by incising from the proximal dorsal side of the penis in 32 Wistar Albino rats. The rats were randomly assigned to 4 main groups of 8 each. In the control group the incision was not repaired and it was left to secondary healing. In the glue group cyanoacrylic glue was only applied to the incision region. In the primary repair group the incision was primarily repaired and in the final group cyanoacrylic glue was applied to the incision region following primary repair. Three weeks later penectomy materials were examined histopathologically.

RESULTS

When the control group was compared with the other groups, the differences in cavernous tissue healing with fibrosis and hyperemia-bleeding were statistically significant (p = 0.043 and 0.003, respectively). In the glue group fibrosis was observed in 2 rats. This group was the best according to cavernous healing. Although there was no significant difference between the control group and the other groups according to inflammation (p = 0.057), the glue group was better than the primary repair group (p = 0.026). No significant inflammation or hyperemia-bleeding was observed in the glue group. When the experimental groups were evaluated for histopathological parameters, it was observed that the best results were obtained in the glue group.

CONCLUSIONS

Cyanoacrylic glue can be used in cavernous surgery due to its hemostatic, adhesive and anti-inflammatory properties.

The efficacy of N-2-butyl cyanoacrylate in the fixation of nasal septum to the anterior nasal spine in rabbits: experimental study

In nasal septal surgery, fixing the caudal portion of the nasal septum to the anterior nasal spine is difficult with the present techniques. N-2-butyl cyanoacrylate is a form of cyanoacrylate which is bioabsorbable and biocompatible. The feasibility and efficacy of the compound, which is easy to apply to the tissues, for the above purpose is investigated in this experimental study. Fourteen New Zealand rabbits were included in the study. The nasal septum was exposed with the open approach (transcolumellar). In the study group (n=10), the septum was detached from the nasal floor and attached to a point 3 mm lateral to the nasal spine on the right side, using 2-butyl cyanoacrylate. In control group (n=4) it was deviated 3 mm to the right side and left for spontaneous healing without using any fixation method. Beginning on the third postoperative week, one animal was sacrificed under general anesthesia, every week in the study group and every third week in the control group, and the septum was analysed. Foreign body reaction, histotoxicity, and the structure of the regenerative tissue in the junction of bone and cartilage were analysed with histopathology. The success of stabilization in the study group, where the septum was attached with N-2-butyl cyanoacrylate, was significantly superior to the control group where no fixation method was used (P<0.05). Histopathologically, there were no differences between the two groups with respect to foreign body reaction, histotoxicity, and the tissue that formed between the bone and cartilage (P>0.05). This study demonstrated that N-2-Butyl cyanoacrylate was successful in the fixation of the caudal edge of the nasal septum to the anterior nasal spine. No serious infections, foreign body reaction, necrosis or histotoxicity were observed.

SURGICAL APPLICATIONS OF CYANOACRYLATE ADHESIVES: A REVIEW OF TOXICITY

Cyanoacrylate (CA) and its homologues have a variety of medical and commercial applications as biological adhesives and sealants. Homologues of CA are being widely promoted in surgery as a tissue adhesive to replace traditional suturing techniques. Potential benefits of using CA adhesives include better cosmetic results, more rapid wound closure, and perhaps most significantly, the potential for significant reductions in percutaneous injuries from suture needles, which would in turn also reduce the risk of transmission of infectious diseases. Nevertheless, certain concerns have been raised regarding the potential toxicity of CA within patients, as well as among health professionals who are occupationally exposed when using CA compounds. Reported toxicity of CA in the workplace may result in dermatological, allergic and respiratory conditions. To help reduce the occupational burden, therefore, medical staff using CA adhesives should avoid direct contact with the compound and use appropriate personal protective measures at all times. Maintaining higher levels of humidity, optimizing room ventilation and using special air conditioning filters in surgical suites and operating theatres may also be useful in minimizing the exposure to volatile CA adhesives.

A comparison of dermabond tissue adhesive and sutures in the primary repair of the congenital cleft lip

OBJECTIVE

To compare the long-term cosmesis of Dermabond (octyl-2-cyanoacrylate) and traditional skin sutures among patients undergoing primary cleft lip +/- palate repair.

MATERIALS AND METHODS

Eleven patients underwent photographic analysis following primary cleft lip +/- palate repair, including the use of Dermabond. Eleven age-matched controls who underwent cleft lip +/- palate repair with traditional suture closure served as controls. Cosmesis was assessed by 3 blinded plastic surgeons using a visual analogue scale (VAS) and the Hollander Wound Evaluation Scale (HWES).

RESULTS

The overall mean VAS score for the patients treated with and without Dermabond was 70.0 (SD, 9.5) and 68.3 (SD, 13.4), respectively (P = 0.46). The overall mean HWES score for the patients treated with and without Dermabond was 1.7 (SD 1.7) (P = 0.92).

CONCLUSIONS

Dermabond tissue adhesive offers equivalent mature wound cosmesis as traditional suture closure in the repair of the congenital cleft lip +/- palate.

Underlay Tympanoplasty with Laser Tissue Welding

We investigated the feasibility of using laser tissue welding techniques to perform transcanal underlay tympanoplasty. We used 10 temporal bones obtained from human cadavers. After creating a subtotal tympanic membrane perforation, we introduced harvested periosteum through the perforation and used laser tissue welding to secure the periosteum graft in place in an underlay fashion. The procedure was performed via a transcanal approach and did not require middle ear packing. Immediately after the graft had been placed, we qualitatively tested its integrity with a blunt probe. The graft was as strong as the native cadaver tympanic membrane in all 10 cases. We conclude that laser transcanal underlay tympanoplasty is a feasible and effective method of repairing a tympanic membrane. The ultimate goal is to develop a technique that will allow physicians to routinely perform underlay tympanoplasty on moderately sized perforations in an office setting.

Lichtenstein Inguinal Hernioplasty Using Butyl-2-Cyanoacrylate versus Sutures

The Lichtenstein hernioplasty has become a popular method in inguinal hernia repair. This study compared two methods of mesh fixation and wound closure. Forty-six men with unilateral inguinal hernia were randomized into two groups. In the control group polypropylene mesh was anchored with 3/0 Dexon sutures, fascia and skin were closed with sutures 3/0 Dexon and 3/0 Monosof. In the study group, the mesh was secured with butyl-2-cyanoacrylate adhesive and the fascia and skin were also glued with the adhesive. The costs of materials, duration of the operation, amount of postoperative analgesic doses, pain score after the first and the 7th postoperative day and return to daily activity were recorded. No recurrences during the mean follow-up of 4.7 months were observed and the cosmetic effect was very good. In the study group with tissue adhesive the patients had significantly lower pain score after the first postoperative day and had a tendency to require less analgetic doses and to return earlier to their daily activity. Duration of the operation was similar in both groups. The cost of sutures and tissue adhesive used in both procedures was comparable. The use of tissue adhesive in mesh fixation and wound closure seems to be a promising technique in Lichtenstein hernia repair.

2-octyl cyanoacrylate adhesive for conjunctival wound closure in rabbits

PURPOSE

To evaluate the efficacy and histology of 2-octyl cyanoacrylate in conjunctival wound closure in rabbits.

METHODS

Ten eyes of 10 New Zealand white rabbits were used. Eight rabbits had conjunctival wounds that were repaired with 2-octyl cyanoacrylate. Two rabbits were killed at 1 week and two rabbits were killed at 2 weeks and their conjunctivae were examined histologically. From two additional rabbits, conjunctival strips were obtained that underwent tensile strength testing.

RESULTS

All conjunctival wounds closed well with 2-octyl cyanoacrylate. Histology revealed minimal inflammation of the wounds. The tensile strength of conjunctival strips glued together was 25.5 g (standard deviation, 1.9 g).

CONCLUSION

2-Octyl cyanoacrylate may be a possible tissue adhesive for conjunctival wound closure.

Fibrin glue-reinforced closure of postlaryngectomy pharyngocutaneous fistula

Pharyngocutaneous fistulization is a dreaded and devastating complication of laryngectomy. Although the specific risk factors are controversial, a history of prior radiation therapy has generally been accepted to be a major risk factor for developing this complication. We present a case of a postlaryngectomy pharyngocutaneous fistula developing in a previously irradiated patient that was successfully managed by incorporating fibrin glue into the surgical closure. We also discuss the underlying theoretical basis for this approach by reviewing the relevant literature.

Cyanoacrylate tissue adhesives for skin closure in the outpatient setting

Cyanoacrylate and fibrin tissue adhesives can aid the facial plastic surgeon performing surgery in the outpatient setting. Octyl-2-cyanoacrylate is ideal for superficial skin closure and eliminates the need for suture removal. Subcutaneous sutures are needed in most cases to provide the best cosmetic outcomes. Fibrin tissue adhesives can be used to aid in attaining hemostasis or to seal or fixate tissues. Cyanoacrylate and fibrin-based adhesives can simplify office-based facial plastic surgery.

Aesthetic comparison of wound closure techniques in a porcine model

OBJECTIVE

To compare various commonly used closure techniques and their esthetic results. Also to look for differences in cost, time, and ease of use among the methods.

DESIGN

A prospective comparison in a porcine skin model with a blinded assessment of outcomes.

METHODS

Thirty 6-cm, full-thickness skin incisions were made on the back of two domestic white swine. Undermining was accomplished, and buried simple, interrupted, absorbable, braided (Polysorb, US Surgical) subdermal sutures were placed in a uniform fashion in each wound. The skin was then closed using one of the following five methods: running subcuticular 4-0 nylon, running subcuticular 4-0 absorbable monofilament (Biosyn, US Surgical), tissue glue (Dermabond, Ethicon), adhesive tape, or running subcuticular nylon with intradermal injection of hyaluronic acid. Nonabsorbable sutures and tape were removed on postoperative day 7, and photographs were taken at regular intervals during a 12-week healing period. Biopsies were taken from wounds in each group at 2 weeks and 12 weeks for histologic comparison. Independent observers evaluated the photographs, and an independent histologist evaluated the biopsies to look for differences in inflammation and scar formation. The surgeons who performed the wound closure rated the ease of use and amount of time required for each technique.

RESULTS

Adhesive tape closure was faster and easier to perform. There were no significant differences among the adhesive tape, nylon, or absorbable suture groups regarding cosmetic appearance throughout the study period. The tissue glue wounds had more of a tendency to dehisce. Adhesive tape is less expensive than the other methods when material costs and operating room time are considered.

CONCLUSION

Adhesive tape closure of surgical wounds is cosmetically acceptable, convenient, and saves both time and material costs. We recommend it as an alternative for closure of neck incisions.

Octylcyanoacrylate Tissue Adhesive as an Alternative to Mechanical Fixation of Expanded Polytetrafluoroethylene Prosthesis

In minimally invasive incisional hernia repair positioning and fixation of the expanded polytetrafluoroethylene (ePTFE) mesh prosthesis on the deep surface of the abdominal wall may be facilitated using tissue adhesives. Octylcyanoacrylate (OCTYL), a new adhesive, forms a strong flexible bond with antimicrobial properties. In a rabbit model for incisional hernia we investigated characteristics of the bond created by OCTYL between ePTFE and abdominal wall musculature. We studied initial bond strength and the postoperative host response to the adhesive over a 6-week period. We compared sutured, stapled, and glued mesh prostheses and examined the tissue-prosthesis interface. The ePTFE mesh was fixed successfully to the abdominal wall with OCTYL and remained tightly attached at 6 weeks. Prostheses fixed with OCTYL and spiral tacks induced few intra-abdominal adhesions compared with sutured mesh. All prostheses were completely reperitonealized at 2 weeks. The force required to displace mesh fixed with sutures and staples was greater than mesh fixed with OCTYL. Analysis of the ePTFE/tissue interface by light and scanning electron microscopy showed host cellular migration into the interstices of the mesh with fixation by tacks and suture, whereas an inflammatory infiltrate was seen on the muscular surface with OCTYL fixation of the mesh.

Fibrin sealants in surgical practice: An overview

The need to effectively manage hemostasis and tissue sealing during surgery has had a strong influence on the development of modern surgical techniques. A group of agents known as surgical tissue adhesives has been developed to promote hemostasis and tissue sealing during surgery, and these comprise both natural and synthetic agents. Fibrin sealants are the most effective tissue adhesives currently available, and they are biocompatible and biodegradable. The fibrin sealants are comprised of purified, virus-inactivated human fibrinogen, human thrombin, and sometimes added components, such as virus-inactivated human factor XIII and bovine aprotinin. These agents mimic the final steps of the physiological coagulation cascade to form a fibrin clot. The use of any plasma-derived product in the surgical setting carries a potential risk of viral transmission. In fact, it was the risk of viral transmission from fibrinogen and thrombin that halted development work on fibrin sealants in the United States. Since that time, new techniques for isolating and concentrating plasma fractions have been developed, and national and international guidelines have been introduced to ensure the safety of all plasma products. All plasma donors are carefully selected and their plasma units screened for viral contamination before processing. All plasma donations and bovine tissue used in the production of commercial fibrin sealants undergo rigorous viral reduction/elimination steps. As a result of this carefully controlled and monitored process, there have been no proven cases of viral transmission associated with the use of commercial fibrin sealant. Fibrin sealants are currently used in a number of surgical specialties, including cardiovascular surgery, thoracic surgery, neurosurgery, plastic and reconstructive surgery, and dental surgery. The use of fibrin sealants has a positive effect on surgical outcomes, such as improved time to hemostasis, reduced blood loss, and reduced complications. This review describes the development of fibrin sealants, the composition of currently available products, and their use in surgical practice.

Tissue sealing

The tissue adhesive property of fibrinogen was first described 60 years ago. However, it was not until the availability of concentrated plasma fibrinogen and bovine thrombin that the use of fibrin sealants in surgical practice became widespread. Today, fibrin sealants are used for tissue sealing across a range of surgical procedures, including cardiothoracic, gastrointestinal, neurosurgery, and vascular surgery. Tissue sealing with fibrin sealant reduces perioperative hemorrhage and controls blood loss from cut surfaces of tissues that are difficult to suture. The use of fibrin sealants can also reduce perioperative and postoperative complications by reducing fluid leakage, air leakage, and by preventing fistulae formation. Fibrin sealants have a unique physiologic action, and the resulting fibrin clot is fully degraded by the body's natural wound healing process. The range of surgeries and types of procedure that incorporate the use of fibrin sealants in tissue sealing is expanding. As commercially prepared fibrin sealants become more widely available, the number of patients and surgeons benefiting from improved surgical outcomes is also set to increase. This article reviews the areas of surgery within which fibrin sealants are currently used to assist tissue sealing and highlights the improved surgical outcomes, such as reduced blood loss, operative time, and postoperative complications.

2-Octyl cyanoacrylate tissue adhesive and muscle attachment to porous anophthalmic orbital implants

PURPOSE

To investigate the tolerance and efficacy of a topical bioadhesive for direct muscle attachment to porous orbital motility implants.

METHODS

Ten New Zealand White rabbits underwent unilateral enucleation with unwrapped 12-mm spherical porous implants placed into the muscle cone. Four animals received porous polyethylene implants and 6 received bone-derived hydroxyapatite implants. Small amounts of a bioadhesive (2-octyl cyanoacrylate) were applied to the underside of the muscles. Muscles were placed onto the desired location of the implant with pressure for 15 seconds. The conjunctiva was closed with a 6-0 plain gut suture, and the animals were observed for 6 weeks. At 6 weeks, animals were killed and the surgical orbit was exenterated. Orbits and implants were processed for histologic analysis. In addition, tensile strength testing of muscle-implant attachments was performed and compared with various other types of muscle-implant or muscle-sclera attachments.

RESULTS

All cases resulted in integration of the muscles without slippage. All unwrapped hydroxyapatite implants (n = 6/6) had small anterior implant exposures without infection, significant inflammation, or exposure. No exposures were noted in porous polyethylene implants (n = 0/4). All implants were filled with fibrovascular tissue by 6 weeks. 2-Octyl cyanoacrylate yielded tensile strengths similar to that of sutured muscle coupling.

CONCLUSIONS

2-Octyl cyanoacrylate is well tolerated in the orbit, inducing minimal inflammation. It effectively attaches muscles to porous implants without hindering permanent integration or vascularization. The exposure rate for unwrapped hydroxyapatite spheres was not caused by the adhesive, as evidenced by the lack of exposures in the porous polyethylene implant group. 2-Octyl cyanoacrylate may be effective in reducing the cost and time for enucleation surgeries when porous motility implants are used.

An evaluation of fibrin tissue adhesive concentration and application thickness on skin graft survival

OBJECTIVES

To examine the effects of fibrinogen concentration and application thickness of fibrin tissue adhesive on skin graft survival.

STUDY DESIGN

Prospective controlled study.

METHODS

Ten domestic pigs were included in the study. A 20 x 5-cm area of skin was harvested bilaterally along the flanks of the animals using a Padgett dermatome. The harvested grafts were trimmed into four 4 x 4-cm squares. Donor sites were treated according to group assignment and the non-meshed grafts were placed on the side opposite their initial orientation and secured with staples. Both single- and multiple-donor human fibrin tissue adhesive preparations, with low and high average fibrinogen concentrations of 30 mg/mL and 60 mg/ mL, were used. Adhesive preparations were applied in either a thin layer (0.015 mL/cm2) or a thick layer (0.06 mL/cm2) using a spray applicator. A constant thrombin concentration of 10 U/mL was used in the study. No adhesive was used in the control group and grafts were stabilized with staples. No topical dressings were applied to any of the treatment sites. Animals were sacrificed 4 weeks after graft application.

RESULTS

Based on statistical analysis, thickness of adhesive application had a significant effect on skin graft survival. Percent mean graft survival in the control and thin application groups was found to be 92% and 97.8% respectively; the mean survival rate in the thick application group was 63.1%. Fibrinogen concentration, when evaluated independently within the thin and thick application groups, was found to have no significant effect on graft survival.

CONCLUSION

Independent of fibrinogen concentration, a thin layer of fibrin tissue adhesive, when applied between two opposing surfaces, does not interfere with and may support the healing process, whereas a thick layer of adhesive inhibits skin graft healing.

Evaluation of fibrin sealants in cutaneous wound closure

Human fibrin sealant (HFS) and bovine fibrin sealant (BFS) were delivered as preformulated fibrinogen-thrombin mixtures that are light activated. These formulations were evaluated in the healing of incised cutaneous wounds in beagle dogs. Four groups were differentiated by sealant type and study duration with group: BFS for 10 days, HFS for 10 days, BFS for 30 days, and HFS for 30 days. Healing was evaluated by noting incidences of open wounds, laser Doppler perfusion imaging (LDPI), planimetry, breaking strength, and histopathology. In the absence of tension, both sealants tended to hold wound edges together; however, HFS tended to be better than its controls and BFS. Both sealants augmented suture closure, necessitating fewer sutures for wound closure. At 5 and 30 days BFS wounds had more perfusion than HFS wounds, indicating more inflammation. At 10 and 30 days BFS wounds had larger scar areas than their controls, while scar areas of HFS wounds were smaller than either BFS wounds or controls. Breaking strengths indicated that HFS wounds were stronger than their controls and BFS wounds. Histologically, mild to moderate chronic-active inflammation was observed in wounds receiving either sealant, and this persisted longer in BFS wounds. Overall, HFS had positive qualities, thus showing potential for functional and cosmetic wound closure.

Cytotoxicity of polymerized commercial cyanoacrylate adhesive on cultured human oral fibroblasts

Cyanoacrylate (CA) has been used as both a commercial and tissue adhesive. Dentists may have had the experience of patients repairing their own acrylic-based dentures using a cyanoacrylate (CA) adhesive known as 'super glue'. This study evaluated the cytotoxicity of commercial CA adhesives when fully polymerized, as well as the toxicity of substances released from polymerized commercial CA adhesives after incubation of these materials for various periods of time. Toxicity was tested on cultured oral fibroblasts. Dead cells found around the various CA-coated filter papers constituted inhibitory zones which varied from 200-1000 microns and which persisted for two weeks. Control oral fibroblasts grew to approach the wax-coated filter paper. Cell viability testing using MTT and crystal violet staining methods supported the conclusion that polymerized CA-coated filter paper released substances that are toxic to cells, while wax-coated filter paper gave the same result as the control. The crystal violet staining method was also used to investigate the cytotoxicity of various CA materials after incubation for one, three, seven and 14 days and showed that CA continued to release cytotoxic substances at about the same level for at least two weeks. It can be concluded that, if CA adhesive is used for repair of broken dentures, it will release substances which are toxic to human oral fibroblast cells. This release of substances may persist for at least two weeks.

Repair of an osseous facial critical-size defect using augmented fibrin sealant

OBJECTIVE

Osseous defects of the head and neck are a common challenge for the otolaryngologist. To develop improved reconstructive options, osteoconductive engineering experiments are being conducted. A nasal critical-size defect (CSD) model has previously been described in which less than 7% bone healing is observed over 6 months. An implant containing fibrin sealant with and without osteoprogenitor cells is evaluated in this model.

STUDY DESIGN

Randomized controlled trial using a rodent model.

METHODS

A nasal CSD was surgically created in 18 male retired breeder Sprague-Dawley rats. Six animals were not implanted with any material, six received fibrin sealant consisting of fibrin (25 mg/mL) and thrombin (1000 U/mL), and six were implanted with fibrin sealant and rat calvarial osteoprogenitor cells (1.8 x 10(6) cells/mL). Thirty days later, the animals were examined at necropsy by planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness.

RESULTS

A thin layer of bone covered the defect in all of the treated animals. A statistically significant increase in bone density (P < .05) between fibrin sealant plus osteoprogenitor cells and each of the other groups was shown using radiodensitometric analysis. Histological analysis also confirmed this difference.

CONCLUSION

Osteoprogenitor cells contained within fibrin sealant result in a greater augmentation of bone regeneration than controls or fibrin sealant alone.

Dural Closure with Laser Tissue Welding

This study investigates the use of tissue-soldering techniques to substitute or reinforce traditional suture closure of dural incisions. Fresh human cadaveric dura was incised and subsequently closed by use of three techniques: (1) conventional interrupted suture with 4–0 silk ( n = 25), (2) laser solder reinforced suture closure ( n = 25), and (3) laser solder closure alone ( n = 25). Anastomosis tensile strength and hydrostatic leak pressures were measured. Dural repair was also performed in 15 live Lewis rats. Dural closure was accomplished with 9–0 Prolene sutures ( n = 5), laser-reinforced suture closure ( n = 5), and laser solder closure alone ( n = 5). Histologic examination of the closure immediately after soldering and 2 weeks later was performed. Suture closure alone had the lowest leak pressure, 9.4 ± 1.7 mm Hg, and an intermediate break point, 13.3 ± 2.1 Kgf/cm2. Measurements with laser solder alone revealed a mean leak pressure of 26.2 ± 3.7 mm Hg and a break point of 4.6 ± 1.4 Kgf/cm2. Solder-reinforced suture closure leak pressure measured 64.0 ± 6.7 mm Hg and 21.4 ± 2.4 Kgf/cm2. There was a statistically significant increase in leak pressure and tensile strength in the closures performed with laser weld reinforcement of traditional suture technique ( p = 0.0001). Dural closure with laser tissue welding alone provided an immediate leak-free closure, but with poor tensile strength. Histologic examination of welded dura and underlying brain tissue showed no evidence of thermal injury in four of five animals studied. Laser welding may significantly decrease the incidence of cerebrospinal fluid leak after dural closure. In addition, laser tissue welding also makes dural closure possible where space constraints make traditional suture closure difficult.