Comparison of autologous in situ blood coagulum versus sutures for conjunctival autografting after pterygium excision

Our aim was to compare the efficacy and safety of autologous in-situ blood coagulum versus sutures for attaching conjunctival limbal autografts (CAG) among patients undergoing primary pterygium excision over a period of 1 year. Thirty-two eyes of 32 patients with primary pterygium were randomly divided in into two groups: group I (16 eyes) underwent CAG with 10-0 monofilament nylon sutures and group II (16 eyes) underwent CAG with patient's own in-situ blood coagulum acting as bioadhesive or fixative followed by bandaging for 48 h. Patients were followed up postoperatively on the 2nd day, 1 week, 2 weeks, 4 weeks, and 12 months. All the surgeries were done by the same surgeon. Graft success, recurrence rate, operating time, patient comfort, graft retraction or any other complication were studied. The duration of surgery was significantly less (P < 0.001) in group II (mean duration 15 ± 2 min) than group I (mean duration 67 ± 2 min). Postoperative symptoms were fewer for group II than group I. Rate of recurrence was equal in both groups (one patient in each group, 6.25 %). But complications regarding graft failure and graft retraction were more common in group II (two patients, 12.5 %) than group I (one patient, 6.25 %); however, the difference was not statistically significant (Z = 0.61). Thus, autologous in-situ blood coagulum is a useful method for graft fixation in pterygium surgery with shorter operating time and less postoperative discomfort.

Technical tips: Electrode application and preventing skin breakdown techniques

The recording electrodes including their precise location, their ability to record during movements that can be intense during a convulsive seizure, and their capability to record for several days without causing skin breakdown are an integral part of long-term EEG recording. Many of the facets of EEG technology have changed dramatically with the introduction of digital EEG. But the electrode and the electrode/skin interface have not had many dramatic changes. The technologist still looks for ways to ensure correct electrode placement, good recording capabilities, and a patient with healthy skin when the electrodes are removed. This Technical Tips features ideas and experiences from several technologists. These technologists express suggestions and opinions which are accepted in Technical Tips.

Elastomeric surgical sealant for hemostasis of cardiovascular anastomosis under full heparinization

PURPOSE

We developed a novel surgical sealant, a viscous diisocyanated prepolymer, applicable to arterial hemostasis. The purpose of this study is to evaluate hemostatic effect of this surgical sealant under heparinized conditions.

METHODS

The effectiveness of this sealant was verified by applying it to the end-to-end anastomosis of canine carotid arteries. Five mongrel dogs were used. After a complete heparinization, the carotid arteries were clamped, divided, and end-to-end anastomoses were performed with four simple interrupted sutures. The sealant was coated on the anastomosis. After 5 min the clamps were removed and the hemostatic effect was evaluated. Three dogs were immediately subjected to macroscopic evaluation. Two dogs were subjected to angiography after 3 months and 16 months, respectively.

RESULTS

No bleeding occurred in any of the anastomoses immediately after the removal of the clamp. Macroscopic finding revealed no leakage of the sealant into the lumen. Carotid angiography revealed patent anastomoses without stenosis.

CONCLUSION

A novel surgical sealant exhibited rapid and potent hemostatic effect on a moisturized tissue under full heparinization.

Tests of experimental tissue adhesive sealants: analysis of strength effects in relation to tissue adhesive sealant standards

The sealing efficiencies (SE% = surfaces sealed/surfaces tested) of 2 experimental tissue adhesive sealants (TASs), L.C. TAS and glutaraldehyde TAS (GA TAS), were determined by applications in 12 mixed-breed pigs (weight range, 40-60 kg) that had been anticoagulated with heparin and divided into groups of 6: Group I, L.C. TAS; and Group II, GA TAS. Leaking tissue surfaces used were 5-mm aortic punch holes and lacerated splenic, hepatic, and lung surfaces (2 of each, in each pig). First-application SEs were as follows: for aortic punch holes, 91% in Group I and 16.6% in Group II (P <0.001; 95% confidence interval [CI], 49%-100%); for splenic leaking tissue surfaces, 83.3% in Group I and 0 in Group II (P < 0.001; 95% CI, 78%-88%); for hepatic leaking tissue surfaces, Group I, 83.3%; Group II, 16.6%; P <0.001 (95% CI, 37%-97%); and for lung leaking tissue surfaces, 75% in Group I and 0 in Group II (P <0.001; 95% CI, 50%-99%). For both 1st and 2nd applications on all leaking tissue surfaces, SEs were 98% in Group I and 29% in Group II (P <0.001; 95% CI, 37%-99%). These results are consistent with the hypothesis that a TAS with higher cohesive and adhesive strengths, such as L.C. TAS (cohesive strength, >6.5 kg/cm(2); adhesive strength, >1.5 kg/cm(2)), will have higher SEs for leaking tissue surfaces than will a TAS with lower cohesive and adhesive strength. An analysis of these data in relation to TAS standards is discussed.

Comparison of four techniques for the fixation of a collagen scaffold in the human cadaveric knee

OBJECTIVE

Four fixation techniques for a fibrinogen and thrombin coated collagen fleece, used as a scaffold in the cartilage repair, were compared simulating the initial postoperative period in the cadaveric knee joints.

METHODS

Full-thickness chondral lesions were made on the medial femoral condyles of seven human cadaveric inferior extremities. Four scaffolds without seeded chondrocytes were implanted into each lesion using four fixation techniques consecutively: self-adhesion without additional material (SA), fibrin sealant (FS), bone sutures (BS), and periosteal cover (PC). After each implantation 150 cycles of continuous passive motion (CPM) were performed. Two cases were additionally exposed to 50 cycles of 10 and 20 kg loading each after the completion of CPM. The scaffolds were evaluated after every 30 cycles, and the fixation strength was tested after the motion was completed.

RESULTS

All the SA scaffolds were detached before 60 cycles. The other scaffolds remained stable throughout the testing with only minor disruptions. The endpoint fixation strength was higher for BS and PC than for the FS scaffolds. The FS scaffolds were detached as a result of additional load cycles, while the BS and PC scaffolds showed substantial deformations.

CONCLUSION

SA of tested scaffold did not provide sufficient fixation. The FS fixation was easy to perform and assured satisfactory scaffold stability. BS and PC provided excellent scaffold stability, but the techniques were difficult and caused additional injuries. Regardless of the fixation technique used, the tested collagen scaffold may not be exposed to loading in the initial postoperative period.

[Clinical appliance of new biologic glue "Biokley-LAB" in cardiac surgery with artificial circulation]

Data on clinical appliance of domestically produced two-component gelatin-resorcin glue "Biokley-LAB" in difficult surgeries on the ascending aorta and aortal valve with artificial circulation demonstrate that this glue is good prophylactic haemostatic remedy which reduces risk of postoperative bleedings.

Prospective randomized trial of skin adhesive versus sutures for closure of 217 laparoscopic port-site incisions

BACKGROUND

The purpose of this study is to determine whether closure of laparoscopic port-site incisions using octylcyanoacrylate (OCA) is feasible, whether it is faster than traditional subcuticular suturing, whether the number and length of incisions impact on closure time, and to determine wound morbidity and patient satisfaction outcomes.

STUDY DESIGN

A prospective randomized trial was performed on adult patients scheduled for elective laparoscopic surgery in three surgical specialties at a tertiary referral center. Patients were randomized to have closure of laparoscopic port sites using either OCA or sutures. Patients were followed up 2 to 3 weeks postoperatively. At 2 months patients were mailed a questionnaire regarding their satisfaction with the method of closure and the appearance of their scars.

RESULTS

A total of 175 incisions in 50 patients were closed with OCA, and 142 incisions in 42 patients were closed with subcuticular sutures. Time to close was significantly faster for OCA (median 2.5 minutes versus 6 minutes, p < 0.001). OCA was faster than traditional subcuticular suturing for cases involving three or more port sites (median 2.5 minutes versus 6 minutes, p < 0.001), and for cases with total length of incisions >4 cm (median 2.6 minutes versus 7 minutes, p < 0.001). OCA and subcuticular suturing groups did not differ significantly on patient acceptance or assessment of scars.

CONCLUSIONS

Closure of laparoscopic port-site incisions is feasible with OCA. Closure with OCA requires significantly less operative time than subcuticular suturing, particularly in cases when three or more port sites are used or when total incision length is greater than 4 cm. OCA appears to have equivalent adverse wound outcomes and patient acceptance rates as subcuticular suturing.

[Effectiveness of fibrin tissue adhesive for colocolic anastomosis reliability]

Leakage from a colonic anastomosis remains a major complication of surgery for colon emergencies and is associated with a significant increase in postoperative hospital stay and mortality rate. The purpose of our study was to investigate whether fibrin sealant, a well known tissue adhesive, will augment healing of bowel anastomosis in an experimental peritonitis model. Forty-eight male Sprague-Dawley rats were randomized into four groups. All rats underwent conventional sutured colo-colic anastomosis. The rats in group 3 and 4 had been exposed peritonitis before that procedure. In groups 2 and 4 fibrin sealant was added to the suture line. The measurements of bursting pressure and histopathological evaluations of suture lines revealed that peritonitis was deleterious to healing of colonic anastomosis. It was also seen that fibrin sealant augments healing of colonic anastomosis both in normal and peritonitis models.

Fibrin sealant: clinical use and the development of the University of Virginia Tissue Adhesive Center

The utilization of fibrin sealants to augment hemostasis, seal tissues, and facilitate targeted delivery of drugs is increasing. In 1985, a hospital-based program was established to provide autologous and allogeneic cryoprecipitate that serves as a fibrin sealant when combined with bovine thrombin. To date, more than 4,000 patients have been treated with this product at our institution, with an efficacy rate greater than 90%. Collaboration among surgical services and the blood bank fostered multispecialty expertise with this product that led, in 1997, to the establishment of the University of Virginia Tissue Adhesive Center. The Tissue Adhesive Center is a multidisciplinary center whose physician director and nursing and administrative support staff facilitate basic research, laboratory investigation, and preclinical and clinical trials with collaborators throughout the university. The Tissue Adhesive Center also provides educational programs and clinical consultation, and tracks and participates in peer review of sealant use. The licensure of a commercially produced, virally inactivated, pooled-plasma fibrin sealant in May 1998 provided an alternative source of adhesive. Utilization of the commercial product surpassed use of the blood bank product in April 1999. At present, use of the commercial product is approximately 3 times that of the blood bank-produced sealant. This report reviews the clinical uses of fibrin sealant, its regulatory history, the production of fibrin sealants, the evolution of a blood bank fibrin sealant program, the development of the Tissue Adhesive Center, and the utilization of commercial and blood bank-produced sealant at our university hospital.

Skin adhesives and skin adhesion. 1. Transdermal drug delivery systems

The use of pressure-sensitive adhesives (PSAs) for skin-contact applications is discussed. The requirements of such adhesives in various applications are examined in detail. Commercially available classes of PSAs used for skin-contact applications are the acrylics, the polyisobutylenes, and the silicones. The main application examined in this review is transdermal drug delivery. The roles played by the PSA in two types of transdermal designs are described. Correlations between in vivo and ex vivo measurements of adhesion are discussed. Also, the reported human studies of various commercially available transdermals are examined critically, with a view to assessing the relative performance capabilities of each type of transdermal design. Finally, a comprehensive listing of currently commercialized transdermals is given.

Development of intracoronary local adhesive delivery technique

Acute coronary occlusion may occur in weak coronary atherosclerotic lesions, including dissection, ulceration or thrombus. In some cases of occlusion "bail-out" is performed by using recently developed New Devices. However, these have not yet completely solved the problem to this end, we designed a new method of coronary revascularization, the Intracoronary Local Adhesive Delivery Technique, utilizing antithrombotic and absorbable adhesive injected locally into the fragile and morbid arterial wall using a drug delivery PTCA catheter more flexible than the existing New Devices. This adhesive strengthened and hardened the lesions. In this study, we examined the efficacy of making an adhesive cylinder in arteries of similar size to the coronary, through acute animal experiments using the existing clinical adhesives and drug delivery PTCA catheters and 12 femoral arteries of adult goats. We were successful in forming firm tunnels along the inside of six arteries, infused with approximately 0.04 ml Cyanoacrylate. These tunnels were observed with intravascular ultrasound (IVUS) imaging and evaluated microscopically. These results suggest the feasibility of this method as a new approach for making synthetic resinous stents.

[Initial clinical experiences with the fibrin adhesive Beriplast in heart surgery]

Fibrin glue Beriplast was used during cardiovascular surgery in 97 patients. The fibrin seal was used for hemostasis on anastomoses, patches and suture lines. Moreover, the glue was applied for epicardial fixation of aorto-coronary vein grafts to prevent postoperative graft kinking. Following extrapleural ligation of patent duct in premature infants, the parietal pleura was fastened to the thoracic wall to prevent extrapleural pneumothorax or hemorrhage. After accidental dissection of the thoracic duct in infants, leakage of chyle could be sealed successfully in 6 cases. Hemorrhage from the sealed surfaces of suture lines was not observed. Viral hepatitis occurred postoperatively in 2 patients (3% of the operations for acquired heart disease), both of whom had also received clotting factor concentrate and blood transfusion because of postoperative hemorrhage not related to fibrin sealed surfaces. A causal relation between the hepatitis and application of the pasteurized fibrin glue seems very unlikely. Although fibrin glue certainly cannot replace the surgical suture, it appears to be a valuable aid under special conditions.

Adhesives in orthopaedic surgery. A review of the literature and in vitro bonding strengths of bone-bonding agents

Adhesives may offer a number of advantages over conventional metal osteosynthesis in the treatment of fractures: ease and speed of fixation are improved, they have the anatomy to anatomically coapt small fragments, and hardware removal is not necessary. A review of the literature was performed to evaluate experiments with collagen and other biologic adhesives, epoxy resins, polyurethane foam, cyanoacrylates, zinc polycarboxylate, polymethylmethacrylates, and fibrin adhesives pertaining to osteosynthesis. Cyanoacrylates, polymethylmethacrylates, and fibrin adhesives are currently being investigated. These agents are tested to evaluate their bone-bonding strength. Cyanoacrylates of biologically tolerated chain length did not develop useful bonding in cancellous bone; they bond well to cortical bone only with meticulous surface preparation. Fibrin adhesives developed only minimally useful bonding. Polymethylmethacrylate developed surgically useful bonding in osteosynthesis where conventional fixation is impossible.

[Adhesives in surgery of the skeleton system, part 2: the adhesive strength from 22 adhesives in bone surgery (author's transl)]

For the first time all relevant adhesive groups were analyzed for their adhesive strength in bone-surgery. After having glued bone pieces in a special designed system, the tensil- and shearing-strength was determined. All adhesives showed a loss of adhesive strength under in vivo-conditions. Moderate moisture increased the tensile strength in some adhesives. While the fibrin adhesive had only a low adhesive strength under simulated in vivo-conditions, the adhesives containing gelatine, epoxy resin or acrylates reached reasonable results. The relationship between chemical structure and adhesive strength will be further used for the development of a special bone adhesive as a new surgeon's tool.

[Bioelectrode jellies for long-term monitoring (author's transl)]

The properties of 18 electrode jellies were investigated: electrical conductivity, ionic content, pH, skin irritation, and skin impedance reduction with different skin preparations, motion artifact, electrochemical noise with different electrode material, susceptibility to drying, ease of handling, and cost. There were significant differences of performance. Skin compatibility after 8 h ranged from "no irritation" to "severely irritating". A skin irritation most likely occurred with decornifying skin preparation. The specific skin impedance 24 min after the application ranged from 15 k omega . cm2 to 125 k omega . cm2. The motion artifacts differed up to 250%. All jellies produced negligible noise with Ag/AgCl and stainless steel electrodes. However, with gold and silver electrodes the noise amounted to 19 and 23 mu V. The NaCl content was correlated to the skin irritation and the impedance reduction. The impedance reduction correlated inversely to the skin compatibility and the motion artifact. Guidelines for the selection of an appropriate jelly in ergonomic long-term monitoring are given.

Use of biological glue in acute aortic dissection. Preliminary clinical results with a new surgical technique

Use of a biological glue (GRF) is common in certain fields such as hepatic or renal surgery, but its use in vascular surgery, especially in acute aortic dissection, has not yet been reported. Our experience has demonstrated many advantages: The glue is very simple and safe to use. The aortic tissues are firmly reinforced and the sutures tighten immediately. The proximal aortic stump is anatomically reconstructed, and generally the aortic valve can be preserved and coronary reimplantation avoided. The preoperative and postoperative bleeding rates are low and the postoperative course generally is simple. The risk of maintenance or recurrence of the dissection process is reduced. Consequently, the hospital mortality rate can be reduced to about 10 percent and the long-term survival rate greatly improved.

[Relationship between hardness, abrasion and bending strength of UV-polymerizable adhesives]

These experiments were undertaken to explore the influence of hardening on bending and bending strength of photopolymerisable adhesives. It was shown that light sources at present in use only influence the bending strength to a small degree but enable 40% variation in bending. The use of more intensive light sources not yet in commercial use led to further improvements.

[Comparative studies on the breaking strength of tissue adhesives of the butylcyanoacrylate type]

Four tissue adhesives of the butylcyano-acrylate type were tested for breaking strength. The addition of dyes and stabilizers results in an increase in breaking strength. Adhesives coloured with an anthraquinone dye and stabilized with SO2 significantly surpass in breaking strength adhesives that are only coloured or stabilized. Fiomed II (coloured, stabilized with SO2) yields significantly (at P=0.001) better values than Histoacryl blue. Addition of the dye alone seems to exert a better effect on breaking strength than addition of the stabilizer alone. As evidenced by our results, the breaking strength is in the order: 1. Fiomed II (coloured, stabilized with SO2), 2. Histoacryl blue, 3. Fiomed III (coloured, without SO2), 4. Fiomed I (without dye, stabilized with SO2).

[Heterologous fibrinogen for tissue adhesion. immunological and histological investigations (author's transl)]

The immunological reactions of heterologous fibrin were investigated in a sensitive experimental system. In 10 rabbits autologous full-thickness skin grafts were glued with bovine fibrinogen cryoprecipitate. 5 of these animals had been immunized against this adhesive before transplantation. In a control group the graft was fixed with homologous fibrinogen cryoprecipitate. Examination of the sera of the animals for antibodies against fibrinogen was performed before immunization, 1 day prior to and 14 days after skin grafting. 14 days after skin adhesion all grafted areas were examined by histological methods. In the group without preoperative immunization antibodies were found against fibrinogen. The skin graft healed in this series in the same manner as in the sham group. In the series with preoperative immunization the glued skin graft was discharged early and the healing procedure of the defect was retarded.