Prevention of postoperative air leakage from lungs using a purified human collagen membrane-polyglycolic acid sheet

Residual middle lobectomy after right upper or lower lobectomy: indications and outcome

OBJECTIVES

Residual middle lobectomy after upper lobectomy and lower lobectomy differs in their indications and perioperative outcomes. Therefore, we aimed to evaluate the indications and perioperative outcomes of residual middle lobectomy after upper and lower lobectomy.

METHODS

The data of 14 patients who underwent residual middle lobectomy after upper or lower lobectomy between January 1997 and December 2021 were extracted and analyzed.

RESULTS

Overall, six patients underwent residual middle lobectomy after upper lobectomy. The indication was second primary lung cancer in five patients and local recurrence in the hilar lymph node between the middle and lower lobar bronchi in one patient. However, one patient was treated with the R2 operation. The remaining eight patients underwent residual middle lobectomy after lower lobectomy. The indication was second primary lung cancer and bronchopleural fistula or stenosis in two and six patients, respectively. No postoperative 90-day mortality was observed.

CONCLUSIONS

Residual middle lobectomy for second lung cancer after upper lobectomy is difficult because of severe hilar adhesions. Simultaneous resection of hilar structures or pulmonary artery and parenchyma might be an option. Residual middle lobectomy could be a treatment option for bronchopleural fistula or stenosis after lower lobectomy.

The clinical impact of modified transpancreatic mattress sutures with polyglactin 910 woven mesh on postoperative pancreatic fistula in distal pancreatectomy

BACKGROUND

We previously reported the stump closure method for the remnant pancreas in distal pancreatectomy, in which soft coagulation and polyglycolic acid felt attached with fibrin glue were utilized. Transpancreatic mattress suture with polyglactin 910 woven mesh was recently reported as a novel stump closure technique. We developed the modified transpancreatic mattress suture with polyglactin 910 woven mesh method, which combined our polyglycolic acid felt method with the transpancreatic mattress suture with polyglactin 910 woven mesh method.

METHODS

The polyglycolic acid felt group included patients undergoing distal pancreatectomy in whom the pancreatic stump was closed with the polyglycolic acid felt method from 2017 to 2018 (n = 54); whereas the modified transpancreatic mattress suture with polyglactin 910 woven mesh group included those whose stump was closed with the modified transpancreatic mattress suture with polyglactin 910 woven mesh method from 2019 to 2020 (n = 51). Perioperative parameters, including grade B/C postoperative pancreatic fistula (clinically relevant postoperative pancreatic fistula), were assessed according to the stump closure method.

RESULTS

The incidence of clinically relevant postoperative pancreatic fistula was significantly lower in the modified transpancreatic mattress suture with polyglactin 910 woven mesh group than in the polyglycolic acid felt group (7.8% vs 22.2%, P = .036). In multivariate analysis, the use of neoadjuvant chemoradiotherapy and the transpancreatic mattress suture with polyglactin 910 woven mesh method were independent factors for preventing clinically relevant postoperative pancreatic fistula (P = .011 and 0.0038, respectively). Moreover, in the modified transpancreatic mattress suture with polyglactin 910 woven mesh group, the incidence of clinically relevant postoperative pancreatic fistula in patients with a thick pancreas (≥13 mm, 6.7%) was comparably as low as that in patients with a thin pancreas (<13 mm, 9.5%).

CONCLUSION

The modified transpancreatic mattress suture with polyglactin 910 woven mesh method is an effective stump closure technique to prevent clinically relevant postoperative pancreatic fistula after distal pancreatectomy. Our results warrant further prospective investigation to evaluate the efficacy of the modified transpancreatic mattress suture with polyglactin 910 woven mesh method compared with other standard closure methods (eg, stapler closure or hand-sewn closure).

Development of an effective method utilizing fibrin glue to repair pleural defects in an ex-vivo pig model

Background

The present study aimed to use an ex-vivo model to investigate whether a new method involving the use of fibrin glue and a polyglycolic acid (PGA) sheet under ventilation enhances the sealing effect after repair of the pleural defect.

Methods

Ex-vivo pig lungs were used in this study. We investigated the maximum pressure tolerance of pleural defects repaired using three methods: 1, directly spraying fibrin glue over a PGA sheet; 2, spreading fibrinogen on the site then sealing with a PGA sheet and spraying with fibrin glue; and 3, spreading fibrinogen while maintaining ventilation then sealing with a PGA sheet and spraying with fibrin glue.

Results

The maximum tolerable pressures were as follows (mean ± standard deviation, cmH₂O): Method 1, 37.1 ± 13.6, Method 2, 71.4 ± 27.7, Method 3, 111.5 ± 8.8. Histological findings explained the difference in tolerable pressure at the repaired site between methods. Microscopic findings of lungs repaired using Method 3 indicated that the fibrinogen penetrated into deeper tissues to act as an anchor.

Conclusions

Fibrin glue sealing under ventilation increases the anchoring effect of repairing air leakages due to pleural defect in an ex-vivo model. This method may have clinical application. For example, it may be useful to reduce severe air leakage in patients who undergo lung-sparing surgery for a pleural tumor.

Two cases of granuloma mimicking local recurrence after pulmonary segmentectomy

Background

Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/CT is the most sensitive non-invasive imaging method for the detection of tumor metastasis and recurrence, but sometimes reveals false-positive results. Herein, we report two cases of false-positive results on PET/CT scans along with elevated serum carcinoembryonic antigen (CEA) levels, mimicking local recurrence after pulmonary segmentectomy.

Case presentation

Case 1; A 75-year-old woman underwent thoracoscopic left basal segmentectomy for primary lung cancer. Follow-up at 6 months after the surgery revealed serum CEA level elevation and chest CT showed a nodule measuring 25 × 22 mm in the residual left lower lobe. PET/CT revealed FDG uptake in the nodule diagnosed as local recurrence of lung cancer, and the patient underwent partial resection of the nodule. Microscopic examination of the resected specimen revealed granuloma caused by polyglycolic acid (PGA) sheet. Case 2; A 58-year-old man underwent VATS right S1 segmentectomy for lung metastasis from rectal carcinoma. Serum CEA levels gradually increased after surgery, and PET/CT revealed FDG uptake in the stump diagnosed as local recurrence of the lung metastasis. The patient underwent completion lobectomy 6 months after the segmentectomy, and the pathology of the resected specimen revealed an inflammatory granuloma caused by PGA suture.

Conclusions

Although suture and stapler granulomas have been reported, granuloma caused by PGA sheets has never been reported. Postoperative recurrence of lung cancer should be diagnosed with not only PET/CT scans and serum tumor markers but also pathological findings, to avoid unnecessary treatment such as chemotherapy, radiation, and difficult reoperation.

Defect repair with fibrin glue/polyglycolic acid after endoscopic laryngopharyngeal cancer resection

OBJECTIVES/HYPOTHESIS

In 2013, we introduced a modified technique for mucosal/muscle layer defect coverage with fibrin glue and polyglycolic acid (PGA) sheets (mMCFP technique) in patients undergoing endoscopic transoral surgeries for laryngopharyngeal cancers. This technique allows easy and convenient coverage of the wound surface, even when it involves the laryngopharyngeal lumen. To our knowledge, use of the MCFP technique for coverage of postoperative mucosal and/or muscle layer defects involving the laryngopharyngeal lumen has not been reported. The aim of the present study was to retrospectively evaluate the safety of our mMCFP technique used simultaneously with endoscopic transoral resection of Tis, T1, T2, and select T3 pharyngeal and supraglottic cancers.

STUDY DESIGN

A single centre retrospective study.

METHODS

Between June 2013 and February 2019, 102 patients underwent simultaneous end-flexible-rigidscopic transoral surgery and wound coverage using our mMCFP technique. All patients required mucosal and/or muscle layer resection. For all patients, we recorded the incidence of postoperative complications and the time period for which the PGA sheets could be observed after surgery.

RESULTS

In 41%, 35%, and 8% patients, the PGA sheets could be observed on the wound surface for 2, 3, and 4 weeks, respectively. Other than postoperative bleeding in two patients (2%), no postoperative complications were recorded.

CONCLUSIONS

The findings of this study suggest that our mMCFP technique is a safe and simple method for the repair of mucosal and/or muscle layer defects after endoscopic transoral surgery for laryngopharyngeal cancers.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1740-1745, 2020.

In Vitro Evaluation for Potential Calcification of Biomaterials Used for Staple Line Reinforcement in Lung Surgery

Bovine pericardium (BPC) and polytetrafluoroethylene (PTFE) have been widely used to reinforce staple lines in lung resection. Since limited Information regarding the calcification of these biomaterials is available, we undertook an In vitro study to evaluate their calcification potential. Commercially available BPC and PTFE biomaterials were evaluated and compared with custom-prepared BPC tissue. In vitro calcification was performed via submersion in supersaturated solution In a double-walled glass reactor at 37.0°C ± 0.1°C, pH 7.4 ± 0.1, mimicking most ion concentrations of human blood plasma. In processing of calcification, the pH decrease of the solution simulated the addition of consumed H+, Ca2+, and PO43– ions from titrant solutions, the concentrations of which were based on the stolchiometry of octacalcium phosphate. The molar ion addition with time was recorded, and the initial slope of the curve was computed for each experiment. The rate of calcification developed (molar calcium phosphate ion addition rate per time and total surface area) (R) was computed after that with respect to the relative supersaturation (σ) used in each experiment. R for custom-prepared BPC tissues was found to be in the range of 0.19 ± 0.08 to 0.52 ± 0.19 (n = 17) in σ range of 0.72 to 1.42. Commercial BPC was found to be 0.016 to 0.052 (n = 4), and PTFE was 0.005 to 0.05 (n = 8) in the same σ range. Both clinically applied biomaterials, BPC and PTFE, seemed to be calcified with rates of at least one order of magnitude lower than the custom-prepared BPC tissue. This data suggested that BPC and PTFE biomaterials showed a similar, relatively very low tendency for calcification compared with custom-prepared BPC tissue. Although further studies are necessary, staple line reinforcement by these two biomaterials should be considered safe from the calcification point of view.

Fibrin Sealant with Polyglycolic Acid Felt vs Fibrinogen-Based Collagen Fleece at the Liver Cut Surface for Prevention of Postoperative Bile Leakage and Hemorrhage: A Prospective, Randomized, Controlled Study

BACKGROUND

The incidence of postoperative biliary leakage and hemorrhage is low, but these factors remain important in liver surgery, and this study's objective was to explore the efficacy of fibrin sealant (FS) with polyglycolic acid (PGA) vs fibrinogen-based collagen fleece (CF) at the liver cut surface. Fibrinogen-based collagen fleece is generally used for hemostasis; PGA-FS has reduced biliary leakage in several retrospective studies.

STUDY DESIGN

We designed a multicenter, randomized, controlled trial. The primary outcome was the rate of biliary leakage and hemorrhage. Secondary outcomes included morbidities and effusion at the liver cut surface at 3 months post-surgery. Biliary leakage was diagnosed when the drain/serum bilirubin ratio was >5. Hemorrhage was diagnosed when relaparotomy or transfusion was needed.

RESULTS

Of 786 patients from 11 institutions enrolled from 2009 to 2014, a total of 391 were randomly assigned to PGA-FS and 395 to CF. Regarding primary outcomes, rates of biliary leakage were 4.1% with PGA-FS and 5.1% with CF, and rates of hemorrhage were 1.0% in each group; groups did not differ significantly. For secondary outcomes, morbidity rates were 18.7% in the PGA-FS group and 24.6% in the CF group (p = 0.0450). Effusion at the cut liver surface was less with PGA-FS (22.2%) than with CF (32.9%) (p = 0.0142). Regarding morbidity, infection around the liver, jaundice, and abdominal paracentesis were less in the PGA-FS group.

CONCLUSIONS

Compared with CF, PGA-FS did not reduce biliary leakage and hemorrhage. Surgical site infection around the liver, effusion at the liver cut surface, and abdominal paracentesis were less in the PGA-FS group.

The dynamics and clinical significance of alpha 2 plasmin inhibitor-plasmin complex and thrombin-antithrombin complex in postoperative pleural effusion following a pulmonary lobectomy

PURPOSE

The overall incidence of postoperative alveolar air leakage (AAL) remains high; however, the mechanism regarding how to adequately heal such postoperative AAL remains to be elucidated. The aim of this study was to determine any correlations between the activity of the fibrinolytic and coagulation system in the postoperative pleural effusion and appearance or disappearance of postoperative AAL.

METHODS

This study prospectively investigated 25 patients who underwent a pulmonary lobectomy from July 2005 to March 2006. Pleural effusion was collected through the chest tube. Alpha 2 plasmin inhibitor-plasmin complex (PIC), as a fibrinolytic marker, and thrombin-antithrombin complex (TAT), as a coagulation marker, were measured.

RESULTS

The activity of the coagulation system was higher than that of the fibrinolytic system. The concentration of TAT tended to increase (3rd vs 4th postoperative day [POD], P = 0.0907). The mean time of appearance and disappearance of postoperative AAL was 1.4 days and 3.2 days, respectively. The patients with postoperative AAL had a TAT level significantly below the average on the 3rd POD in comparison to the patients without postoperative AAL (P = 0.0163). Moreover, the concentration of TAT in patients with postoperative AAL was significantly lower than that in patients without postoperative AAL (1824.0 +/- 137.3 ng/ml vs 3444.0 +/- 287.6 ng/ml, P = 0.0113) on the 3rd POD. On the 4th POD, the concentration of TAT was almost same and there was no significance (P = 0.6759).

CONCLUSIONS

This study demonstrated for the first time the course of the fibrinolytic and coagulation activity in the pleural effusion after a pulmonary lobectomy, and showed that the delayed activity of the coagulation system is associated with the appearance of the postoperative AAL.

Development of new biodegradable hydrogel glue for preventing alveolar air leakage

OBJECTIVE

Air leakage is a frequent complication during lung surgery. A new hydrogel glue was created by mixing aldehyded dextran and epsilon-poly(l-lysine), and its feasibility as a surgical sealant was evaluated in comparison with that of conventional fibrin glue.

METHODS

Bursting pressure after application of each glue to 30 x 30-mm pleuroparenchymal defects was evaluated in two groups of 14 beagle dogs. Biodegradability and histotoxicity of the glues were evaluated in another 6 dogs with 15-mm circular pleuroparenchymal defects. Adhesions, infections, and histologic changes were observed on scheduled days for 6 months.

RESULTS

The mean bursting pressure after application was 38.4 +/- 4.6 cm H2O for the new glue and 32.1 +/- 4.5 cm H2O for fibrin glue (P = .02), the former providing more effective sealing of pulmonary air leakage than the latter. Macroscopically, no adhesions or infections were observed in areas of glue application. About 90% of the new glue degraded within 3 months, but complete disappearance was not observed by 6 months. On the other hand, the fibrin glue was replaced by white pleural tissue at 4 weeks. Histologically, the new glue was covered by one layer of mesothelial cells at 2 weeks and completely covered by thick fibrous tissue at 4 weeks. Inflammatory reaction was minimal around the residual glue after 3 months. Although the new glue degraded more slowly than did the fibrin glue, the biocompatibility of the new glue was sufficient for clinical use.

CONCLUSION

Our new hydrogel glue demonstrates a strong sealing effect, with good biocompatibility, and has potential usefulness as an adhesive in lung surgery.

Creation of a uniform pleural defect model for the study of lung sealants

OBJECTIVE

Animal models are indispensable for the development of new therapeutic methods for the closure of alveolar air leakage. However, it is difficult to create a uniform pleural defect model. The purpose of this study was to establish an appropriate animal model for assessing the efficacy and histotoxicity of synthetic sealants for lung surgery.

METHODS

Nine beagle dogs were used to evaluate the pleural defect model in comparison with conventional resection procedures. A donut-shaped silicon ring with an inner diameter of 15 mm was placed on the pleura, and 0.1 mL of cyanoacrylate was dropped into the ring. A pleural defect was created by sliding a microtome blade just beneath the polymerized cyanoacrylate. Hemostasis was performed by pressure with a sponge.

RESULTS

Morphologically, round areas of the pleura were uniformly resected with our procedure. The resected tissue consisted of pleura and thin underlying lung parenchyma. Among the results from 3 surgeons, there were no significant differences in the mean time required for hemostasis (P = .69), the mean thickness of the resected tissue (P = .13), and the mean amount of air leakage from the resected area (P = .19). No penetration of cyanoacrylate into the lung parenchyma was evidenced by immunofluorescence microscopy. Histologically, when the pleura was resected without using cyanoacrylate, a thick fibrocellular layer extended to the lung parenchyma. Furthermore, severe fibrosis was observed when electrocautery was used for hemostasis. However, when the pleura was resected using cyanoacrylate, the normal alveolar structure was preserved.

CONCLUSIONS

Our uniform pleural defect model using cyanoacrylate may be feasible for the evaluation of synthetic sealants for alveolar air leakage.

Pleural space sterilization using gentian violet irrigation for postbullectomy empyema associated with artificial material infection

Postoperative empyema associated with artificial material infection involves several treatment problems. We report the successful treatment of a case of post-bullectomy empyema with a small alveolar fistula that was associated with artificial material infection by Streptococcus viridans. In this case, complete empyema space sterilization was obtained by tube drainage and daily pleural irrigation using 0.1% gentian violet solution. This treatment circumvented the need for invasive surgery, including removal of the infected artificial materials and space-filling and/or collapse procedures. Consequently, gentian violet irrigation may be a useful treatment option in selected cases with complicated thoracic empyema.

Production of an acellular amniotic membrane matrix for use in tissue engineering

A clinical need exists for an immunologically compatible surgical patch with a wide range of uses including soft tissue replacement, body wall repair, cardiovascular applications, and as a wound dressing. This study aimed to produce an acellular matrix from human amniotic membrane for future assessment as a surgical patch and a delivery system for epithelial cells. A novel detergent-based protocol was modified to remove all cellular components from amnion to render it non-immunogenic. Amnion was harvested within 24 h after elective caesarean section (n = 12). One sample group remained fresh, whereas the other was treated with 0.03% (w/v) sodium dodecyl sulphate, with hypotonic buffer and protease inhibitors, nuclease treatment, and terminal sterilization, using peracetic acid (0.1% v/v). Fresh and treated amnion was analyzed histologically for the presence of cells, deoxyribonucleic acid (DNA), collagen, glycosaminoglycans (GAGs), and elastin. Quantitative analysis was performed to determine levels of GAGs, elastin, hydroxyproline, denatured collagen, and DNA. The biomechanical properties of the membrane were determined using uniaxial tensile testing to failure. Histological analysis of treated human amnion showed complete removal of cellular components from the tissue; the histoarchitecture remained intact. All major structural components of the matrix were retained, including collagen type IV and I, laminin, and fibronectin. Differences were observed between fresh and decellularized amnion in matrix hydroxyproline (34.7 microg/mg vs 49.7 microg/mg), GAG (42.5 microg/mg vs 85.4 microg/mg), denatured collagen (2.2 microg/mg vs 1.7 microg/mg), and elastin (359.2 microg/mg vs 490.8 microg/mg) content. DNA content was diminished after treatment. Acellular matrices were biocompatible, cells grew in contact, and there was no decrease in cell viability after incubation with soluble tissue extracts. In addition, no significant reduction in ultimate tensile strength, extensibility, or elasticity was found after decellularization. Removal of the cellular components should eliminate immunological rejection. The resulting matrix was biocompatible in vitro and exhibited no adverse effects on cell morphology or viability.

Diffuse bullous emphysema of the lung: conservative resection with a local application of a biological glue

A middle-aged man suffered a recurrent right pneumothorax with a prolonged air leak due to diffuse bullous emphysema of the lung. On December 19, 2001, he underwent a successful conservative resection of the bullae with a local application of a gelatin-resorcin-formalin biological glue.

Fibrin glue in pulmonary resection: a prospective, randomized, blinded study

BACKGROUND

In contrast to the rare large-airway bronchopleural fistulas after lung resection, peripheral or alveolar air leaks (AAL) are very common, often prolong hospital stay, increase utilization of resources, and on occasion result in significant morbidity. Various adjuncts have been used in attempts to reduce AAL. One of these, the topical application of fibrin glue, has to date failed to demonstrate efficacy in small clinical trials. This study reexamines the role of fibrin glue in routine lobar and wedge pulmonary resections.

METHODS

Of 113 patients enrolled, 13 became ineligible because of intraoperative findings. The remaining 100 patients were randomly assigned to one of two groups at the conclusion of lung resection, regardless of the presence or absence of identifiable air leak. The control group received no additional intervention. The experimental group underwent application of 5 mL of fibrin glue delivered by a pressurized, aerosolized spraying mechanism. Postoperatively a blinded clinical observer recorded outcomes including the incidence and duration of AAL, prolonged AAL (PAAL), the volume of pleural drainage, the time to tube removal, and the postoperative length of stay (LOS), as well as any complications related to treatment.

RESULTS

Both groups were comparable with regard to demographics, diagnoses, and procedures. Statistically significant reductions were found in the experimental group in the overall incidence of AAL (34% versus 68%, p = 0.001), mean duration of AAL (1.1 versus 3.1 days, p = 0.005), mean time to chest tube removal (3.5 versus 5.0 days, p = 0.02), and the incidence of PAAL (2% versus 16%, p = 0.015). There was no significant difference in the volume of chest tube drainage or LOS (4.6 days glue and 4.9 days control, p = 0.318). There were no complications related to the use of fibrin glue.

CONCLUSIONS

Aerosolized fibrin glue appears to be safe and effective in reducing AAL. The overall incidence of AAL was reduced by 50% and PAAL occurred in only 1 treated patient (2% versus the usually reported 15%). Further studies with this and other methods are required to delineate routine versus selective use, to compare methods, and clarify cost benefit.

The influence of pulmonary staple line reinforcement on air leaks

OBJECTIVES

Although uncommon, prolonged postoperative air leaks are a troublesome complication of lung surgery. This study was performed to determine if buttressing pulmonary staple lines would reduce air leakage at varying airway pressures, and if there was a difference between buttressing materials.

METHODS

Using cadaver lungs, the development of air leak from staple lines was evaluated at incremental airway pressures. Unreinforced staples were compared to staples reinforced with bovine pericardium and staples reinforced with expanded polytetrafluorethylene (ePTFE).

RESULTS

Unreinforced staple lines began to leak air at an airway pressure of 20 mm Hg, and > 90% leaked at a pressure of 35 mm Hg. Both bovine pericardium and ePTFE significantly reduced the incidence of air leak at these airway pressures. At higher airway pressures, ePTFE was superior to bovine pericardium.

CONCLUSION

Staple line reinforcement with either material protects against air leak. Patients at risk for elevated airway pressures and/or postoperative ventilator support should be considered for utilization of these staple reinforcing materials.

Novel application of biological glue in the management of a complicated pneumothorax in cystic fibrosis

Spontaneous pneumothorax is a frequent complication in advanced lung disease of cystic fibrosis. We describe a case of a complicated pneumothorax in a 21-year old-woman with cystic fibrosis who was effectively treated with the application of biological glue via a minithoracotomy.

Randomized controlled trial of a synthetic sealant for preventing alveolar air leaks after lobectomy

BACKGROUND

The intraoperative application of synthetic surgical lung sealant (SLS) to surfaces leaking air or at risk of air leaks has been advocated to reduce alveolar air leaks (AAL) after lobectomy.

METHODS

This study was designed to investigate the effectiveness of SLS in reducing AAL in patients considered intraoperatively to have moderate to severe AAL, after all conventional measures to reduce such leaks had been used. Over 17 months, 124 patients undergoing standard lobectomy were randomized to standard closure of parenchymal surgical sites, with or without SLS.

RESULTS

In treated patients, the mean numbers of intraoperative AAL after application of SLS were significantly smaller than in untreated patients (38.5 mL versus 59.9 mL, p = 0.0401). Postoperatively, the mean time to last observable AAL was shorter in the treated group (33.7 hours versus 63.2 hours, p = 0.0134) and the mean percentage of patients free of AAL at days 3 and 4 was smaller (87% versus 58.5%, p = 0.002). However, the occurrence of incomplete lung expansion after drain removal, and the length of the postoperative hospital stay due to prolonged AAL, were not different. In the treatment group, 4 patients developed localized empyema and incomplete lung expansion without bronchopleural fistula 7, 12, 15, and 20 days, respectively, after operation. In these 4 patients, inserted chest tubes drained infected sealant.

CONCLUSIONS

Surgical lung sealant may be a useful adjunct to conventional techniques for reducing moderate and severe AAL after lobectomy, but its use seems to increase the risk of postoperative empyema.

Mixing collagen with fibrin glue to strengthen the sealing effect for pulmonary air leakage

BACKGROUND

To strengthen the sealing effect of fibrin glue for pulmonary air leakage, atelocollagen was mixed with the glue and the mixing effect was examined.

METHODS

A mixture of fibrinogen and thrombin with atelocollagen was used as a test sample. The concentrations of atelocollagen were adjusted to levels of 0%, 0.375%, 0.75%, 1.1%, and 1.5%. We next performed air leakage tests on a plastic cap with pin holes and swine lung and also measured the elasticity and the adhesion strength.

RESULTS

The pressure required to rupture the sealant on a plastic cap with pin holes increased as the concentration of atelocollagen increased, and the bursting pressures were significantly higher in the glue with 0.75%, 1.1%, and 1.5% of atelocollagen than in the glue without atelocollagen (p < 0.01 and p < 0.001). The air leakage pressure on the swine lung was significantly higher in the glue with 0.375%, 0.75%, and 1.1% of atelocollagen than in the glue without atelocollagen (p < 0.05 and p < 0.01), and it was the highest with 0.75%. The elasticity of the glue significantly increased as the concentration of atelocollagen increased (p < 0.001). However, the adhesion strength of the glue significantly decreased as the concentration of atelocollagen increased (p < 0.05 to p < 0.001).

CONCLUSIONS

The mixing of atelocollagen with fibrin glue more effectively sealed pulmonary air leakage due to an increased elasticity of the glue while its adhesion strength decreased. The optimal concentration of atelocollagen in the fibrin glue to obtain the best sealing effect was 0.75%.