Investigation of the appropriate viscosity of fibrinogen in repairing pleural defects using ventilation and anchoring in an ex vivo pig model.

OBJECTIVE: Our previous study revealed that the viscosity of fibrinogen could influence the effectiveness of ventilation and anchoring (V/A) methods for controlling air leakages. Here, we examined the association between the viscosity of fibrinogen and effectiveness using an ex vivo pig model. METHODS: The fibrin glue used in this study was BOLHEAL® (KM Biologics Co., Ltd., Kumamoto, Japan). We prepared three types of fibrinogen with different viscosities (higher and lower than normal), including one without additives. Using an ex vivo pig model, a pleural defect was made, and the defect was repaired using three different viscosities of fibrinogen through the V/A method. We measured the rupture pressure at the repair site (N = 10) and histologically evaluated the depth of fibrin infiltration into the lung parenchyma at the repair sites. RESULTS: The median rupture pressure was 51.5 (40-73) cmH2O in Group 1 (lower viscosity), 47.0 (47-88) cmH2O in Group 2 (no change in viscosity), and 35.5 (25-61) cmH2O in Group 3 (higher viscosity). There was no statistically significant difference between Groups 1 and 2 (p = 0.819), but the rupture pressure was significantly higher in Group 2 than in Group 3 (p = 0.0136). Histological evaluation revealed deep infiltration of fibrin into the lung parenchyma in Groups 1 and 2, but no such infiltration was observed in the higher-viscosity group. CONCLUSIONS: The results of this experiment suggested that the V/A method using fibrin glue containing low-viscosity fibrinogen was more effective in controlling air leakage due to pleural defects.

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.

A novel and effective delivery method for polyglycolic acid sheets to post-endoscopic submucosal dissection ulcers.

Background and aims Shielding methods for post-endoscopic submucosal dissection (ESD) ulcers have delivery-related problems. We developed an enveloped device for this purpose and evaluated its usefulness. Materials and methods Polyglycolic acid (PGA) sheets were delivered to six 3.0-cm ulcers in two resected porcine stomachs and six 5.0-cm ulcers in another three stomachs. In the regular method group, small PGA sheets were delivered via forceps. In the novel method group, a large PGA sheet was delivered via the new device. The methods were compared in terms of time, and macroscopic and histological findings of the ulcer floor. Results The median time required to cover a 3.0-cm ulcer was 0.39 min/cm2 in the novel method group and 1.03 min/cm2 in the regular method group (P = 0.03), and to cover a 5.0-cm ulcer was 0.38 min/cm2 and 0.85 min/cm2, respectively (P = 0.03). In the novel method group, the PGA sheets were in close contact, fully covering the ulcer floor. In the regular method group, the sheets were partly elevated from the ulcer floor. Conclusions This novel technique seems promising in this preliminary study.

Triple-layer sealing with absorptive mesh and fibrin glue is effective in preventing air leakage after segmentectomy: results from experiments and clinical study.

OBJECTIVES: Fibrin glue in combination with polyglycolic acid (PGA) mesh is effective in preventing air leakage after segmentectomy, but we frequently experienced air leakage with single-layer application. To investigate improved usage, we compared the sealing effect among single-, double- and triple-layer PGA mesh and fibrin glue in both experimental and clinical segmentectomy. METHODS: Ex vivo pig lungs were used for experiments. As a model of segmentectomy, the lateral segment of the left lung was removed using electrocautery. As a model of peripheral lung defect, peripheral lung tissue was resected with scissors. The inter-segmental plane and the peripheral lung defect were sealed using one of the following four methods: (i) fibrin glue alone (Group 1, n = 8), (ii) single-layer with PGA mesh and fibrin glue (Group 2, n = 8), (iii) double-layer (Group 3, n = 8) and (iv) triple-layer (Group 4, n = 8). The seal-breaking pressures among them were compared. In clinical segmentectomy, the periods of chest-tube drainage were compared retrospectively between 17 patients treated by the single-layer and 17 treated by the triple-layer method. RESULTS: In experimental segmentectomy, the seal-breaking pressure in the triple-layer (100 ± 25 cmH2O) was significantly higher than those in the other methods (26 ± 17, 48 ± 12 and 69 ± 19 cmH2O in the Groups 1, 2 and 3, respectively, P < 0.001-0.05), while there were no significant differences among other methods. For peripheral lung defect, the seal-breaking pressures did not differ among the methods. In clinical segmentectomy, the mean chest-drainage period with the triple-layer was 2 ± 0.9 days, which was significantly shorter than 3.6 ± 2.8 days with the single-layer (P = 0.009). CONCLUSIONS: Stronger sealants are required to prevent air leakage from inter-segmental planes than from peripheral lung. To prevent air leakage after segmentectomy, triple-layer PGA mesh and fibrin glue is recommended.