Double stapling method for closure of intraoperative alveolar air leakage adjacent to the staple line: a randomized experimental study on ex vivo porcine lungs

Abstract

Background: Alveolar air leakage from a pleural defect around the staple line is one of the complications after wedge resection of the lung. An intraoperative closure of the pleural defect by suturing can cause additional pleural rupture due to tension of the pleura adjacent to staple lines. Therefore, we have introduced a novel closure method for pleural defect adjacent to the staple line, named the double stapling method. This study compared the efficacy of two closure methods; the double stapling method and conventional suturing method with pledgets using ex vivo porcine lungs.

Methods: The double stapling method involves closing the pleural defect by suturing the two parallel staple lines at both sides of the pleural defect. This method was developed to distribute the pleural tension around the needle holes of suturing. As a model of pleural defect adjacent to the staple line after wedge resection, wedge resection of the caudal lobe of left porcine lungs was performed, and a superficial square pleural defect (10 mm × 10 mm) adjacent to the staple line was made by scalpel. The defect was closed using the following two methods: (I) suturing with pledgets (n=10); and (II) double stapling method (n=10). The lobe was inflated in water at an airway pressure of 20, 25, and 30 cmH₂O; closure success or failure was judged by the absence or presence of air leakage.

Results: The closure success was confirmed in 2 (20%) out of 10 cases in the suturing with pledgets group and 9 (90%) out of 10 in the double stapling method group (P=0.007). In 4 out of 10 cases in the suturing with pledgets group, new pleural clefts longer than 3 mm were created around the needle holes of suturing.

Conclusions: Ex vivo experiments have suggested the superiority of the double stapling method for the intraoperative closure of alveolar air leakage adjacent to the staple line after wedge resection, compared to conventional suturing with the pledget method.

Keywords: Alveolar air leak; stapler; wedge resection.

Figure 1

The model of visceral pleural defect adjacent to the staple line after wedge resection. (A) Wedge resection of the left caudal lobe was performed using two staplers crossed at 120°. The maximum thickness of the stapled lung was 60 mm when it was inflated. (B) A pleural defect (10 mm × 10 mm) developed adjacent to the crossing point of the staple lines using a scalpel.

Figure 2

Procedures of the suturing with pledget and the double stapling method. (A) Suturing with pledgets method: a pledget pad (3 mm × 7 mm) was attached to the pleural defect on the opposite side of the staple line. Then two pledget pads and the staple line were closely sutured with 2-0 Surgipro V-20. (B) Double stapling method: another staple along the pleural defect parallel to the original staple line. (C) Double stapling method: two staple lines were sutured using 2-0 Surgipro V-20. (D) Double stapling method: two staple lines were closely attached, and the lobe was inflated.

Figure 3

Schema of our hypothesis regarding the distribution of tension after suturing with pledgets and the double stapling method. (A) Pleural defects (black circles) adjacent to the staple line (dotted lines) were closed by suturing with pledget pads (white squares) and the original staple line. The tension derived from suturing was concentrated around the needle hole after suturing with the pledget method (large black arrows). On the side of the original staple line, tension derived from suturing (small black arrows) was distributed over the integrated structure of the lung parenchyma, staples, buttress materials, and suture strings. (B) All the tension derived from suturing (small black arrows) was distributed over the integrated structure of the lung parenchyma, staples, buttress materials, and suture strings after the double stapling method.

Figure 4

Air leak test: the caudal lobe was inflated in water at pressures up to 30 cmH₂O. The absence of air leakage was confirmed (suturing with pledgets).

Figure 5

Rate of closure success in double stapling method group and the suturing with pledgets group. The double stapling method group showed a higher closure success rate (90% vs. 20%, P=0.007).

Figure 6

Macroscopic and microscopic findings of the specimen. (A) Macroscopic findings of closure failure in the suturing with pledgets method: a 3 mm long cleft, vertical to the staple line (arrow), newly appeared around the suture needle hole after inflation. (B) Hematoxylin-eosin stain of lung specimen in the suturing with pledgets method (failure case, original ×40). The visceral pleura is partially lacking, and bare alveoli are exposed (arrows). Bronchioles (arrowhead) are contained near the staple line (dashed line). (C) Hematoxylin-eosin stain of lung specimen in the double stapling method (success case, original ×40). The visceral pleura around the closure sites was not interrupted (arrows), suggesting closure of the defect without pleural damage.