Closure of the pleural dead space after pneumonectomy in a rabbit model: use of bioabsorbable lactic acid and caprolactone copolymer cubes.

The remaining pleural dead space after pulmonary resection sometimes causes serious complications, such as empyema. The objective of this study was induction of granulation tissue in uninfected pleural space after pneumonectomy in a rabbit model using implantation of bioabsorbable and porous poly-l-lactic acid and epsilon-caprolactone copolymer (PLAC) cubes. Twelve Japanese white rabbits were randomly split into two groups: the control group (n = 6) underwent simple left pneumonectomy, whereas the experimental group (n = 6) underwent left pneumonectomy followed by filling of the left hemithorax with PLAC cubes. One rabbit in each group was killed at 1, 2, 3, and 6 months after surgery, and pleural tissue was evaluated. In the experimental group, granulation tissue inside the PLAC cubes had begun to form at 1 month after implantation. From 3 months to 6 months, proliferated granulation tissue occupied the left postpneumonectomy pleural space with no residual space. The implanted PLAC material was being gradually degraded. We were able to induce self-assembled granulation tissue in the pleural space after pneumonectomy in a rabbit model using bioabsorbable PLAC cubes. The use of this technique allowed the residual pleural space to be closed after pulmonary resection.