A synthetic bioabsorbable sheet may prevent postoperative intrapleural adhesions following thoracotomy: a canine model.

OBJECTIVES: Intrapleural adhesions following thoracotomy may be associated with prolonged operating time or a higher complication rate at reoperation. The aim of this experimental study was to investigate the anti-adhesion property of a bioabsorbable sheet following thoracotomy in a canine model.

METHODS: Ten adult beagle dogs underwent bilateral muscle-sparing thoracotomies with single ribs resected under general anaesthesia. A bioabsorbable sheet composed of poly-L-lactide copolymer (45 wt%) and ε-caprolactone (45 wt%) layered with polyglycolic acid (10 wt%) was sutured intrapleurally on the parietal pleura to cover the defect on the left, but not placed on the right side as a control. All the dogs were followed up with chest computed tomography until being sacrificed (6 months at the maximum). Thoracoscopic evaluations were performed at 1, 3 and 6 months for intrapleural adhesions at the thoracotomy site and absorption of the bioabsorbable sheet. The incidences of intrapleural adhesions were compared between the experimental side and the control side by the χ(2) test. Histological (macroscopic and microscopic) analyses of regenerated chest wall tissue were also performed at 1, 3 and 6 months.

RESULTS: All the dogs survived uneventfully until being sacrificed without any postoperative complications or significant radiological findings. The bioabsorbable sheet prevented intrapleural adhesions in all subjects. There were statistically significant differences in the incidence of intrapleural adhesions between the experimental side and the control side at the thoracotomy incision (0 vs 80%, P = 0.0014) at 1 month, (0 vs 66.7%, P = 0.014) at 3 months and (0 vs 75%, P = 0.028) at 6 months. The bioabsorbable sheet was found residual at 1, 3 and 6 months in all subjects. Histological analyses confirmed regenerated chest wall layers with significantly more capillary vessels at 1 month (P = 0.015), but not at 3 and 6 months (P = 0.84 and 0.41, respectively), in the regenerated mucosal and submucosal layers on the experimental side.

CONCLUSIONS: Our findings suggest that the bioabsorbable sheet may prevent intrapleural adhesions with parietal pleurae regenerated with more vascularization at 1 month following thoracotomy. No adverse findings were noted with the sheet.