title: A synthetic bioabsorbable sheet may prevent postoperative intrapleural adhesions following thoracotomy: a canine model.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Bioartificial Organs, Graduate School of Medicine, Kyoto University, Kyoto, Japan Department of Thoracic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan mhamaji@kuhp.kyoto-u.ac.jp.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Hamaji
authors.affiliation: Department of Bioartificial Organs, Graduate School of Medicine, Kyoto University, Kyoto, Japan Department of Thoracic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Fumitsugu
authors.initials: F
authors.lastname: Kojima
authors.affiliation: Department of Bioartificial Organs, Graduate School of Medicine, Kyoto University, Kyoto, Japan Department of Thoracic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Teruya
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Center for Anatomical, Pathological and Forensic Medical Researches, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Tsuruyama
authors.affiliation: Department of Thoracic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Date
authors.affiliation: Department of Bioartificial Organs, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002208:Caproates / Q000737:chemistry; D004285:Dogs; D007783:Lactones / Q000737:chemistry; D023421:Models, Animal; D018919:Neovascularization, Physiologic; D010995:Pleural Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D011091:Polyesters / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013536:Suture Techniques; D013908:Thoracotomy / Q000009:adverse effects*; D013997:Time Factors; D000267:Tissue Adhesions; D014057:Tomography, X-Ray Computed; D058106:Wound Closure Techniques / Q000295:instrumentation*; D014945:Wound Healing
chemical_list: D002208:Caproates; D007783:Lactones; D011091:Polyesters; D011108:Polymers; D011100:Polyglycolic Acid; C033616:poly(lactide); C121056:caprolactone
keywords: Adhesion; Reoperation; Thoracotomy