Evaluation of Anastomosis Efficiency in Arteriovenous Shunts Created by Using Hand-Sewn Microsurgery and Microvascular Anastomotic Coupler Device.

OBJECTIVE: Microsurgery has made great contributions to the advancement of surgery. In parallel with the developments in microsurgery, various techniques have been developed to perfect the technique. Microvascular anastomotic coupler device (MACD) is one of these techniques. The aim of the study was to evaluate the effectiveness of anastomoses created by using hand-sewn microsurgery (HSM) and MACD. METHODS: Twenty male Sprague-Dawley rats weighing 250 to 300 g were divided into 2 groups randomly. Arteriovenous shunt was performed between carotid artery and internal jugular vein with the principles of HSM in the first group (n=10) and by using the 1-mm anastomotic microvascular device in the second group (n=10). Groups were evaluated for anastomose time, success of anastomosis, thrombosis formation, color Doppler ultrasonography, and histopathological features. RESULTS: Anastomotic time was faster with the coupler device compared with HSM technique. Flow rates were found significantly higher in the MACD group. Endothelialization and wall integrity rates were better in MACD group. CONCLUSIONS: Microvascular anastomotic coupler device is faster than HSM. High quality and durability of vascularization, insignificant foreign body reactions are histopathological advantages of MACD.

Comparison of different methods of circumferential tracheal reconstruction: an experimental study.

OBJECTIVES: This study was designed to compare different prefabrication models for circumferential tracheal reconstruction. MATERIALS AND METHODS: Thirty adult female New Zealand rabbits were divided into six groups for circumferential tracheal reconstruction with a different tissue combination. Prefabrication of neotrachea was performed without anastomosis. Lateral thoracic fascia or pectoralis major muscle were used for vascular supply. Polypropylene mesh, polytetrafluoroethylene (Gore-Tex), or cartilage rings were used for skeletal framework. Hairless epithelial skin graft was used for inner lining. The groups were compared in terms of viability of hairless epithelial graft, longitudinal flexibility, rigidity, flap wall thickness, internal diameter, and flap viability. RESULTS: Epithelial skin graft was almost totally viable (95%-99%) in the polypropylene mesh groups. Gore-Tex groups exhibited almost total necrosis (74%-71%). Longitudinal flexibility and rigidity were similar to the native trachea in Gore-Tex and polypropylene mesh groups. Neotrachea prefabricated with cartilage grafts showed more than normal longitudinal flexibility and collapsed easily. CONCLUSION: The prefabricated model with the use of polypropylene mesh for skeletal framework and lateral thoracic fascia for vascular supply seems to be the best alternative in the reconstruction of circumferential tracheal defects.

Circumferential trachea reconstruction with a prefabricated axial bio-synthetic flap: experimental study.

OBJECTIVE: The ideal method, in reconstruction of circumferential tracheal defects more than 50% of the total tracheal length, is still a question. Current methods lack either in epithelial lining or in skeletal framework. In this study, we designed an axial biosynthetic prefabricated flap to reconstruct the circumferential tracheal defects in rabbits. METHODS: Ten rabbits are used. The inner mucosal lining is substituted by hairless epithelium obtained from proximal ear. The tracheal cartilage is substituted by polypropylene mesh and the tracheal adventitia is substituted by lateral thoracic fascia as a vascular supply. The study is designed in three stages. Stage 1: Hairless epithelial graft is obtained by secondary healing of a full thickness skin defect in ear. Stage 2: Epithelial graft, polypropylene mesh and lateral thoracic fascia are tubed around a silicone catheter. This structure is dissected through its pedicle (lateral thoracic vessels and fascia) to the axilla and mobilized. The prefabricated neotrachea is carried on its pedicle to the cervical area through a subcutaneous tunnel formed superficial to the sternum and left there for 2 weeks. Stage 3: The silicone catheter is taken out and prefabricated neotrachea is adapted to the defect formed in native trachea and anastomized. Later the animals are evaluated for 4 weeks. The patency of the lumen, the viability of the epithelial graft and fascia, airtightness of the anastomoses and other features of the reconstruction are evaluated by radiological, macroscopical and histological examinations. RESULTS: Survival at 4 weeks was 70%. All of the prefabricated neotracheas and epithelial grafts were viable. The rigidities, longitudinal elasticities, diameters and wall thickness were similar to native tracheas. Occlusion of lumen is encountered only in one animal. There was no hair growth from the epithelial lining. CONCLUSION: The study defines a new method of circular tracheal reconstruction with successful substitution of inner lining, skeletal framework and vascular supply.