A new, simple stapling technique for pulmonary emphysema: its effects and safety for improving respiratory function.

PURPOSE: We performed lung volume reduction surgery (LVRS) in an experimental model using a simple stapling technique (SST) for pulmonary emphysema. The technique uses a stapler to isolate the affected lung from the remaining lung instead of removing it. We performed the present experiment using dogs to study the effects and safety of LVRS using the SST. METHODS: Pulmonary emphysema was induced in 12 dogs with papain. They were divided into three groups: those operated on with SST composed the operation (Op) group; those receiving an experimental thoracotomy composed the sham-operation (Sham-op) group; and those not operated on composed the nonoperation (Non-op) group. Respiratory function was compared among the groups before induction of emphysema (baseline), after induction of emphysema (preoperation), and at 8 weeks after the operation (postoperation Op and Sham-op groups only). The lung was removed and histologically examined 8 weeks after the SST operation. RESULTS: In the Op group, alteration in forced expiratory volume (FEV) 0.5%, airway resistance (Raw) and specific airway conductance (sGaw) showed significantly favorable results. Histologically, the isolated area was widely replaced by fibrous tissue with numerous blood vessels in the circumference in the Op group; no signs of infection such as polykaryoleukocytes or microabscesses were observed in any of the samples. CONCLUSION: The LVRS for pulmonary emphysema using a simple stapling technique improved the expiratory flow and alleviated airway resistance. The isolated remaining lung was well organized without any infectious events or secondary adversity, thus demonstrating the safety of this technique. From these results, this technique is therefore suggested to be effective and applicable to clinical use.

Improved healing of small-caliber, long-fibril expanded polytetrafluoroethylene vascular grafts by covalent bonding of fibronectin.

PURPOSE: To evaluate the intermediate performance of small-caliber, long-fibril expanded polytetrafluoroethylene (ePTFE) vascular grafts pretreated with covalent bonding of fibronectin in dogs. METHODS: Small-caliber (4 mm), long-fibril (60 microm), ePTFE vascular grafts, 10 cm in length, were pretreated by covalent bonding of fibronectin. Bilateral iliac grafting was done in dogs using a fibronectin-bonded graft on one side and a nonbonded control graft on the other side. The grafts were retrieved 12 weeks after implantation, and subjected to histomorphometric analysis. RESULTS: Although the patency rates of the fibronectin-bonded and control grafts were the same (3/7, 43%), the fibronectin-bonded grafts showed almost complete neointimal healing, whereas the nonbonded control grafts showed only partial neointimal healing, proximally and distally. CONCLUSIONS: Small-caliber, long-fibril ePTFE vascular grafts with covalent bonding of fibronectin achieved almost complete neointimal healing by the time of retrieval at 12 weeks. This indicates that, with further modifications, our new technique for covalent bonding of fibronectin has great potential in the development of small-caliber arterial prosthetic grafts.

Relationship between fibril length and tissue ingrowth in the healing of expanded polytetrafluoroethylene grafts.

PURPOSE: To determine whether fibril length is correlated with graft healing as well as cellular and capillary ingrowth in a canine carotid implantation model. METHODS: Expanded polytetrafluoroethylene (ePTFE) vascular grafts with three different fibril lengths (30, 60, and 90 microm) were implanted into the carotid artery in dogs. They were retrieved 4 weeks later, and subjected to histomorphometric analysis. RESULTS: Endothelial healing was best in the 60-microm grafts. Not only cellular ingrowth but also capillary ingrowth was most evident in the 60-microm grafts, followed by the 90-microm grafts and then the 30-microm grafts. CONCLUSION: Better endothelial healing of ePTFE vascular grafts is correlated with more cellular and capillary ingrowth, but more cellular and capillary ingrowth is not correlated with longer fibril length or higher air porosity.