Experimental Fusiform Aneurysm Model at Common Carotid Artery in Rat

ABSTRACT

PURPOSE: An ideal suturing material should be strong, easy to handle, should produce minimal tissue reaction and finally should disappear without a trace. Various micro-vascular suture materials have been produced in the past several decades in order to meet these demands. We have used nylon suturing material in experimental microsurgery because it is less expensive than polypropylene. After carotid artery end-to-end anstomosis, we found fusiform aneurysm incidentally. In this study 9-0 nylon (group I) and 9-0 polypropylene (group II) were compared to 10-0 nylon (group III), and 10-0 polypropylene (group IV) in order to survey the incidence of aneurysmal development in each material for use in microvascular surgery. METHOD: Forty Sprague-Dawley rats, 230 g to 350 g body weight, were used for this study. The carotid arteries were anastomosed end-to-end with 9-0 nylon, and 10-0 nylon, in addition to 9-0 polypropylene, and 10-0 polypropylene. The suture number of all arteries was 10 points except for two cases were 11 points due to uncontrolled bleeding. Specimens were harvested 1 week, 3 weeks, 6weeks and 10 weeks postoperatively. RESULT: The number of animals studied during the first week totaled 20 carotid arteries and they showed no interval change. After 3 weeks, we identified aneurysms in following cases group I 3 cases, group II 2 cases, group III 1 case and group IV 1 case per five cases in each group. After 6 weeks, gross aneurysmal changes seen group I, all (5) cases; Group II, 2 cases; group III, all (5) cases; Group IV, 3 cases. After 10 weeks, many aneurysms were observed group I, all (5) cases; group II, all (5) cases; group III, 0 case; group IV, 2 cases. The aneurysms were measured and ranged in size from 1.3 mm to 8.1 mm. Histological analysis for inflammation, fibrosis and medial necrosis at the anastomosis site revealed no significant difference between same sized suture materials. If the experimental aneurysms were more than 5 times the diameter of the carotid artery, the aneurysms were considered to be experimental giant aneurysms. Seventy of our 34 experimental aneurysms were considered to be giant aneurysms. CONCLUSION: Our findings demonstrate that the development of aneurysms was related to size of the suture material and not the type of suturing material used. An ideal suture material for anastomosisof the carotid artery in the rat wasd a 10-0 monofilament suture material with suture numbers was above 10 points. We also made good aneurysm model. When we used 9-0 suture material and suture numbers were below 10 points multiple aneurysms developed. This model demonstrated the development mechanism of giant fusiform aneurysms.