Study Of The Rabbit Model Of Dural Arteriovenous Fistula(DAVF)

Purpose: The two, venous hypertension and dural sinus thrombosis, may be the major factors which can induce dural arteriovenous fistula (DAVF). The level of estrogen in a body has been described as a probably important precipitating cause of DAVF also. This study is mainly about the relationship of the change of venous hypertension or sex hormone and the formation of DAVF Through the direct anastomosis between the artery and the vein in the neck. Method: Forty male and forty female Chinese rabbits, each weighing approximately from 2.0 to 2.5 Kg and about 4 to 6 months old, were used for this study. In 10 Group A rabbits (Sham-operated group), both of the external and the internal jugular vein were unobstructe~i In 10 Group B rabbits (Simple ligation group), both of the external and the internal jugular vein were obstructed without anastomosis of the vein and the artery in the neck. In 20 Group C rabbits (AVF I group), both of the external and the internal jugular vein were obstructed and the right external jugular vein were anastomosed to the collateral common carotid artery in an end-to- side fashion, using 10-0 microsutures. In 20 Group D rabbits (AVF II group), the same operations were performed except that the right internal jugular vein, which took the place of the external carotid artery, was anastomosed to the -4---- E梸k~ 97 眫kIt~ collateral common carotid artery in an end-to-side fashion. In 10 Group E and 10 Group F rabbits, both of the external and the internal jugular vein were unobstructed, estrogen or androgen was used to all the rabbits in these two group through the deep muscle injection. Each of the animals was measured for its basic system signs including RR.. HR.. MABP~ EJVP and EJVD for four times, as is the right before the operation, one month, two month and three month after the operation. Three months later, cerebral vascular angiography was performed in every animals and then the dural sinuses were avulsed and their sections stained by hematoxylin and eosin and examined by light microscopy Results: New acquired AVF developed in four (20.00/c) of the 20 rabbits in Group C, and one (5.0%) of the 20 rabbits in Group D. EJVP and EJVD were elevated significantly in both of the two groups. Histopathological findings of the dural AVF sinus showed thickening of the sinus walls with formation of many small vessels present within the sinus wall itself. The direct evidence of DAVF was obtained in one of the animals in Group C. There are no different happenning ratios between the male and the female animals. Conclusion: The venous hypertention can be obtained obviously through the direct anastomosis between the vein and the artery in the neck and it can induce DAVF in several animals. There have no difference between the happening ratio of DAVF in male and female ones. DAVF can not be induced by simply injection of estrogen or androgen. The 4 anatomy basis of the DAVF is dural artery opened to the sinus directly.