A protocol for the reduction of applied torque on parent vessel duringelastase-induced aneurysm formation using rabbit animal models

Endovascular therapies for intracranial aneurysms requires animal models for testing the safety and effectiveness prior to translation to the clinic. Rabbits combined with the elastase and right common carotid artery (RCCA) ligation methods is currently a widely used animal model for endovascular device testing. However, the injection of elastase utilizing angiocatheters may potentially exerts adverse torque to the parent vessel and the optimal aneurysm creation period has not been well investigated. In this study, we present a modification to the elastase/RCCA-ligation method by replacing the angio-catheter with a butterfly catheter. Formation of saccular aneurysms was introduced in New Zealand white rabbits (n = 6), and were maintained for 2, 4 and 6 weeks. The formed aneurysms exhibited an elongated geometry and were stable during the study period. We found that the modification in the animal surgery procedure provides improved manipulation of the surgical area, prolonged injection of elastase, and effective degradation of the vascular elastic lamina. Compared to the traditional elastase/RCCA-ligation method, the present technique can more effectively reduce unwanted injury to the parent vessel and, therefore, improved stability of the vasculature for testing the efficacy of newly developed endovascular embolization devices.