We report a new variation of the well-established experimental arteriovenous malformation (AVM) model in swine. To provide high flow through the rete mirabile (nidus, RM) and thereby to reduce the rate of spontaneous thrombosis of the AVM, we performed an end-to-end anastomosis of the left common carotid artery (CCA) and the external jugular vein (EJV) microsurgically in three micropigs. After 1 and 4 months the animals underwent angiograms of the CCA and vertebral artery (VA). In all cases the diversion of the blood through the RM was patent, up to the 4 months follow-up. We observed an arteriovenous fistula (arteriovenous pseudomalformation, pAVF) between the VA and the EJV in each case at both 1 and 4 months. This modification of the well-known AVM model in the micropig could be used to monitor long-term changes after embolisation, avoiding the naturally high rate of spontaneous thrombosis. This two-in-one model is thus well suited for preclinical testing of embolic materials.
Giant intracranial aneurysms, especially giant aneurysms of the distal posterior inferior cerebellar artery (PICA), remain the most difficult and challenging cerebrovascular lesions for neurosurgeons to treat. The morbidity and mortality rates of microsurgical clipping are relatively high, and endovascular embolization is also associated with many complications. In the present report, the case of a 46-year-old female patient who presented with headache and dizziness for 3 years, which was aggravated and combined with limb weakness for 1 day, is presented. A CT scan showed a lesion occupying the fourth ventricle, with slight bleeding. A MR scan also revealed a lesion occupying the fourth ventricle and compressing the brainstem, and there was distortion of the cisterns around the brainstem. CT angiography examination showed a giant irregular aneurysm located in the PICA. After evaluation, the PICA aneurysm was removed, and the PICA was clipped via a microsurgical technique without ischemia or neurological sequelae. Long-term follow-up demonstrated that the symptoms of headache and dizziness disappeared without relapse. Based on a review of the literature, this method may represent an alternative strategy for the treatment of giant PICA aneurysms, especially for aneurysms not suitable for direct clipping or endovascular embolization.
The well-known porcine arteriovenous malformation (AVM) model introduced by Massoud et al has been widely used as an acute-phase model. However, there are no data available on the patency rate in long-term follow-up. Therefore this study is dedicated to the natural history of porcine AVM model after creation. Three piglets (Yucatan micropigs, aged 12 to 14 months) were used in this study. The model was created by microsurgical anastomosis in an end-to-end fashion between the common carotid artery (CCA) and external jugular vein (EJV) on the left side, and by direct ligation of the left external carotid artery (ECA). Angiography was performed before and immediately after model creation, as well as at 44, 103, 188 and 245 days in all animals. A successful high-flow brain AVM model was established in all animals. The fistula created by end-to-end anastomosis remained intact and thus the successful AVM model maintained in all models over a follow-up period as long as more than eight months. The AVM-model in swine could be used as a chronic model to test the neurointerventional techniques of AVM treatment. We re-created the well known AVM-model by a terminal anastomosis between CCA and EJV and we hypothesize that the good long-term patency of the model is related to the type of anastomosis performed between CCA and EJV.
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