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  • Author or Editor: Rafael J. Tamargo x
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Ingrid M. Burger, Rafael J. Tamargo, Jennifer Broussard and Philippe Gailloud

✓The authors report on the case of a 28-year-old woman presenting with an intraosseous arteriovenous fistula (AVF) located in the left parietal bone. The fistula was formed by direct arteriovenous shunts connecting branches of the left middle meningeal and superficial temporal arteries with a parietal diploic vein. Drainage occurred through both the external and internal jugular venous systems. Therapy consisted of combined surgical and endovascular approaches. The results of a pathological examination of the resected AVF showed mild enlargement of the diploic space. The angiographic appearance, pathological anatomy, and treatment of this rare lesion are discussed, as is a possible relationship between diploic AVFs and the development of aneurysm bone cysts.

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Edison P. Valle, Rafael J. Tamargo and Philippe Gailloud

The cases of 2 children with true aneurysmal subarachnoid hemorrhages (SAHs) and initial false-negative angiograms are reported. In both cases, the initial angiogram was of adequate technical quality and included the projections on which aneurysms were later documented. There was no significant vasospasm at the time of initial angiography; therefore, transient aneurysm sac thrombosis was the most likely explanation for the initial false-negative studies. It is particularly interesting to note that 1 of the 2 patients had a pattern of hemorrhage compatible with the most limited definition of a perimesencephalic SAH, that is, a small prepontine cistern hemorrhage. If a second angiogram had been deemed unnecessary based on that criterion alone, a ruptured basilar tip aneurysm would have escaped detection and treatment.

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Rush H. Chewning, A. Daniel Sasson, Lori C. Jordan, Rafael J. Tamargo and Philippe Gailloud

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Richard E. Clatterbuck, Philippe Gailloud, Travis Tierney, Victoria M. Clatterbuck, Kieran J. Murphy and Rafael J. Tamargo

Object. Results of prior studies in rats and rabbits show that the alteration of vasomotor tone in vasospasm following periadventitial blood exposure may be reversed, at least in part, by the administration of compounds releasing nitric oxide (NO). The authors have now generalized this finding to nonhuman primates.

Methods. Ten cynomolgus monkeys underwent cerebral angiography before and 7 days following the induction of subarachnoid hemorrhage (SAH) by the placement of 2 to 3 ml clotted autologous blood around the supraclinoid carotid, proximal anterior cerebral, and proximal middle cerebral arteries. An ethylene vinyl acetate copolymer, either blank (five animals) or containing 20% w/w (Z)-1-[2-(2-aminoethyl)-N-(2-aminoethyl)amino]diazen-1-ium-1,2-diolate (DETA/NO, 4.3 mg/kg; five animals) was placed adjacent to the vessels at the time of surgery. Animals were killed on Day 7 post-SAH following repeated cerebral angiography. The mean percentage of control vascular areal fraction was calculated from angiograms. Cerebral vessels were sectioned and the mean percentage of lumen patency was calculated.

One animal that had received the DETA/NO polymer died prior to repeated angiography. In the remaining animals, DETA/NO caused a significant decrease in vasospasm compared with controls, according to both angiographic (84.8 ± 8.6 compared with 56.6 ± 5.2%, respectively, p < 0.05) and histological studies (internal carotid artery 99.3 ± 1.8 compared with 60.1 ± 4.4%, respectively, p < 0.001; middle cerebral artery 98.4 ± 3 compared with 56.1 ± 3.7%, respectively, p < 0.001; and anterior cerebral artery 89.2 ± 8.5 compared with 55.8 ± 6.3%, respectively, p < 0.05).

Conclusions. The controlled release of DETA/NO is effective in preventing delayed cerebral vasospasm in an SAH model in nonhuman primates. The death of one animal in the treatment group indicates that the present dosage is at the threshold between therapeutic efficacy and toxicity.

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Richard E. Clatterbuck, Philippe Gailloud, Lynn Ogata, Abeyu Gebremariam, Gregory N. Dietsch, Kieran J. Murphy and Rafael J. Tamargo

Object. Leukocyte—endothelial cell interactions occurring in the first hours after subarachnoid hemorrhage (SAH) initiate changes in the endothelium and vessel wall that lead to an influx of leukocytes and the development of chronic vasospasm days later. Upregulation of intercellular adhesion molecule—1 (ICAM-1), also called CD54, appears to be a crucial step in this process. There is increasing experimental evidence that blocking the interaction between ICAM-1, which is expressed on endothelium, and integrins such as lymphocyte function—associated antigen—1 (CD11a/CD18) and macrophage antigen—1 (complement receptor 3, CD11b/CD18), which are expressed on the surface of leukocytes, prevents not only inflammation of vessel walls but also chronic vasospasm. The authors extend their previous work with monoclonal antibody (mAb) blockade of leukocyte migration to a nonhuman primate model of chronic, posthemorrhagic cerebral vasospasm.

Methods. Before surgery was performed, six young adult male cynomolgus monkeys underwent baseline selective biplane common carotid and vertebrobasilar artery cerebral angiography via a transfemoral route. On Day 0, a right frontosphenotemporal craniectomy was performed with arachnoid microdissection and placement of 2 to 3 ml of clotted autologous blood in the ipsilateral basal cisterns. The animals were given daily intravenous infusions of 2 mg/kg of either a humanized anti-CD11/CD18 or a placebo mAb beginning 30 to 60 minutes postoperatively. The monkeys were killed on Day 7 after a repeated selective cerebral angiogram was obtained. The area of contrast-containing vessels observed in each hemisphere on anteroposterior angiographic views was calculated for the angiograms obtained on Day 7 and expressed as a percentage of the area on baseline angiograms (percent control areal fraction). Review of flow cytometry and enzyme immunoassay data confirmed the presence of the anti-CD11/CD18 antibody in the serum and bound to leukocytes in the peripheral blood of treated animals. Comparisons of the groups revealed 53 ± 4.8% control vascular areal fraction in the placebo group (two animals) and 95.8 ± 9.4% in the anti-CD11/CD18—treated group (three animals), a statistically significant difference (p = 0.043, t-test).

Conclusions. These results show that blockade of leukocyte migration into the subarachnoid space by an anti-CD11/CD18 mAb is effective in preventing experimental cerebral vasospasm in nonhuman primates, despite the unaltered presence of hemoglobin in the subarachnoid space. These experimental data support the hypothesis that inflammation plays a role in cerebral vasospasm after SAH.

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Geoffrey P. Colby, Alexander L. Coon, Daniel M. Sciubba, Ali Bydon, Philippe Gailloud and Rafael J. Tamargo

Spinal dural arteriovenous fistulas (DAVFs) are the most common type of spinal arteriovenous malformation and are an important, underdiagnosed cause of progressive myelopathy and morbidity in patients with spine disorders. Successful microsurgical management of these lesions is dependent on the surgeon's ability to identify vessels of the fistula and to confirm its successful obliteration postintervention. Indocyanine green (ICG) fluorescent angiography is an emerging tool for delineating intraoperative vascular anatomy, and it has significant potential utility in the treatment of vascular disease in the spine.

The authors present the case of a 76-year-old man with progressive and debilitating bilateral lower-extremity weakness and numbness on exertion, in whom a left T-8 spinal DAVF was diagnosed based on results of conventional spinal angiography. Unfavorable anatomy based on angiographic findings precluded endovascular embolization of the fistula, and the patient subsequently underwent T7–9 bilateral laminectomies for microsurgical clip occlusion. Intraoperative ICG fluorescent angiography was used before clip placement to identify the arterialized veins of the fistula, and after clip placement to confirm obliteration of the fistulous connection and restoration of normal blood flow.

Intraoperative ICG angiography serves an important role in the microsurgical treatment of DAVF. It can be used to map the anatomy of the fistula in real time during surgery and to verify fistula obliteration rapidly after clip placement. This report adds to the growing body of literature demonstrating the importance of ICG angiography in vascular neurosurgery of the spine.