Microsurgical anatomy of the perforating branches of the vertebral artery

BACKGROUND There is limited data in the literature related to the microanatomic features of the perforating branches of the vertebral artery. METHODS The 44 vertebral arteries and their branches were injected with india ink or a radiopaque substance and examined under the stereoscopic microscope. RESULTS The perforating arteries were noted to range in number from 1 to 11 (mean, 6.5) and in diameter between 100 mum and 520 mum (average, 243 mum). They arose from the vertebral artery (VA) (54.54%), 8 from the right, the left or both VAs. The anterior spinal artery (ASA), which was singular (81.82%), duplicated (13.64%), or plexiform (4.55%), always gave rise to the perforators. The vascular roots of the ASA were the source of the perforators in 95.45% of the brains. The latter vessels arose from the anterolateral arteries in 50% of the cases. The anastomoses involving the perforators, which were present in 40.91% of the brains, varied in diameter between 100 mum and 350 mum (mean, 169 mum). The perforating vessels gave rise to the side branches in 95.45% of the brains that varied in diameter from 100 mum to 300 mum (average, 161 mum). The perforators usually entered the foramen cecum and the anterior median sulcus, and then continued close and parallel to the raphe of the medulla. The perforators can be compressed by a VA aneurysm, which was found in one among the 71 examined patients with cerebral aneurysms. CONCLUSIONS The obtained data give additional information about the vascular anatomy of the pontomedullary region. (C) 2004 Elsevier Inc. All rights reserved.