Aneurysms of the Posterior Cerebral Artery

NEURYSMS of the posterior cerebral artery are unusual; their surgical treatment demands great care for the central perforating branches of this vessel irrigate the midbrain and thalamus while the main trunk nourishes the optic radiation and visual cortex. Experience has been gained with eight cases of which six were operated on, with one death (Table 1 and Fig. 1). Although there were no field defects, one patient had an incomplete hemisensory deficit and another developed a delayed hemiplegia from postoperative temporal lobe swelling. Aneurysms arise from the posterior cerebral artery most commonly at the first major branching as it winds around the midbrain hidden under the hippocampal gyrus; more rarely, they arise from the first portion of the posterior cerebral artery in front of the crus cerebri at or near the junction with the posterior communicating artery. Their incidence in the Co-operative Study ~ was 22 in 2672 cases (0.8%). Undoubtedly this figure is too low, in that vertebral angiography was done in only 27 % of cases. None of our cases had multiple aneurysms, although in Case 8 there was an associated arteriovenous malformation in the ipsilateral occipital lobe. There are very few reports of surgical treatment of posterior cerebral aneurysms except for isolated cases. 1,3,~ Of those cases cited in the Co-operative Study, 5 four were operated on directly and two died; one did well and the other survivor was disabled.