Posterior communicating artery section during surgery for basilar tip aneurysm.

Although dividing the posterior communicating artery (PComA) during surgery has been criticized for increasing the risk of ischaemia, this procedure increase working space improving visibility and the ability to manipulate during treatment of basilar tip aneurysms via the pterional approach. We divided a hypoplastic PComA in 4 of our cases of basilar tip aneurysm. This was necessary because either (1) the length of the PComA and intracranial internal carotid artery (ICA) limited medial retraction of the ICA and access to the basilar bifurcation region, or (2) the PComA and its perforators ran just in front of the aneurysm, interfering with its exposure. We were able to clip the aneurysm neck in all four patients, three of whom had complications including temporary impairment of consciousness, ocular movement disorders and altered sensation in the extremities. Patients with complications showed transient hypersomnolence immediately after surgery; computed tomography showed small thalamic infarctions. However, in two of three patients the ischaemic events occurred contralateral to the side of PComA section. All patients regained consciousness within a week and were discharged with mild ocular movement palsies. In our cases except one with ischaemic complications, thalamic infarction probably resulted from thalamo-perforating artery injury when the aneurysm neck was clipped, rather than tuberothalamic artery injury due to section of the PComA. Taking previous reports and our results into consideration, we believe that division of a hypoplastic PComA is a safe procedure in particular cases when the grade of subarachnoid haemorrhage is not poor and there are no cerebrovascular risk factors, although we realize it is desirable to preserve normal blood flow.