Localization in the Interpeduncular Cistern as Risk Factors for the Thalamoperforators' Ischemia, Poor Outcome, and Oculomotor Nerve Palsy in Patients with Complex Unruptured Basilar Apex Aneurysm Treated with Neck Clipping

Abstract

We aimed to evaluate the relationship between aneurysm morphology, thalamoperforators' ischemia, outcome, and oculomotor nerve palsy (ONP) that continued during the follow-up period in 23 patients with complex unruptured basilar apex aneurysms (BAAs) treated with clipping. Aneurysm morphology included the size, distance of neck from the posterior clinoid process, dome projection, and localization in the interpeduncular cistern (LIC). BAAs with neck >4 mm, posterior projection, retro/subsellar, and dome-to-neck ratios <1.2 were considered as complex. The poor outcome was defined as modified Rankin Scale (mRS) 2-6 at the 12 months' follow-up examination. All patients were treated by anterior temporal approach. Size (P < 0.0001) and LIC (P < 0.0001) were related to thalamoperforators' ischemia (n = 3, 13%). Size (P = 0.0010), dividing-posterior communicating artery (P = 0.0050), thalamoperforator's ischemia (P = 0.034), and LIC (P < 0.0001) were related to poor outcome (mRS 2: n = 3, 13%). The mean follow-up period was 368 ± 52 days. No patients developed a bleed and showed evidence of any residual or recurrent aneurysm during follow-up. Postoperative ONP occurred in 15 patients (65%) and all were partial. During follow-up, full recovery of the ONP was seen in 13 patients (57%), and it continued in 2 (8.7%). Size (P = 0.010) and posterior projection (P = 0.043) and LIC (P = 0.0050) were related to continued ONP. The present study suggested that unruptured BAA patients with LIC should be meticulously treated in case of performing clipping because it was related to thalamoperforators' ischemia, poor outcome, and continued ONP.