Elsevier

World Neurosurgery

Volume 84, Issue 2, August 2015, Pages 475-482
World Neurosurgery

Original Article
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

https://doi.org/10.1016/j.wneu.2015.03.060Get rights and content

Objective

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.

Methods

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.

Results

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.

Conclusions

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.

Introduction

In the International Subarachnoid Aneurysm Trial, basilar apex aneurysm (BAA) (23), in addition to the size of the aneurysm, was the strongest predictor of hemorrhage. In the same study, posterior circulation location was a significant predictor of worse clinical outcome after surgical and endovascular treatment. Neurosurgeons have considered BAA to be the most difficult vascular lesion to surgically treat (27). Because of its deep and narrow location and the fact that it is hindered by different neurovascular structures, endovascular therapy has largely replaced microsurgical clipping, especially in Europe (27). However, not all of these lesions are amenable to endovascular treatment and the problem of postcoiling recanalization also persists for even small BAAs (30).

To date, risk factors, which were related to clinical and surgical outcomes, have remained to be unknown. The aim of this study was to evaluate the relationship between aneurysm morphology and clinical and surgical outcomes in patients with complex unruptured BAAs who were treated with neck clipping.

Section snippets

Material and Methods

The study is reported on the basis of criteria from the STROBE (Strengthening the Reporting of Observational Study in Epidemiology) statement (33). The study protocol was approved by the institutional ethics committee.

We evaluated 23 patients who underwent neck clipping of complex unruptured BAAs at the Teishinkai Hospital between April 2012 and July 2014. BAAs with neck >4 mm, posterior projection, retro/subsellar, and dome-to-neck ratios <1.2 were considered as complex BAA 4, 24. Superior

Results

The mean age of the patient population was 61 ± 9.9 years, and all patients were women. Eleven patients (48%) presented with minor headache or vertigo. One (4.3%) had suffered a previous subarachnoid hemorrhage caused by rupture of another aneurysm. In five patients (22%), the aneurysms were discovered during work-up for the health check-up. In one patient each (4.3%), the aneurysm was discovered as part of an evaluation for a meningioma, Bell's palsy, oculomotor nerve palsy, lacuna infarction,

Discussion

The present study showed that aneurysm localization in the interpeduncular cistern was related to thalamoperforators' ischemia, poor outcome, and continued oculomotor nerve palsy in patients with complex unruptured BAA who were treated with neck clipping by anterior temporal approach.

Conclusions

The results of the present study showed that the anterior temporal approach may increase the safety of the surgical steps and ameliorate the predictability of the surgical and clinical outcomes of clipping for complex unruptured BAA, although it should be improved, and that unruptured BAA patients whose aneurysm were located in the interpeduncular cistern should be meticulously treated when clipping because it was related to thalamoperforators' ischemia, poor outcome, and continued oculomotor

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    Conflict of interest statement: We declare that the manuscript is original, has not been published before, and is not currently being considered for publication elsewhere. We confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome. This manuscript has been read and approved by all named authors.

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