Relationship between abducens nerve palsy and local hematoma in a case series of ruptured vertebral artery dissecting aneurysm

Abstract

Background: Abducens nerve palsy associated with subarachnoid hemorrhage (SAH) has rarely been reported. Its frequency, mechanism of palsy, association with aneurysmal location, and clinical course are poorly described. The purpose of our study was to evaluate patients with abducens nerve palsy caused by SAH occurring from ruptured vertebral artery (VA) dissecting aneurysm and to find aneurysmal location using initial computed tomography (CT) and its association with clinically detected cranial nerve palsy. Methods: Fourteen patients of SAH due to ruptured VA dissecting aneurysm were treated at our hospital from January 2011 to May 2015. The clinical courses and CT findings were reviewed retrospectively. Results: Abducens nerve palsy was observed in 77.8% of cases after excluding patients with decreased levels of consciousness. Clots within the prepontine cistern were significantly thicker in cases of VA dissecting aneurysm than in case of supratentorial aneurysm (P = 0.002). Conclusion: The findings of our study indicated that ruptured VA dissecting aneurysms, even in cases of angio-negative SAH, are likely to present with abducens nerve palsy.

Clinical Course of Abducens Nerve Palsy in Patients with Ruptured Vertebral Artery Dissecting Aneurysms

“…The time of the diagnosis of abducens nerve palsy and the time needed until complete recovery were comparable with those in previous reports. 2 , 5) On the other hand, although complete recovery from abducens nerve palsy might be expected in 71–89% of patients, 2 , 3) complete recovery was observed in only 3 (27.3%) in this study. Although the comparison is difficult because of the absence of reports of the long-term outcome of abducens nerve palsy exclusively in VADA patients with a favorable outcome, the small number of patients with complete recovery in this study might be partly explained by the possibility of detailed questioning about diplopia in all patients, which enabled us to evaluate the presence of abducens nerve palsy more carefully.…”

“…The incidence of abducens nerve palsy that complicates VADA causing SAH was reported to be 26.9–50.0%, 2 , 5) but the abducens nerve palsy cannot be accurately evaluated in many patients because patients with a poor outcome cannot respond to verbal commands and examination of ocular motility is difficult. 2 , 5) In addition, patients in whom abducens nerve palsy poses problems in daily living after treatment are usually mild cases in which walking is possible, and accurate evaluation is possible in such cases. For that reason, patients with mRS ≤3 were thus evaluated as the subjects in this study.…”

“…1 ). 5) Symptomatic cerebral vasospasm was defined as cerebral arterial narrowing diagnosed by CTA or DSA in patients with new neurological deteriorations during acute management of SAH. According to these findings, the patients were divided into those with abducens nerve palsy (palsy [+] group) and those without abducens nerve palsy (palsy [−] group), and differences in the clinical features and detailed clinical characteristics in the palsy (+) group were retrospectively evaluated.…”

“… 2 – 4) In particular, it complicates vertebral artery dissecting aneurysm (VADA) with SAH at a rate of 26.9–50.0%. 2 , 5) VADA is often treated with endovascular surgery, which is considered to be less invasive. 6) Despite this advantage, abducens nerve palsy persists in many patients after endovascular surgery, and there have been few reports about its frequency or long-term outcome.…”

“…In patients with severe SAH, the examination and follow-up of abducens nerve palsy are difficult. 2 , 5) In this study, we evaluated the incidence, risk factors, and clinical course of abducens nerve palsy that developed in patients who had VADA with hemorrhagic onset and were treated with endovascular surgery.…”