Recurrent subarachnoid haemorrhage from an angiographically occult large distal pica aneurysm

Surgical management of ruptured and unruptured symptomatic posterior inferior cerebellar artery aneurysms

This retrospective study analyses the outcome of posterior inferior cerebellar artery aneurysms treated surgically. Thirteen consecutive ruptured and unruptured PICA aneurysm patients from January 1998 to January 2004 were reviewed retrospectively. The mean age was 49.1 +/- 7.4 years. Three were unruptured aneurysms and ten presented with acute subarachnoid haemorrahge. Surgery was performed immediately after completed 4 vessel angiograms using the far lateral approach. Eight were fusiform while five were saccular aneurysms. The saccular aneurysms were clipped. Treatment of the fusiform aneurysms included 3 trappings and three proximal clippings. One patient refused surgery and had endovascular occlusion of a giant PICA aneurysm. Eight out of ten (80%) operated patients needed CSF shunting for hydrocephalus. All check angiograms during follow up demonstrated adequate exclusion of the aneurysms from the circulation. None developed the PICA syndrome clinically or showed infarction on brain scans. All good grade patients recovered without neurological deficits. Our experience showed that early surgery for ruptured PICA aneurysm carries a good prognosis with low morbidity. In aneurysms that cannot be clipped, sacrifice of the PICA without revascularisation procedures in proximally located PICA aneurysms may still be feasible if the occlusion is done distal to the perforators.

Distal posterior inferior cerebellar artery aneurysms: clinical features and management

OBJECT

Aneurysms located on the distal portion of the posterior inferior cerebellar artery (PICA) are uncommon, and their underlying pathology, natural history, and clinical management are poorly understood. To clarify these lesions more fully, the authors undertook a retrospective analysis of the clinical features and management results of 22 distal PICA aneurysms in 20 consecutive patients treated at one institution by the same surgeon during the past decade.

METHODS

The series included 10 men and 10 women (mean age at presentation 51 years). Nine patients presented with only subarachnoid and/or intraventricular hemorrhage (median Hunt and Hess Grade II). In seven patients intracerebellar hemorrhage was also found; two patients presented with pressure effects and two hemorrhages were incidentally discovered. Prominent comorbidities included cigarette smoking (50%) and hypertension (50%). The 13 saccular and nine fusiform distal PICA aneurysms were distributed on the following segments of the PICA: lateral medullary (seven lesions), tonsillomedullary (five lesions), telovelotonsillar (five lesions), and cortical (five lesions). Six oases were associated with cerebellar arteriovenous malformations. Skull-base and far-lateral transcondylar surgical approaches were used to secure the aneurysms in 86% of cases, either by direct clipping (13 lesions), vessel sacrifice (four lesions), or vessel sacrifice plus bypass (two lesions). Two aneurysms were treated using endovascular PICA ablation. Overall outcome at hospital discharge was excellent or good in 70% of cases. At long-term follow up (100% of patients, mean 123 days), an excellent or good outcome had been achieved in 85% of cases.

CONCLUSIONS

Depending on the PICA segment that was affected, variations in clipping strategies and surgical exposures aimed at the PICA branch and main trunk preservation were major contributors to good long-term results.

Aneurysmal and microaneurysmal "angiogram-negative" subarachnoid hemorrhage

The source of bleeding remains obscure in most cases of subarachnoid hemorrhage (SAH) with a negative angiogram. From January 1, 1989, to July 1, 1993, 40 patients were admitted to the Massachusetts General Hospital with angiogram-negative SAH; 9 of these patients underwent surgical exploration. In seven of these explorations, an arterial source of the hemorrhage was discovered. These arterial sources included three anterior communicating artery complex lesions, two middle cerebral artery lesions, one internal carotid artery aneurysm arising at the origin of the posterior communicating artery, and one vertebral/posterior inferior cerebellar artery aneurysm. Three of these seven lesions had small aneurysmal sacs, but the other four were microaneurysms too small to accept a surgical clip. No source of hemorrhage could be found during surgery on one patient with a perimesencephalic pattern of blood. Two of the four patients with a microaneurysmal source of hemorrhage had two episodes of SAH. We propose that microaneurysms are the source of a significant percentage of nonperimesencephalic angiogram-negative SAH and suggest that these lesions may represent a forme fruste of saccular aneurysms. These findings lead us to propose a protocol for the management of angiogram-negative SAH based on the distribution of blood as seen on the patient's first computed tomogram.

Acute lacunar stroke in association with angiogram-negative subarachnoid hemorrhage. Mechanistic implications of two cases

BACKGROUND AND PURPOSE

Although there is much speculation regarding the source of bleeding in patients with subarachnoid hemorrhage when no angiographic abnormality is found, little direct evidence has been obtained to document a cause. We report two cases of stroke in the distribution of a perforating or lenticulostriate artery occurring at the time of angiogram-negative subarachnoid hemorrhage.

CASE DESCRIPTIONS

A 68- and a 60-year-old man each presented with acute onset of headache and meningismus. Computed tomography (CT) revealed subarachnoid hemorrhage in a perimesencephalic pattern and in the left sylvian fissure, respectively. In both instances, immediate CT revealed evidence of an early infarction in the distribution of a perforating artery originating at the site of the subarachnoid blood. Both of these strokes were demonstrated to be acute by evolution on serial imaging studies. No source for the subarachnoid blood could be found in either patient in cerebral angiograms repeated at 2 weeks.

CONCLUSIONS

These observations suggest that in some cases of angiogram-negative subarachnoid hemorrhage the source of blood may be a small artery that is obliterated at the time of hemorrhage. This observation provides an explanation for the low rate of rehemorrhage among patients with angiogram-negative subarachnoid hemorrhage.