Management of Posterior Inferior Cerebellar Artery Aneurysms: A Single Institution Retrospective Analysis (1989-2007)

Yeo, Seok Kon; Kwon, Do Hoon; Ahn, Jae Sung; Jin, Sung Chul; Kim, Hyun Jung; Kwun, Byung Duk

Abstract

OBJECTIVE
The incidence of posterior inferior cerebellar artery (PICA) aneurysms is rare, and neurosurgeons have found that the direct open surgical approach for PICA aneurysms is challenging. [0]We analyzed the results of treating posterior inferior cerebellar artery (PICA) aneurysms by embolization or by open surgery.
METHODS
41 patients (1% of all the aneurysms treated; 13 (32%) men, 18 (68%) women; mean age: 55.5 yr) with ruptured or unruptured PICA aneurysms underwent treatment at our hospital. The clinical outcomes of these patients were studied retrospectively by using the medical records and the neuroimaging studies.
RESULTS
The sites of PICA aneurysms were at the junction of the vertebral artery and PICA (63%), the lateral medullary segment (7%), the tosillomedullary segment (10%), the telovelotonsillar segment (13%) and the cortical segment (7%). The shapes of the PICA aneurysm were either the saccular type (85%) or the fusiform type (15%). 25 patients with PICA aneurysm underwent surgical treatment and 16 patients with PICA aneurysms underwent endovascular treatment. Open surgery was used more often to treat a distal PICA than an endovascular procedure. Within the open surgery group, 24% of the patients received the Hunt and Hess (HH) grades IV and V, whereas among the endovascular-treated patients, 37.5% of the patient had HH IV and V grades. Twenty eight percent of the patients In the surgery group achieved a Glasgow Outcome Scale (GOS) score of I through III, and 72% patients had gained a GOS score IV or V. For the endovascular-treated patients, 37% of these patients achieved a GOS score of I through III and 63% patients gained a GOS score IV or V.
CONCLUSION
We found that the open surgery patients had better clinical outcomes than the endovascular treated patients and they especially achieved higher HH grades. However, Fisher's exact test and Chi-square tests did not show any statistically significant difference between the two groups (p=0.49, which is explained by the selection bias). In the previous literature, the predictors of the outcome for intracranial aneurysms, such as age, the size of the aneurysms, the HH grade and the Fisher grade showed statistical significance for the GOS grade. Yet in our study, we showed that there was no statistical significance between the above mentioned predictors and the GOS grade, while a strong correlation existed between the HH grade and the GOS grade.