Posterior inferior cerebellar artery aneurysms: operative strategies based on a surgical series of 27 patients.

Aim: Posterior inferior cerebellar artery (PICA) aneurysms are uncommon. The natural history and management of these aneurysms remains poorly understood. Surgical treatment of PICA aneurysms is challenging in view of their close neurovascular relationship.
Material and Methods: Data relating to clinical presentation, radiological findings, operative approaches and outcomes were analyzed in 27 consecutive patients surgically treated for PICA aneurysms in a single hospital between January 1991 and December 2010.
Results: Headache was the most common presentation (100%) followed by gait ataxia (14.8%) and lower cranial nerve dysfunction (7.4%). SAH was seen in 20 patients, intraventricular hemorrhage in 22 patients, and 3 had evidence of intracerebellar hematoma. Eighteen aneurysms were located proximally and 9 were located distally. The 25 saccular and 2 fusi-saccular aneurysms were secured by direct clipping (24 cases) or aneurysmorrhaphy (3 cases) using a far-lateral suboccipital (without condylar resection) or midline/ paramedian suboccipital approach. Overall outcome at the time of hospital discharge was excellent or good in 88.9% of the patients.
Conclusion: PICA aneurysms, by virtue of their rarity and strategic location pose a unique technical challenge. Depending on the PICA segment affected, variations in the surgical corridor and clipping strategy were major contributors to good outcomes.