Microsurgical treatment of distal aneurysms of the posterior inferior cerebellar artery

The study objective is to analyze characteristics of distal aneurysms of the posterior inferior cerebellar artery (PICA) using the results of surgical treatment of 11 patients with this disorder.

Materials and methods. Eleven patients with distal PICA aneurysms (7 men and 4 women aged between 32 and 57 years (mean age 44 years)) were operated in N.V. Sklifosovsky Research Institute for Emergency Medicine. Aneurysms were visualized using cerebral angiography in 2 patients and using computed angiography in 9 patients. The aneurysms were classified using the classification system developed by J.R. Lister and A.L. Rhoton. Aneurysms located in the tonsillomedullary segment were most common. Saccular aneurysms were found in 7 (64 %) patients, whereas fusiform aneurysms were observed in 4 (36 %) patients. Two saccular aneurysms had a large neck. The size of aneurysms varied between 2 and 9 mm. The majority of patients (70 %) had aneurysms less than 7 mm.

Results. Five patients were operated via median suboccipital approach, while the remaining 6 patients were operated via lateral suboccipital approach. We performed either reconstructive (n = 9) or deconstructive (n = 2) aneurysm clipping depending on the possibility of preserving the PICA lumen and presence of damage to the perforating arteries of the brain stem. Nine patients (82 %) had Glasgow Outcome Score of 5; two patients (18 %) died (one of them was admitted in sopor with occlusive hydrocephalus; another one had grade III–IV obesity and developed purulent septic respiratory complications and secondary purulent meningitis). Two patients (18 %) developed dysarthria and dysphagia in the postoperative period, but these symptoms disappeared by the moment of discharge.

Conclusion. Distal PICA aneurysms are quite rare and require tailored approach to treatment. A surgeon should bear in mind specific anatomical characteristics of aneurysms, control arterial patency when isolating the aneurysm from the bloodstream, and use revascularizing methods whenever possible. In addition to that, a surgeon should be extremely careful during manipulations with perforating arteries of the brain stem and distal cranial nerves, because their damage result in a more difficult postoperative period.

Conflict of interest. The authors declare no conflict of interest.

Informed consent. All patients gave written informed consent to participate in the study and to the publication of their data.

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