Surgical treatment of unruptured distal basilar artery aneurysm: durability and risk factors for neurological worsening.
BACKGROUND
Distal basilar artery aneurysms (DBAs) consist of basilar apex and basilar artery-superior cerebellar artery bifurcation (BA-SCA) aneurysms. The authors aimed to investigate clinical and radiological differences between two locations and to evaluate the 12-month surgical outcome in unruptured DBAs.


METHODS
Fifty-six consecutive patients who underwent surgical treatment (37 basilar apex and 19 BA-SCA aneurysms) between April 2012 and February 2016 were retrospectively evaluated. In patients with a preoperative modified Rankin Scale score (mRS) of more than 1, neurological worsening (NW) was defined as an increase in one or more mRS. In patients without symptoms, NW was defined as mRS ≥2.


RESULTS
The mean age of the patient population was 64 ± 9.6 years, and 48 (86%) were female. Mean follow-up period was 2.6 ± 0.94 years. An excellent (mRS 0 to 1) outcome was archived in 31 (55%), 45 (82%), and 48 (87%) patients at 30 days, 6 months, and 12 months, respectively. Clinical and radiological characteristics showed no differences between two locations. One early death (1.8%) and one severe morbidity (1.8%) due to rupture were observed. The postoperative annual rupture rate was 1.4% overall (145 patient-years). After adjustment for age and location, large or giant DBA was related to 30-day and 12-month NW [n = 22 (39%) and n = 6 (11%); p = 0.009 and 0.002, respectively], aneurysm localization in the interpeduncular cistern (LIC) and perforator territory infarction were related to 30-day NW (p = 0.002 and 0.002), and DBA that needed bypass surgery and previously treated recurrent DBA were related to NW at 12 months (p = 0.017 and 0.001). Multivariate analysis showed that LIC was significantly related to perforator territory infarction (p = 0.003).


CONCLUSIONS
Clinical and radiological characteristics were not different between basilar apex and BA-SCA aneurysms; therefore, they should not be discussed separately. To avoid neurological worsening, results of surgical treatment for unruptured DBAs should be improved.
['Matsukawa|Hidetoshi|H|', 'Kamiyama|Hiroyasu|H|', 'Miyazaki|Takanori|T|', 'Kinoshita|Yu|Y|', 'Tsuboi|Toshiyuki|T|', 'Noda|Kosumo|K|', 'Ota|Nakao|N|', 'Saito|Norihiro|N|', 'Takeda|Rihee|R|', 'Tokuda|Sadahisa|S|', 'Tanikawa|Rokuya|R|']
D000328:Adult D000368:Aged D001488:Basilar Artery D002533:Cerebral Angiography D000072226:Computed Tomography Angiography D005260:Female D006801:Humans D021621:Imaging, Three-Dimensional D002532:Intracranial Aneurysm D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D015999:Multivariate Analysis D017063:Outcome Assessment, Health Care D012189:Retrospective Studies D012307:Risk Factors D016896:Treatment Outcome
Basilar artery Risk factors Outcome Surgery Intracranial aneurysm Unruptured aneurysm