OBJECTIVETo study the clinical characteristics and treatment strategies of mirror aneurysms.

METHODSNineteen patients with 20 pairs of mirror aneurysms from November 2007 to November 2012 were retrospectively analysed. Among the 19 patients, 13 were female and 6 were male, mean age was 56 years (ranged 32-75 years). Distribution of the lesions included 11 bilateral posterior communicating artery aneurysms (one with a pair of anterior choroidal artery aneurysm), 4 bilateral middle cerebral artery aneurysms, 3 bilateral paraclinoidal aneurysms, and 1 bilateral pericallosal-callosomarginal artery aneurysm. Surgical strategies were selected according to location of hemorrhage, Hunt-Hess grade, location and size of aneurysm, etc.

RESULTSFour mirror aneurysms were clipped at one stage, 3 mirror aneurysms were clipped at two stages, 2 were treated with combination of clipping and coiling and remaining 10 were clipped unilaterally. At discharge, 15 out of 19 patients had a Glasgow Outcome Scale score of 5, 4 patients had a score of 4. The mean clinical follow-up was 18.6 months (range 3-50 months). Two patients had oculomotor nerve palsy postoperatively. At 3-month follow-up, 1 improved and 1 unchanged. In 10 patients with unilateral clipping, contralateral aneurysms were unruptured, small ( < 5 mm) and regular. No remnant or recurrence of aneurysm were found in other 9 patients whose bilateral aneurysms had been treated.

CONCLUSIONSThe mirror aneurysms are rare kinds of multiple aneurysms. The aneurysm responsible for hemorrhage should be treated with first priority. The contralateral unruptured aneurysm could be observed, clipped or coiled in one stage, or treated in two separate stages.