Outcomes of Microsurgical Treatment for Unruptured Intracranial Aneurysms: A 7-Year Institutional Review.

[BACKGROUND AND OBJECTIVES] The optimal management of unruptured intracranial aneurysms (UIAs) remains controversial. Options include observation, endovascular treatment, microsurgical intervention, or a combination. However, clear outcome data for UIA treatment remain elusive. This study analyzed UIA treatment outcomes at a quaternary center and explored factors associated with poor neurological outcomes.

[METHODS] All records of patients treated for UIA from 2014 through 2020 were retrospectively reviewed. Inclusion criteria were availability of treatment data, adequate follow-up, and a modified Rankin Scale (mRS) score of ≤2 at admission. Outcomes analyzed included 1-year mRS scores, with a poor neurological outcome defined as an mRS score of >2. Multivariate logistic regression analysis included variables with < .2 on univariate analysis.

[RESULTS] A total of 390 patients met the inclusion criteria (294 [75.4%] women, 96 [24.6%] men). Forty-one (10.5%) had previous aneurysmal subarachnoid hemorrhages (SAHs). The mean (SD) population, hypertension, age, size of aneurysm, earlier SAH from another aneurysm, site of aneurysm (PHASES) score was 4.5 (2.7). Thirty-eight patients (9.7%) had mRS scores >2 at the 1-year follow-up. Of 555 UIAs, 388 (69.9%) were saccular and 77 (13.9%) were in the posterior circulation. Multivariate analysis showed that no tobacco use (odds ratio [OR] 4.35, 95% CI: 1.72-12.5, = .003), diabetes mellitus (OR 3.09, 95% CI: 1.00-9.29, = .045), hyperlipidemia (OR 4.33, 95% CI: 1.33-14.0, = .01), and PHASES score ≥6 (OR 3.92, 95% CI: 1.30-12.7, = .02) were predictors of poor neurological outcome at the 1-year follow-up. Of the 555 UIAs treated, 1 (0.2%) required retreatment and 12 (2.5%) residual aneurysms were noted on follow-up, with no aneurysmal SAH post-treatment.

[CONCLUSION] Microsurgical treatment of UIAs is associated with low rates of residual aneurysms, retreatment, and poor neurological outcomes. Risk factors for a poor neurological outcome included no history of tobacco use, presence of diabetes mellitus, hyperlipidemia, and a high PHASES score. These findings refute the potential value of treating patients with low PHASES scores.