The clinical management of unruptured intracranial aneurysms (UIA) requires a balance between the risks of treatment and the consequences of potential aneurysm rupture. Risk assessment scores such as PHASES, ELAPSS, and UIATS provide quantitative evaluations of rupture and growth risks, thus supporting decision-making. However, their predictive value for postoperative outcomes remains uncertain.

In this single-center study, aneurysm characteristics and common risk assessment scores were collected for patients with UIA. The focus was on the predictive value for the risk of poor postoperative outcomes. From January 2010 to January 2021, 378 patients were included. Clinical outcomes were assessed using the modified Rankin scale (mRS).

The cohort of 378 patients was predominantly female, with an average age of 54.8 years. The average aneurysm diameter was 8.03 mm, with most being saccular. PHASES and UIATS achieved statistical significance in predicting poor clinical outcomes (P<0.05), and all 3 scores were able to predict the increased risk for new neurological deficits postoperatively (P<0.05). Age was a significant factor for postoperative neurological deficits and worse clinical outcome (P<0.03), while aneurysm size was significant for new neurological deficits (P=0.01).

Scoring systems that allow for surgical risk estimation are still lacking. While the ELAPSS score was effective in predicting immediate postoperative complications, it was less predictive for long-term clinical outcome. The PHASES and UIATS scores showed significant predictive value for both new neurological deficits and overall clinical outcome. Aneurysm size seems to be a significant predictor of postoperative morbidity, while the presence of intraluminal thrombi or multiple aneurysms did not increase postoperative morbidity.

Our study highlights the potential role of PHASES, ELAPSS, and UIATS scores in the preoperative assessment of UIA and provides valuable insights for surgical risk assessment, aiming to improve clinical decision-making and patient outcome.