Minimally Invasive Supraorbital vs. Traditional Pterional Approaches in Unruptured Aneurysm Surgery: Evaluating Risks and Results

<b>Background/Objectives:</b> Intracranial aneurysms affect 3-5% of the population and are associated with high morbidity and mortality, particularly after rupture. Treatment options for unruptured aneurysms include microsurgical clipping, with the pterional and supraorbital approaches commonly employed. This study compares these two approaches regarding complications and outcomes. <b>Methods:</b> A retrospective analysis was conducted on 241 patients treated between 2004 and 2023 at the University Hospital of Graz. Patients underwent microsurgical clipping via the pterional (<i>n</i> = 170) or supraorbital (<i>n</i> = 71) approach, chosen according to aneurysm characteristics and surgeon preference. Data on demographics, aneurysm location and size, intraoperative complications, postoperative outcomes, and follow-up were evaluated. <b>Results:</b> The pterional approach was predominantly used for middle cerebral artery (MCA) aneurysms (79.2%), while the supraorbital approach was more frequently applied for internal carotid artery (ICA) and anterior communicating artery (ACOM) aneurysms. Aneurysms treated via the pterional approach were significantly larger (mean width 6.88 mm vs. 5.04 mm; <i>p</i> < 0.01). Severe intraoperative complications, including aneurysm rupture, were significantly more common in the supraorbital group (26.8% vs. 8.8%; <i>p</i> < 0.001). Postoperative hypo-/anosmia occurred more often after the supraorbital approach (8.5% vs. 1.8%; <i>p</i> = 0.013), while temporalis muscle atrophy (11.9% vs. 1.8%; <i>p</i> = 0.029) and chewing difficulties (19.5% vs. 1.8%; <i>p</i> = 0.002) were more frequent after the pterional approach. The supraorbital group had a shorter hospital stay (7.96 vs. 8.76 days; <i>p</i> = 0.001). No significant differences were found in 30-day mortality (<i>p</i> = 0.521). At one-year, functional outcomes assessed by the modified Rankin Scale showed no significant difference (<i>p</i> = 0.899). Complete aneurysm occlusion and recurrence rates were also comparable between groups. <b>Conclusions:</b> Both approaches provide effective treatment for unruptured aneurysms with favorable long-term outcomes. The pterional approach is associated with increased muscle-related complications, whereas the supraorbital approach carries higher risks of intraoperative complications and olfactory dysfunction. Tailoring the surgical approach based on patient and aneurysm characteristics remains essential.