Early and late microsurgical clipping of previously ruptured, partially coiled intracranial aneurysms

Background: Endovascular treatment of ruptured intracranial aneurysms has largely become the preferred initial approach in management. Although there is decreased upfront morbidity in endovascular approaches when compared to craniotomy for microsurgical clipping, there is a higher rate of aneurysm recurrence with endovascular techniques. Additionally, complete occlusion of wide-necked aneurysms may be difficult with coiling alone. Coiling of ruptured aneurysms in the acute setting with the intention of securing the aneurysm, followed by semi-elective microsurgical clipping may offer a safe alternative. We aim to demonstrate that this combined approach may provide durability of treatment, and evaluate optimal time course for intervention.

Methods: Patients undergoing initial partial coiling of ruptured cerebral aneurysms followed by staged microsurgical clipping at two academic tertiary medical centers between 2020 and 2025 were retrospectively reviewed. These patients were divided into early clipping (EC; ≤4 weeks following rupture) and late clipping (LC; >4 weeks following rupture) and analyzed for differences in baseline demographics, as well as Hunt-Hess (HH) and modified Fisher Scale (mFG), location, size of ruptured aneurysms, and modified Rankin Scale (mRS) at follow-up.

Results: Twenty-five patients had initial endovascular coiling followed by microsurgical clipping during this time. Twelve patients underwent EC and thirteen patients underwent LC. The study did not find a difference in age (early 55.2±13.5 versus 52.1±10.0 years, P=0.55, sex distribution, HH [early median 3 (interquartile range, 2–3) versus late 3 (2.8–3), P=0.15], mFG, or rate of favorable outcome (mRS 0–1) at discharge (P=0.99) or follow up (P=0.61). The study did not find a difference in the distribution of aneurysm location (P=0.59) or size between treatment groups (P=0.90). No complications were observed in the EC group. The LC group had three patients with associated complications: a postoperative epidural hematoma, a seizure, and a retroorbital hematoma.

Conclusions: A tailored approach, including safe intentional under-coiling of ruptured, wide-necked intracranial aneurysms with the goal of dome protection, followed by non-urgent microsurgical clipping, is a reasonable approach to address the increased risk of recurrence with endovascular approaches while providing a more definitive cure. The study did not find an advantage to delayed interval microsurgical clipping more than four weeks post-rupture.