Long-term outcomes of endovascular simple coiling versus neurosurgical clipping of unruptured intracranial aneurysms: A systematic review and meta-analysis.

Background: Previous studies on ruptured intracranial aneurysms have shown favourable long-term outcomes of patients undergoing endovascular coiling compared to neurosurgical clipping. We aimed to evaluate if these results also apply to patients with unruptured intracranial aneurysms (UIAs).

Methods: Embase, PubMed, and Cochrane Library were systematically searched for all studies reporting long-term (≥3 years) follow-up after coiling or clipping of UIAs. Thirteen studies involving 16,622 coiled patients and 13,606 clipped patients were included. Short-term outcome was defined as death ≤30 days after treatment. Long-term outcomes (>3 years) included all-cause mortality, morbidity (defined as modified Rankin Score 3-5 or Glasgow Outcome Score 2-3), cerebrovascular accident, intracerebral haemorrhage, additional repairs, and lost to follow-up. We calculated relative risk (RR), incidence and mortality rates (IR and MR), together with incidence and mortality rate ratio (IRR and MRR).

Results: Patients treated with simple coiling had lower short-term mortality than clipped patients (RR = 0.62 (95%CI 0.42-0.91)), but this difference disappeared after long-term follow-up ((MRR) = 0.89 (95%CI: 0.78-1.02). Coiled patients had higher retreatment rates than clipped patients (IRR = 1.70 (95%CI 1.50-1.93)).

Conclusions: This systematic review and meta-analysis reports benefits and drawbacks of simple coiling versus neurosurgical clipping of UIAs. Future studies with longer follow-up time should account for differences in coiling techniques and confounding factors such as size and location of UIAs.