Endovascular Management of Unruptured Cerebral Aneurysms in Patients with Nickel Allergy: Three Cases.

Objective: Nickel allergy is one of the most common forms of metal hypersensitivity, yet its relevance to neuroendovascular therapy has rarely been reported. We describe 3 cases of unruptured intracranial aneurysms in patients with confirmed nickel allergy, and review the literature to highlight safe endovascular management strategies. Case Presentation: Three female patients (2 in their 70s and 1 in her 60s) were incidentally diagnosed with unruptured intracranial aneurysms located at the internal carotid artery (n = 2) and the vertebral artery (n = 1). All patients tested positive on patch testing for nickel. To minimize allergic risk, devices with low nickel content were chosen, including bare platinum coils (i-ED coils; Kaneka Medix, Osaka, Japan) and a flow diverter (Surpass Evolve; Stryker, Kalamazoo, MI, USA). Endovascular treatment was completed without perioperative complications, and no allergic reactions were observed during a mean follow-up of 12.7 months. Corticosteroids were not administered in any of the cases. Conclusion: Endovascular treatment of unruptured intracranial aneurysms in patients with nickel allergy can be performed safely by avoiding devices with high nickel content and by performing preoperative allergy testing. Awareness of device materials is critical for preventing adverse reactions and ensuring favorable outcomes.