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

Sep 29, 2026

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Nickel allergy is a common metal hypersensitivity, but its implications for neuroendovascular therapy have rarely been detailed. This report describes three cases of unruptured intracranial aneurysms in patients with confirmed nickel allergy, and reviews approaches for safe endovascular management. Device selection prioritized low-nickel materials, endovascular procedures proceeded without perioperative complications, no allergic reactions emerged over 12.7 months mean follow-up, and preoperative testing guided avoidance of high-nickel devices.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages8

Reading Time20 min

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Objective

Case Presentation

Case 1

Case 2

Case 3

Conclusion

Keywords

Journal of Neuroendovascular Therapy 2025; 19: 2025-0115 DOI: [10.5797/jnet.cr.2025-0115](10.5797/jnet.cr.2025-0115) Endovascular Management of Unruptured Cerebral Aneurysms in Patients with Nickel Allergy: Three Cases Kento Asakura , Yu Kato, Sadayoshi Nakayama, Ryo Irie, Minako Kubo, Tsuneshi Sato, and Tomoyuki Tsumoto Objective: Nickel allergy is one of the most common forms of metal hypersensitivity, yet its relevance to neuro endovascular 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. Keywords▶ nickel allergy, cerebral aneurysm, endovascular treatment Introduction Nickel allergy is one of the most common types of metal hypersensitivity, affecting approximately 8%–19% of the adult population in Europe. 1) While occasionally encountered in dermatologic practice, it has also become relevant in neuroendovascular therapy due to the widespread use of nickel-containing devices such as coils, neck-bridge stents, and flow diverters. Allergic reactions to these devices have been linked to complications including stroke, in-stent stenosis, and delayed white matter lesions. In this report, we describe 3 cases ofunruptured cerebral aneurysms treated Department of Neurosurgery, Showa Medical University Fujigaoka Hospital Received: September 20, 2025; Accepted: November 21, 2025 Corresponding author: Kento Asakura. Department of Neurosurgery, Showa Medical University Fujigaoka Hospital, 1-30 Fujigaoka, Aoba-ku, Yokohama, Kanagawa 227-8501, Japan [Email: kento.a.0522@gmail.com](Email: kento.a.0522@gmail.com) This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. ©2025 The Japanese Society for Neuroendovascular Therapy endovascularly in patients with confirmed nickel allergy, all of whom experienced favorable outcomes without any apparent allergic reactions. Case Presentation Case 1 A woman in her 60s was referred to our hospital for further evaluation and treatment of an unruptured aneurysm measuring over 5 mm at the right internal carotid–posterior communicating artery junction, which had been identified at another hospital. Cerebral angiography confirmed the presence of the aneurysm (Fig. 1A), and preventive treatment was planned. Following the angiographic evaluation, the patient reported a history of metal allergy. Patch testing conducted by our dermatology department revealed positive reactions to both nickel and gold (Fig. 1B) . Although surgical clipping with titanium clips was considered, the patient preferred an endovascular approach; therefore, coil embolization was selected. Because certain embolization coils are known to contain nickel, often as a component of stainless steel or nitinol, there was concern that implantation could trigger an allergic reaction.2) Accordingly

FAQs

Why is nickel allergy relevant to neuroendovascular therapy?

Nickel allergy can be triggered by nickel-containing devices used in endovascular procedures, and has been linked to complications such as stroke, in-stent stenosis, and delayed white matter lesions.

How were devices selected to reduce allergic risk in the reported cases?

Devices with low nickel content were chosen, including nickel-free bare platinum coils and a flow diverter, with the goal of avoiding high-nickel materials.

What role did preoperative testing play in treatment planning?

Patch testing confirmed nickel allergy before intervention, enabling clinicians to plan an endovascular approach while selecting appropriate low-nickel devices and avoiding unnecessary corticosteroid administration.

Sep 29, 2026

Uploaded by Melati