Utility of Anterior Clinoidectomy in Neck Clipping for Reccurent Aneurysms After Coil Embolization

Introduction: As endovascular treatment becomes more widespread, opportunities to directly treat aneurysms that recur after coil embolization are also increasing. Recurrent aneurysms after coil embolization exhibit low mobility, necessitating careful planning to ensure a clear view around the aneurysm and adequate working space for safe completion of clipping. Anterior clinoidectomy is considered particularly useful in clipping IC-Pcom aneurysms that recur after coiling. Subjects and Methods: We present two cases of IC-Pcom cerebral aneurysms treated with clipping after coiling, based on our experience, and discuss the differences in visualization and working space achieved with and without anterior clinoidectomy. Additionally, we compared the rates of complete occlusion and complications between 89 cases treated with re-coiling and 6 cases treated with clipping among 95 IC-PC aneurysms that recurred after coiling and required re-treatment, selected from 609 IC-PC aneurysms treated at 16 institutions between January 1, 2018, and December 31, 2022. Results: Both cases presented with SAH and underwent coil embolization initially. Due to neck recurrence, they were subsequently treated with simple neck clipping. In one case, combined anterior clinoidectomy was performed to reduce tension on the anterior clinoidal fold. This facilitated clear visualization of the entire neck and aneurysm, allowing safe neck clipping under adequate working space. The tip of the blade was also clearly visible. Furthermore, with the clip already in place, the endoscope could be reinserted to confirm blood flow in the perforating branches of the posterior communicating artery. In the second case, the approach was performed without anterior clinoidectomy. As a result, adequate visualization and working space could not be secured, and neck clipping was completed while the aneurysm remained relatively immobile. Complete occlusion was achieved in 6 cases (100%) in the Clip group and 23 cases (25.8%) in the Coil group, significantly more in the Clip group ( p = 0.0005). Postoperative recurrence was observed in 0 cases (0.0%) in the Clip group and 42 cases (47.1%) in the Coil group, with significantly more recurrence in the Coil group ( p = 0.03). Regarding complications: oculomotor nerve palsy [Clip group: 0 cases (0.0%) vs Coil group: 13 cases (14.6%) p = 0.59], symptomatic cerebral infarction [Clip group: 0 cases (0.0%) vs Coil group: 2 cases (2.2%) p = 1.00], and cerebral infarction in the Pcom territory [Clip group: 0 cases (0.0%) vs Coil group: 5 cases (5.6%) p = 0.55]. Discussion: In neck clipping of IC-Pcom aneurysms that recurred after coil embolization, anterior clinoidectomy enhances the safety and reliability of the procedure by expanding the surgical field and working space. This provides a treatment offering a high complete occlusion rate while maintaining safety. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany