Safety and Efficacy of Endovascular Treatment of Previously Clipped Aneurysms: A Systematic Review and Meta-Analysis

World Neurosurg. 2018 Jun;114:e137-e150. doi: 10.1016/j.wneu.2018.02.103. Epub 2018 Feb 25.


Background/objective: The safety and efficacy of endovascular treatment of previously clipped aneurysms have not been well-established. We conducted a systematic review of the literature to evaluate the outcomes of endovascular treatment of previously clipped aneurysms.

Methods: A systematic search of MEDLINE, Embase, Scopus, and the Web of Science was performed for studies published until October 2017. We included studies with ≥2 patients that described endovascular treatment of previously clipped aneurysms. A random-effects meta-analysis was used to pool the following outcomes: technical success, aneurysm occlusion/recurrence/rebleed, ischemic/thrombotic/thromboembolic events, neurologic/procedure-related morbidity/mortality, and favorable neurologic outcomes. We performed subgroup analyses by aneurysm rupture status on presentation to the endovascular procedure, treatment timing, and by aneurysm location (anterior vs. posterior circulation).

Results: In total, 27 studies with 271 patients were included. Overall complete occlusion was 76.1% (95% confidence interval [CI] 0.676-0.836) and technical success was 97.9% (95% CI 0.958-0.993). Combined procedure-related morbidity/mortality was 4.5% (95% CI 0.024-0.073). There were no statistically significant differences in any of the safety and efficacy outcomes by aneurysm location. Overall long-term favorable neurologic outcome was 78.5% (95% CI 0.732-0.834). All included studies are retrospective.

Conclusions: Our meta-analysis demonstrated that endovascular treatment is acceptably safe and effective. It is important to point out that the complication rate of treatment of these aneurysms is not negligible. These findings should be considered when deciding the best therapeutic strategy. Our findings may suggest that endovascular treatment of previously clipped aneurysms should only be considered in circumstances in which conservative management seems to be unsafe.

Keywords: Endovascular treatment; Meta-analysis; Previously clipped aneurysm.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Aneurysm, Ruptured / surgery
  • Embolization, Therapeutic / methods
  • Endovascular Procedures* / methods
  • Humans
  • Intracranial Aneurysm / surgery*
  • Postoperative Complications / prevention & control
  • Treatment Outcome