Your new experience awaits. Try the new design now and help us make it even better

SYSTEMATIC REVIEW article

Front. Neurol., 26 November 2025

Sec. Endovascular and Interventional Neurology

Volume 16 - 2025 | https://doi.org/10.3389/fneur.2025.1706462

This article is part of the Research TopicInnovation Application and Outcomes in Flow Diverter Interventions for Complex Intracranial AneurysmsView all 6 articles

Efficacy and safety of flow diverters in small intracranial aneurysms: a systematic review and single-arm meta-analysis

Kuerban Maimaitiaili&#x;Kuerban Maimaitiaili1Maimaitiaili Nuermaimaiti&#x;Maimaitiaili Nuermaimaiti2Adili RouziAdili Rouzi1Aisan SeyitiAisan Seyiti1Mairidan YashengMairidan Yasheng1Xiong GuoXiong Guo1Moming AbulaitiMoming Abulaiti1Ying XiaoYing Xiao1Hongbo PanHongbo Pan1Ainipai SidikeAinipai Sidike3Yanbing Hu
Yanbing Hu1*Dawutijiang Yilamu
Dawutijiang Yilamu1*
  • 1Department of Neurosurgery, The Second People’s Hospital of Kashgar Region, Kashgar, Xinjiang, China
  • 2Department of Neurology, The Second People’s Hospital of Kashgar Region, Kashgar, Xinjiang, China
  • 3Kashgar No. 8 Middle School, Kashgar, Xinjiang, China

Objective: This study aimed to evaluate the efficacy and safety of flow diverters (FDs) in the treatment of small intracranial aneurysms (≤10 mm).

Methods: PubMed, Embase, Web of Science, and Cochrane Library were comprehensively searched up to July 2025. Eligible studies included retrospective cohort studies reporting angiographic and clinical outcomes of FD treatment in small intracranial aneurysms. Data analysis was conducted using STATA 15.0. Pooled proportions and 95% confidence intervals (CIs) were calculated using Freeman–Tukey double arcsine transformation. Publication bias was evaluated using funnel plots and Egger’s test.

Results: Ten retrospective studies comprising 2,275 patients with 1,938 aneurysms were included. The pooled complete or near-complete occlusion rate was 86% (95% CI: 80–92%). The treatment-related mortality rate was 1% (95% CI: 0–2%), and the hemorrhagic event rate was 1% (95% CI: 1–2%). The ischemic event rate was 2% (95% CI: 1–3%), and the stroke rate was 3% (95% CI: 1–5%). The overall complication rate was 9% (95% CI: 5–12%), while 98% (95% CI: 94–100%) of patients achieved favorable functional outcomes. Egger’s test showed no significant publication bias (p = 0.791).

Conclusion: FDs appear to be both effective and safe for the treatment of small intracranial aneurysms, achieving high occlusion rates and favorable functional outcomes with low rates of mortality and complications. However, given the high heterogeneity and retrospective nature of the included studies, further large-scale prospective studies are warranted to confirm these findings and refine treatment strategies.

1 Introduction

Intracranial aneurysms are among the most common cerebrovascular disorders, with a prevalence of approximately 3.2% in the adult population (1). Rupture can lead to aneurysmal subarachnoid hemorrhage (aSAH), which carries a high case fatality rate, the 30-day in-hospital mortality is about 20%, and prehospital deaths further increase the overall burden (2). With advances in neuroimaging, an increasing number of SIAs (≤10 mm in diameter) have been detected, accounting for 70–80% of unruptured aneurysms (3). Although their rupture risk is generally lower than that of large or giant aneurysms, rupture of small intracranial aneurysms (SIAs) can result in devastating consequences. The Unruptured Cerebral Aneurysm Study of Japan (UCAS Japan) reported an annual rupture rate of 0.36% for aneurysms <7 mm, yet emphasized the poor prognosis once rupture occurs, underscoring the clinical challenges in managing SIAs (4).

Current treatment options include microsurgical clipping and endovascular coiling. Microsurgical clipping achieves high occlusion rates but requires craniotomy, with greater risks in anatomically complex cases (5). Endovascular coiling offers a minimally invasive alternative, particularly wide-necked or morphologically complex aneurysms remain prone to incomplete occlusion and recurrence (6, 7).

Flow diverters (FDs) represent an alternative therapeutic strategy by reconstructing parent vessel hemodynamics, promoting intra-aneurysmal thrombosis, and facilitating vessel wall remodeling, leading to progressive occlusion. Their efficacy and feasibility in large and giant aneurysms are well established (8, 9). More recently, evidence has accumulated in SIAs. The prospective multicenter PREMIER trial (≤12 mm, predominantly small-to-medium aneurysms) demonstrated high complete occlusion rates and low permanent neurological morbidity, findings later supported by other series (1012). However, systematic evaluations of long-term outcomes and complication profiles in SIAs remain limited.

Therefore, this study conducted a systematic review and single-arm meta-analysis to comprehensively evaluate the efficacy and safety of FD treatment in SIAs, aiming to provide evidence-based insights for clinical practice and future research.

2 Methods

This systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (13) and was prospectively registered in the PROSPERO database (registration number: CRD420251136570).

2.1 Search strategy

PubMed, Web of Science, EMBASE, and the Cochrane Library were searched from inception to July 15, 2025. Search terms combined MeSH and free-text words: “Intracranial Aneurysm” OR “Small intracranial aneurysms” AND “Flow diverter” OR “Pipeline Embolization Device.” The full search strategy is provided in Supplementary Table S1.

2.2 Eligibility criteria

Inclusion criteria: (1) adult patients with SIAs (≤10 mm); (2) treatment with an FD (e.g., Pipeline Embolization Device (PED), Pipeline Flex, FRED X); (3) reporting at least one of the following outcomes: complete occlusion (Raymond–Roy Grade I), incomplete/partial occlusion, perioperative complications (ischemia, hemorrhage, thrombosis), mortality, recurrence, or functional outcome (modified Rankin Scale, mRS); (4) ≥ 20 patients with SIAs; and (5) prospective or retrospective observational studies.

Exclusion criteria: large or giant aneurysms (>10 mm); non-intracranial aneurysms; non-FD interventions; insufficient data; case reports, reviews, meta-analyses, editorials, conference abstracts; and duplicate or overlapping cohorts.

2.3 Study selection and quality assessment

All records were imported into EndNote 21. Duplicates were removed, and two reviewers independently screened titles/abstracts and full texts, with disagreements resolved by a third reviewer. Quality assessment was performed using the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Series (14).

2.4 Data extraction

Two reviewers independently extracted data using a standardized electronic form, including study characteristics (author, year, country), patient demographics, aneurysm features, treatment details.

2.5 Statistical analysis

Analyses were performed using Stata 15.0. Outcomes were expressed as proportions, and pooled using single-arm meta-analysis. To stabilize variance, the Freeman–Tukey double arcsine transformation was applied. Pooled estimates with 95% CIs were reported. Heterogeneity was assessed with Cochran’s Q test and the I2 statistic; random-effects models (DerSimonian–Laird) were applied when I2 > 50%, otherwise fixed-effects models were used. Publication bias was assessed with funnel plots and Egger’s test.

3 Results

3.1 Study selection

From 14,782 records, 5,476 duplicates were removed, leaving 9,306 for screening. After excluding 9,205 based on titles/abstracts, 101 full texts were assessed, and 10 studies met inclusion criteria (shown in Figure 1).

Figure 1
Flowchart detailing the identification and screening of studies via databases. Initially, 14,782 records were identified from four databases. After removing 5,476 duplicates, 9,306 records were screened. Of these, 9,205 were excluded for reasons such as unmatched disease or intervention, or inappropriate study type. After full-text assessment of 101 records, further exclusions were made for reasons like small sample size or unmatched intervention. Ultimately, 10 studies were included in the review.

Figure 1. PRISMA flow diagram of study selection.

3.2 Study characteristics

The 10 retrospective studies (3, 1523) included 2,275 patients with 1,938 SIAs. Five studies used PED, two FRED X, one PED Flex, and two reported mixed FD devices (SILK, Derivo, Surpass). Studies were conducted in the United States, Turkey, China, and Brazil. Study characteristics are summarized in Table 1.

Table 1
www.frontiersin.org

Table 1. Basic characteristics information of included studies.

3.3 Quality assessment

Based on the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Case Series, 10 clinical studies were evaluated across ten domains assessing aspects such as case selection, disease evaluation, and data reporting. The results of quality assessment are provided in Table 2.

Table 2
www.frontiersin.org

Table 2. The results of JBI critical appraisal checklist for case series.

3.4 Meta-analysis results

3.4.1 Complete or near-complete occlusion

Eight studies reported complete or near-complete occlusion (Raymond–Roy Grade I). The pooled analysis demonstrated an overall rate of 86% (95% CI: 80–92%). Significant heterogeneity was observed (I2 = 84.73%, p = 0.00). These findings indicate that most patients achieved favorable angiographic outcomes following FD treatment (shown in Figure 2).

Figure 2
Forest plot showing effect sizes (ES) and 95% confidence intervals (CI) for several studies. The studies listed are Akgul et al. 2021, Chalouhi et al. 2015, Clausen et al. 2025, Griessenauer et al. 2017, Lin et al. 2013, Roy et al. 2025, Trivelato et al. 2018, and Zhang et al. 2022. Each study shows a point estimate and bar representing CI. The overall effect is shown at the bottom with an ES of 0.86 and a CI of 0.80 to 0.92, with a weight of 100%. Heterogeneity is I-squared equals 84.73%, p equals 0.00.

Figure 2. Forest plot of complete or near-complete occlusion.

3.4.2 Incomplete occlusion (<90%)

Four studies reported incomplete occlusion (<90%). The pooled incidence was 7% (95% CI: 3–13%) with high heterogeneity (I2 = 70.16%, p = 0.02). This suggests that although most patients achieve complete or near-complete occlusion, a minority may experience incomplete occlusion, warranting careful clinical follow-up (shown in Figure 3).

Figure 3
Forest plot showing effect sizes (ES) with 95% confidence intervals for studies by Akgul, Chalouhi, Griessenauer, and Trivelato. Individual weights range from 22.27% to 27.39%. Overall ES is 0.07 with I² = 70.16% and p = 0.02.

Figure 3. Forest plot of incomplete occlusion (<90%).

3.4.3 Mortality

Four studies reported mortality outcomes. The pooled mortality rate was 1% (95% CI: 0–2%) with low heterogeneity (I2 = 12.08%, p = 0.33), suggesting robust and consistent results. This indicates that FD treatment is associated with a very low risk of treatment-related death (shown in Figure 4).

Figure 4
Forest plot showing effect sizes (ES) with 95% confidence intervals for four studies: Akgul et al. 2021, Kallmes et al. 2015, Lin et al. 2013, and Zhang et al. 2022. Weights vary, with Zhang et al. 2022 having the highest weight at 53.78%. The overall ES is 0.01 with I-squared at 12.08%, p = 0.33.

Figure 4. Forest plot of mortality.

3.4.4 Hemorrhagic events

Seven studies reported hemorrhagic complications. The pooled rate was 1% (95% CI: 1–2%), with very low heterogeneity (I2 = 2.70%, p = 0.40), indicating highly consistent findings across studies. These results confirm that hemorrhagic risk following FD treatment is low (shown in Figure 5).

Figure 5
Forest plot depicting effect sizes (ES) and 95% confidence intervals (CI) for multiple studies. Each study is represented by a horizontal line with a central square, indicating the point estimate. The overall effect is shown as a diamond. Weights are noted on the right, with Zhang et al. 2022 having the largest weight at 40.62%. The plot includes a dashed vertical line at zero and heterogeneity statistics at the bottom.

Figure 5. Forest plot of hemorrhagic events.

3.4.5 Stroke

Five studies reported stroke as an outcome. The pooled rate was 3% (95% CI: 1–5%) with moderate heterogeneity (I2 = 55.03%, p = 0.06). Although relatively uncommon, stroke remains a clinically relevant complication, underscoring the importance of perioperative risk management (shown in Figure 6).

Figure 6
Forest plot showing effect sizes (ES) with 95% confidence intervals for five studies. Each study is listed with its ES, CI, and weight percentage. Overall ES is 0.03 with a CI of 0.01 to 0.05, and total weight is 100%. The heterogeneity (I²) is 55.03% with a p-value of 0.06.

Figure 6. Forest plot of stroke.

3.4.6 Ischemic events

Six studies reported ischemic complications. The pooled rate was 2% (95% CI: 1–3%), with low heterogeneity (I2 = 0.00%, p = 0.70). This demonstrates that ischemic risk is consistently low across studies (shown in Figure 7).

Figure 7
Forest plot showing effect sizes (ES) and 95% confidence intervals (CI) from six studies: Brasiliense et al. 2019, Chalouhi et al. 2015, Kallmes et al. 2015, Roy et al. 2025, Trivelato et al. 2018, and Zhang et al. 2022. The overall effect size is 0.02 with no heterogeneity (I-squared = 0.00 percent, p = 0.70). Weights range from 6.65 to 43.18 percent. The plot includes a dashed vertical line at zero for reference.

Figure 7. Forest plot of ischemic events.

3.4.7 Favorable functional outcomes

Four studies reported favorable functional outcomes (mRS 0–2). The pooled incidence was 98% (95% CI: 94–100%), although substantial heterogeneity was observed (I2 = 73.39%, p = 0.01). These results suggest that most patients maintained good neurological function following FD treatment (shown in Figure 8).

Figure 8
Forest plot showing effect sizes (ES) with 95% confidence intervals (CI) for four studies: Chalouhi et al. 2015, Griessenauer et al. 2017, Roy et al. 2025, Zhang et al. 2022. Each study displays its ES and weight, with an overall ES of 0.98 (CI: 0.94, 1.00) and I-squared of 73.39%, p-value 0.01.

Figure 8. Forest plot of favorable functional outcomes.

3.4.8 Complications

Nine studies reported overall complications. The pooled complication rate was 9% (95% CI: 5–12%), with high heterogeneity (I2 = 82.26%, p = 0.00). This indicates considerable variability in reported complication rates across studies, highlighting that although FD treatment is generally safe, certain patients remain at risk of peri- or post-procedural complications that require clinical vigilance (shown in Figure 9).

Figure 9
Forest plot displaying effect sizes (ES) with 95% confidence intervals (CI) for various studies on the left. Each study is represented by a horizontal line indicating CI, with a diamond for ES. The dashed vertical line represents the overall effect. Weights are shown on the right. Overall ES is 0.09 with CI of 0.05 to 0.12, and I-squared value of 82.26%.

Figure 9. Forest plot of overall complications.

3.5 Publication bias

The funnel plot suggested some asymmetry, indicating the potential presence of publication bias or small-study effects. However, Egger’s regression test yielded p = 0.791, suggesting no statistically significant evidence of publication bias; thus, the results should be interpreted with caution.

4 Discussion

This meta-analysis included 10 retrospective studies comprising 2,275 patients with 1,938 SIAs. The pooled analysis demonstrated a complete or near-complete occlusion rate of 86%, indicating high efficacy of FDs in the treatment of small aneurysms. In addition, the rates of treatment-related mortality and hemorrhage were both 1%, ischemic events occurred in 2%, stroke in 3%, and favorable functional outcomes were achieved in 98% of patients. The overall complication rate was 9%. These findings suggest that FDs provide not only excellent angiographic outcomes but also favorable safety and functional profiles in the management of small intracranial aneurysms.

SIAs present unique therapeutic challenges due to their small size and complex anatomy. Conventional treatment approaches, such as microsurgical clipping or endovascular coiling, often face limitations including incomplete occlusion or recurrence. By reconstructing parent vessel hemodynamics, FDs promote intra-aneurysmal thrombosis and vessel wall remodeling, thereby achieving progressive occlusion. The present study indicates that in SIAs, FDs can achieve high occlusion rates without substantially increasing the risk of severe complications, which holds important clinical implications.

Our findings are largely consistent with previous prospective studies and meta-analyses, though several methodological differences should be considered. The PREMIER trial investigated unruptured wide-neck aneurysms ≤12 mm and reported complete occlusion rates of 76.8% at one year and 83.3% at three years, with a primary safety event rate of 2.8% (11, 24). However, the PREMIER cohort included both small (<10 mm) and medium-sized (10–12 mm) aneurysms, whereas our meta-analysis focused only on small aneurysms. Differences in aneurysm size, baseline characteristics, and patient selection likely account for part of the discrepancy. Bhatia et al. reported a major complication rate of only 0.9% in <10 mm aneurysms treated with the Pipeline Flex device, which is much lower than our pooled rate (25). This is largely due to methodological differences. Bhatia defined complications strictly as major adverse events (death, major ischemic stroke, or symptomatic intracranial hemorrhage), while our analysis included all reported complications, both major and minor. Their review also focused only on the second-generation Pipeline Flex, whereas our study covered multiple flow diverters across different devices and settings. Fiorella et al. conducted a meta-analysis of predominantly small to medium sized unruptured ICA aneurysms (26). They reported a 12-month complete occlusion rate of 74.9% and a composite primary safety event rate of 7.8%, providing performance benchmarks that are broadly in line with our findings. In our pooled analysis, the complete or near-complete occlusion rate was 86%, slightly higher than some prospective studies, while the overall complication rate was 9%. This higher rate likely reflects the greater heterogeneity of retrospective studies, variation in device type and operator experience, and differences in antiplatelet regimens. Nevertheless, when broken down by event type, treatment-related mortality and hemorrhagic events were 1%, ischemic events 2%, and stroke 3%. These remain lower than rates reported in cohorts of large or giant aneurysms. Finally, the proportion of patients with favorable functional outcomes reached 98%, reinforcing the clinical benefit of flow diverter treatment in small aneurysms.

This study has several limitations. First, all included studies were retrospective in design, which may introduce selection bias. Second, the relatively small sample sizes of some studies limit the robustness of the pooled estimates. Third, variability in follow-up duration and imaging assessment criteria across studies may have contributed to heterogeneity in the results. Fourth, most of the included studies mixed ruptured and unruptured small aneurysms, with only a few reporting results separately. Because of limited available data, we were unable to conduct a subgroup meta-analysis by rupture status. Future studies should stratify and report outcomes by rupture status to reduce heterogeneity and improve the quality of evidence. Therefore, future large-scale, multicenter, prospective randomized controlled trials with standardized imaging assessments and long-term follow-up are warranted to further validate the efficacy and safety of FDs in SIAs.

5 Conclusion

In this systematic review and single-arm meta-analysis, flow diverters demonstrated high efficacy and acceptable safety in the treatment of small intracranial aneurysms. With an overall complete occlusion rate of 86% and a favorable functional outcome rate of 98%, FD treatment offers a promising therapeutic option. Nonetheless, the high heterogeneity and retrospective design of included studies highlight the need for prospective, multicenter randomized trials to validate these findings and establish standardized clinical protocols.

Data availability statement

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding authors.

Author contributions

KM: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Resources, Software, Visualization, Writing – original draft, Writing – review & editing. MN: Conceptualization, Investigation, Methodology, Resources, Writing – original draft, Writing – review & editing. AR: Investigation, Methodology, Visualization, Writing – review & editing. ASe: Data curation, Investigation, Software, Writing – review & editing. MY: Methodology, Software, Visualization, Writing – review & editing. XG: Investigation, Methodology, Resources, Writing – review & editing. MA: Investigation, Methodology, Software, Writing – review & editing. YX: Investigation, Methodology, Validation, Writing – review & editing. HP: Data curation, Investigation, Methodology, Writing – review & editing. ASi: Investigation, Methodology, Software, Writing – review & editing. YH: Conceptualization, Investigation, Methodology, Resources, Supervision, Writing – review & editing. DY: Conceptualization, Supervision, Validation, Writing – review & editing.

Funding

The author(s) declare that no financial support was received for the research and/or publication of this article.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declare that no Gen AI was used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fneur.2025.1706462/full#supplementary-material

References

1. Vlak, MH, Algra, A, Brandenburg, R, and Rinkel, GJ. Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis. Lancet Neurol. (2011) 10:626–36. doi: 10.1016/S1474-4422(11)70109-0

PubMed Abstract | Crossref Full Text | Google Scholar

2. Asikainen, A, Korja, M, Kaprio, J, and Rautalin, I. Case fatality in patients with aneurysmal subarachnoid Hemorrhage in Finland: a Nationwide register-based study. Neurology. (2023) 100:e348–56. doi: 10.1212/WNL.0000000000201402

PubMed Abstract | Crossref Full Text | Google Scholar

3. Zhang, H, Li, L, Zhang, H, Liu, J, Song, D, Zhao, Y, et al. Small and medium-sized aneurysm outcomes following intracranial aneurysm treatment using the pipeline embolization device: a subgroup analysis of the plus registry. Front Neurol. (2022) 13:881353. doi: 10.3389/fneur.2022.881353

PubMed Abstract | Crossref Full Text | Google Scholar

4. Morita, A, Kirino, T, Hashi, K, Aoki, N, Fukuhara, S, Hashimoto, N, et al. The natural course of unruptured cerebral aneurysms in a Japanese cohort. N Engl J Med. (2012) 366:2474–82. doi: 10.1056/NEJMoa1113260

Crossref Full Text | Google Scholar

5. Deshmukh, AS, Priola, SM, Katsanos, AH, Scalia, G, Costa Alves, A, Srivastava, A, et al. The Management of Intracranial Aneurysms: current trends and future directions. Neurol Int. (2024) 16:74–94. doi: 10.3390/neurolint16010005

PubMed Abstract | Crossref Full Text | Google Scholar

6. Jin, J, Guo, G, Ren, Y, Yang, B, Wu, Y, Wang, S, et al. Risk factors for recurrence of intracranial aneurysm after coil embolization: a Meta-analysis. Front Neurol. (2022) 13:869880. doi: 10.3389/fneur.2022.869880

PubMed Abstract | Crossref Full Text | Google Scholar

7. Park, DS, Roh, HG, Chun, YI, and Jeon, YS. Efficacy of coil embolization in small, anterior circulation aneurysms in patients less than 40 years old. J Clin Med. (2024) 13:4764. doi: 10.3390/jcm13164764

PubMed Abstract | Crossref Full Text | Google Scholar

8. Booth, TC, Bassiouny, A, Lynch, J, Sonwalkar, H, Bleakley, A, Iqbal, A, et al. Outcome study of the pipeline vantage embolization device (second version) in unruptured (and ruptured) aneurysms (Pedvu(R) study). J Neurointerv Surg. (2024) 16:1136–44. doi: 10.1136/jnis-2023-020754

PubMed Abstract | Crossref Full Text | Google Scholar

9. Shehata, MA, Ibrahim, MK, Ghozy, S, Bilgin, C, Jabal, MS, Kadirvel, R, et al. Long-term outcomes of flow diversion for unruptured intracranial aneurysms: a systematic review and meta-analysis. J Neurointerv Surg. (2023) 15:898–902. doi: 10.1136/jnis-2022-019240

PubMed Abstract | Crossref Full Text | Google Scholar

10. Elek, A, Karagoz, S, Dindar, GN, Yucel, S, Cinar, C, Kusbeci, M, et al. Safety and efficacy of low profile flow diverter stents for intracranial aneurysms in small parent vessels: systematic review and meta-analysis. J Neurointerv Surg. (2025), 1–8. doi: 10.1136/jnis-2024-022834

Crossref Full Text | Google Scholar

11. Hanel, RA, Cortez, GM, Lopes, DK, Nelson, PK, Siddiqui, AH, Jabbour, P, et al. Prospective study on embolization of intracranial aneurysms with the pipeline device (Premier study): 3-year results with the application of a flow diverter specific occlusion classification. J Neurointerv Surg. (2023) 15:248–54. doi: 10.1136/neurintsurg-2021-018501

PubMed Abstract | Crossref Full Text | Google Scholar

12. Li, L, Gao, BL, Shao, QJ, Zhang, GL, Wang, ZL, Li, TX, et al. Small unruptured intracranial aneurysms can be effectively treated with flow-diverting devices. Front Neurol. (2022) 13:913653. doi: 10.3389/fneur.2022.913653

PubMed Abstract | Crossref Full Text | Google Scholar

13. Page, MJ, Mckenzie, JE, Bossuyt, PM, Boutron, I, Hoffmann, TC, Mulrow, CD, et al. The Prisma 2020 statement: an updated guideline for reporting systematic reviews. BMJ. (2021) 372:n71. doi: 10.1136/bmj.n71

Crossref Full Text | Google Scholar

14. Munn, Z, Barker, TH, Moola, S, Tufanaru, C, Stern, C, Mcarthur, A, et al. Methodological quality of case series studies: an introduction to the Jbi critical appraisal tool. Jbi Evid Synth. (2020) 18:2127–33. doi: 10.11124/JBISRIR-D-19-00099

PubMed Abstract | Crossref Full Text | Google Scholar

15. Akgul, E, Onan, HB, Bilgin, SS, Tahta, A, Khanmammadov, E, Gungoren, FZ, et al. Flow diverter stents in the treatment of cerebral aneurysms less than 5 mm. Turk Neurosurg. (2021) 31:31–7. doi: 10.5137/1019-5149.JTN.28762-19.2

PubMed Abstract | Crossref Full Text | Google Scholar

16. Brasiliense, LBC, Aguilar-Salinas, P, Lopes, DK, Nogueira, D, Desousa, K, Nelson, PK, et al. Multicenter study of pipeline flex for intracranial aneurysms. Neurosurgery. (2019) 84:E402–e409. doi: 10.1093/neuros/nyy422

PubMed Abstract | Crossref Full Text | Google Scholar

17. Chalouhi, N, Zanaty, M, Whiting, A, Yang, S, Tjoumakaris, S, Hasan, D, et al. Safety and efficacy of the pipeline embolization device in 100 small intracranial aneurysms. J Neurosurg. (2015) 122:1498–502. doi: 10.3171/2014.12.JNS14411

PubMed Abstract | Crossref Full Text | Google Scholar

18. Clausen, TM, Nakamura, R, Conching, A, Choi, JW, Zhang, YJ, Hui, F, et al. Flow diversion in the treatment of intracranial aneurysms using the novel Fred X device: an early experience from a single high-volume center. Interv Neuroradiol. (2025) 15910199251319059:10. doi: 10.1177/15910199251319059

PubMed Abstract | Crossref Full Text | Google Scholar

19. Griessenauer, CJ, Ogilvy, CS, Foreman, PM, Chua, MH, Harrigan, MR, He, L, et al. Pipeline embolization device for small intracranial aneurysms: evaluation of safety and efficacy in a multicenter cohort. Neurosurgery. (2017) 80:579–87. doi: 10.1227/NEU.0000000000001377

PubMed Abstract | Crossref Full Text | Google Scholar

20. Kallmes, DF, Hanel, R, Lopes, D, Boccardi, E, Bonafé, A, Cekirge, S, et al. International retrospective study of the pipeline embolization device: a multicenter aneurysm treatment study. AJNR Am J Neuroradiol. (2015) 36:108–15. doi: 10.3174/ajnr.A4111

PubMed Abstract | Crossref Full Text | Google Scholar

21. Lin, LM, Colby, GP, Kim, JE, Huang, J, Tamargo, RJ, and Coon, AL. Immediate and follow-up results for 44 consecutive cases of small (<10 mm) internal carotid artery aneurysms treated with the pipeline embolization device. Surg Neurol Int. (2013) 4:114. doi: 10.4103/2152-7806.117711

Crossref Full Text | Google Scholar

22. Roy, JM, El Naamani, K, Amaravadi, C, Majmundar, S, Mouchtouris, N, Paul, AR, et al. Long-term safety and efficacy of the Fred X flow diverter for intracranial aneurysms: a multicenter study of 154 patients. J Neurosurg. (2025) 143:232–42. doi: 10.3171/2024.10.JNS241233

PubMed Abstract | Crossref Full Text | Google Scholar

23. Trivelato, FP, Salles Rezende, MT, Ulhôa, AC, Henrique De Castro-Afonso, L, Nakiri, GS, and Abud, DG. Occlusion rates of intracranial aneurysms treated with the pipeline embolization device: the role of branches arising from the sac. J Neurosurg. (2018) 130:543–9. doi: 10.3171/2017.10.JNS172175

PubMed Abstract | Crossref Full Text | Google Scholar

24. Hanel, RA, Kallmes, DF, Lopes, DK, Nelson, PK, Siddiqui, A, Jabbour, P, et al. Prospective study on embolization of intracranial aneurysms with the pipeline device: the Premier study 1 year results. J Neurointerv Surg. (2020) 12:62–6. doi: 10.1136/neurintsurg-2019-015091

PubMed Abstract | Crossref Full Text | Google Scholar

25. Bhatia, KD, Kortman, H, Orru, E, Klostranec, JM, Pereira, VM, and Krings, T. Periprocedural complications of second-generation flow diverter treatment using pipeline flex for unruptured intracranial aneurysms: a systematic review and meta-analysis. J Neurointerv Surg. (2019) 11:817–24. doi: 10.1136/neurintsurg-2019-014937

PubMed Abstract | Crossref Full Text | Google Scholar

26. Fiorella, D, Gache, L, Frame, D, and Arthur, AS. How safe and effective are flow diverters for the treatment of unruptured small/medium intracranial aneurysms of the internal carotid artery? Meta-analysis for evidence-based performance goals. J Neurointerv Surg. (2020) 12:869–73. doi: 10.1136/neurintsurg-2019-015535

PubMed Abstract | Crossref Full Text | Google Scholar

Keywords: flow diverters, small intracranial aneurysms, intracranial aneurysms, FDs, meta-analysis

Citation: Maimaitiaili K, Nuermaimaiti M, Rouzi A, Seyiti A, Yasheng M, Guo X, Abulaiti M, Xiao Y, Pan H, Sidike A, Hu Y and Yilamu D (2025) Efficacy and safety of flow diverters in small intracranial aneurysms: a systematic review and single-arm meta-analysis. Front. Neurol. 16:1706462. doi: 10.3389/fneur.2025.1706462

Received: 16 September 2025; Revised: 23 October 2025; Accepted: 07 November 2025;
Published: 26 November 2025.

Edited by:

Osama O. Zaidat, Northeast Ohio Medical University, United States

Reviewed by:

Muhammad Hussain Ahmadvand, Tehran University of Medical Sciences, Iran
Shenghao Ding, Renji Hospital, Shanghai Jiao Tong University, China

Copyright © 2025 Maimaitiaili, Nuermaimaiti, Rouzi, Seyiti, Yasheng, Guo, Abulaiti, Xiao, Pan, Sidike, Hu and Yilamu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Yanbing Hu, MTQyODMxOTQ4OEBxcS5jb20=; Dawutijiang Yilamu, a2VkYXd1dGphbkAxNjMuY29t

These authors have contributed equally to this work and share first authorship

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.