Skip to main content
Download PDF

Therapeutic Effects of Microsurgical Clipping at Different Time Points on Intracranial Aneurysm and Prognostic Factors

Artery Research volume 27, pages 135–142 (2021)Cite this article

Abstract

Background

Microsurgical clipping is effective for treating early rupture hemorrhage in intracranial aneurysm (IA) patients. We aimed to evaluate the therapeutic effects of microsurgical clipping at different time points on IA and to explore prognostic factors.

Methods

A total of 102 eligible patients were divided into good prognosis group (n = 87) and poor prognosis group (n = 15) according to Glasgow Outcome Scale (GOS) scores at discharge. The effects of microsurgical clipping at different time points (within 24 h, 48 h and 72 h) were compared. The incidence rates of postoperative complications in patients with different Hunt–Hess grades were compared. Prognostic factors were determined by multivariate logistic regression analysis. The nomogram prediction model was established based on independent risk factors and validated.

Results

The good recovery and success rates of complete aneurysm clipping were significantly higher in patients undergoing surgery within 24 h after rupture. The incidence rate of complications was significantly higher in patients with Hunt–Hess grade IV. Good and poor prognosis groups had significantly different age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, later surgery, postoperative complications and National Institute of Health Stroke Scale (NIHSS) score, as independent risk factors for prognosis. The nomogram model predicted that poor prognosis rate was 14.71%.

Conclusion

Timing (within 24 h after rupture) microsurgical clipping benefits the prognosis of IA patients. Age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, later surgery, postoperative complications and NIHSS score are independent risk factors for poor prognosis.

Introduction

As a cerebrovascular disease with abnormal tumor-like protrusions on the intracranial arterial walls [1], intracranial aneurysm (IA) is mainly caused by hypertension, atherosclerosis, vasculitis or local congenital defects in intracranial arterial walls [2]. IA will gradually develop and expand, ultimately resulting in rupture. The incidence rate of IA rupture is second only to that of cerebral thrombosis and hypertensive cerebral hemorrhage in patients with cerebrovascular diseases. The fatality rate of initial rupture hemorrhage can be up to 15% [3], seriously threatening the life health and significantly reducing the quality of life of patients. After IA diagnosis, the condition of disease should be assessed immediately, and complications should be avoided as far as possible through the most effective treatment means [4]. Currently, the major treatment methods for IA rupture are endovascular interventional therapy and microsurgical treatment, and aneurysm clipping is the preferred method in the latter, which is also regarded as the golden standard for the treatment of IA [5]. Early surgery refers to surgery performed within 72 h after IA rupture, and it can eliminate intracranial hematoma promptly and lower the incidence and risk of re-bleeding [6]. Microsurgical clipping is effective for treating early aneurysm rupture hemorrhage in IA patients, and the sooner it is performed after hemorrhage, the better the surgical effect will be, which can significantly reduce the incidence of postoperative complications, and produce a better prognosis [7]. In the present study, the effects of microsurgical clipping at different time points on IA were explored, and the influencing factors for the prognosis were analyzed.

Materials and Methods

General Data

A total of 102 IA patients undergoing microsurgical clipping from January 2017 to January 2019 in our hospital were selected as the objects, including 49 males and 53 females aged 33–72 years old, with an average of (56.54 ± 5.62) years old. All patients underwent aneurysm clipping within 72 h after IA rupture, including 21 cases within 24 h, 54 cases at 24–48 h, and 27 cases at 48–72 h. According to the postoperative treatment effect, the patients were divided into good prognosis group (n = 87) and poor prognosis group (n = 15).

Inclusion criteria were as follows: (1) patients diagnosed with IA by digital subtract angiography (DSA), CT angiography (CTA) or/and magnetic resonance angiography (MRA); (2) those in preoperative Hunt–Hess grade I–IV. The Hunt–Hess grading system, which describes the severity of subarachnoid hemorrhage due to intracerebral aneurysm rupture, is utilized to predict survival in clinical practice. Grade I: Asymptomatic or mild headache and neck stiffness; grade II: moderate to severe headache and neck stiffness, without neurologic deficit except for cranial nerve palsy; grade III: drowsy, with mild neurologic deficit; grade IV: stuporous, moderate to severe hemiparesis, with the possibility of early decerebrate rigidity and vegetative disturbances; grade V: deep coma, decerebrate rigidity and moribund; (3) those undergoing microsurgical clipping in our hospital; (4) those with complete medical records.

Exclusion criteria were as follows: (1) patients aged > 75 years old; (2) those with red blood cell, infectious, mental or other neurological diseases; (3) those with severe insufficiency of the heart, lung, liver, kidney or spleen. Seven cases were excluded, including one patient older than 75 years, three patients suffering from red blood cell, infectious, mental or other neurological diseases, and another three patients suffering from severe insufficiency of the heart, lung, liver, kidney or spleen.

This study was approved by the Ethics Committee of our hospital, and the patients and their families signed the informed consent.

Surgical Methods

All patients with IA underwent early surgery, namely microsurgical clipping within 72 h after aneurysm hemorrhage. The location of aneurysm was determined by CTA combined with DSA, the appropriate approach was selected, and the patient received general anesthesia with tracheal intubation in a supine position. If the patient had intracranial hypertension, mannitol was intravenously infused additionally. The lateral fissure cistern and the carotid cistern were dissected and separated under a microscope. The optic chiasm cistern was opened, and the cerebrospinal fluid was slowly released to fully expose the parent artery. Then, the aneurysmal neck was separated and clipped using appropriate clipping forceps, followed by wet dressing using papaverine cotton pads. During operation, the patient's blood pressure, blood gas and electrocardiogram were monitored.

Collection of Clinical Data

The general data of all patients were collected through the electronic medical record system, including age, gender, body mass index (BMI), preoperative Hunt–Hess grade (I, II, III and IV), history of hypertension, preoperative intracranial hematoma volume, aneurysm size, timing of surgery, length of hospital stay, postoperative complications (cerebral vasospasm, aneurysm rupture, cerebral edema, cerebral infarction, intracranial infection, and severe pulmonary infection), and the National Institute of Health Stroke Scale (NIHSS) score upon admission to hospital.

Assessment of Surgical Treatment Outcomes

The short-term prognosis of patients was assessed using the Glasgow Outcome Scale (GOS) score at discharge [8], as follows: 5 points (good recovery): the patient returned to normal life at discharge; 4 points (mild disability): the patient was disabled at discharge but could live independently; 3 points (severe disability): the patient was awake and disabled at discharge, and could act as instructed but needed daily care; 2 points (vegetative state): the patient could not interact with the outside world at discharge, and only had the least response; 1 point: death. 4–5 points indicate a good prognosis, while 1–3 points indicate a poor prognosis.

The postoperative clipping status (complete clipping, most clipping, and partial clipping) was recorded.

Statistical Analysis

SPSS 19.0 software was used for one-way analysis of variance of data. The t test and χ2 test were performed to compare the differences between two groups. The factors affecting the prognosis of IA patients were explored through multivariable logistic regression analysis and the variables with statistically significant differences were assigned values. The nomogram prediction model was established using R software (R3.3.2) and rms software package. The discrimination of the model was evaluated using receiver operating characteristic (ROC) curves, and the area under the curve was calculated. Concordance index (C-index) ranges from 0.5 to 1, and the value closer to 1 indicates that the prediction result is closer to the truth. Bootstrap method was used for internal validation. The actual C-index was compared with the internally validated C-index, and the closer the difference is to 0, the better the conformance of the model. Besides, 80 patients undergoing microsurgical clipping from February 2019 to August 2019 in our hospital were selected for external validation, and C-index was calculated to assess the accuracy of the model. The inclusion and exclusion criteria were the same as those in this study. P < 0.05 suggested statistically significant difference.

Results

General Data

According to the GOS score at discharge, the patients were divided into good prognosis group and poor prognosis group, and the general data were compared between the two groups. There were statistically significant differences in age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, timing of surgery, length of hospital stay, postoperative complications and NIHSS score between the two groups (P < 0.05) (Table 1).

Table 1 General data
Full size table

Therapeutic Effect of Surgery at Different Time Points

The therapeutic effect of microsurgical clipping at different time points after aneurysm rupture on IA patients was compared. It was found that the good recovery rate was significantly higher among patients undergoing surgery within 24 h (85.71%) than that among patients undergoing surgery within 48 h (74.07%) and 72 h (59.26%) (P < 0.05). There were 87 cases with a good prognosis and 15 cases with a poor prognosis. Patients undergoing surgery within 24 h had a significantly higher good prognosis rate and a significantly lower poor prognosis rate than those undergoing surgery within 48 h and 72 h (P < 0.05) (Table 2).

Table 2 Therapeutic effects of surgery at different time points
Full size table

Status After Microsurgical Clipping at Different Time Points

The aneurysm clipping status after microsurgical clipping at different time points was compared among patients. The results showed that the proportion of complete clipping was significantly higher among patients undergoing surgery within 24 h than that among patients undergoing surgery within 48 h and 72 h, showing statistically significant differences (P < 0.05). Patients undergoing surgery within 24 h had significantly lower proportions of most clipping and partial clipping than those undergoing surgery within 48 h and 72 h, and there were statistically significant differences (P < 0.05) (Table 3).

Table 3 Status after microsurgical clipping at different time points
Full size table

Postoperative Complications Among Patients with Different Hunt–Hess Grades

The incidence rate of complications was significantly higher among patients in preoperative Hunt–Hess grade IV than that among patients in Hunt–Hess grade I–III, and the difference was statistically significant (P < 0.05) (Table 4).

Table 4 Postoperative complications among patients with different Hunt–Hess grades
Full size table

Multivariable Logistic Regression Analysis Results of Prognostic Factors

With the general data with statistically significant differences in both groups as independent variables (Table 1), and the prognosis (0 = good prognosis, 1 = poor prognosis) of patients as the dependent variable, the influencing factors for the prognosis of IA patients were analyzed through logistic regression analysis. The results manifested that age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, later surgery, postoperative complications and NIHSS score were all independent risk factors for the poor prognosis of IA patients (Table 5).

Table 5 Multivariable logistic regression analysis results of prognostic factors
Full size table

Establishment of Nomogram Prediction Model

Variables affecting the prognosis of patients were assigned values (Table 6), and the nomogram prediction model was established using R software. Age ≥ 58 years old, presence of history of hypertension, preoperative intracranial hematoma volume ≥ 20 mL, aneurysm size ≥ 8 mm, preoperative Hunt–Hess grade IV, surgery performed within 72 h, presence of postoperative complications and NIHSS score ≥ 13 points were scored 20 points, 25 points, 27 points, 25 points, 24 points, 32 points and 25 points, respectively. The value corresponding to the total score (196 points) indicated the incidence rate of poor prognosis of patients (14.71%) predicted by the model (Fig. 1).

Table 6 Variable assignment
Full size table
Fig. 1
figure 1

Nomogram prediction model of prognostic factors. According to the influence of factors on prognosis, corresponding points were assigned, and those of all factors were summed up to predict the probability of poor prognosis

Full size image

Validation of Nomogram Prediction Model

The discrimination of the model was detected to assess the conformance of the model. The actual C-index of the model was 0.815, the internally validated C-index was 0.809, and the externally validated C-index was 0.805. It can be seen that the difference between the actual C-index of the model and the internally validated C-index was 0.006, indicating good concordance and high accuracy (Fig. 2).

Fig. 2
figure 2

Evaluation of nomogram prediction model for poor prognosis. A ROC curve of internal validation for 102 IA patients undergoing microsurgical clipping from January 2017 to January 2019, which compares the established model and actual results. B ROC curve of external validation for 80 patients undergoing microsurgical clipping from February 2019 to August 2019, which assesses the accuracy of this model

Full size image

Discussion

As a common neurosurgery disease, IA seriously affects the lives of patients after rupture, with extremely high mortality and disability rates [9]. IA is commonly treated by clipping after craniotomy and endovascular embolization in clinical practice [10]. The treatment outcomes of clipping have been markedly improved using microscopes. Compared with microsurgical clipping, endovascular embolization is safer and less traumatic [11]. Additionally, endovascular embolization can be used to treat patients for whom surgical clipping is unsuitable. For instance, endovascular embolization is the first choice for elderly patients, those with complicated IA or narrow necks, or those intolerable to surgery [12]. However, the coils for embolization are irregularly shaped, which may cause blood flow disorder, aggravate histological defects and lead to IA recurrence. In addition, placing coils may induce IA rupture hemorrhage [13]. Moreover, microsurgical clipping has the advantages of high early clearance rate and low incidence rate of vasospasm. Notably, microsurgical clipping is preferable for patients with anterior circulation aneurysms or failed history of endovascular embolization [14].

In recent years, microsurgical clipping has become the golden standard for the microsurgical treatment of IA, which can eliminate the aneurysm from the normal blood circulation in patients, ensuring the sufficient blood perfusion in brain tissues [15]. However, fatal complications may also be caused in IA patients during and after microsurgical clipping. As the most common and serious complications during microsurgical clipping, cerebral vasospasm and aneurysm rupture greatly disturb the operation process, prolong the duration of operation and even threaten the life of patients [16]. Therefore, it is of great importance to analyze the complications during microsurgical clipping for IA, take targeted prevention measures and develop reasonable therapeutic regimens for reducing the disability and mortality rates of patients.

Early surgery refers to microsurgical clipping performed within 72 h after IA rupture [17]. Currently, the timing of microsurgical clipping for IA has always been controversial [18], but it has been confirmed that early surgery can avoid the worsening of conditions and prevent IA re-rupture and re-bleeding [19]. Early surgery can promptly remove blood clots or hematomas in the cistern, thereby effectively lowering the incidence rate of complications such as cerebral vasospasm. However, the risk of death and disability in patients may also be raised by early surgery [20]. It has been reported that the mortality rate greatly declines in patients above preoperative Hunt–Hess grade IV after early surgery, suggesting that severely ill patients with IA should receive operation promptly after aneurysm rupture and bleeding [21]. In the present study, the effect of microsurgical clipping at different time points on IA was compared. The results manifested that patients undergoing surgery within 24 h after aneurysm rupture had a significantly higher good recovery rate and a good prognosis rate, and a significantly lower poor prognosis rate than those undergoing surgery within 48 h and 72 h. It has been found that the sooner the microsurgical clipping is performed after aneurysm rupture in IA patients, the higher the success rate of complete aneurysm clipping will be [22]. In this study, the success rate of complete aneurysm clipping was significantly higher among patients undergoing surgery within 24 h than that among patients undergoing surgery within 48 h and 72 h. It can be inferred that the sooner the microsurgical clipping is performed after aneurysm rupture, the better the effect on IA patients will be.

After microsurgical clipping, severe complications, such as aneurysm re-rupture, cerebral vasospasm, cerebral infarction, cerebral edema, pulmonary infection and intracranial infection, easily occur among IA patients [23]. It can be seen that the preoperative Hunt–Hess grade of IA patients has a close correlation with the incidence of postoperative complications.

Many factors are involved in the prognosis of IA patients after microsurgical clipping. It has been confirmed that age, preoperative Hunt–Hess grade, aneurysm size, and presence or absence of complications are all independent risk factors for the prognosis of IA patients [24]. In this study, age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, later surgery, postoperative complications and NIHSS score were all independent risk factors for the poor prognosis of IA patients. Besides, the established model can effectively predict the risk factors for the death of patients, with high accuracy.

Conclusion

In conclusion, timing (within 24 h after aneurysm rupture) microsurgical clipping benefits the prognosis of IA patients. Age, history of hypertension, preoperative intracranial hematoma volume, aneurysm size, preoperative Hunt–Hess grade, later surgery, postoperative complications and NIHSS score are all independent risk factors for the poor prognosis of IA patients.

Data availability

The data that support the findings of this study are available from the corresponding author, X.T., upon reasonable request.

References

  1. Roloff C, Stucht D, Beuing O, Berg P. Comparison of intracranial aneurysm flow quantification techniques: standard PIV vs stereoscopic PIV vs tomographic PIV vs phase-contrast MRI vs CFD. J Neurointerv Surg. 2019;11:275–82.

    Article  Google Scholar 

  2. Park JM, Kim BJ, Kwon SU, Hwang YH, Heo SH, Rha JH, et al. Intensive blood pressure control may not be safe in subacute ischemic stroke by intracranial atherosclerosis: a result of randomized trial. J Hypertens. 2018;36:1936–41.

    CAS  Article  Google Scholar 

  3. Kataoka H, Nakagawa S, Takahashi JC, Takagi Y. Current status of problems with initial treatment for aneurysmal subarachnoid hemorrhage. Jpn J Neurosurg. 2019;28:542–51.

    Article  Google Scholar 

  4. Burkhardt JK, Chua MH, Winkler EA, Rutledge WC, Lawton MT. Incidence, classification, and treatment of angiographically occult intracranial aneurysms found during microsurgical aneurysm clipping of known aneurysms. J Neurosurg. 2019;132:434–41.

    Article  Google Scholar 

  5. Kosty JA, Andaluz NO, Gozal YM, Krueger BM, Scoville J, Zuccarello M. Microsurgical treatment for unruptured intracranial aneurysms: a modern single surgeon series. Br J Neurosurg. 2019;33:322–7.

    CAS  Article  Google Scholar 

  6. Jiang S, Xie X. Early interventional embolization in the treatment of cerebral aneurysm rupture. Pak J Med Sci. 2018;34:1463–7.

    Article  Google Scholar 

  7. Marbacher S, Spiessberger A, Diepers M, Remonda L, Fandino J. Early intracranial aneurysm recurrence after microsurgical clip ligation: case report and review of the literature. J Neurol Surg Rep. 2018;79:e93–7.

    Article  Google Scholar 

  8. Huh CW, Lee JI, Choi CH, Lee TH, Choi JY, Ko JK. Endosaccular treatment of very large and giant intracranial aneurysms with parent artery preservation: single center experience with long term follow-up. J Korean Neurosurg Soc. 2018;61:450–7.

    Article  Google Scholar 

  9. Zhang X, Zuo Q, Tang H, Xue G, Yang P, Zhao R, et al. Stent assisted coiling versus non-stent assisted coiling for the management of ruptured intracranial aneurysms: a meta-analysis and systematic review. J Neurointerv Surg. 2019;11:489–96.

    Article  Google Scholar 

  10. Ellis JA, Nossek E, Kronenburg A, Langer DJ, Ortiz RA. Intracranial aneurysm: diagnostic monitoring, current interventional practices, and advances. Curr Treat Option Cardiovasc Med. 2018;20:94.

    Article  Google Scholar 

  11. Ruan C, Long H, Sun H, He M, Yang K, Zhang H, et al. Endovascular coiling vs. surgical clipping for unruptured intracranial aneurysm: a meta-analysis. Br J Neurosurg. 2015;29:485–92.

    Article  Google Scholar 

  12. Ilyas A, Buell TJ, Chen CJ, Ding D, Raper DM, Taylor DG, et al. SMART coils for intracranial aneurysm embolization: initial outcomes. Clin Neurol Neurosurg. 2018;164:87–91.

    Article  Google Scholar 

  13. Park YK, Yi HJ, Choi KS, Lee YJ, Chun HJ. Intraprocedural rupture during endovascular treatment of intracranial aneurysm: clinical results and literature review. World Neurosurg. 2018;114:e605–15.

    Article  Google Scholar 

  14. Arnaout OM, El Ahmadieh TY, Zammar SG, El Tecle NE, Hamade YJ, Aoun RJ, et al. Microsurgical treatment of previously coiled intracranial aneurysms: systematic review of the literature. World Neurosurg. 2015;84:246–53.

    Article  Google Scholar 

  15. Seng LB, Yamada Y, Rajagopal N, Mohammad AA, Teranishi T, Miyatani K, et al. Multimodality techniques in microsurgical clipping as the gold standard treatment in the management of basilar tip aneurysm: a case series. Asian J Neurosurg. 2018;13:1148–57.

    Article  Google Scholar 

  16. Jang KM, Choi HH, Nam TK, Park YS, Kwon JT. Arachnoid plasty to prevent and reduce chronic subdural hematoma after clipping surgery for unruptured intracranial aneurysm: a meta-analysis. J Korean Neurosurg Soc. 2020;63:455–62.

    CAS  Article  Google Scholar 

  17. Kim JJ, Cho KC, Suh SH, Chung J, Jang CK, Joo JY, et al. Evaluation of the angiographic outcomes after clipping of intracranial aneurysms: determination of predisposing factors for occurrence of aneurysm remnants. Neurol Res. 2020;42:354–60.

    Article  Google Scholar 

  18. O’Donnell JM, Morgan MK, Manuguerra M. Functional outcomes and quality of life after microsurgical clipping of unruptured intracranial aneurysms: a prospective cohort study. J Neurosurg. 2018;130:278–85.

    Article  Google Scholar 

  19. Chen J, Zhu J, He J, Wang Y, Chen L, Zhang C, et al. Ultra-early microsurgical treatment within 24 h of SAH improves prognosis of poor-grade aneurysm combined with intracerebral hematoma. Oncol Lett. 2016;11:3173–8.

    CAS  Article  Google Scholar 

  20. Dasenbrock HH, Smith TR, Rudy RF, Gormley WB, Aziz-Sultan MA, Du R. Reoperation and readmission after clipping of an unruptured intracranial aneurysm: a National Surgical Quality Improvement Program analysis. J Neurosurg. 2017;128:756–67.

    Article  Google Scholar 

  21. Munich SA, Vakharia K, McPheeters MJ, Tso MK, Waqas M, Snyder KV, et al. Make clipping great again: microsurgery for cerebral aneurysms by dual-trained neurosurgeons. World Neurosurg. 2020;137:e454–61.

    Article  Google Scholar 

  22. Alijani B, Emamhadi M, Yosefzadeh Chabok S, Jafari S, Naseri A. Surgical protocol and outcome of 60 cases with intracranial aneurysm. Iran J Neurosurg. 2018;4:75–82.

    Article  Google Scholar 

  23. Kateryna G, Michaela-Maria SL, Camillo S. Economic comparison between endovascular coiling vs neurosurgical clipping for ruptured and unruptured intracranial aneurysms in Austria. Neurosurgery. 2019;84:272–3.

    Article  Google Scholar 

  24. Zheng K, Zhong M, Zhao B, Chen SY, Tan XX, Li ZQ, et al. Poor-grade aneurysmal subarachnoid hemorrhage: risk factors affecting clinical outcomes in intracranial aneurysm patients in a multi-center study. Front Neurol. 2019;10:123.

    Article  Google Scholar 

Download references

Acknowledgements

This study was not financially supported.

Funding

This study was not financially supported.

Author information

Authors and Affiliations

  1. Department of Graduate School, Tianjin Medical University, Tianjin, 300350, China

    Ge Huang, Yang Sun & Xiaoguang Tong

  2. Department of Neurosurgery, Jiangmen Central Hospital, Jiangmen, 529030, Guangdong Province, China

    Ge Huang, Jinhong Li & Zhengyuan Xie

  3. Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, 300350, China

    Xiaoguang Tong

Authors
  1. Ge Huang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Yang Sun
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jinhong Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Zhengyuan Xie
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Xiaoguang Tong
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

GH & XT designed this study and prepared this manuscript; YS, JL & ZX collected and analyzed clinical data. All authors approve the publication of this manuscript.

Corresponding author

Correspondence to Xiaoguang Tong.

Ethics declarations

Conflict of interest

The authors declare they have no conflicts of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Huang, G., Sun, Y., Li, J. et al. Therapeutic Effects of Microsurgical Clipping at Different Time Points on Intracranial Aneurysm and Prognostic Factors. Artery Res 27, 135–142 (2021). https://doi.org/10.1007/s44200-021-00001-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s44200-021-00001-x

Keywords

  • Time point
  • Microsurgical clipping
  • Intracranial aneurysm
  • Prognosis

Artery Research

ISSN: 1876-4401

Contact us