|Year : 2019 | Volume
| Issue : 2 | Page : 422-426
Small aneurysms should be clipped?
Gustavo Noleto1, Nícollas Nunes Rabelo1, Leonardo Abaurre1, Hugo Sterman Neto1, Mario Siqueira1, Manoel J Teixeira2, Eberval Gadelha Figueiredo1
1 Department of Neurosurgery, University of São Paulo Medical School, São Paulo, Brazil
2 Department of Neurosurgery, São Paulo University, São Paulo, Brazil
|Date of Web Publication||26-Apr-2019|
Eberval Gadelha Figueiredo
Av. Dr. Enéas De Carvalho Aguiar, 255, Cerqueira César, São Paulo 01246-000
Source of Support: None, Conflict of Interest: None
Background: Cerebral aneurysm prevalence may vary from 0.4% to 10%. The decision to treat or not incidental aneurysms remains controversial, especially when the lesions are small (<5 mm). Many recent publications are demonstrating that these lesions often bleed. Methods: We reviewed admitted patients with angiographic studies submitted to intracranial aneurysm surgical treatment from April 2012 to July 2013 in the Neurosurgery Department of São Paulo Medical School University (15 months), to define the rate and risk of bleeding. In addition, we proceeded literature review with collected 357 papers (past 5 years) which were selected 50 that were focused on our research. Clinical patients' status at the time of discharge was evaluated with the modified Rankin scale. Results: A series of 118 cases of surgically clipped aneurysms was analyzed: 73.7% woman; Ruptured (61 cases, 51%); middle cerebral artery (51 cases, 43%) was the more common aneurysm. Small size (<5 mm) was 25 cases (21%); that 2 died (16%), 3 (25%) with severe disability,restricted to bed and dependent on nursing care; blood pressure was the main risk factors (56%); and an aneurysm <2 mm (100%) was ruptured. Conclusion: The number of small aneurysms in our series was significant (25 cases, 21%), and its rate of bleeding was high (25 cases, 48%), resulting in death and disability in a significant number of cases. Our tendency is for surgical treatment when it is associated with risk factors.
Keywords: Aneurysm clipped, cerebral hemorrhage, intracranial aneurysm, small cerebral aneurysm, subarachnoid hemorrhage
|How to cite this article:|
Noleto G, Rabelo NN, Abaurre L, Neto HS, Siqueira M, Teixeira MJ, Figueiredo EG. Small aneurysms should be clipped?. Asian J Neurosurg 2019;14:422-6
|How to cite this URL:|
Noleto G, Rabelo NN, Abaurre L, Neto HS, Siqueira M, Teixeira MJ, Figueiredo EG. Small aneurysms should be clipped?. Asian J Neurosurg [serial online] 2019 [cited 2019 Nov 15];14:422-6. Available from: http://www.asianjns.org/text.asp?2019/14/2/422/252943
| Introduction|| |
Cerebral aneurysm prevalence may vary from 0.4% to 10%., The incidence of subarachnoid hemorrhage (SAH) ranges from 6 to 21.6 per 100,000 persons per year, depending on the study population and methodology.,, A more significant number of related cases have been identified with the development and availability of more sophisticated brain diagnostic methods. Despite this, the management of these aneurysm groups is still controversial. There is no consensus about the best treatment for an incidental aneurysm, especially when it is small.
According to the International Study of Unruptured Intracranial Aneurysms, the risk of rupture of anterior circulation aneurysms smaller than 7 mm is only 0.1% per year. However, experienced neurosurgeons and interventional neuroradiologists reported that, in clinical practice, small aneurysms are ruptured in most of the time,,,, and the SAH after small aneurysm rupture is often more significant, compared to massive aneurysm rupture.,
In this paper, the authors present one series analysis of small ruptured and intact aneurysms, treated surgically in the past 15 months, emphasizing clinical and surgical aspects of aneurysms smaller than 5 mm.
| Methods|| |
We reviewed the electronic files and admitted patients with angiographic studies submitted to intracranial aneurysm surgical treatment from April 2012 to July 2013 in the Neurosurgery Department of São Paulo Medical School University. This study was approval in our Institutional Board Review.
Patients were characterized by age and gender. The aneurysm localization, the occurrence of rupture, and the dimensions of the lesion were also observed, focusing in smaller aneurysms (<5 mm) and their powerful bleeding.
Aneurysms were arbitrarily classified according to its largest diameter: small (<5 mm), medium (5–10 mm), large (11–25 mm), and giant (>25 mm). In cases with more than one aneurysm, only the treatment with clipped lesion was considered.
Clinical patients' status at the time of discharge was evaluated with the modified Rankin scale (mRS) to characterize the related morbidity.
A Medline literature search in the past 5 years was performed using the terms: “an intracranial aneurysm,” “small cerebral aneurysm,” “cerebral hemorrhage,” “subarachnoid hemorrhage,” and “an aneurysm clipped.” We collected 357 papers from the literature search from which we selected 50 that were focused on our research. Articles published before the period of the search were eventually consulted given to its relevance to our discussion.
| Results|| |
During the 15-month period of the study, 125 patients underwent surgery for the treatment of cerebral aneurysms. Seven patients were due to incomplete information in the medical files.
Among the 118 patients considered for analysis, 31 (26.3%) were male and 87 (73.7%) female. The average age was 54.1 years, with a mean deviation of 8.07, ranging between 28 and 86 years. Ruptured aneurysms were prevalent in 61 patients (51.6%) and according to the Hunt-Hess scale were classified as Grade 1 (3 cases), Grade 2 (30 cases), Grade 3 (12 cases), Grade 4 (8 cases), and Grade 5 (6 cases).
The majority of the aneurysms were located in the middle cerebral artery (MCA; 51 cases, 43.2%; 25 ruptured and 26 unruptured), in the posterior communicating artery (23 cases, 19.4%; 13 ruptured and 10 unruptured), and in the anterior communicating artery (18 cases, 15.2%; 14 ruptured and 4 unruptured) showing in [Table 1]. In the small aneurysm group, the most common site of the lesion was MCA (15 cases, 60%; 5 ruptured and 10 unruptured) and Acoma (5 cases, 20%; all ruptured), representing in [Table 1].
|Table 1: Distribution by the topography of ruptured and unruptured aneurysms (all cases)|
Click here to view
Among the patients with small unruptured aneurysms submitted to surgery, all (13/13) evolved with mild symptoms, remaining functional and independent for most daily activities (mRS-0, mRS-1, and mRS-2). Considering the 12 cases of aneurysms with <5 mm in diameter, two of these patients (16.6%) died – mRS-6. Three (25%) evolved with severe disability, restricted to bed, dependent on nursing care – mRS-5 [Table 2].
|Table 2: Distribution by the topography of ruptured and unruptured (aneurysms <5 mm)|
Click here to view
According to the size, the aneurysms were classified as small (25 cases, 21%), medium (61 cases, 52%), large (28 cases, 24%), and giant (4 cases, 3%). The bleeding rate for the aneurysms of small size was 48%, 57% for the medium size, 46% for the large, and 25% for the giant aneurysms.
Among the risk factors, high blood pressure was found in 14 patients (56%) with small aneurysms (6 in the ruptured group and 8 in the unruptured), dyslipidemia in 6 patients (24%), smoking in 3 (12%), and diabetes mellitus in 2 (8%). The mean age of the patients with small aneurysms was 50.32 ± 11.48 years.
Stratifying the patients with smaller than five aneurysms in three subgroups, namely: I (5–4.1 mm), 7 cases; II (4–2.1 mm), 15 cases; and III (≤2 mm), 3 cases, we observed a prevalence of rupture of 42.8% (3/7) in the first, 40% (6/15) in the second, and 100% (3/3) in the third subgroup, with a respective mean age of 51.1 ± 12.4, 51.8 ± 9.8, and 40.7 ± 17 years. In addition, the prevalence of hypertension in these groups was 71.4% (5/7), 53.3% (8/15), 13.3% (2/15), and 0%, respectively. There was a trend to increased morbidity in subgroup II and III [Table 3].
|Table 3: Morbidity on discharge for patients with small aneurysms and in each subgroup of small aneurysms|
Click here to view
| Discussion|| |
SAH has a mortality rate of 40%–50%, and approximately 20% of the survivals present significant neurologic disability., There is a consensus toward an early treatment of ruptured aneurysms. On the other hand, the recommendations regarding unruptured intracranial aneurysm management are still controversial.
Aneurysm treatment complication should be considered in this context. Regarding embolization, the risks are aneurysm perforation, mechanical vasospasm, thromboembolism, and coil migration. Adverse events associated with surgery include infection, epidural or subdural hematomas, cranial nerve palsies, and ischemic infarction after clipping.,,,, In a review of the subject, in 2013,, found that an average rate of complications associated with clipping was 11%, ranging from 6.6% to 50%. Embolization analyses: the mean complication rate was 9%, between 4.1% and 28.6%.
A strong correlation between the aneurysm size aneurysm and the bled risk was pointed out by some authors,,,,,,,,,,,,,,, for whom the conservative treatment for aneurysms with <10 mm in diameter should be the recommendation. However, many published series demonstrated that small aneurysms (<10 mm) could bleed and should be operated.,,,,,,,,,,,,,, This different point, they mean that the aneurysm diameter alone is not an accurate predictor for the risk of rupture. Risk factors such as high blood pressure, young age, posterior circulation localization, and family history of SAH certainly contribute for aneurysm rupture.,
In our casuistic, aneurysms of all sizes presented SAH. The small number of patients with giant aneurysms (4 patients), the absence of a follow-up (retrospective analysis), selection bias, and the lack of control of some risk factors may be a possible mechanism. Among our cases, 48% (12/25) of aneurysms smaller than 5 mm ruptured, a bleeding tendency higher than the previously published.,,, This trend was confirmed when we stratified the group of small aneurysms in subgroups, noting that the prevalence of bleeding in small aneurysms remained high even in the subgroups below 2 mm, with a tendency to poor functional outcome after rupture of these smaller aneurysms.,,,,,,,,
Besides, some authors suggest that small aneurysms are associated with more extensive SAH. Taylor et al. reported that aneurysms <5 mm tend to a more significant association with a higher score on the Fisher scale, although there was no difference in the incidence of vasospasm or overall outcomes.
In a review of 100 cases of patients with SAH reported an inverse relationship between the size of an aneurysm and the volume of cisternal blood. Besides, some authors concluded that there is a higher risk of rupture during embolization of aneurysms smaller than 5 mm.,,
The reason for this fact presented in our casuistic is unclear, and prospective studies are necessary to explain this inverse relationship between the size and the volume of blood. For large aneurysms (>10 mm), the reported bled risk was significantly higher, reaching 33.5% at 5 years and 55.9% at 10 years. In our retrospective analysis, the rate of bleeding for these aneurysms was 44% and 52% for aneurysms more significant than 10 and 5 mm, respectively.
Some of the risk factors of aneurismal rupture (high blood pressure, diabetes mellitus, dyslipidemia, and smoking) were presented in our patients with small aneurysms, but there was no significant difference when comparing ruptured and unruptured lesions.
An aspect that was not considered in our study is the tendency to the aneurysm growth, and its implications on the aneurysm bled risk. In 2013 following 319 small untreated aneurysms (<7 mm), with a mean follow-up of 29.2 ± 20.6 months, observed an increase in size in 42 of these, 5 of which over 7 mm. Another interesting point to discuss is the decrease in the size of an aneurysm after its rupture, as described by some authors., Taking this into account, the aneurysms considered to be small after rupture, could have their previous rupture risk underestimated by only analysing the size. Thus, retrospective analysis, such as ours, may overestimate the rates of bleeding for small aneurysms.
This study suggests that small aneurysms represent a significant number of the ruptured lesions (20%, 2/61), leading us to postulate that the standard aneurysm treatment has to be considered.
Limitations of the study
This is a retrospective study, and all inherent method limitations do apply. The limited sample, losses of data registration, and its heterogeneity are potential flaws. We also did not have a sufficiently large number of cases; however, we can only affirm that we also have to consider surgery in a small aneurysm because they even can bleed and we deal with SAH.
| Conclusion|| |
Our data showed that aneurysms smaller than 5 mm (small) account for a significant portion of all aneurysms diagnosed, incidentally or not, with a considerable rupture rate. There was a trend to increased morbidity in subgroup < 4 mm. Consequently, our tendency nowadays is for the surgical treatment of these lesions, especially when it is associated with risk factors, such as hypertension and smoking, which are present. Further prospective studies with longer follow-up and larger samples are needed to strengthen these conclusions.
We would like to thank Professors Dr. Manoel Jacobsen Teixeira and Eberval Gadelha Figueiredo for their encouragement and dedication to their students.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Chason JL, Hindman WM. Berry aneurysms of the circle of Willis; results of a planned autopsy study. Neurology 1958;8:41-4.
Inagawa T, Hirano A. Autopsy study of unruptured incidental intracranial aneurysms. Surg Neurol 1990;34:361-5.
Ishibashi T, Murayama Y, Urashima M, Saguchi T, Ebara M, Arakawa H, et al.
Unruptured intracranial aneurysms: Incidence of rupture and risk factors. Stroke 2009;40:313-6.
Iwamoto H, Kiyohara Y, Fujishima M, Kato I, Nakayama K, Sueishi K, et al.
Prevalence of intracranial saccular aneurysms in a Japanese community based on a consecutive autopsy series during a 30-year observation period. The Hisayama study. Stroke 1999;30:1390-5.
Wiebers DO, Whisnant JP, Huston J 3rd
, Meissner I, Brown RD Jr., Piepgras DG, et al.
Unruptured intracranial aneurysms: Natural history, clinical outcome, and risks of surgical and endovascular treatment. Lancet 2003;362:103-10.
Forget TR Jr., Benitez R, Veznedaroglu E, Sharan A, Mitchell W, Silva M, et al.
Areview of size and location of ruptured intracranial aneurysms. Neurosurgery 2001;49:1322-5.
Guglielmi G, Viñuela F, Dion J, Duckwiler G. Electrothrombosis of saccular aneurysms via endovascular approach. Part 2: Preliminary clinical experience. J Neurosurg 1991;75:8-14.
Russell SM, Lin K, Hahn SA, Jafar JJ. Smaller cerebral aneurysms producing more extensive subarachnoid hemorrhage following rupture: A radiological investigation and discussion of theoretical determinants. J Neurosurg 2003;99:248-53.
Roos EJ, Rinkel GJ, Velthuis BK, Algra A. The relation between aneurysm size and outcome in patients with subarachnoid hemorrhage. Neurology 2000;54:2334-6.
Fogelholm R, Hernesniemi J, Vapalahti M. Impact of early surgery on outcome after aneurysmal subarachnoid hemorrhage. A population-based study. Stroke 1993;24:1649-54.
van Gijn J, Rinkel GJ. Subarachnoid haemorrhage: Diagnosis, causes and management. Brain 2001;124:249-78.
Maslehaty H, Ngando H, Meila D, Brassel F, Scholz M, Petridis AK, et al.
Estimated low risk of rupture of small-sized unruptured intracranial aneurysms (UIAs) in relation to intracranial aneurysms in patients with subarachnoid haemorrhage. Acta Neurochir (Wien) 2013;155:1095-100.
Salary M, Quigley MR, Wilberger JE Jr. Relation among aneurysm size, amount of subarachnoid blood, and clinical outcome. J Neurosurg 2007;107:13-7.
Weir B, Disney L, Karrison T. Sizes of ruptured and unruptured aneurysms in relation to their sites and the ages of patients. J Neurosurg 2002;96:64-70.
Sonobe M, Yamazaki T, Yonekura M, Kikuchi H. Small unruptured intracranial aneurysm verification study: SUAVe study, Japan. Stroke 2010;41:1969-77.
Juvela S, Porras M, Heiskanen O. Natural history of unruptured intracranial aneurysms: A long-term follow-up study. J Neurosurg 1993;79:174-82.
Beck J, Rohde S, Berkefeld J, Seifert V, Raabe A. Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography. Surg Neurol 2006;65:18-25.
Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: Probability of and risk factors for aneurysm rupture. J Neurosurg 2008;108:1052-60.
Ohashi Y, Horikoshi T, Sugita M, Yagishita T, Nukui H. Size of cerebral aneurysms and related factors in patients with subarachnoid hemorrhage. Surg Neurol 2004;61:239-45.
Kashiwazaki D, Kuroda S; Sapporo SAH Study Group. Size ratio can highly predict rupture risk in intracranial small (<5 mm) aneurysms. Stroke 2013;44:2169-73.
Dhar S, Tremmel M, Mocco J, Kim M, Yamamoto J, Siddiqui AH, et al
. Morphology parameters for intracranial aneurysm rupture risk assessment. Neurosurgery 2008;63:185-96.
Nahed BV, DiLuna ML, Morgan T, Ocal E, Hawkins AA, Ozduman K, et al.
Hypertension, age, and location predict rupture of small intracranial aneurysms. Neurosurgery 2005;57:676-83.
Hamada J, Morioka M, Yano S, Kai Y, Ushio Y. Incidence and early prognosis of aneurysmal subarachnoid hemorrhage in Kumamoto Prefecture, Japan. Neurosurgery 2004;54:31-7.
International Study of Unruptured Intracranial Aneurysms Investigators. Unruptured intracranial aneurysms – Risk of rupture and risks of surgical intervention. N Engl J Med 1998;339:1725-33.
Juvela S. Prevalence of and risk factors for intracranial aneurysms. Lancet Neurol 2011;10:595-7.
Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: Probability of and risk factors for aneurysm rupture. J Neurosurg 2000;93:379-87.
Tsutsumi K, Ueki K, Morita A, Kirino T. Risk of rupture from incidental cerebral aneurysms. J Neurosurg 2000;93:550-3.
Raymond J, Guillemin F, Proust F, Molyneux AJ, Fox AJ, Claiborne JS, et al.
Unruptured intracranial aneurysms. A Critical review of the international study of unruptured intracranial aneurysms (ISUIA) and of appropriate methods to address the clinical problem. Interv Neuroradiol 2008;14:85-96.
Bederson JB, Awad IA, Wiebers DO, Piepgras D, Haley EC Jr., Brott T, et al.
Recommendations for the management of patients with unruptured intracranial aneurysms: A Statement for healthcare professionals from the stroke council of the American Heart Association. Stroke 2000;31:2742-50.
Komotar RJ, Mocco J, Solomon RA. Guidelines for the surgical treatment of unruptured intracranial aneurysms: The first annual J. Lawrence pool memorial research symposium – Controversies in the management of cerebral aneurysms. Neurosurgery 2008;62:183-93.
Güresir E, Vatter H, Schuss P, Platz J, Konczalla J, de Rochement Rdu M, et al.
Natural history of small unruptured anterior circulation aneurysms: A prospective cohort study. Stroke 2013;44:3027-31.
Kemp WJ 3rd
, Fulkerson DH, Payner TD, Leipzig TJ, Horner TG, Palmer EL, et al.
Risk of hemorrhage from de novo
cerebral aneurysms. J Neurosurg 2013;118:58-62.
Raabe A, Seifert V, Schmiedek P, Steinmetz H, Bertalanffy H, Steiger HJ, et al.
Recommendations for the management of unruptured intracranial aneurysms. Zentralbl Neurochir 2002;63:70-6.
Wermer MJ, van der Schaaf IC, Algra A, Rinkel GJ. Risk of rupture of unruptured intracranial aneurysms in relation to patient and aneurysm characteristics: An updated meta-analysis. Stroke 2007;38:1404-10.
Sato K, Yoshimoto Y. Risk profile of intracranial aneurysms: Rupture rate is not constant after formation. Stroke 2011;42:3376-81.
Kalani MY, Zabramski JM, Kim LJ, Chowdhry SA, Mendes GA, Nakaji P, et al.
Long-term follow-up of blister aneurysms of the internal carotid artery. Neurosurgery 2013;73:1026-33.
Signorelli F, Scholtes F, Bojanowski MW. Very small intracranial aneurysms: Clip or coil. Neurochirurgie 2012;58:156-9.
Chien A, Liang F, Sayre J, Salamon N, Villablanca P, Viñuela F, et al.
Enlargement of small, asymptomatic, unruptured intracranial aneurysms in patients with no history of subarachnoid hemorrhage: The different factors related to the growth of single and multiple aneurysms. J Neurosurg 2013;119:190-7.
Chien A, Sayre J, Viñuela F. Comparative morphological analysis of the geometry of ruptured and unruptured aneurysms. Neurosurgery 2011;69:349-56.
Matsubara S, Hadeishi H, Suzuki A, Yasui N, Nishimura H. Incidence and risk factors for the growth of unruptured cerebral aneurysms: Observation using serial computerized tomography angiography. J Neurosurg 2004;101:908-14.
Ohman J, Heiskanen O. Timing of operation for ruptured supratentorial aneurysms: A prospective randomized study. J Neurosurg 1989;70:55-60.
Whitfield PC, Kirkpatrick PJ. Timing of surgery for aneurysmal subarachnoid haemorrhage. Cochrane Database Syst Rev 2001;(2):CD001697.
Kassell NF, Torner JC, Haley EC Jr., Jane JA, Adams HP, Kongable GL, et al.
The international cooperative study on the timing of aneurysm surgery. Part 1: Overall management results. J Neurosurg 1990;73:18-36.
Li H, Pan R, Wang H, Rong X, Yin Z, Milgrom DP, et al.
Clipping versus coiling for ruptured intracranial aneurysms: A systematic review and meta-analysis. Stroke 2013;44:29-37.
Fraser JF, Riina H, Mitra N, Gobin YP, Simon AS, Stieg PE, et al.
Treatment of ruptured intracranial aneurysms: Looking to the past to register the future. Neurosurgery 2006;59:1157-66.
Taylor CL, Steele D, Kopitnik TA Jr., Samson DS, Purdy PD. Outcome after subarachnoid hemorrhage from a very small aneurysm: A case-control series. J Neurosurg 2004;100:623-5.
Sluzewski M, Bosch JA, van Rooij WJ, Nijssen PC, Wijnalda D. Rupture of intracranial aneurysms during treatment with Guglielmi detachable coils: Incidence, outcome, and risk factors. J Neurosurg 2001;94:238-40.
van Rooij WJ, Sluzewski M, Beute GN, Nijssen PC. Procedural complications of coiling of ruptured intracranial aneurysms: Incidence and risk factors in a consecutive series of 681 patients. AJNR Am J Neuroradiol 2006;27:1498-501.
[Table 1], [Table 2], [Table 3]