Endovascular treatment of very small intracranial aneurysms

Flow alteration surgery using a radial artery graft for recurrent ruptured vertebral artery dissecting aneurysm after stent-assisted coil embolization: A case report

BACKGROUND

Ruptured vertebral artery dissecting aneurysm (VADA) is often treated surgically with coil embolization and sometimes recurs. We herein report a case of recurrent ruptured VADA after stent-assisted coil embolization (SAC) that was successfully treated with flow alteration surgery using a radial artery (RA) graft.

CASE DESCRIPTION

A 67-year-old woman presented with headache and coma. Enhanced CT revealed subarachnoid hemorrhage due to right VADA. Since the left VA was hypoplastic, the aneurysm was treated with SAC. However, follow-up angiography revealed recurrence of the aneurysm. Additional embolization was not considered due to the small size of the recurrent lesion and the presence of a stent; therefore, flow alteration surgery was performed using a RA graft. There were no neurological deficits after surgery or recurrence.

CONCLUSION

Flow alteration surgery using a RA graft is useful for recurrent VADA after SAC.

A comparison of endovascular coil systems for the treatment of small intracranial aneurysms

BACKGROUND

Endovascular coiling of small, intracranial aneurysms remains controversial and difficult, despite advances in technology.

METHODS

We retrospectively reviewed data for 62 small aneurysms (<3.99 mm) in 59 patients. Occlusion rates, complications rates, and coil packing densities were compared between subgroups based upon coil type and rupture status.

RESULTS

Ruptured aneurysms predominated (67.7%). Aneurysms measured 2.99 ± 0.63 mm by 2.51 ± 0.61 mm with an aspect ratio of 1.21 ± 0.34 mm. Brands included Optima (Balt) (29%), MicroVention Hydrogel (24.2%), and Penumbra SMART (19.4%) coil systems. Average packing density was 34.3 ± 13.5 mm³. Occlusion rate was 100% in unruptured aneurysms; 84% utilized adjuvant devices. For ruptured aneurysms, complete occlusion or stable neck remnant was achieved in 88.6% while recanalization occurred in 11.4%. No rebleeding occurred. Average packing density (p = 0.919) and coil type (p = 0.056) did not impact occlusion. Aspect ratio was smaller in aneurysms with technical complications (p = 0.281), and aneurysm volume was significantly smaller in those with coil protrusion (p = 0.018). Complication rates did not differ between ruptured and unruptured aneurysms (22.6 vs. 15.8%, p = 0.308) or coil types (p = 0.830).

CONCLUSION

Despite advances in embolization devices, coiling of small intracranial aneurysms is still scrutinized. High occlusion rates are achievable, especially in unruptured aneurysms, with coil type and packing density suggesting association with complete occlusion. Technical complications may be influenced by aneurysm geometry. Advances in endovascular technologies have revolutionized small aneurysm treatment, with this series demonstrating excellent aneurysm occlusion especially in unruptured aneurysms.

Target Ultra and Nano coils in the endovascular treatment of small intracranial aneurysms (ULTRA Registry)

OBJECTIVE

The ULTRA Registry is a national multicenter prospective study designed to assess aneurysm occlusion rates and safety profiles of the Target Ultra and Nano coils in the treatment of small intracranial aneurysms (IAs).

METHODS

Patients with small (≤ 5 mm) ruptured and unruptured IAs were treated exclusively with Target Ultra and Nano coils. The primary endpoints were the initial rate of complete or near-complete aneurysm occlusion, aneurysm recurrence, and need for retreatment. Secondary endpoints were device- and procedure-related adverse events, hemorrhage from the coiled aneurysm at any time during follow-up, and clinical outcomes.

RESULTS

The ULTRA Registry included 100 patients with a mean ± SD age of 56 ± 11.6 years, of whom 75 were women and 48 presented after aneurysm rupture. The mean aneurysm size was (3.5 ± 0.9) × (2.8 ± 0.9) × (3.0 ± 1.0) mm, and the mean packing density was 34.4% ± 16.7%. Posttreatment complete or near-complete occlusion reported by an independent imaging core laboratory was seen in 92% of patients at baseline and in 87%, 87%, and 83% of patients at first, second, and final follow-up, respectively. At first, second, and final follow-up, 10%, 11%, and 15%, respectively, of patients were deemed to require retreatment. There were three procedural-related ischemic strokes and one intracranial hemorrhage from wire perforation of a parent artery not involved by the aneurysm. There were no coil-related adverse events, including no intraoperative aneurysm ruptures and no known aneurysm ruptures after coiling.

CONCLUSIONS

This assessment of aneurysm occlusion rates and safety profiles in ULTRA Registry study participants demonstrates excellent safety and efficacy profiles for Target Ultra and Nano coils in the treatment of small IAs.

Neuroform atlas stent-assisted coiling of tiny wide-necked intracranial aneurysms

Objective

To investigate the safety and efficacy of Neuroform Atlas stent-assisted coiling for the treatment of tiny wide-necked intracranial aneurysms and evaluate risk factors associated with procedure-related complications.

Methods

We retrospectively examined 46 patients with 46 tiny wide-necked aneurysms who were treated using Atlas stent-assisted coiling at our institution from August 2020 to May 2022. Patient and aneurysm characteristics, procedural details, procedure-related complications, and angiographic and clinical outcomes were analyzed.

Results

A total of 10 patients presented with aneurysmal rupture. Atlas stent placement was successful in all patients. Angiography immediately after the procedure showed complete occlusion in 38 patients (82.6%), neck remnant in 7 (15.2%), and partial occlusion in 1 (2.2%). The mean angiographic follow-up was 8.4 months (range, 6–16). At the last follow-up, angiography showed complete occlusion in 41 patients (89.1%) and neck remnant in 5 (10.9%). No aneurysm recurrence or in-stent stenosis occurred. Incidence of procedure-related complications was 10.8% (intraprocedural aneurysm rupture, two cases; acute thrombosis, two cases; and coil migration, one case); only one patient (2.2%) experienced procedural neurological morbidity. The mean clinical follow-up was 9.7 months. A favorable outcome was achieved in 45 patients (97.8%). In univariate logistic regression analysis, aneurysm size (odds ratio, 4.538; P = 0.045) was significantly associated with procedure-related complications. However, multivariate analysis found no independent risk factors.

Conclusion

Atlas stent-assisted coiling of tiny wide-necked intracranial aneurysms is feasible and effective. Outcomes and occlusion rates are favorable and morbidity is low. The complication rate may be higher in larger tiny aneurysms.

Balloon-Assisted Coil Embolization and Balloon Angioplasty for Post Subarachnoid Hemorrhage Vasospasm: Initial Experience with Scepter Mini Balloon

The scope of this technical note is to report our experience with balloon remodeling for wideneck aneurysms and balloon angioplasty of post-subarachnoid hemorrhage vasospasm using the novel Scepter Mini balloon (SMB). Five cases were treated with balloon remodeling for aneurysmal subarachnoid hemorrhage, 2 of which were additionally treated with angioplasty due to post-bleeding vasospasm. All patients had their aneurysm located on parent vessels with a diameter smaller than 2 mm. Complete occlusion was noted in all aneurysms, and the patients had no short-term complications attributed to the catheterization. Additionally, we confirm the previously reported smooth navigation of the balloon through vessels with tortuous anatomy without catheter-induced vasospasm. Based on our experience, the SMB can be a safe and efficient device for applying the balloon remodeling technique for distally located wide-neck aneurysms and distal balloon angioplasty.

Discrepancy between two-dimensional and three-dimensional digital subtraction angiography for the planning of endovascular coiling of small cerebral aneurysms <5 mm

BACKGROUND

To investigate the discrepancy between two-dimensional digital subtraction angiography and three-dimensional rotational angiography for small (<5 mm) cerebral aneurysms and the impact on decision making among neuro-interventional experts as evaluated by online questionnaire.

MATERIALS AND METHODS

Eight small (<5 mm) ruptured aneurysms were visually identified in 16 image sets in either two-dimensional or three-dimensional format for placement in a questionnaire for 11 invited neuro-interventionalists. For each set, two questions were posed: Question 1: "Which of the following is the preferred treatment choice: simple coiling, balloon remodeling or stent assisted coiling?"; Question 2: "Is it achievable to secure the aneurysm with pure simple coiling?" The discrepancies of angio-architecture parameters and treatment choices between two-dimensional-digital subtraction angiography and three-dimensional rotational angiography were evaluated.

RESULTS

In all eight cases, the neck images via three-dimensional rotational angiography were larger than two-dimensional-digital subtraction angiography with a mean difference of 0.95 mm. All eight cases analyzed with three-dimensional rotational angiography, but only one case with two-dimensional-digital subtraction angiography were classified as wide-neck aneurysms with dome-to-neck ratio < 1.5. The treatment choices based on the two-dimensional or three-dimensional information were different in 56 of 88 (63.6%) paired answers. Simple coiling was the preferred choice in 66 (75%) and 26 (29.6%) answers based on two-dimensional and three-dimensional information, respectively. Three types of angio-architecture with a narrow gap between the aneurysm sidewall and parent artery were proposed as an explanation for neck overestimation with three-dimensional rotational angiography.

CONCLUSIONS

Aneurysm neck overestimation with three-dimensional rotational angiography predisposed neuro-interventionalists to more complex treatment techniques. Additional two-dimensional information is crucial for endovascular treatment planning for small cerebral aneurysms.

Safety and efficacy of treatment of very small intracranial aneurysms

Purpose

Very small intracranial aneurysms (VSIAs) may cause many neurological complications and even death. Thanks to technological progress and higher quality of non-invasive neuroimaging methods, these pathologies can be investigated sooner and treated earlier. Due to the controversy surrounding invasive treatment of these pathologies, the aim of the study was to analyse methods of treatment, their outcome, and complications in a group of patients with VSIAs.

Material and methods

Out of 444 cases of intracranial aneurysms treated in our centre, 65 aneurysms met the radiological criteria of VSIAs. The parameters – width and length of the aneurysm’s neck and width, length, and height of the aneurysm’s dome – were measured. The analysed parameters were as follows: symptoms upon admission and after treatment, days in hospital, and intraoperative complications. Clinical and radiological intensity of subarachnoid haemorrhage (SAH) was evaluated by using the Hunt-Hess and Fisher scales. The degree of embolisation of the aneurysm after the procedure was assessed using the Montreal Scale. Clinical outcome was assessed by Glasgow Outcome Scale.

Results

50.77% of VSIAs were treated with endovascular procedures and 49.23% with neurosurgical clipping. SAH was presented in 38.46% of patients with VSIAs. Intraoperative complications were presented in 16.92% of patients with VSIAs, and the most common complication was ischaemic stroke. Stents were used in 51.52% of VSIAs. In 69.70% of embolisation procedures at VSIAs complete obliteration was achieved. The average result in the Montreal Scale was 1.31 (SD = 0.66).

Conclusion

VSIAs can be treated as effectively and safely as larger aneurysms, by both endovascular and surgical methods.

Flow diverter embolization device for endovascular treatment of ruptured blister and wide necked very small aneurysms

Purpose

Ruptured blood blisters (BBA) and very small, wide necked aneurysms (VSA) remain challenging lesions to treat due to their small size, wide necks, and thin, fragile walls. In the present study, we reviewed our experience with these aneurysms treated by flow diversion.

Methods

A total of 18 patients with hemorrhage due to a ruptured BBAs and VSAs, treated with flow diversion between July 2014 and March 2016 were included in this study. We analyzed clinical and radiographic outcomes.

Results

A total of 12 (66.7%) VSAs and 6 (33.3%) BBAs were treated with flow diversion. Fifteen (83.3%) and three (16.7%) aneurysms were located on the internal carotid artery and the basilar artery, respectively. On admission, a GCS score of 15 and WFNS grade 1 were found in 14 (77.7%) patients, 3 patients had an admission GCS of 13 and WFNS grade 2, one had an admission GCS of 8 and WFNS of 4. Fisher CT grades 2, 3, and 4 were observed in 11 (61.1%), 1 (5.6%), and 6 (33.3%) patients, respectively. Flow diversion was performed on average 5.6 days after onset of hemorrhage. 6 months post-intervention angiography showed complete obliteration of the aneurysms in all patients.

Conclusion

Our findings indicate that flow diversion in the acute and subacute phase of hemorrhage is a reliable treatment for reducing complications in patients with BBAs and VSAs. In patients with poor clinical presentation it might be reasonable to delay treatment until the first signs of recovery become apparent.

Recurrence of Small Cerebral Aneurysms (< 4 mm) Treated Endovascularly Using Target® Nano™ Coils

OBJECTIVE

In our series, endovascular coiling with Target® Nano™ coils (Stryker Neurovascular, Fremont, CA, USA) with diameters of 1 or 1.5 mm exhibited favorable technical feasibility in the treatment of small cerebral aneurysms (< 4 mm). However, little is known about the recurrence of small cerebral aneurysms treated using Target® Nano™ coils. We investigated recurrence following the treatment of small cerebral aneurysms using Target® Nano™ coils.

MATERIALS AND METHODS

Between January 2012 and November 2013, 143 patients with 148 small cerebral aneurysms (< 4 mm) were included our study. A total of 135 cerebral aneurysms (91.2%) were unruptured; 45 cerebral aneurysms (30.4%) were treated by endovascular coiling using Target® Nano™ coils. Follow-up radiological images were obtained for 132 cerebral aneurysms (89.2%) over a range of 3 to 58 months (mean, 34.3 months; standard deviation, 14.2).

RESULTS

In the group treated with Target® Nano™ coils, radiological outcomes revealed complete occlusion in 33 (73.3%), residual necks in eight (17.8%), and residual sacs in four (8.9%) cases. Follow-up radiological outcomes revealed complete occlusion in 35 (77.8%) and residual necks in four (8.9%) cases that exhibited stable coil masses. In the group that was not treated with Target® Nano™ coils, radiological outcomes revealed complete occlusion in 69 (67%), residual necks in 18 (17.5%), and residual sacs in 16 (15.5%) cases. Follow-up radiological outcomes revealed complete occlusion in 87 (84.5%) and residual necks (5.8%) in six cases that exhibited stable coil masses. No significant differences were observed in the radiological outcomes or follow-up radiological outcomes between the two groups. No recurrences or retreatments occurred in our series.

CONCLUSION

Endovascular treatment using Target® Nano™ coils may be a robust treatment option for small cerebral aneurysms (< 4 mm).

Ultra-small diameter coils for treatment of intracranial aneurysms

This study reports our initial clinical experience treating very small intracranial aneurysms using only Target® Nano™ coils. Retrospective angiographic and clinical analysis was performed on a non-randomized single arm registry of all intracranial aneurysms treated with only Target® Nano™ coils (1 mm and 1.5 mm diameter only) during a 12 month period at two academic hospitals. Fourteen patients with 14 intracranial aneurysms were treated. The maximum diameter of saccular aneurysms treated ranged from 1.5 to 3.5 mm; minimum aneurysm diameter was 1.1 to 2 mm. The immediate complete aneurysm occlusion rate was 86% (12/14), and a small residual within the aneurysm was seen in 14% (2/14) of cases. Packing density from coils ranged between 24% and 83% (mean 51%). The immediate complication rate was 0% (0/14). The angiographic/MR angiography follow-up period was 22 to 70 weeks (mean 37 weeks) with an overall complete occlusion rate of 9/11 (81%), recurrence in 18% (2/11), and lack of follow-up in three cases, two due to death during hospitalization and one procedure not yet due for imaging follow-up. Both patients who died presented with brain aneurysm ruptures prior to treatment. Both recurrences were retreated with repeat coiling procedures. Our initial results using only Target® Nano™ coils for the endovascular treatment of very small intracranial aneurysms have demonstrated initial good safety and efficacy profiles.

Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a neurological emergency with high risk of neurological decline and death. Although the presentation of a thunderclap headache or the worst headache of a patient's life easily triggers the evaluation for SAH, subtle presentations are still missed. The gold standard for diagnostic evaluation of SAH remains noncontrast head computed tomography (CT) followed by lumbar puncture if the CT is negative for SAH. Management of patients with SAH follows standard resuscitation of critically ill patients with the emphasis on reducing risks of rebleeding and avoiding secondary brain injuries.

Stent-Assisted Coiling May Prevent the Recurrence of Very Small Ruptured Intracranial Aneurysms: A Multicenter Study

OBJECTIVE

To evaluate the safety and efficacy of endovascular treatments, including stent-assisted coiling, of very small (≤3 mm), ruptured intracranial aneurysms.

METHODS

Ninety-three endovascularly treated patients with very small ruptured aneurysms were recruited from 4 high-volume centers between September 2010 and February 2014. Factors influencing procedural complications and outcomes were analyzed.

RESULTS

Fifty-one (54.8%) aneurysms were treated by stent-assisted coiling, 41 (44.1%) by coiling alone, and 1 (1.1%) by balloon-assisted coiling. Intraprocedural or postprocedural complications occurred in 13 patients (14.0%): coil migration in 1, intraprocedural rupture in 1, hydrocephalus in 6, and ischemic event in 1. No tested factor was able to predict procedural complications. Angiographic follow-up of 67 aneurysms (72%) revealed recurrence in 5 patients (7.5%). One recurrent case was treated initially by stent-assisted coiling and the remaining four by coiling alone (P = 0.044). Multivariate regression analysis showed that coiling alone was significantly associated with aneurysm recurrence (odds ratio, 13.8; 95% confidence interval, 1.1-175.3; P = 0.043).

CONCLUSIONS

Endovascular treatment of very small ruptured aneurysms was safe and effective and was not associated with a high rate of intraprocedural rupture. Treatment with the use of stents significantly lowered the recurrence rate without additional risks.

Stent-assisted coiling of very small wide-necked intracranial aneurysms: Complications, anatomical results and clinical outcomes

BACKGROUND AND OBJECTIVE

Treatment of very small (≤3mm) wide-necked intracranial aneurysms remains controversial, we investigated the efficacy and safety of stent-assisted coiling of such aneurysms.

METHODS

From September 2008 to December 2012, 112 very small wide-necked intracranial aneurysms in 108 patients were embolized with stent-assisted coiling. We assessed the initial neurological conditions, complications and anatomic results. The follow-up results were evaluated with DSA and mRS.

RESULTS

Stent deployment was successful in 104 of 108 procedures (96.3%). 11 complications (10.2%) occurred during procedures, including 5 events of aneurysm rupture, 3 events of thromboembolism. The rate of complication, rupture and thromboembolism was not statistically different between the ruptured and unruptured patients (P=0.452, P=0.369, P=1.000, respectively). The initial aneurysmal occlusion was Raymond scale (RS) 1 in 34 patients (31.5%), RS2 in 53 patients (49.1%), and RS3 in 21 patients (19.4%). 79 aneurysms were available for anatomic follow-up of 12-47 months, stable occlusion in 45 aneurysms (57.0%), progressive complete occlusion in 34 aneurysms (43.0%). 95 patients(88.0%) were available for a clinical follow-up of 12-52 months, 92 patients (96.8%) had favorable clinical outcomes (mRS ≤2), 3 patients (3.2%) had morbidity (mRS: 3-5). The morbidity was not statistically different between the ruptured and unruptured patients (P=1.000).

CONCLUSIONS

Stent-assisted coiling of very small wide-necked intracranial aneurysms may be effective and safe. Because of low risk of rupture in such aneurysms, the coiling of unruptured such aneurysms must be selective. The long-term efficacy and safety of coiling such aneurysms remains to be determined in larger prospective series.

Practical Feasibility and Packing Density of Endovascular Coiling Using Target® Nano™ Coils in Small Cerebral Aneurysms

Objective

Based on the use of Nano™ coils, we retrospectively compared the proportion of the coils (≤ 1.5 mm) and packing density in two patient groups with small cerebral aneurysms (< 4 mm diameter) who were treated with or without Nano™ coils.

Materials and Methods

Between January 2012 and November 2013, in 548 cerebral aneurysms treated by endovascular coiling, 143 patients with 148 small cerebral aneurysms underwent endovascular coiling. After March 2013, coiling with Nano™ coils was performed on 45 small cerebral aneurysms (30.4%).

Results

There were no significant differences in the size and locations of the cerebral aneurysms, the age of the patients, and the procedural modalities between the two groups. The proportion of the coil (≤ 1.5 mm) of the group treated with Nano™ coils (53.6%) was higher than the proportion of the coil (≤ 1.5 mm) of the group treated without Nano™ coils (14.7%) with statistical significance (p < 0.001). The packing density of the group treated with Nano™ coils (31.3 ± 9.69%) was higher than the packing density of the group treated without Nano™ coils (29.49 ± 7.84%), although the difference was not significant. Procedural complications developed in 3 lesions (2 thromboembolisms and 1 carotid dissection) (2.0%). Treatment-related transient neurological deficits due to thromboembolism developed in 1 lesion, which had not been treated with Nano™ coils. There was no treatment-related permanent morbidity or mortality in either of the groups.

Conclusion

In our series, the small cerebral aneurysms treated with Nano™ coils showed more packing density with no additive procedural risk or difficulty.

Endovascular Treatment of Very Small Intracranial Aneurysms: Meta-Analysis

BACKGROUND AND PURPOSE

Outcomes of endovascular treatment of very small intracranial aneurysms are still not well-characterized. Recently, several series assessing coil embolization of tiny aneurysms have presented new promising results. Thus, we performed a systematic review and meta-analysis of studies evaluating endovascular treatment of very small intracranial aneurysms.

MATERIALS AND METHODS

We conducted a computerized search of Scopus, Medline, and the Web of Science for studies on endovascular treatment of very small (≤3 mm in diameter) intracranial aneurysms published between January 1996 and May 2015. Using a random-effects model, we evaluated clinical and angiographic outcomes.

RESULTS

Twenty-two studies with 1105 tiny aneurysms (844 ruptured and 261 unruptured) endovascularly treated were included. Postoperative and long-term complete occlusion was achieved in 85% (95% CI, 78%-90%) and 91% (95% CI, 87%-94%) of aneurysms, respectively. The recanalization rate was 6% (95% CI, 4%-11%) and retreatment occurred in 7% (95% CI, 5%-9%) of cases. Seventy-nine percent (95% CI, 64%-89%) of patients had good neurologic outcome at long-term follow-up. Intraprocedural rupture occurred in 7% (95% CI, 5%-9%) of the coiling procedures, while thromboembolic complications occurred in 4% (95% CI, 3%-6%).

CONCLUSIONS

Coil embolization of very small intracranial aneurysms can be performed safely and effectively. In the case of unruptured aneurysms, procedure-related complications are not negligible. Patients and providers should consider such risks when engaged in a shared decision-making process.

Height of aneurysm neck and estimated extent of brain retraction: powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms

OBJECTIVE

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction.

METHODS

A total of 102 patients who underwent a pterional or superciliary keyhole approach to clip an unruptured ACoA aneurysm from 2006 to 2013 were included in this study. Those patients who complained of permanent olfactory dysfunction after their aneurysm surgery, during a postoperative office visit or a telephone interview, were invited to undergo an olfactory test, the Korean version of the Sniffin' Sticks test. In addition, the angiographic characteristics of ACoA aneurysms, including the maximum diameter, the projecting direction of the aneurysm, and the height of the neck of the aneurysm, were all recorded based on digital subtraction angiography and sagittal brain images reconstructed using CT angiography. Furthermore, the extent of the brain retraction was estimated based on the height of the ACoA aneurysm neck.

RESULTS

Eleven patients (10.8%) exhibited objective olfactory dysfunction in the Sniffin' Sticks test, among whom 9 were anosmic and 2 were hyposmic. Univariate and multivariate analyses revealed that the direction of the ACoA aneurysm, ACoA aneurysm neck height, and estimated extent of brain retraction were statistically significant risk factors for postoperative olfactory dysfunction. Based on a receiver operating characteristic (ROC) analysis, an ACoA aneurysm neck height > 9 mm and estimated brain retraction > 12 mm were chosen as the optimal cutoff values for differentiating anosmic/hyposmic from normosmic patients. The values for the area under the ROC curves were 0.939 and 0.961, respectively.

CONCLUSIONS

In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction.

Comparative Cost Analysis for Surgical and Endovascular Treatment of Unruptured Intracranial Aneurysms in South Korea

OBJECTIVE

A cost comparison of the surgical clipping and endovascular coiling of unruptured intracranial aneurysms (UIAs), and the identification of the principal cost determinants of these treatments.

METHODS

This study conducted a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of UIAs between January 2011 and May 2014. The medical records, radiological data, and hospital cost data were all examined.

RESULTS

When comparing the total hospital costs for surgical clipping of a single UIA (n=188) and endovascular coiling of a single UIA (n=188), surgical treatment [mean±standard deviation (SD) : ₩8,280,000±1,490,000] resulted in significantly lower total hospital costs than endovascular treatment (mean±SD : ₩11,700,000±3,050,000, p<0.001). In a multi regression analysis, the factors significantly associated with the total hospital costs for endovascular treatment were the aneurysm diameter (p<0.001) and patient age (p=0.014). For the endovascular group, a Pearson correlation analysis revealed a strong positive correlation (r=0.77) between the aneurysm diameter and the total hospital costs, while a simple linear regression provided the equation, y (₩)=6,658,630+855,250x (mm), where y represents the total hospital costs and x is the aneurysm diameter.

CONCLUSION

In South Korea, the total hospital costs for the surgical clipping of UIAs were found to be lower than those for endovascular coiling when the surgical results were favorable without significant complications. Plus, a strong positive correlation was noted between an increase in the aneurysm diameter and a dramatic increase in the costs of endovascular coiling.

Aneurismal subarachnoid hemorrhage: who remains for surgical treatment in the post-ISAT era?

INTRODUCTION

Although there have been a number of studies on changes and trends in the management of aneurismal subarachnoid hemorrhage (aSAH) since publication of the International Subarachnoid Aneurysm Trial (ISAT), no data exist on what category of patients still remains for surgical treatment. Our goal was to investigate the changes that occurred in the characteristics of a population of aSAH patients treated surgically in the post-ISAT period in a single neurosurgical center, with limited availability of endovascular service.

MATERIAL AND METHODS

The study included 402 aSAH patients treated surgically in our unit between January 2004 and December 2011. Each year, data regarding number of admissions, age, aneurysm location and size, clinical and radiological presentation, outcome and mortality rates were collected and analyzed.

RESULTS

The annual number of admissions more than halved in the study period (from 69 in 2004 to 32 in 2011). There were no linear trends regarding patients' mean age, clinical presentation and outcomes, but the number of patients in Fisher grade 4 increased and mortality slightly decreased. An unexpected, statistically significant increase occurred in the incidence of anterior communicating artery aneurysms (from 36.2% to 50%) and medium size aneurysms (from 34.7% to 56.2%) treated surgically, with a corresponding decrease in the incidence of middle cerebral artery aneurysms (from 40.5% to 34.3%) and large aneurysms (from 21.7% to 12.5%).

CONCLUSIONS

Unexpected trends in characteristics of aSAH patients treated surgically could be related to treatment decision modality. Trend patterns could be properly expressed in the constant availability of endovascular services.

Formal protocol for emergency treatment of ruptured intracranial aneurysms to reduce in-hospital rebleeding and improve clinical outcomes

OBJECT

While the incidence of a recurrent hemorrhage is highest within 24 hours of subarachnoid hemorrhage (SAH) and increases with the severity of the clinical grade, a recurrent hemorrhage can occur anytime after the initial SAH in patients with both good and poor clinical grades. Therefore, the authors adopted a 24-hour-a-day, formal protocol, emergency treatment strategy for patients with ruptured aneurysms to secure the aneurysms as early as possible. The incidences of in-hospital rebleeding and clinical outcomes were investigated and compared with those from previous years when broadly defined early treatment was used (<3 days of SAH).

METHODS

During an 11-year period, a total of 1224 patients with a ruptured aneurysm were managed using a strategy of broadly defined early treatment between 2001 and 2004 (Period B, n=423), a mixture of early or emergency treatment between 2005 and 2007, and a formal emergency treatment protocol between 2008 and 2011 (Period A, n=442). Propensity score matching was used to adjust the differences in age, sex, modified Fisher grade, World Federation of Neurosurgical Societies (WFNS) clinical grade at admission, size and location of a ruptured aneurysm, treatment modality (clip placement vs coil embolization), and time interval from SAH to admission between the two time periods. The matched cases were allotted to Group A (n=280) in Period A and Group B (n=296) in Period B and then compared.

RESULTS

During Period A under the formal emergency treatment protocol strategy, the catheter angiogram, endovascular coiling, and surgical clip placement were started at a median time from admission of 2.0 hours, 2.9 hours, and 3.1 hours, respectively. After propensity score matching, Group A showed a significantly reduced incidence of in-hospital rebleeding (2.1% vs 7.4%, p=0.003) and a higher proportion of patients with a favorable clinical outcome (modified Rankin Scale score 0-3) at 1 month (87.9% vs 79.7%, respectively; p=0.008). In particular, the patients with good WFNS grades in Group A experienced significantly less in-hospital rebleeding (1.7% vs 5.7%, respectively; p=0.018) and better clinical outcomes (1-month mRS score of 0-3: 93.8% vs 87.7%, respectively; p=0.021) than the patients with good WFNS grades in Group B.

CONCLUSIONS

Patients with ruptured aneurysms may benefit from a strategy of emergency application of surgical clip placement or endovascular coiling due to the reduced incidence of recurrent bleeding and improved clinical outcomes.

Clinical practice guideline for the management of intracranial aneurysms

Purpose

An intracranial aneurysm, with or without subarachnoid hemorrhage (SAH), is a relevant health problem. The rupture of an intracranial aneurysm is a critical concern for individual health; even an unruptured intracranial aneurysm is an anxious condition for the individual. The aim of this guideline is to present current and comprehensive recommendations for the management of intracranial aneurysms, with or without rupture.

Materials and Methods

We performed an extensive literature search, using Medline. We met in person to discuss recommendations. This document is reviewed by the Task Force Team of the Korean Society of Interventional Neuroradiology (KSIN).

Results

We divided the current guideline for ruptured intracranial aneurysms (RIAs) and unruptured intracranial aneurysms (UIAs). The guideline for RIAs focuses on diagnosis and treatment. And the guideline for UIAs focuses on the definition of a high-risk patient, screening, principle for treatment and selection of treatment method.

Conclusion

This guideline provides practical, evidence-based advice for the management of patients with an intracranial aneurysm, with or without rupture.

Conventional endovascular treatment of small intracranial aneurysms is not associated with additional risks compared with treatment of larger aneurysms

BACKGROUND

Endovascular treatment of small intracranial aneurysms has historically been technically challenging and has been associated with high rates of complications and intraprocedural rupture. In this study, we compared complication and recurrence rates for treatment of small aneurysms (≤ 4 mm) versus large aneurysms in the context of the advent of improvements in endovascular techniques and technologies.

METHODS

A retrospective cohort study was performed to include all patients who underwent coiling of an intracranial aneurysm between 2005 and 2012. Small aneurysms were defined as any aneurysm 4.0 mm or smaller in all dimensions. The primary outcome was a composite outcome of the occurrence of an intraoperative rupture or a perioperative thromboembolic event. The secondary outcome of interest was aneurysm recurrence.

RESULTS

During the study period, 483 patients were treated using endovascular techniques; 85 (17.6%) of these patients had small aneurysms. In the small aneurysm group, there was only one (1.2%) intraoperative rupture, three (3.5%) perioperative thromboembolic events, and 11 (12.9%) incidents of aneurysm recurrence. Both the primary and secondary outcomes of interest were similar in patients presenting with small or large aneurysms. Small aneurysm size was not a risk factor for either the composite primary outcome or aneurysm recurrence in multivariate analysis.

CONCLUSIONS

Treatment of small intracranial aneurysms via conventional endovascular coiling techniques is not inferior to endovascular treatment of larger aneurysms based on our single institution experience. While technically challenging, such aneurysms may be treated safely and effectively with acceptable rates of complications and recurrence.

Perioperative variables contributing to the rupture of intracranial aneurysm: an update

Background. Perioperative aneurysm rupture (PAR) is one of the most dreaded complications of intracranial aneurysms, and approximately 80% of nontraumatic SAHs are related to such PAR aneurysms. The literature is currently scant and even controversial regarding the issues of various contributory factors on different phases of perioperative period. Thus this paper highlights the current understanding of various risk factors, variables, and outcomes in relation to PAR and try to summarize the current knowledge. Method. We have performed a PubMed search (1 January 1991–31 December 2012) using search terms including “cerebral aneurysm,” “intracranial aneurysm,” and “intraoperative/perioperative rupture.” Results. Various risk factors are summarized in relation to different phases of perioperative period and their relationship with outcome is also highlighted. There exist many well-known preoperative variables which are responsible for the highest percentage of PAR. The role of other variables in the intraoperative/postoperative period is not well known; however, these factors may have important contributory roles in aneurysm rupture. Preoperative variables mainly include natural course (age, gender, and familial history) as well as the pathophysiological factors (size, type, location, comorbidities, and procedure). Previously ruptured aneurysm is associated with rupture in all the phases of perioperative period. On the other hand intraoperative/postoperative variables usually depend upon anesthesia and surgery related factors. Intraoperative rupture during predissection phase is associated with poor outcome while intraoperative rupture at any step during embolization procedure imposes poor outcome. Conclusion. We have tried to create such an initial categorization but know that we cannot scale according to its clinical importance. Thorough understanding of various risk factors and other variables associated with PAR will assist in better clinical management as well as patient care in this group and will give insight into the development and prevention of such a catastrophic complication in these patients.

Comparison of 3D TOF-MRA and 3D CE-MRA at 3T for imaging of intracranial aneurysms

PURPOSE

To compare 3T elliptical-centric CE MRA with 3T TOF MRA for the detection and characterization of unruptured intracranial aneurysms (UIAs), by using digital subtracted angiography (DSA) as reference.

MATERIALS AND METHODS

Twenty-nine patients (12 male, 17 female; mean age: 62 years) with 41 aneurysms (34 saccular, 7 fusiform; mean diameter: 8.85 mm [range 2.0-26.4mm]) were evaluated with MRA at 3T each underwent 3D TOF-MRA examination without contrast and then a 3D contrast-enhanced (CE-MRA) examination with 0.1mmol/kg bodyweight gadobenate dimeglumine and k-space elliptic mapping (Contrast ENhanced Timing Robust Angiography [CENTRA]). Both TOF and CE-MRA images were used to evaluate morphologic features that impact the risk of rupture and the selection of a treatment. Almost half (20/41) of UIAs were located in the internal carotid artery, 7 in the anterior communicating artery, 9 in the middle cerebral artery and 4 in the vertebro-basilar arterial system. All patients also underwent DSA before or after the MR examination.

RESULTS

The CE-MRA results were in all cases consistent with the DSA dataset. No differences were noted between 3D TOF-MRA and CE-MRA concerning the detection and location of the 41 aneurysms or visualization of the parental artery. Differences were apparent concerning the visualization of morphologic features, especially for large aneurysms (>13 mm). An irregular sac shape was demonstrated for 21 aneurysms on CE-MRA but only 13/21 aneurysms on 3D TOF-MRA. Likewise, CE-MRA permitted visualization of an aneurismal neck and calculation of the sac/neck ratio for all 34 aneurysms with a neck demonstrated at DSA. Conversely, a neck was visible for only 24/34 aneurysms at 3D TOF-MRA. 3D CE-MRA detected 15 aneurysms with branches originating from the sac and/or neck, whereas branches were recognized in only 12/15 aneurysms at 3D TOF-MRA.

CONCLUSION

For evaluation of intracranial aneurysms at 3T, 3D CE-MRA is superior to 3D TOF-MRA for assessment of sac shape, detection of aneurysmal neck, and visualization of branches originating from the sac or neck itself, if the size of the aneurysm is greater than 13 mm. 3T 3D CE-MRA is as accurate and effective as DSA for the evaluation of UIAs.

Endovascular treatment of ruptured tiny, wide-necked posterior communicating artery aneurysms using a modified stent-assisted coiling technique

The endovascular treatment of patients with tiny, wide-necked aneurysms is technically challenging, due to the small volume for microcatheterization and coil stabilization inside the aneurysm sac. We performed a retrospective study to evaluate the feasibility, effectiveness, and safety of stent-assisted embolization for patients with ruptured, tiny, wide-necked posterior communicating artery (PcomA) aneurysms. Between January 2007 and August 2011, 17 tiny, wide-necked PcomA aneurysms that had ruptured were treated at our institution using a modified stent-assisted technique, with delivery of the first coil inside the aneurysm followed by placement of a self-expanding stent via a second microcatheter. All patients were treated successfully using this modified stent-assisted coiling technique. Initial results showed aneurysm occlusion of Raymond Class 1 in 10 patients, Class 2 in four patients, and Class 3 in three patients. The angiographic follow-up results for 13 patients (mean, 12.5 months) showed that all aneurysms remained stable or improved, without any in-stent stenosis or recurrence. Of the other four patients, three refused angiography for economic or personal reasons, and one was lost in follow-up. Clinical follow-up of 16 patients for a mean of 23.8 months showed no death or rebleeding. These results imply that endovascular treatment of ruptured tiny, wide-necked PcomA aneurysms using our modified stent-assisted coiling technique is safe and feasible. This technique improves the long-term outcomes of these aneurysms by increasing the packing density and diverting the intra-aneurysmal blood flow.

Endovascular treatment of very small and very large ruptured aneurysms of the anterior cerebral circulation: a single-center experience

INTRODUCTION

Endovascular treatment of aneurysms has been introduced as a less invasive method for decreasing the rate of aneurysm rerupture and subsequent subarachnoid hemorrhage. The outcome and complication rate for endovascular treatment of very small (≤3 mm) and very large (15-25 mm) intracranial aneurysms has been controversial. Here we report our experience with endovascular coiling of very small and very large ruptured aneurysms of the anterior cerebral circulation.

METHODS

Patients were included in the study if the maximum dimension of the intracranial ruptured aneurysm was reported to be ≤3 mm or 15-25 mm and if the aneurysm was within the anterior cerebral circulation. The largest dimension was calculated using CT angiography and was confirmed by digital subtraction angiography. Endovascular coiling was performed using Guglielmi detachable coils. All patients underwent follow-up contrast MR angiography every 6 months.

RESULTS

A total of 40 cases (18 females and 22 males) were included in this single-center study. Twenty-one very small and 19 very large ruptured aneurysms were analyzed. Preprocedural Hunt and Hess grades were determined. Endovascular coiling was performed successfully in most cases (97.5%), with unsuccessful coiling in 1 patient with a very small ruptured aneurysm. In the very small aneurysm group, the most common location was the anterior communicating artery and, in the large aneurysm group, the most common location was the middle cerebral artery (MCA) bifurcation. The mean follow-up time was 15.08 months (range: 6-30 months). The 6th month modified Rankin scale (mRS) values for very small aneurysm cases were 0 (no symptoms at all) in 16 cases (76.2%) and 1 (no significant disability despite symptoms) in 5 cases (23.80%). For the very large aneurysm cases, the mRS values were 1 in 2 cases (10.5%), 2 in 7 cases (36.8%), 3 in 6 cases (31.6%), 4 in 3 cases (15.8%) and 6 in 1 case (died due to vasospasm 72 h later; 5.2%). The immediate complications that were observed were MCA branch occlusion in 1 very small aneurysm patient and early vasospasms in 3 very large aneurysm patients. The late complication that was observed was recanalization in 1 very small aneurysm case (1/21, 4.76%) and in 5 very large aneurysm cases (5/18, 27.77%).

CONCLUSION

Endovascular treatment of very small aneurysms is an effective method of treatment with acceptable immediate and long-term outcomes. Immediate and long-term complications were more prevalent in very large ruptured aneurysms.

Results of Stent-Assisted vs Non-Stent-Assisted Endovascular Therapies in 489 Cerebral Aneurysms

BACKGROUND:

Whether the addition of stenting to intracranial aneurysm coil embolization results in benefit in terms of occlusion rates or additional risk in terms of periprocedural adverse events is not clear.

OBJECTIVE:

To report retrospectively analyzed results of endovascular aneurysm treatment comparing stent-assisted coiling with coiling without stents at our hospital from 2005 to 2009.

METHODS:

In this retrospectively reviewed case series, aneurysms were grouped as intent-to-treat or initially treated with stent-assisted coiling (A) vs coiling alone (B) or as-treated—those that ultimately received a stent (C) or not (D). Complication and occlusion rates were compared between groups. Some patients crossed from group B to C after receiving stent placement at a later treatment following the initial therapeutic modality (without a stent).

RESULTS:

In 459 patients, 489 aneurysms were treated by group as follows: A = 181, B = 308, C = 225, and D = 264. In stent groups (A and C), there were significantly lower frequencies of ruptured aneurysms (A vs B = 11% vs 62%, P &lt; .001; C vs D = 20.4% vs 62.5%, P &lt; .001) and more giant aneurysms (A vs B = 7.3% vs 1.0%, P = .001; C vs D = 5.9% vs 1.1%, P &lt; .001). There was no statistically significant difference in permanent event-related morbidity (A vs B = 4.4% vs 4.2%, P = 1.0; C vs D = 4.4% vs 4.2%, P = 1.0). Average angiographic follow-up after last treatment was 18.2 ± 15 months (median = 14). Higher rates of complete occlusion at last angiographic follow-up were observed in stented aneurysms (A vs B = 64.6% vs 49.7%, P = .001; C vs D = 62.7% vs 48.9%, P = .003).

CONCLUSION:

Stent-assisted aneurysm treatment resulted in higher total occlusion rates than non-stent-assisted treatment, with acceptable, comparable periprocedural event rates.

Unruptured Supraclinoid Internal Carotid Artery Aneurysm Surgery : Superciliary Keyhole Approach versus Pterional Approach

Objective

A superciliary keyhole approach is an attractive, minimally invasive surgical technique, yet the procedure is limited due to a small cranial opening. Nonetheless, an unruptured supraclinoid internal carotid artery (ICA) aneurysm can be an optimal surgical target of a superciliary approach as it is located in the center of the surgical view and field. Therefore, this study evaluated the feasibility and surgical outcomes of a superciliary keyhole approach for unruptured ICA aneurysms.

Methods

The authors report on a consecutive series of patients who underwent a superciliary approach for clipping unruptured ICA aneurysms between January 2007 and February 2012. The data were compared with a historical control group who underwent a pterional approach between January 2003 and December 2006.

Results

In the superciliary group, a total of 71 aneurysms were successfully clipped without a residual sac in 70 patients with a mean age of 57 years (range, 37-75 years). The maximum diameter of the aneurysms ranged from 4 mm to 14 mm (mean±standard deviation, 6.6±2.3 mm). No direct mortality or permanent morbidity was related to the surgery. The superciliary approach demonstrated statistically significant advantages over the pterional approach, including a shorter operative duration (mean, 100 min), no intraoperative blood transfusions, and no postoperative epidural hemorrhages.

Conclusion

A superciliary keyhole approach provides a sufficient surgical corridor to clip most unruptured supraclinoid ICA aneurysms in a minimally invasive manner.

Treatment of small ruptured intracranial aneurysms: comparison of surgical and endovascular options

Background

Small intracranial aneurysms pose significant challenges to endovascular therapy. Surgical clipping is considered by many to be the preferred treatment for these lesions. We present the results of the first study comparing the 2 treatment modalities in small ruptured aneurysms.

Methods and Results

Between 2004 and 2011, 151 patients with small ruptured aneurysms (≤3 mm) were treated in our institution: 91 (60.3%) with endovascular therapy and 60 (39.7%) with surgical clipping. The surgical and endovascular groups were generally comparable with regard to baseline demographics, with the exception of larger mean aneurysm size in the endovascular group versus the surgical group (2.8 versus 2.5 mm, respectively; P<0.001) and a higher proportion of posterior circulation aneurysms in the endovascular group. Endovascular treatment failed in 9.9% of patients. Procedure-related complications occurred in 23.3% of surgical patients versus 9.8% of endovascular patients (P=0.01). Only 3.7% of patients undergoing endovascular therapy experienced an intraprocedural aneurysm rupture. There were no procedural deaths or rehemorrhages in either group. The rates of aneurysm recanalization and retreatment after endovascular therapy were 18.2% and 12.7%, respectively. Favorable outcomes (moderate, mild, or no disability) were not statistically different between the endovascular (67.1%) and surgical (56.7%) groups (P=0.3).

Conclusions

Surgical clipping was associated with a higher rate of periprocedural complications, but overall disability outcomes were similar. Endovascular therapy, if technically feasible, might be a preferred option in this setting. Inclusion of patients with small aneurysms in randomized controlled trials seems feasible and will be needed to provide definitive information on the best therapeutic approach. (J Am Heart Assoc. 2012;1:e002865 doi: 10.1161/JAHA.112.002865.)

Superciliary keyhole approach for small unruptured aneurysms in anterior cerebral circulation

BACKGROUND

Neurovascular surgeons have been trying to find a solution to the problem of surgical invasiveness by applying minimally invasive keyhole approaches.

OBJECTIVE

To evaluate the feasibility and surgical outcomes of a superciliary keyhole approach for unruptured intracranial aneurysms (UIAs) as an alternative to a pterional approach.

METHODS

The authors report on a consecutive series of patients who underwent a superciliary approach for clipping UIAs smaller than 15 mm arising at the supraclinoid internal carotid artery (ICA), A1 segment, anterior communicating artery (ACoA), and M1 segment including the middle cerebral artery (MCA) bifurcation. The data were compared with a historical control group (n = 90) who underwent a pterional approach for UIAs.

RESULTS

A total of 120 aneurysms were successfully clipped in 102 patients with a mean age of 58 years. There was no direct mortality related to the surgery, and only 1 (1.0%) patient developed significant morbidity adversely affecting the Glasgow Outcome Scale score. The superciliary approach demonstrated statistically significant advantages over the pterional approach, including a shorter operative duration (mean, 120 min), no intraoperative blood transfusion, and extremely rare postoperative epidural hemorrhages. In addition, temporalis atrophy was rare and palsy of the frontalis persisting more than 6 months only occurred in 6 patients (5.9%) and was resolved within 2 years. The overall cosmetic outcome was excellent.

CONCLUSION

A superciliary approach can be a reasonable alternative to a pterional approach for small (<15 mm) UIAs arising at the supraclinoid ICA, A1, ACoA, and M1 segment including the MCA bifurcation.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Suitability of cerebral aneurysms for endovascular treatment: Evolution of criteria with technological developments

With the introduction of electrically detachable coils in 1991 and later the results of the ISAT trial in 2002, endovascular approach became the primary treatment for cerebral aneurysms in many countries. The suboptimal quality of anatomical results and the relatively high rate of aneurysm recurrence after treatment still hamper an even more widespread of the technique. In this paper, we will make a review of the anatomical factors associated with poor anatomical results as well as technological developments aiming at improvement of aneurysm healing.

[Very small intracranial aneurysms: Clip or coil]

INTRODUCTION

It is not unusual for very small aneurysms (≤3mm) to be responsible for subarachnoid haemorrhage. In addition, modern imaging has increased diagnosis of those that are asymptomatic. Because of their spatial configuration and thin and fragile walls, very small aneurysms can be a sizeable challenge for both open surgical and endovascular treatment. Based on recent literature data, the present manuscript reviews treatment indications and the choice of treatment strategy to occlude these particular aneurysms.

METHODS

Literature review concerning surgical and endovascular treatment of very small aneurysms (≤3mm). Arterial dissections and blister aneurysms were excluded.

RESULTS

We found no study that systematically and specifically assessed surgical treatment of very small aneurysms. Investigations of endovascular treatment are almost exclusively retrospective, usually evaluating a small number of patients, and are limited by selection bias. Despite often contradictory results, it appears that very small aneurysms carry a higher risk of rupture during endovascular procedures and higher ensuing mortality, as compared to larger aneurysms. The use of more flexible coils and additional endovascular tools appears to reduce this risk. There is no study comparing surgical to endovascular treatment.

CONCLUSION

Very small aneurysms carry higher treatment risks than larger aneurysms. A prospective randomised trial is justified for those very small aneurysms for which treatment is indicated.

Endovascular treatment of very small intracranial aneurysms

The endovascular treatment of intracranial aneurysms 3 mm or less is considered controversial. The purpose of this study is to report angiographic and clinical results following coiling of such aneurysms and compare them to those of larger aneurysms (> 3 mm).Between November 1999 and November 2009 endovascular treatment was attempted in 956 consecutive intracranial aneurysms. Of 956 aneurysms, 111 aneurysms were very small aneurysms with a maximal diameter of 3 mm or less. We conducted a retrospective analysis of angiographic and clinical outcome following coiling of very small aneurysms and subsequently comparing it to the results of larger aneurysms.Coiling initially failed in eight aneurysms. In the remaining 103 aneurysms endovascular treatment was accomplished and immediate angiographic results showed complete aneurysm occlusion in 43 aneurysms, nearly complete aneurysm occlusion in 54 aneurysms and less than 90% aneurysm occlusion in six aneurysms. Complications occurred in the treatment of 15 aneurysms, including eight procedural ruptures, six thromboembolic events and one case of early hemorrhage. Compared with larger aneurysms, treatment of very small aneurysms was associated with a higher rate of procedural ruptures (7.2% versus 4.4%) and procedural mortality (4.7% versus 2.7%) but a lower procedural morbidity (1.9% versus 4.0%). However none of these differences reached statistical significance (p = 0.186, p= 0.388, respectively). The retreatment rate was higher for the larger aneurysms (8.2% and 6.3%), but this was not significant either (p= 0. 496). At nine-month follow-up significantly more small aneurysms were found to have a stable occlusion grade compared to large aneurysms.Endovascular treatment of very small aneurysms is feasible with a lower retreatment rate compared to large aneurysms (> 3 mm). However the data also suggest that endovascular treatment of very small aneurysms might be associated with an increased risk of procedural ruptures and mortality. At nine-month follow-up results indicate significantly less compaction in the very small aneurysms.

Neck clipping of paraclinoid small aneurysms

Paraclinoid small aneurysms with a diameter less than 5 mm may be difficult to handle intraoperatively. We have encountered 9 such aneurysms among 375 cases. The most frequent location was the ophthalmic segment (n = 6) followed by the anterior wall (n = 3) of the internal carotid artery (ICA). The endovascular procedure was not suitable for this particular lesion because of the difficulty in deploying the coil across such small aneurysms. One patient with an ophthalmic segment aneurysm underwent endovascular treatment first; however, the procedure was aborted because of mechanical vasospasm. Finally the patient underwent craniotomy, and the aneurysm was successfully clipped. Two patients with anterior wall aneurysms presented with subarachnoid hemorrhage, and the blood blister-like aneurysms were clipped without sacrifice of the ICA. Five patients with unruptured aneurysms of the ophthalmic segment and one such case of the anterior wall of ICA were all clipped uneventfully. The operative procedure for these small aneurysms is deemed straightforward: (1) high attention should be paid to avoid premature rupture; (2) both the internal carotid artery and optic nerve are mobilized and the anterior clinoid process and falciform ligament are removed, then the aneurysmal neck is created; (3) the neck of the aneurysm is created by pushing the wall of the ICA slightly away during clip application; this is called the "nip on method." Although neck clipping of small aneurysms can be difficult, no efforts should be spared to accomplish direct neck clipping.

Tiny intracranial aneurysms: endovascular treatment by coil embolisation or sole stent deployment

PURPOSE

Tiny intracranial aneurysms pose a significant therapeutic challenge for interventional neuroradiologists. The authors report their preliminary results of endovascular treatment of these aneurysms.

METHODS

Between January 2002 and December 2009, 52 tiny intracranial aneurysms (defined as ≤ 3 mm in maximum diameter) in 46 patients (22 men; mean age, 57.9 years) were treated by endosaccular coil embolisation or sole stent deployment in the parent artery. Of 52 aneurysms, 29 had ruptured and 23 remained unruptured. The initial angiographic results, procedural complications, and clinical outcomes were assessed at discharge. Imaging follow-up was performed with cerebral angiography.

RESULTS

One aneurysm coiling procedure failed because of unsuccessful micro-catheterization. Forty-three aneurysms were successfully coil embolized, of which complete occlusion was obtained in 14, subtotal occlusion in 18 and incomplete occlusion in 11. The other 8 aneurysms were treated by sole stent deployment in the parent artery. Procedural complications (2 intraprocedural ruptures and 3 thromboembolic events) occurred in 5 (9.6%) of 52 aneurysms, resulting in permanent morbidity in only 1 (2.2%, 1/46) patient. No rebleeding occurred during clinical follow-up (mean duration, 46.7 months). Of the 16 coiled aneurysms that receiving repetitive angiography, 6 initially completely and 3 subtotally occluded aneurysms remained unchanged, 4 initially subtotally and 3 incompletely occluded aneurysms progressed to total occlusion. Five sole stent deployed aneurysms received angiographic follow-up (mean duration, 10.0 months), of which 3 remained unchanged, 1 became smaller and 1 progressed to total occlusion.

CONCLUSION

Endovascular treatment of tiny intracranial aneurysms is technical feasible and relatively safe. Coil embolisation seems to be effective in preventing early recanalisation, whereas sole stenting technique needs further investigation to determine its effectiveness.