Shaping and Navigating Methods of Microcatheters for Endovascular Treatment of Paraclinoid Aneurysms

Comparison of coating damage and shape retention quantity of microcatheter by different shaping methods

OBJECTIVE

To compare the coating damage and shape retention quality of microcatheter by steam (ST), hot air gun (HA), and HA + ST shaping.

METHOD

SL-10, XT-17, and Q-track microcatheters were included in the study. MarSurf CM explorer (a non-contact 3D confocal microscopy system) and MATLAB software were used to detect the surface coating damage. To detect the shape retention quantity, ImageJ software was used to analyze the images of the shaped microcatheters. Temperature of the outlet of the ST and HA was measured using a high precision contact digital thermometer.

RESULTS

HA could reach the preset temperature (3 ∼ 4 s) 17 times faster than an ST (54 s). HA + ST produced relatively consistent heat flow output. HA had better shape retention quantity than ST, and HA + ST had a relatively better shape retention quantity compared with ST or HA alone. ST had a protective effect on the hydrophilic coating on the surface of microcatheter, and shaping by ST + HA could reduce the damage caused by HA to the surface coating.

CONCLUSIONS

HA and ST had their own advantages in microcatheter shaping. HA had a better shape retention quantity than ST, and reached the setting temperature faster than ST. ST had the ability to better protect the coating than HA. A device capable of simultaneously generating efficient and stable heat flow and eliminating heat flow damage to the surface coating can be designed for ideal microcatheter shaping.

Effectiveness of S-Shaping of the Tip of the FUBUKI Guiding Catheter to Match the Shape of the Cervical Internal Carotid Artery in Anterior Circulation Cerebral Aneurysm Embolization

Objective

During cerebral aneurysm embolization of the anterior circulation, the guiding catheter (GC) should be placed as distally as possible in the cervical internal carotid artery (ICA) to secure the maneuverability of the microcatheter and distal access catheter. However, if the shape of the tip of the GC does not appropriately match the course of the ICA, blood stasis might occur. We investigated whether shaping the tip of the GC into an S-shape would allow more stable catheterization to the distal ICA than the conventional GC with an angled tip.

Methods

We included patients with cerebral aneurysms of the anterior circulation who were treated at our institution from April 2019 to April 2021. First, we evaluated the cervical ICA course in these patients through cerebral angiography and classified the courses into type S, type I, and type Z. Then, we focused on the most frequently encountered type-S cervical ICA to investigate the forging effect of the GC tip into an S-shape. We evaluated the lateral view of the carotid angiograms to examine whether the catheter tip reached the foramen magnum (FM) without interrupting ICA blood flow. The effects of age, sex, side, a history of hypertension and smoking, and an S-shape modification of the GC tip on the outcome of GC placement were analyzed.

Results

A total of 67 patients were included in this study. The tip of the GC was placed at the FM in 27 cases. Among these factors, only the S-shape modification was significantly associated with whether the GC could be placed at the level of the FM (p <0.0001).

Conclusion

By forging the tip of the GC into an S-shape, the GC can be safely advanced to the distal part of the cervical ICA, which may contribute to the improved maneuverability of microcatheters.

Stent-assisted coiling of unruptured paraclinoid aneurysms with wide neck or unfavorable dome-to-neck ratio: Results of ventral wall vs dorsal wall with propensity score matching analysis

OBJECTIVE

This study aimed to evaluate the clinical safety and efficacy of stent-assisted coil embolization of unruptured wide-necked paraclinoid aneurysms based on the projection distribution.

METHODS

Between November 2015 and September 2020, 267 unruptured paraclinod aneurysms in 236 patients were identified with a wide neck or unfavorable dome-to-neck ratio and treated with stent-assisted coiling technique. The classification of this segment aneurysms was simplified to the dorsal group (located on the anterior wall) and ventral group (Non-dorsal). Following propensity score matching analysis, the clinical and radiographic data were compared between the two groups.

RESULTS

Among 267 aneurysms, 186 were located on the ventral wall and 81 were on the dorsal wall. Dorsal wall aneurysms had a larger size (p < .001), wider neck (p = .001), and higher dome-to-neck ratio (p = .023) compared with ventral wall aneurysms. Propensity score-matched analysis found that dorsal group had a significantly higher likelihood of unfavorable results in immediate (residual sac, 39.4% vs. 18.2%, p = .007) and follow-up angiography (residual sac, 14.8% vs. 1.9%, p = .037) compared with ventral group, with significant difference in recurrence rates (9.3% vs. 0%, p = .028). The rates of procedure-related complications were not significantly different, but one thromboembolic event occurred in the dorsal group with clinical deterioration.

CONCLUSIONS

Traditional stent-assisted coiling can be given preference in paraclinoid aneurysms located on the ventral wall. The relatively high rate of recurrence in dorsal wall aneurysms with stent assistance may require other treatment options.

Three-Dimensional (3D) Microcatheter Shaping Using Touch Screen Devices for Cerebral Aneurysm Coil Embolization

OBJECTIVE

In cerebral aneurysm coil embolization, proper microcatheter shaping is crucial to reduce complications and achieve sufficient embolization. Shaping a microcatheter in 3 dimensions (3D) is often required but can be challenging. We assessed the usefulness of a novel shaping on screen (SOS) method that displays real-size 3D rotational angiography (RA) images on a touch screen device during cerebral aneurysm embolization to facilitate 3D microcatheter shaping.

METHODS

In this study, 18 patients with cerebral aneurysm treated with this technique were included. Real-size 3D-RA images obtained during the embolization procedure were displayed on the touch screen device, which allowed for real-time manipulation. The shape of the microcatheter was adjusted to conform to the curvature of the vessel by swiping the touch screen device and bending the mandrel accordingly. We assessed the clinical and angiographic results, along with the accuracy and stability of the microcatheter.

RESULTS

No procedure-related complications were observed. The mean packing density was 41% ± 12%. In all but 1 case, microcatheters were inserted into the aneurysms without guidewire assistance. After coiling, all microcatheter forms were stable.

CONCLUSIONS

Three-dimensional (3D) microcatheter shaping using touch screen devices during cerebral aneurysm coil embolization may be simple and safe and can achieve high packing density of aneurysms.

Computer-assisted microcatheter shaping for intracranial aneurysm embolization: evaluation of safety and efficacy in a multicenter randomized controlled trial

BACKGROUND

This study aimed to evaluate the efficacy, stability, and safety of computer-assisted microcatheter shaping (CAMS) in patients with intracranial aneurysms.

METHODS

A total of 201 patients with intracranial aneurysms receiving endovascular coiling therapy were continuously recruited and randomly assigned to the CAMS and manual microcatheter shaping (MMS) groups. The investigated outcomes included the first-trial success rate, time to position the microcatheter in aneurysms, rate of successful microcatheter placement within 5 min, delivery times, microcatheter stability, and delivery performance.

RESULTS

The rates of first-trial success (96.0% vs 66.0%, P<0.001), successful microcatheter placement within 5 min (96.04% vs 72.00%, P<0.001), microcatheter stability (97.03% vs 84.00%, P=0.002), and 'excellent' delivery performance (45.54% vs 24.00%, P<0.001) in the CAMS group were significantly higher than those in the MMS group. Additionally, the total microcatheter delivery and positioning time (1.05 minutes (0.26) vs 1.53 minutes (1.00)) was significantly shorter in the CAMS group than in the MMS group (P<0.001). Computer assistance (OR 14.464; 95% CI 4.733 to 44.207; P<0.001) and inflow angle (OR 1.014; 95% CI 1.002 to 1.025; P=0.021) were independent predictors of the first-trial success rate. CAMS could decrease the time of microcatheter position compared with MMS, whether for junior or senior surgeons (P<0.001). Moreover, computer assistance technology may be more helpful in treating aneurysms with acute angles (p<0.001).

CONCLUSIONS

The use of computer-assisted procedures can enhance the efficacy, stability, and safety of surgical plans for coiling intracranial aneurysms.

Navigating complexity: a comprehensive review of microcatheter shaping techniques in endovascular aneurysm embolization

The endovascular intervention technique has gained prominence in the treatment of intracranial aneurysms due to its minimal invasiveness and shorter recovery time. A critical step of the intervention is the shaping of the microcatheter, which ensures its accurate placement and stability within the aneurysm sac. This is vital for enhancing coil placement and minimizing the risk of catheter kickback during the coiling process. Currently, microcatheter shaping is primarily reliant on the operator's experience, who shapes them based on the curvature of the target vessel and aneurysm location, utilizing 3D rotational angiography or CT angiography. Some researchers have documented their experiences with conventional shaping methods. Additionally, some scholars have explored auxiliary techniques such as 3D printing and computer simulations to facilitate microcatheter shaping. However, the shaping of microcatheters can still pose challenges, especially in cases with complex anatomical structures or very small aneurysms, and even experienced operators may encounter difficulties, and there has been a lack of a holistic summary of microcatheter shaping techniques in the literature. In this article, we present a review of the literature from 1994 to 2023 on microcatheter shaping techniques in endovascular aneurysm embolization. Our review aims to present a thorough overview of the various experiences and techniques shared by researchers over the last 3 decades, provides an analysis of shaping methods, and serves as an invaluable resource for both novice and experienced practitioners, highlighting the significance of understanding and mastering this technique for successful endovascular intervention in intracranial aneurysms.

Endovascular Treatment and Microsurgical Clipping for the Management of Paraclinoid Intracranial Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVE

We aimed to compare the efficacy and safety of microsurgical clipping versus endovascular treatment (EVT) for paraclinoid aneurysms.

METHODS

A systematic search for studies including patients with paraclinoid aneurysms treated with a microsurgical or endovascular technique was conducted in 6 databases from inception to February 2022. Efficacy outcomes included complete angiographic occlusion at last follow-up, favorable functional outcome, and recurrence of the aneurysm. For safety, we assessed a composite of intraoperative and postoperative complications. Data were pooled using a random-effects model.

RESULTS

A total of 95 studies including 6711 patients, 3029 in the surgical group and 3682 in the EVT group were found. Pooled rates of complete occlusion were 94% (95% CI 91%-96%; I2 = 0%) in the surgical group and 69% (95% CI 63%-74%; I2 = 79%) in the EVT group, respectively. The favorable functional outcome rate was 86% (95% CI 76%-92%; I2 = 72%) with surgical treatment and 95% (95% CI 92%-97%; I2 = 61%) with EVT. The rate of aneurysm recurrence with surgical treatment was 1% (95% CI 0%-4%; I2 = 0%) and 12% (95% CI 9%-16%; I2 = 57%) with EVT. The composite safety outcome rate in the surgical group was 24% (95% CI 18%-30%; I2 = 90%) and 10% (95% CI 8%-13%; I2 = 71%) in the EVT group.

CONCLUSIONS

Our findings suggest that microsurgical clipping seems to have a higher efficacy than EVT in terms of angiographic occlusion and aneurysm recurrence; however, EVT seems to be safer in terms of intraoperative and postoperative complications. Considering the heterogeneity and low-level evidence of the data available, further prospective randomized studies are warranted to confirm our findings.

Application of microcatheter shaping based on computational fluid dynamics simulation of cerebral blood flow in the intervention of posterior communicating aneurysm of the internal carotid artery

Introduction

The present study aimed to investigate the application of the aneurysm embolization microcatheter plasticity method based on computational fluid dynamics (CFD) to simulate cerebral blood flow in the interventional treatment of posterior communicating aneurysms in the internal carotid artery and to evaluate its practicality and safety.

Methods

A total of 20 patients with posterior internal carotid artery communicating aneurysms who used CFD to simulate cerebral flow lines from January 2020 to December 2022 in our hospital were analyzed. Microcatheter shaping and interventional embolization were performed according to the main cerebral flow lines, and the success rate, stability, and effect of the microcatheter being in place were analyzed.

Results

Among the 20 patients, the microcatheters were all smoothly placed and the catheters were stable during the in vitro model test. In addition, the microcatheters were all smoothly placed during the operation, with a success rate of 100%. The catheter tips were stable and well-supported intraoperatively, and no catheter prolapse was registered. The aneurysm was completely embolized in 19 cases immediately after surgery, and a small amount of the aneurysm neck remained in one case. There were no intraoperative complications related to the embolization catheter operation.

Conclusion

Microcatheter shaping based on CFD simulation of cerebral blood flow, with precise catheter shaping, leads to a high success rate in catheter placing, stability, and good support, and greatly reduces the difficulty of catheter shaping. This catheter-shaping method is worthy of further study and exploration.

Virtual simulation with AneuShape™ software for microcatheter shaping in intracranial aneurysm coiling: a validation study

Background

The shaping of an accurate and stable microcatheter plays a vital role in the successful embolization of intracranial aneurysms. Our study aimed to investigate the application and the role of AneuShape™ software in microcatheter shaping for intracranial aneurysm embolization.

Methods

From January 2021 to June 2022, 105 patients with single unruptured intracranial aneurysms were retrospectively analyzed with or without AneuShape™ software to assist in microcatheter shaping. The rates of microcatheter accessibility, accurate positioning, and stability for shaping were analyzed. During the operation, fluoroscopy duration, radiation dose, immediate postoperative angiography, and procedure-related complications were evaluated.

Results

Compared to the manual group, aneurysm-coiling procedures involving the AneuShape™ software exhibited superior results. The use of the software resulted in a lower rate of reshaping microcatheters (21.82 vs. 44.00%, p = 0.015) and higher rates of accessibility (81.82 vs. 58.00%, p = 0.008), better positioning (85.45 vs. 64.00%, p = 0.011), and higher stability (83.64 vs. 62.00%, p = 0.012). The software group also required more coils for both small (<7 mm) and large (≥7 mm) aneurysms compared to the manual group (3.50 ± 0.19 vs. 2.78 ± 0.11, p = 0.008 and 8.22 ± 0.36 vs. 6.00 ± 1.00, p = 0.081, respectively). In addition, the software group achieved better complete or approximately complete aneurysm obliteration (87.27 vs. 66.00%, p = 0.010) and had a lower procedure-related complication rate (3.60 vs. 12.00%, p = 0.107). Without this software, the operation had a longer intervention duration (34.31 ± 6.51 vs. 23.87 ± 6.98 min, p < 0.001) and a higher radiation dose (750.50 ± 177.81 vs. 563.53 ± 195.46 mGy, p < 0.001).

Conclusions

Software-based microcatheter shaping techniques can assist in the precise shaping of microcatheters, reduce operating time and radiation dose, improve embolization density, and facilitate more stable and efficient intracranial aneurysm embolization.

Endovascular treatment of aneurysms of the paraophthalmic segment of the internal carotid artery: Current status

The paraophthalmic segment of the internal carotid artery (ICA) originates from the distal border of the cavernous ICA and terminates at the posterior communicating artery. Aneurysms arising from the paraophthalmic segment represent ~5–10% of intradural aneurysms. Due to the advent of endovascular treatment (EVT) techniques, specifically flow-diverting stents (FDSs), EVT has become a good option for these aneurysms. A literature review on EVT for paraophthalmic segment aneurysms is necessary. In this review, we discuss the anatomy of the paraophthalmic segment, classification of the paraophthalmic segment aneurysms, EVT principle and techniques, and prognosis and complications. EVT techniques for paraophthalmic segment aneurysms include coil embolization, FDSs, covered stents, and Woven EndoBridge devices. Currently, coiling embolization remains the best choice for ruptured paraophthalmic segment aneurysms, especially to avoid long-term antiplatelet therapy for young patients. Due to the excessive use of antiplatelet therapy, unruptured paraophthalmic segment aneurysms that are easy to coil should not be treated with FDS. FDS is appropriate for uncoilable or failed aneurysms. Other devices cannot act as the primary choice but can be useful auxiliary tools. Both coiling embolization and FDS deployment can result in a good prognosis for paraophthalmic segment aneurysms. The overall complication rate is low. Therefore, EVT offers promising treatments for paraophthalmic segment aneurysms. In addition, surgical clipping continues to be a good choice for paraophthalmic segment aneurysms in the endovascular era.

CTA Study of Ruptured Aneurysms of the Posterior Communicating Artery

Background

Only a few reported studies have used computed tomography angiography (CTA) to image ruptured aneurysms at the junction of the internal carotid artery (ICA) and posterior communicating artery (PcomA) in the context of the adjacent arteries. Therefore, we performed such a study using a GE Workstation.

Methods

The parameters of each aneurysm and its adjacent arteries were measured. Then, statistical assessments were performed to compare the parameters of the aneurysm side and the lesion-free (control) side.

Results

Sixty-three patients were included in this study. The average age was 62.1 ± 11.0 years, and the ratio of males to females was 0.8 : 1. The measurement results showed that the mean aneurysmal height was 5.2 ± 2.3 mm, the mean width was 4.7 ± 2.2 mm, and the mean neck width was 4.5 ± 1.9 mm. On the aneurysm side, the intradural ICA diameter was 4.34 ± 0.90 mm, and the diameter of the ICA at its termination was 3.55 ± 0.72 mm. A fetal-type PcomA was found in 52.4% of aneurysms. The other measured parameters were also provided. Statistical results showed that the height of the aneurysm was larger than the width (P < 0.05). The intradural ICA diameter, the ICA diameter at termination, the intradural ICA length, and the angle between the ICA and PcomA were larger in the aneurysm group than in the control group (P < 0.05).

Conclusions

This CTA study showed that the ruptured PcomA aneurysm was often wide-necked, nonspherical, and approximately 5 mm in size. In the presence of a ruptured PcomA aneurysm, the affected intradural ICA became thicker and longer than the contralateral control ICA, and the aneurysm significantly reduced the angle between the ICA and the PcomA.

Three-dimensional printing-assisted precision microcatheter shaping in intracranial aneurysm coiling

Optimal microcatheter shaping is essential for successful endovascular coiling procedures which is sometimes challenging. Our aim was not only to introduce a new shaping method using three-dimensional (3D) printed vessel models but also to prove its feasibility, efficiency and superiority. This was a retrospective cohort study. From September 2019 to March 2021, 32 paraclinoid aneurysms managed with endovascular coiling were retrospectively included and identified. Sixteen aneurysms were coiled using 3D microcatheter shaping method (3D shaping group), and traditional manual shaping method using shaping mandrels was adopted for another 16 patients (control group). The cost and angiographical and clinical outcomes between the two groups were compared, and the feasibility and effectiveness of the new 3D shaping method were evaluated and described in detail. With technical success achieved in 93.75%, most of the 16 shaped microcatheters using new shaping method could be automatically navigated into the target aneurysms without the assistance of microguidewires and could be assessed with favorable accessibility, positioning and stability. Twenty-seven out of 32 aneurysms (84.38%) were completely occluded with the rate of perioperative complications being 12.50%. Although there was no significant difference between the occlusion rates and complication rates of the two groups, the new shaping method could dramatically decrease the number of coils deployed and reduce the overall procedure time. Patient specific shaping of microcatheters using 3D printing may facilitate easier and safer procedures in coil embolization of intracranial aneurysms with shorter surgery time and less coils deployed.

Artificial intelligence-assisted microcatheter shaping for intracranial aneurysm coiling: A preliminary study

OBJECTIVE

To evaluate the efficacy of artificial intelligence (AI) technology-assisted microcatheter shaping for coil embolization of intracranial aneurysms.

METHODS

From June 2019 to May 2021, 30 aneurysms in 24 patients were treated with coiling embolization using computer software-assisted microcatheter shaping at our institute. All patients underwent digital subtraction angiography (DSA) before coiling embolization. After three-dimensional (3D) rotational angiography, digital imaging and communications in medicine (DICOM) data were extracted and imported into computer software based on an artificial intelligence algorithm. 3D images of the parent artery and aneurysm were constructed with the software, and data including the central axis of the parent artery, aneurysm location, aneurysm size, and 3D structure were automatically obtained. The optimal microcatheter path was calculated and the shape of the mandrel was automatically generated. Surgeons shaped the mandrel and microcatheter following the artificial intelligence-generated template and completed the endovascular procedure.

RESULTS

All patients successfully completed the endovascular procedure without peri-operative complications. The microcatheters shaped according to the artificial intelligence template accurately entered the aneurysm sacs in one attempt, 15 aneurysms required no micro-guidewire assistance in catheterizing the aneurysm sac, and 15 did. The stability of the microcatheters during the procedures was satisfactory. No rebound incidence was observed and no re-shaping was necessary.

CONCLUSION

Artificial intelligence-assisted microcatheter shaping technology provides a new method to generate the optimal shape for the mandrel and microcatheter during endovascular procedures. The technology facilitates microcatheter accuracy and stability during coiling embolization and provides technical support for surgeons.

Comparison of Pipeline Embolization and Coil Embolization for the Treatment of Large Unruptured Paraclinoid Aneurysms

The efficacy of flow diversion (FD) in the treatment of paraclinoid aneurysms has been established. The pipeline embolization device (PED) is one of the most commonly used FD devices. Coil embolization is also useful for treating paraclinoid aneurysms. This study aimed to compare the efficacy and safety of PED treatment and coil embolization for large unruptured paraclinoid aneurysms. This was a single-center, retrospective study of large unruptured paraclinoid aneurysms treated endovascularly between 2009 and 2019 (coil embolization between 2009 and 2015, and PED between 2015 and 2019). Cases with a follow-up period of less than 1 year and recurrence after coil embolization were excluded. The treatment outcomes between coil embolization and PED were compared. We investigated 45 patients with 45 large unruptured paraclinoid aneurysms treated by endovascular surgery in our institution. Twenty-four patients were treated with coil embolization and 21 with PED. In the PED group, the device cost was significantly lower (2,770.4 ± 699.5 vs. 1941.2 ± 552.8 [1000 yen], P = 0.03), procedure duration was significantly shorter (155.4 ± 66.7 vs. 95.1 ± 35.4 min, P <0.01), and the numbers of re-treatments were lower than those in the coil embolization group (41.7 vs. 14.3%, P = 0.05). Both PED and coil embolization were effective and safe for large unruptured paraclinoid aneurysms, and their treatment results were similar. The PED is more beneficial because of its lower cost, shorter procedure duration, and fewer retreatments, and is therefore more useful for the treatment of large unruptured paraclinoid aneurysms.

A Novel Technique of Microcatheter Shaping using Real Image Display for Endovascular Aneurysmal Coil Embolization

In coil embolization of intracranial aneurysms, guiding the microcatheter to an appropriate site in the aneurysm and stabilizing it there are important. In paraclinoid internal carotid aneurysms, complicated three-dimensional (3-D) shaping of the microcatheter tip is occasionally required. We devised a novel shaping method for microcatheters by using a real image display (RID). The usefulness of this technique was validated. We used a RID consisting of a couple of concave mirrors. A piece of patient-specific vascular model, which was made using a 3-D printer before the operation, was set inside the RID. We obtained a real 3-D image just above the RID. As a microcatheter and its shaping inner mandrel could be entered in the hologram of the vasculature, we could create the actual shape of the microcatheter. The shaped microcatheter could be navigated at the desired position in the aneurysm. Complete obliteration of the aneurysm was achieved without any trouble among 30 consecutive cases. We evaluated the effectiveness of the RID for making and navigating a microcatheter in cases with challenging anatomies. It was useful for favorable microcatheter shaping, as the RID could be entered inside the aneurysm models, unlike when tracing the outer surface of rigid 3-D models.

Microcatheter Stabilization Technique Using Partially Inflated Balloon for Coil Embolization of Paraclinoid Aneurysms

PURPOSE

Coil embolization of paraclinoid aneurysms should be simple, safe, and effective considering the benign nature of the aneurysm. Here, we present a microcatheter stabilization technique using a partially inflated balloon for the treatment of paraclinoid aneurysms.

MATERIALS AND METHODS

This retrospective study included 58 patients who underwent balloon-assisted coiling (BAC) for unruptured paraclinoid aneurysms at a tertiary neuro-intervention center between January 2019 and March 2020. We applied a technique to stabilize the microcatheter's position using the modified BAC technique in paraclinoid aneurysms showing various projections around the ophthalmic curve of the internal carotid artery. The basic concept of the technique is to place a partially inflated balloon just distal to the aneurysm neck and support the distal curve of the microcatheter using the proximal bottom of the balloon. Immediate radiological outcomes were analyzed, and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores.

RESULTS

The BAC was successfully performed in 51 of 58 patients (88%). We treated the remaining 7 patients by switching to stent-assisted coiling. We obtained a 37% mean packing density resulting in favorable occlusion in all 58 aneurysms (complete occlusion in 35 and residual neck in 23). There were no intraprocedural thromboembolic or hemorrhagic events except one that revealed an asymptomatic infarction after the procedure (1.7%). Magnetic resonance angiography follow-up was performed in 37 patients at an average of 11.8 months, in which 11 minor recurrences (29.7%) were found. There was no major recurrence nor retreatment. The mRS score was 0 in all patients during a mean follow-up of 17.7 months (range, 12-25 months).

CONCLUSION

The modified balloon-assisted coiling technique using a partially inflated balloon was safe and effective and could serve as an option for treating paraclinoid aneurysms.

Microwire navigation and microcatheter positioning by balloon manipulation for the treatment of intracranial aneurysms: A pilot study

Background and Objective:

An intracranial aneurysm (IA) is a life-threatening condition and endovascular treatment (EVT) is a demanding procedure, especially in IAs with an unfavorable anatomy. The aim of this study was to investigate the safety and efficacy of balloon-assisted microwire navigation and microcatheter positioning in the EVT of IAs with challenging anatomies.

Materials and Methods:

This retrospective study included patients that underwent balloon-assisted microwire navigation and microcatheter positioning in the EVT of IAs between September 2016 and January 2019. All EVT procedures and data collection were performed by the same two neurointerventional radiologists. Technical success and complication rates, safety, and efficiency of the balloon manipulation method were evaluated. Statistical software was used to analyze the basic descriptive data of the patients and aneurysms.

Results:

This study included 14 patients. The microwire navigation of the target artery with balloon manipulation was used in 4 aneurysms of 4 patients. Microcatheter positioning with balloon manipulation was used in 10 aneurysms of 10 patients. There was no complication caused by the balloon manipulation technique. The technical success rate was 100%.

Conclusion:

In the EVT of IAs with challenging anatomies, the presented technique is a safe and effective option without additional complications, especially in the target artery with an acute angle and in small aneurysms.

Microcatheter Re-Shaping Using Fusion Image in Coil Embolization: A Technical Note

Objective

We report the utility of microcatheter reshaping by referring to fusion images with 3D-DSA and microcatheter 3D images made using non-subtraction and non-contrast (non-SC) rotational images.

Case Presentations

Case 1: The patient was a 74-year-old man who had an internal carotid-anterior choroidal artery bifurcation aneurysm with a tortuous proximal parent artery. The initial attempt to introduce the microcatheter into the aneurysm was unsuccessful. During this unsuccessful microcatheter introduction, we created fusion images with 3D-DSA and microcatheter 3D images by acquiring positional information of the microcatheter using the non-SC method. By reshaping the microcatheter with reference to the fusion images, the direction of the distal end of the microcatheter was reshaped to be in accordance with the long axis of the aneurysm, a shape more suitable for coiling. Case 2: The patient was a 47-year-old man who had an anterior communicating (A-com) artery aneurysm with two daughter sacs. We successfully placed two microcatheters in the direction of each sac to make more stable framing by referring to 3D fusion images after the first microcatheter was positioned. In both cases, microcatheter reshaping was necessary because of the vessel and aneurysm anatomy. We have used this technique successfully in 15 patients, for both ruptured and unruptured aneurysms. The average number of microcatheter reshaping was 1.3 times.

Conclusion

This method provides effective microcatheter reshaping for coil embolization of aneurysms, particularly those with differences between the axis of the parent artery and the vertical axis of aneurysm, or with a tortuous proximal artery.

Usefulness of Preoperative Simulation Using a Stereolithographic 3D Printer in Cerebral Aneurysm Coil Embolization

Objective

We present a preoperative simulation of cerebral aneurysm coil embolization using a hollow model of cerebral blood vessels created by a stereolithography (SLA) 3D printer.

Case Presentation

The patient was a 66-year-old woman. During follow-up, coil embolization was planned for an expanding paraclinoid aneurysm. A hollow cerebral vascular model was created preoperatively using an SLA 3D printer. The catheter was malleable and inserted into the hollow model, which enabled the surgeons to confirm its movement, stability, and ease of insertion. In the surgical procedure, the catheter was easily inserted into the aneurysm without reshaping. The procedure was completed without stability problems.

Conclusion

The use of a hollow model of cerebral blood vessels was useful as a preoperative simulation and improved the safety of the procedure.

Optimal microcatheter shaping method customized for a patient-specific vessel using a three-dimensional printer

Objective

In coil embolization of cerebral aneurysms, it is very important to guide microcatheters to the appropriate location in the aneurysm and stabilize them during procedures. To do this, microcatheters need to be properly shaped. In this study, we aim to use a computer application program and a three-dimensional (3D) printer to make a patient-specific shaped microcatheter.

Methods

We simplified, skeletalized, and oversized the existing 3D vascular imaging structures and created the central line structure of the blood vessels. These processes were performed using a computer application program developed by our team. The microcatheters were shaped according to the skeletalized data shape, and the catheterization procedures were simulated using the 3D hollow model of the blood vessel region of interest; the number of hollow models was 10. The compatibility of the microcatheters shaped according to the skeletalized data shape was validated if the microcatheter tip was positioned into the aneurysm.

Results

In all 10 hollow models, the positioning of the microcatheter into the aneurysms was successful following one or two attempts.

Conclusions

When shaping microcatheters during endovascular coil embolization, it may be useful to use central line structures with some expansions customized for a patient-specific vessel using a computer application program and a 3D printer. In the future, it may be necessary to apply this technique to actual patients.

A novel intelligent microcatheter-shaping method for embolization of intracranial aneurysm

Objective:

This study proposed and validated an intelligent microcatheter-shaping algorithm for interventional embolization of intracranial aneurysms.

Methods:

A stepwise microcatheter simulation algorithm constrained by a vessel center line was developed based on the geometry of aneurysms and parent arteries, and a collision correction factor of vessel walls was introduced to automatically calculate the optimal microcatheter path and tip shape. The efficacy of this intelligent shaping method was verified in an in vitro aneurysm model experiment.

Results:

The microcatheter path can be automatically generated using the intelligent microcatheter-shaping algorithm. Furthermore, the experiment verified that the delivery performance of an intelligently shaped microcatheter was excellent with 100% placement accuracy, superior to that of three pre-shaped microcatheters: straight (0°), 45°, and 90°. In three typical cases, the microcatheter could not be placed in the aneurysms successfully within 5 min with the aid of a microwire using a manual shaping scheme; however, it can be placed in the aneurysms successfully within 5 min using an intelligent microcatheter- shaping scheme, and the time of microcatheter placement in aneurysms was short.

Conclusion:

This intelligent microcatheter-shaping algorithm based on three-dimensional image data is effective and reasonable. This approach has advantages over standard pre-shaped microcatheters, with a potential clinical application value.

＜Editors' Choice＞ Initial experience with in vivo "endovascular shaping" technique that utilizes the vascular configuration for small cerebral aneurysm coiling

Optimal shaping of a microcatheter tip is a key factor in cerebral aneurysm coiling. However, safe cannulation and stabilization of a microcatheter can be technically challenging with small aneurysms requiring precise microcatheter shaping. We devised a new microcatheter shaping technique which bends a microcatheter tip in the intended direction by placing and keeping the tip in the selected branch of the parent artery for 5 minutes: endovascular shaping technique. Our method can complete microcatheter shaping only inside the patient's body; an endovascularly shaped microcatheter will never face a straightening deformity and rotation problem associated with catheter reinsertion. The aim was to assess the feasibility and safety of endovascular shaping for small aneurysm coiling. Clinically, 10 consecutive challenging small terminal-type aneurysms (< 5 mm) treated with endovascular shaping were included. We retrospectively analyzed the newly acquired bend angle of a microcatheter tip after the shaping, the procedural success, and clinical outcomes. An artificial vascular model was used to confirm our findings. In all the 10 patients (three middle cerebral artery, four anterior communicating artery, and three basilar artery aneurysms), the endovascularly shaped microcatheters were bent toward the placement branch at an average of 21.7° and excellently guided into the aneurysms. Coil embolization was successfully accomplished without any complications. The results of the vascular model experiment demonstrated that an endovascularly shaped microcatheter acquired new bend angle toward the placement branch. Endovascular shaping was feasible and safe for small terminal-type aneurysm coiling. Our method can provide accurate shaping and stability during aneurysm coiling procedure.

[Endovascular Treatment of Cerebral Aneurysms: Technical Options in Coil Embolization]

Since the endosaccular coil embolization technique was introduced as an alternative for treating selected patients with aneurysms, it has become a mainstay of treatment for cerebral aneurysms. In lesions with a neck larger than the aneurysmal body, an irregular shape, or arterial branches incorporated within the sac, endovascular treatment using detachable coils are traditionally contraindicated because of technical difficulties. Coil embolization has evolved as a result of both the development of related devices and the introduction of technical improvements using various devices. Use of various technical and device options can make endovascular treatment of cerebral aneurysms safer and can widen the treatment indications. Various technical options, including the technical modification of device-assisted techniques, will be presented, and the related practical points will be discussed in this issue.

Simple and Reproducible Microcatheter Shaping Method for Coil Embolization of Medially-directed Paraclinoid Internal Carotid Artery Aneurysms

Objective

It is important to guarantee intra-aneurysmal stability of microcatheters during coil embolization. We developed a simple and reproducible microcatheter shaping method for medially-directed paraclinoid internal carotid artery aneurysms.

Methods

An injection needle cap was used to make a smooth curve on the mandrel, which was first wound around the back end of the cap to create a primary curve. Next, a secondary curve was created using near the tip of the cap. Thus, a two-dimensional (2D), pigtail-shaped mandrel with a two-stage curve was created. The pigtail-shaped mandrel was inserted from the tip of a straight microcatheter and heat-shaped using a heat gun. Lastly, a microcatheter having a curve whose tip was approximately 6 mm longer than that of the preshaped J was created. We evaluated the ease of navigating the microcatheter into the aneurysm and its stability during coil embolization.

Results

In all, 34 consecutive medially-directed paraclinoid internal carotid artery aneurysms were treated using the shaped catheters. It took 50-300 seconds (intermediate value: 90 seconds) from inserting the microcatheter with a microguide wire to navigate and place it into an aneurysm. There were no cases that required reshaping of the microcatheters during navigation into the aneurysm. There were no cases that resulted in kickback of the microcatheters from the aneurysm during coil placement, and microcatheter stability was good until the end of the procedure. In all, 12 cases required the balloon-assisted technique and three cases required stent-assisted coiling. The angiographic outcomes immediately after embolization were as follows: 25 cases (73.5%) with complete occlusion; 3 cases (8.8%) with dome filling; and 6 cases (17.6%) with a neck remnant. There were no perioperative complications.

Conclusion

The shaping method with a pigtail-shaped mandrel using an injection needle cap is simple and reproducible, and is useful for medially-directed paraclinoid internal carotid artery aneurysms.

Microcatheter shaping using three-dimensional printed models for intracranial aneurysm coiling

Background and purpose

Microcatheterization is an important, but also difficult, technique used for the embolization of intracranial aneurysms. The purpose of this study was to investigate the application of three-dimensional (3D) printing technology in microcatheter shaping.

Methods

Nine cases of internal carotid artery posterior communicating artery aneurysm diagnosed by CT angiography were selected, and 3D printing technology was used to build a 3D model including the aneurysm and the parent artery. The hollow and translucent model had certain flexibility; it was immersed in water and the microcatheter was introduced into the water to the target position in the aneurysm, followed by heating the water temperature to 50°C. After soaking for 5 min, the microcatheter was taken out and the shaping was completed. After sterilization, the shaped microcatheter was used for arterial aneurysm embolization and evaluation was conducted.

Results

Nine cases of microcatheter shaping were satisfactory and shaping the needle was not necessary; no rebound was observed. The microcatheter was placed in an ideal position, and the stent-assisted method was used in three cases of wide-neck aneurysm. There were no complications related to surgery.

Conclusion

A new microcatheter shaping method using 3D printing technology makes intracranial artery aneurysm embolization more stable and efficient.

A Novel Technique for Microcatheter Additional Shaping During Intracranial Aneurysmal Coil Embolization: Microcatheter Shaping Cast

Background:

When a shaping mandrel is inserted into the tip of a preshaped microcatheter, the existing curve becomes uncertain because the tip is straightened by the inner mandrel. Therefore, we developed a way to perform microcatheter shaping by means of an external cast, which we named “microcatheter shaping cast.”

Techniques:

A shaping mandrel attached to a microcatheter was used and coiled 4–5 times around a metallic introducer, which was attached using a microguidewire. Then, a stent-like handmade cast was prepared. After the microcatheter tip was inserted into the cast, it was manually bent according to the aneurysmal shape and size. The tip and cast were heated with a hot air gun. We evaluated the relationship between degrees of bending and heating time to achieve appropriate right-angled shaping memory.

Conclusions:

The presented microcatheter shaping method should be more useful than conventional internal shaping, especially in cases that require an additional microcatheter shaping or reshaping during aneurysmal coil embolization.

Precision microcatheter shaping in vertebrobasilar aneurysm coiling

BACKGROUND

Inventing an optimal curve on a microcatheter is required for successful intracranial aneurysm coiling. Shaping microcatheters for vertebrobasilar artery aneurysm coiling is difficult because of the vessel's long, tortuous and mobile anatomy. To overcome this problem, we devised a new method of shaping the microcatheter by using the patient's specific vessel anatomy and the highly shapable microcatheter. We report our preliminary results of treating posterior circulation aneurysms by this method.

METHODS

An unshaped microcatheter (Excelsior XT-17; Stryker Neurovascular, Fremont, CA, USA) was pretreated by exposure to the patient's vessel for five minutes. The microcatheter was placed in the vicinity of the targeted aneurysm and was left in contact with the patient's vessel before extraction. This treatment precisely formed a curve on the microcatheter shaft identical to the patient's vessel anatomy. Following the pretreatment, the tip of the microcatheter was steam shaped according to the long axis of the target aneurysm. Five consecutive vertebrobasilar aneurysms were treated using this shaping method and evaluated for the clinical and anatomical outcomes and microcatheter accuracy and stability.

RESULTS

All of the designed microcatheters matched the vessel and aneurysm anatomy except in one case that required a single modification. All aneurysms were successfully catheterized without the assistance of a microguidewire, and matched the long axis of the aneurysm. All microcatheters retained stability until the end of the procedure.

CONCLUSIONS

A precise microcatheter shaping for a vertebrobasilar artery aneurysm may be achieved by using the patient's actual vessel anatomy and the highly shapable microcatheter.

A new method to statistically describe microcatheter tip position in patient-specific aneurysm models

BACKGROUND AND PURPOSE

Evidence on how to select microcatheters to facilitate aneurysm catheterization during coil embolization is sparse. We developed a new method to define microcatheter tip location inside a patient-specific aneurysm model as a 3-dimensional probability map. We hypothesized that precision and accuracy of microcatheter tip positioning depend on catheter tip shape and aneurysmal geometry.

MATERIALS AND METHODS

Under fluoroscopic guidance two to three operators introduced differently shaped microcatheters (straight, 45°, 90°) into eight aneurysm models targeting the anatomic center of the aneurysm. Each microcatheter position was recorded with flat-panel CT, and 3-dimensional probability maps of the microcatheter tip positions were generated. Maps were assessed with histogram analyses and compared between tip shapes, aneurysm locations and operators.

RESULTS

Among a total of 530 microcatheter insertions, the precision (mean distance between catheter positions) and accuracy (mean distance to target position) were significantly higher for the 45° tip (1.10±0.64 mm, 3.81±1.41 mm, respectively) than for the 90° tip (1.27±0.57 mm, p=0.010; 4.21±1.60 mm p=0.014, respectively). Accuracy was significantly higher in posterior communicating artery aneurysms (3.38±1.20 mm) than in aneurysms of the internal carotid artery (4.56±1.54 mm, p<0.001).

CONCLUSION

Our method can be used tostatistically describe statistically microcatheter behavior in patient-specific anatomy, which may improve the available evidence guiding microcatheter shape selection. Experience increases the ability to reach the intended position with a microcatheter (accuracy) that is also dependent on the aneurysm location, whereas catheter tip choice determines the variability of catheter tip placements versus each other (precision). Clinical validation is required.

Loop microcatheter technique for coil embolization of paraclinoid aneurysms

BACKGROUND

Although paraclinoid aneurysms do not exhibit a high risk of rupture, coil embolization is not always easy because of unstable microcatheter position. We present a technique that allows a stable microcatheter position for coil embolization of paraclinoid aneurysms.

METHODS

We enrolled 34 consecutive patients who underwent coil embolization for paraclinoid aneurysms. A loop of distal microcatheter was shaped based on three-dimensional rotational angiography. The basic concept is to keep the proximal loop abutting the opposite wall of the aneurysm while using the distal loop for coiling. Then, a proximal curve was made to accommodate the shape of the carotid siphon, which may decide the direction of the loop. Stent-assisted coil embolization was performed in 19 wide-necked aneurysms. Immediate radiological outcomes were analyzed with Raymond classification and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores.

RESULTS

Satisfactory occlusion of aneurysm was achieved in 94.1% (32/34) of patients with a Raymond score of 1 or 2. Packing density of ≥ 31% was achieved in 71% (24/34) of patients. No significant differences were observed between stent-assisted coiling and coiling-only groups. Follow-up magnetic resonance angiography and/or angiogram showed stable coil position, except in one patient with tiny recurrence (from Raymond scores 1 to 2) that did not require retreatment at the 6-month follow-up. mRS scores of 0-1 were obtained in all patients at 6 months.

CONCLUSIONS

Loop microcatheter technique allowed safe and stable coil packing for paraclinoid aneurysms. The same procedural concept is also being used for aneurysms in other vascular territories.

Current status of training environments in neuro-interventional practice: are animal models still contemporary?

PURPOSE

Several different training environments for practicing neurointerventional procedures have been realized in silico, in vitro, and in vivo. We seek to replace animal-based training with suitable alternatives. In an effort to determine present training model distribution and preferences, we interviewed interventional neuroradiologists from 25 different countries about their experience in distinct training environments.

METHODS

A voluntary online survey comprising 24 questions concerning the different training facilities was designed and electronically conducted with the members of the European Society for Minimally Invasive Neurological Therapy.

RESULTS

Seventy-one physicians with an average experience of 11.8 (±8.7) years completed the survey. The majority of participants had experience with animal-based training (eg, stroke intervention: 36; 50.7%). Overall, animal-based training was rated as the most suitable environment to practice coil embolization (20 (±6)), flow diverter placement (13 (±7)), and stroke intervention (13.5 (±9)). In-vitro training before using a new device in patients was supported by most participants (35; 49.3%). Additionally, preference for certain training models was related to the years of experience.

CONCLUSION

This survey discloses the preferred training modalities in European neurointerventional centers with the majority of physicians supporting the general concept of in-vitro training, concomitantly lacking a standardized curriculum for educating neurointerventional physicians. Most suitable training modalities appeared to be dependent on procedure and experience. As animal-based training is still common, alternate artificial environments meeting these demands must be further developed.

Three-dimensional shaping technique for coil placement using the steam-shaped microcatheter for ruptured blood blister-like aneurysm

Treatment of blood blister-like aneurysm (BBA) is a challenge due to its unfavourable morphology, small size and the friable neck of BBA. In the management of ruptured BBA, coil placement can be achieved by stent-assisted coil embolisation. We propose to incorporate a new technique using a steam-shaped microcatheter to improve safety. A 59-year-old woman was transferred to our hospital and diagnosed with subarachnoid haemorrhage (SAH) due to a ruptured BBA of the left internal carotid artery (ICA) at the C2 portion. For coil embolisation, we selected the aneurysm sac using a three-dimensional shaping technique and the jailing method. Post-embolisation angiography revealed complete occlusion of the aneurysmal sac. For safe treatment and stability of BBA, the shape of the catheter tip and the distal portion of the microcatheter are two important factors to consider. The proposed technique could help resolve the problem of catheter shaping in the treatment of BBA.

Risk Factors to Predict Neurologic Complications After Endovascular Treatment of Unruptured Paraclinoid Aneurysms

OBJECTIVE

Unruptured paraclinoid aneurysms are often asymptomatic, and endovascular coiling is the main treatment. However, endovascular treatment of these lesions still leads to neurologic complications. We aimed to identify predictors of neurologic complications in these lesions.

METHODS

We retrospectively analyzed patients with unruptured paraclinoid aneurysms who were treated with endovascular coiling between January 2014 and December 2015. A neurologic complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. Univariate and mulitivariate logistic regression analyses were performed to assess the risk factors of neurologic complications.

RESULTS

Of the 443 unruptured paraclinoid aneurysms that were included in this study, the incidence of neurologic complications was 5.2%. Neurologic complications were highly correlated with hypertension (odds ratio [OR], 3.147; 95% confidence interval [CI], 1.217-8.138; P = 0.018), cerebral ischemic comorbidities (OR, 3.396; 95% CI, 1.378-8.374; P = 0.008), and aneurysm size (OR, 7.714; 95% CI, 1.784-31.635; P < 0.001), and irregular shape (OR, 3.157; 95% CI, 1.239-8.043; P = 0.016) in the univariate analysis. Cerebral ischemic comorbidities (OR, 2.837, 95% CI, 1.070-7.523; P = 0.036) and aneurysm size as dichotomous variables (OR, 7.557; 95% CI, 2.975-19.198; P < 0.001) were strongly correlated with neurologic complications in the final adjusted multivariate logistic analysis.

CONCLUSIONS

Unruptured paraclinoid aneurysms after endovascular treatments had 5.2% of neurologic complications. Cerebral ischemic comorbidities and aneurysm size were predictors of neurologic complications.

Microcatheter shaping using intravascular placement during intracranial aneurysm coiling

Background The selection of a pre-shaped microcatheter or a shaping method must be carefully considered for successful aneurysm coiling. The objective of this report is to verify the use of intravascular placement to establish an appropriate microcatheter shape. Methods Fifteen patients (15 aneurysms) were included in this study because of the predicted difficulty of microcatheter insertion and stabilisation. The SL-10 straight microcatheter was inserted into the parent artery until the tip of the catheter passed through the neck of the aneurysm. After 5 minutes, the microcatheter was pulled out and the shape acquired from intravascular placement was confirmed and compared with the three-dimensional rotational angiography. In addition, the microcatheter tip was steam-shaped for coiling and coil embolisation was performed. A silicone flow model was also used to confirm our findings. The first experiment compared the bend angle in four different microcatheters placed in the model for 5 minutes. In the second experiment, the SL-10 straight microcatheter was placed in the model, and the bend angle was measured at 2.5, 5, 7.5 and 10 minutes to observe the changes in bend angle over time. Results The SL-10 straight microcatheter, in place for 5 minutes, acquired a shape similar to the patient's own vessel. Among the 15 patients included, 13 were treated using an intravascular shaped microcatheter. In the flow model experiments, the SL-10 most easily acquired the vessel shape, and the shape change stabilised after 5 minutes. Conclusion Shaping the SL-10 straight microcatheter using intravascular placement is an effective shaping method for aneurysm coil embolisation.

Microcatheter Looping Technique Facilitates the Embolization of Complex Intracranial Aneurysms with an Acute Angle Branch Incorporated into the Sac

OBJECTIVE

Intracranial aneurysms with an acutely angled parent vessel are difficult to enter using conventional techniques. This study examined efficacy, safety, and technical aspects of intraluminal, intra-aneurysmal, and in vitro microcatheter looping techniques (MLTs).

METHODS

MLTs were used to treat intracranial aneurysms with an incorporated acute angle branch in 29 consecutive patients after failed treatment with conventional techniques. The MLT was adopted based on specific morphologic traits of aneurysms and parent vessels. Narrow-necked aneurysms were generally treated with coiling alone, whereas wide-necked aneurysms and giant aneurysms were treated with stent-assisted coiling.

RESULTS

Technical success was achieved in 28 of 29 cases (96.6%). In vitro MLT was used in 12 patients, intraluminal MLT was used in 14 patients, and intra-aneurysmal MLT was used in 3 patients. Immediate total occlusion was achieved in 8 patients, near-total occlusion was achieved in 8 patients, and subtotal occlusion was achieved in 13 patients.

CONCLUSIONS

The MLT may provide access to an incorporated, acutely angled arterial branch that is difficult to enter using a conventional coiling technique. The in vitro MLT is potentially safer than intraluminal and intra-aneurysmal MLTs because the loop is very stable and requires less manipulation.

Endovascular Treatment of Unruptured Paraclinoid Aneurysms: Single-Center Experience with 400 Cases and Literature Review

BACKGROUND AND PURPOSE

Paraclinoid aneurysms have been increasingly treated endovascularly. The natural history of these aneurysms has gradually been elucidated. The purpose of this study was to assess the safety and efficacy of endovascular treatment for these aneurysms.

MATERIALS AND METHODS

We performed a retrospective review of 377 patients with 400 paraclinoid aneurysms treated between January 2006 and December 2012. Their clinical records, endovascular reports, and radiologic and clinical outcomes were analyzed. Because aneurysms ≥7 mm are at higher risk of rupture, we classified aneurysms as small (<7 mm) or large (≥7 mm).

RESULTS

Overall, 115 of the 400 aneurysms (28.8%) were large (≥7 mm). Thromboembolic complications were found significantly more often with large aneurysms than with small ones (7.4% vs 1.0%, P = .001). Hemorrhagic complications were found only with small aneurysms (0.7%). The 6-month morbidity rates were similar for small (1.0%) and large (0.8%) aneurysms. Immediate angiographic outcomes were similar (P = .37), whereas recurrences and retreatment occurred more frequently with large aneurysms (P = .001 and P = .007, respectively). Multivariate analysis showed that aneurysm size was the only independent predictor for recurrence (P = .005). Most recurrences (81%) were detected by scheduled angiography at 6 months.

CONCLUSIONS

Aneurysm size influenced the type of complication (thromboembolic or hemorrhagic) and the recurrence rate. Given the approximately 1% annual rupture rate for aneurysms ≥7 mm, analysis of our data supports the rationale of using prophylactic endovascular treatment for unruptured paraclinoid aneurysms ≥7 mm.

The gently pull-back technique for neck bypass in treatment of wide-necked internal carotid artery aneurysms: A report of three cases and review of the literature

Neck bypass failure in endovascular treatment of wide-necked internal carotid artery (ICA) aneurysms may adversely affect the technical success of the procedure. We used the gently pull-back technique to bypass the aneurysm neck and access the distal parent artery during endovascular treatment in patients with wide-necked ICA aneurysms. In this technique, a loop was made in the aneurysm and the distal parent artery was reached by using a small diameter microguidewire and a microcatheter. After providing reliable distal access, the microguidewire was removed and the whole system which consists of the microcatheter was gently pulled back. Finally the microcatheter was straightened and the aneurysm neck was passed. After crossing the aneurysm neck, a flow-diverting stent treatment and stent-assisted coiling were performed in three cases with wide-necked ICA aneurysm. The gently pull-back technique is a simple and effective method which requires no extra intravascular device and helps to bypass the aneurysm neck through a small diameter microguidewire and a microcatheter. This technique may be useful for neck aneurysm bypass in endovascular treatment of wide-necked ICA aneurysms.

Microcatheter Looping to Facilitate Aneurysm Selection in Coil Embolization of Paraclinoid Aneurysms

Objective

Described herein is a microcatheter looping technique to facilitate aneurysm selection in paraclinoid aneurysms, which remains to be technically challenging due to the inherent complexity of regional anatomy.

Materials and Methods

This retrospective study was approved by our Institutional Review Board, and informed consent was waived. Microcatheter looping method was employed in 59 patients with paraclinoid aneurysms between January 2012 and December 2013. In the described technique, construction of a microcatheter loop, which is steam-shaped or pre-shaped, based on the direction of aneurysms, is mandatory. The looped tip of microcatheter was advanced into distal internal carotid artery and positioned atop the target aneurysm. By steering the loop (via inner microguidewire) into the dome of aneurysm and easing tension on the microcatheter, the aneurysm was selected. Clinical and morphologic outcomes were assessed with emphasis on technical aspects of the treatment.

Results

Through this looping technique, a total of 59 paraclinoid aneurysms were successfully treated. After aneurysm selection as described, single microcatheter technique (n = 25) was most commonly used to facilitate coiling, followed by balloon protection (n = 21), stent protection (n = 7), multiple microcatheters (n = 3), and stent/balloon combination (n = 3). Satisfactory aneurysmal occlusion was achieved through coil embolization in 44 lesions (74.6%). During follow-up of 53 patients (mean interval, 10.9 ± 5.9 months), only one instance (1.9%) of major recanalization was observed. There were no complications related to microcatheter looping.

Conclusion

This microcatheter looping method facilitates safe and effective positioning of microcatheter into domes of paraclinoid aneurysms during coil embolization when other traditional microcatheter selection methods otherwise fail.

Progressive thrombosis of small saccular aneurysms filled with contrast immediately after coil embolization: analysis of related factors and long-term follow-up

INTRODUCTION

Although it is well-known that incomplete occlusion of aneurysms after coil embolization predisposes to later recanalization, not all aneurysms will be fully occluded by coiling. In follow-up, we evaluated outcomes of small aneurysms (<10 mm) that showed filling of the sac with contrast immediately after coil embolization and assessed factors implicated in subsequent progressive thrombosis.

METHODS

Between January 2008 and December 2010, a total of 1035 aneurysms in 898 patients were treated by endovascular coiling. Of these, 210 small aneurysms displayed filling of the sac by contrast immediately after coil embolization. Time-of-flight magnetic resonance angiography (TOF-MRA; at 6, 12, 24, and 36 months) and digital subtraction angiography (as needed) were used for postoperative monitoring. Complete occlusion of these aneurysms at the 6-month follow-up point was attributed to progressive thrombosis.

RESULTS

In 186 (88.5 %) of the 210 aneurysms that showed filling of the sac with contrast, complete occlusion was observed on follow-up imaging studies at 6 months. Multiple logistic regression analysis indicated that progressive thrombosis was linked to aneurysmal neck diameter ≤4 mm (p < 0.001) and packing density >30 % (p = 0.016). Aneurysms originating from non-branching vessels were of marginal statistical significance (p = 0.056). In 179 progressively thrombosed aneurysms with follow-up evaluations of ≥12 months (mean, 31.9 ± 7.6 months), 168 aneurysms (93.9 %) exhibited stable occlusion, whereas minor recanalization was observed in 6 (3.3 %) instances, and major recanalization occurred in 5 (2.8 %).

CONCLUSIONS

In aneurysms where filling of the sac with contrast was demonstrable after coil embolization, aneurysms with small neck diameters or high coil packing density, and non-branching aneurysms seem predisposed to progressive intra-aneurysmal thrombosis over the course of time.

Endovascular Treatment of 429 Anterior Communicating Artery Aneurysms Using Bare-Platinum Coils : Clinical and Radiologic Outcomes at the Long-term Follow-up

Objective

We reviewed the feasibility, safety and efficacy as well as the clinical outcome and long-term angiographic results of endovascular treatment (EVT) of the anterior communicating artery (ACoA) aneurysms.

Methods

A total of 429 ACoA aneurysms in 426 patients were treated using coil embolization between March 1996 and October 2010 in a single institution. Pretreatment aneurysmal features were checked using angiogram. We had usually used tailored steam shaped microcatheter according to individual angiographic architectures. Immediate postembolization outcomes were evaluated using an angiographic outcome scale and clinical evaluation was performed using the Glasgow Outcome Scale (GOS).

Results

Postembolization angiograms demonstrated total occlusion of aneurysm in 290 of 429 (67.6%) aneurysms, neck remnant in 80 (18.6%) and body filling in 59 (13.8%). Dome direction and aneurysm angle was not associated with initial angiographic outcomes. The procedure-related morbidity rate was 0.9% (4 of 429). Clinical and imaging follow-up more than 6 months were available in 382 (89.0%) patients with a mean of 26.2 months. Overall rate of major recanalization was 7.9% (30 of 382) and all of them were retreated without complications. At the last follow-up, 233 (99.2%) of 235 patients had GOS of 5 in unruptured group, and 152 (79.5%) of 191 patients showed good clinical outcomes (GOS of 4 or 5) in ruptured group.

Conclusion

Tailored steam shaping of the microcatheter is vital to achieve good angiographic outcomes regardless of aneurysmal direction. EVT is feasible and safe for most ACoA aneurysms with acceptable immediate and long-term outcomes.

Microcatheter Shaping for Intracranial Aneurysm Coiling Using the 3-Dimensional Printing Rapid Prototyping Technology: Preliminary Result in the First 10 Consecutive Cases

OBJECTIVE

An optimal microcatheter is necessary for successful coiling of an intracranial aneurysm. The optimal shape may be predetermined before the endovascular surgery via the use of a 3-dimensional (3D) printing rapid prototyping technology. We report a preliminary series of intracranial aneurysms treated with a microcatheter shape determined by the patient's anatomy and configuration of the aneurysm, which was fabricated with a 3D printer aneurysm model.

METHODS

A solid aneurysm model was fabricated with a 3D printer based on the data acquired from the 3D rotational angiogram. A hollow aneurysm model with an identical vessel and aneurysm lumen to the actual anatomy was constructed with use of the solid model as a mold. With use of the solid model, a microcatheter shaping mandrel was formed to identically line the 3D curvature of the parent vessel and the long axis of the aneurysm. With use of the mandrel, a test microcatheter was shaped and validated for the accuracy with the hollow model. All the planning processes were undertaken at least 1 day before treatment. The preshaped mandrel was then applied in the endovascular procedure. Ten consecutive intracranial aneurysms were coiled with the pre-planned shape of the microcatheter and evaluated for the clinical and anatomical outcomes and microcatheter accuracy and stability.

RESULTS

All of pre-planned microcatheters matched the vessel and aneurysm anatomy. Seven required no microguidewire assistance in catheterizing the aneurysm whereas 3 required guiding of a microguidewire. All of the microcatheters accurately aligned the long axis of the aneurysm. The pre-planned microcatheter shapes demonstrated stability in all except in 1 large aneurysm case.

CONCLUSION

When a 3D printing rapid type prototyping technology is used, a patient-specific and optimal microcatheter shape may be determined preoperatively.

Management strategy of surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms

OBJECTIVE

Advances in endovascular treatment (EVT) have greatly improved the treatment outcomes of paraclinoid aneurysms. However, EVT had the shortcoming of durability and thromboembolic complications. As well, surgical treatment of paraclinoid aneurysms is still challenging due to the complexity of adjacent structures. The objective of this study is to report our experience with a combined surgical and endovascular treatment of unruptured paraclinoid aneurysms based on the location of aneurysms.

METHODS

A retrospective review was conducted of 185 cases of unruptured paraclinoid aneurysms that underwent surgical or endovascular treatment between September 2008 and August 2012. Thirty-one aneurysms (16.8%) were treated by microsurgery and 154 (83.2%) were treated by EVT. Fifty aneurysms (27.0%) were classified to the dorsal group and 135 (73%) were classified to the non-dorsal group.

RESULTS

Twenty of 50 dorsal group aneurysms (40%) were treated by microsurgery while 124 of 135 non-dorsal group aneurysms (91.9%) underwent an EVT. The rate of complete occlusion was 96.8% in surgical series and 60.4% in EVT (P < 0.001). Recanalization occurred in 9 aneurysms (5.8%) of EVT and 1 aneurysm (3.2%) of surgical series (P = 0.360). In non-dorsal group, transient complications (10 aneurysms (5.4%), P = 0.018) and morbidity at last visiting (6 aneurysms (3.2%), P = 0.021) were more present in surgically treated cases rather than in EVT cases. Diplopia and visual field defect occurred in the non-dorsal group only; in 2 of 11 surgical cases (18.2%) and in 1 of 124 EVT series (0.8%) (P = 0.017). The overall rate of excellent or good clinical outcomes (Glasgow outcome scale 5 or 4) was 98.9%.

CONCLUSION

EVT is a safe and effective treatment for the non-dorsal group. Based on angiographic and clinical aspects, microsurgical clipping has prior efficacy with better outcomes in the dorsal group under proper individualized selection.

Clinical outcome of paraclinoid internal carotid artery aneurysms after microsurgical neck clipping in comparison with endovascular embolization

OBJECTIVE

Because of the complex anatomical association among vascular, dural, and bony structures, paraclinoid internal carotid artery (ICA) aneurysms remain a major challenge for vascular neurosurgeons. We studied the clinical outcomes of 61 paraclinoid ICA aneurysms after microsurgical clipping in comparison with endovascular coiling.

MATERIALS AND METHODS

Between January 2008 and December 2012, we treated 61 paraclinoid ICA aneurysms created by surgical clipping or endovascular coiling. Preoperative neurologic status and postoperative outcome were evaluated using the Glasgow coma scale (GCS) and the modified Rankin scale (mRS). Postoperative hydrocephalus and vasospasm were reviewed using the patients' medical charts.

RESULTS

Most patients were in good clinical condition before the operations and had good treatment outcomes. Clinical vasospasm was observed after the operation in five patients, and hydrocephalus occurred in six patients. No statistically significant difference regarding aneurysm size, sex, GCS score, H-H grade, and mRS was observed between the surgical clipping group and the endovascular coiling group. In addition, the treatment results and complications did not show statistically significant difference in either group.

CONCLUSION

Surgical occlusion of paraclinoid ICA aneurysms is difficult; however, no significant differences were observed in the treatment results or complications when compared with coil embolization. In particular, use of an adequate surgical technique may lead to better outcomes than those for coil embolization in the treatment of large and/or wide-neck paraclinoid ICA aneurysms.

Using the snare system to cross the acute-angled vertebrobasilar junction in treating posterior inferior cerebellar artery aneurysm with the stent-assisted method via a retrograde approach. A technical note

Retrograde stenting via the contralateral vertebral artery (VA) is a safe and effective treatment for posterior inferior cerebellar artery (PICA) aneurysm. Many methods, including tip shaping and the looping technique, have been attempted as ways to cross the vertebrobasilar (VB) junction. Here, we introduce an alternative method using a Snare system to overcome the acute-angled VB junction after repeated failures using other techniques. The Snare system was navigated to the proximal basilar artery via the ipsilateral VA. A guidewire was introduced in the contralateral VA and gently advanced to the basilar artery in order to pass through the loop of the Snare system. Following this, the Snare system caught the guidewire and it was very carefully pulled down to the ipsilateral VA crossing the VB junction. We suggest this technique as a method to cross the acute-angled VB junction after failure of all other attempts to overcome this challenge.

Could the types of paraclinoid aneurysm be used as a criterion in choosing endovascular treatment? Neuro-radiologists' view

BACKGROUND

The type of paraclinoid aneurysm has been used to decide management methods. Our aim was to assess the relation of the types of paraclinoid aneurysms and outcomes after endovascular treatment and the efficiency of present endovascular techniques.

METHODS

A retrospective analysis was performed on patients with saccular paraclinoid aneurysms that had more than 6 months of angiographic follow-up or recurrence within this period after endovascular treatment from January 2009 to December 2010. Paraclinoid aneurysms were classified into two types and then further into four subtypes by a modified classification method. A classification-based microcatheter shaping method was used in the procedure. The significant risk factors of angiographic results were determined through correlation analysis and logistic regression analysis by SPSS 17.0.

RESULTS

There were 64 aneurysms in 56 patients; 28 aneurysms belonged to Type I, while 36 were Type II. A total of 12 aneurysms were managed with coil embolization, and 52 with stent-assisted coiling technique. Our classification-based microcatheter shaping method was successful in all cases. Coil protrusion happened in two cases without severe complications. Recurrence were found in 13 (20.3 %) aneurysms followed up at 12.42 ± 3.78 (mean±SD) months after treatment. The correlation between aneurysm types and immediate angiographic result or follow-up angiographic results did not reach statistical significance. Aneurysm types were not the risk factor of recurrence.

CONCLUSIONS

The types of paraclinoid aneurysm had not been significant correlated with outcomes of endovascular treatment. Fundus size was the significant risk factor of recurrence after endovascular treatment. A classification-based microcatheter shaping method may be used in endovascular treatment paraclinoid aneurysms. The present endovascular techniques are safe and effective.

Experiences and complications in endovascular treatment of paraclinoid aneurysms

Endovascular treatment is a promising therapeutic alternative for paraclinoid aneurysms. The purpose of this study was to assess the feasibility and results of endovascular treatment for these lesions. We retrospectively reviewed the clinical data, results and complications of endovascular treatment of a series of 47 consecutive patients with paraclinoid aneurysms. Nineteen of these patients presented with acute subarachnoid hemorrhage, and 28 patients were treated for unruptured aneurysms. Endovascular treatment was performed for 50 aneurysms in 47 patients including stent-assisted coiling (19), balloon-assisted coiling (five), coiling without adjunctive techniques (25) and stent alone (one). Technical failures occurred in two patients (one stent deployment failure due to unsuccessful distal access across the aneurysm neck and one coiling failure due to unsuccessful microcatheter navigation through the stent). Periprocedural complications were observed in six patients (12.8%), with permanent morbidity in one patient resulting from a thromboembolic event. Immediate complete occlusion was achieved in 36 aneurysms (72%). During follow up, enlargement of a partially occluded giant aneurysm was observed in one patient, which was treated with parent artery occlusion. No delayed hemorrhagic complications were seen in the remaining patients. Endovascular treatment is technically feasible and safe in most patients with paraclinoid aneurysm, with a low rate of procedural complications.

Unruptured non-branching site aneurysms located on the anterior (dorsal) wall of the supraclinoid internal carotid artery: aneurysmal characteristics and outcomes following endovascular treatment

BACKGROUND

This study was undertaken to evaluate the aneurysmal characteristics and clinico-radiological outcomes of unruptured non-branching site aneurysms located on the anterior (dorsal) wall of the supraclinoid internal carotid artery (ICA).

METHODS

The data of 34 patients that underwent endovascular treatment for 36 unruptured ICA anterior wall aneurysms were reviewed. ICA anterior wall aneurysms were defined as aneurysms that projected superiorly from the anterior wall of the ICA ophthalmic (n = 35) or communicating (n = 1) segment on lateral angiograms, without any branch vessel relationship. In addition, aneurysmal characteristics and treatment outcomes were compared with those of 60 unruptured aneurysms originating from the posterior (ventral) wall of the ICA ophthalmic segment.

RESULTS

Patients with an ICA anterior wall aneurysm frequently had a mirror aneurysm on the contralateral side (14.7 % versus 3.3 %) or another ICA aneurysm (35.3 % versus 15 %). Two of the 36 ICA anterior wall aneurysms exhibited ICA narrowing suggestive of dissection, and another five had dysplastic ICA dilatation around the neck. Stent-assisted embolization was more frequently performed for ICA anterior wall aneurysms (66.7 % versus 36.7 %) because of unfavorable dome/neck (mean, 1.21) and aspect (mean, 1.15) ratios, and because of microcatheter instability associated with superior aneurysmal projections against the abrupt curvature of the carotid siphon. Procedure-related thromboembolic complications occurred in three patients in the anterior aneurysm group, but no patient deteriorated clinically. Immediate radiological outcomes were more unfavorable for ICA anterior wall aneurysms (residual sac, 36.1 % versus 16.7 %). Nevertheless, rates of recanalization (2.9 % versus 5.2 %) and progressive occlusion (24.7 % versus 8.1 %) during follow-up slightly favored ICA anterior wall aneurysms. Two stent-treated ICA anterior wall aneurysms developed asymptomatic ICA steno-occlusion (8.3 %).

CONCLUSIONS

Stent-assisted embolization is safe and effective for the treatment of unruptured ICA anterior wall aneurysms exhibiting unfavorable aneurysmal geometries and projections for coil embolization.

Microcatheter looping technique for coil embolization of complex configuration middle cerebral artery aneurysms

BACKGROUND

Protection techniques using stents or microcatheters allow treatment of aneurysms with complex configurations by coil embolization. However, the application of these techniques is occasionally limited in wide-neck middle cerebral artery (MCA) aneurysms with acute angularity of the efferent branch vessel.

OBJECTIVE

We describe a looping technique for passage of a microcatheter and microwire into the acutely angled efferent branch vessel without navigating the system through the aneurysm lumen.

METHODS

To select the acutely angulated branch, a looped microcatheter was advanced near the orifice of the distal acutely angled branch vessel, followed by microwire passage through the looped microcatheter into the efferent vessel. The microcatheter loop was straightened after the microwire had been sufficiently advanced. The microcatheter was then navigated into the distal branch vessel over the advanced microwire.

RESULTS

A total of 36 wide-neck MCA aneurysms were successfully treated using this looping method. This technique was used to pass the microcatheter for stent protection in 13 patients and for microcatheter protection in 23. The method was most commonly used for aneurysms located at the M1 trunk (n = 21), followed by the MCA bifurcation (n = 15). Complete or near-complete endosaccular occlusion was achieved in 31 aneurysms. There were no complications related to looping the microcatheter.

CONCLUSION

This microcatheter looping technique facilitates safe entry into the distal branch during coil embolization of wide-neck MCA aneurysms incorporating the origins of acutely angulated branches.

Endovascular Treatment of Wide-necked Cerebral Aneurysms with an Acute Angle Branch Incorporated into the Sac: Novel methods of Branch Access in 8 Aneurysms

Purpose

The optimal management of geometrically complex aneurysms remains challenging. The aim of this retrospective study was to evaluate the safety and feasibility of branch-selective technique (BT) in wide-necked aneurysms with an acute angle branch incorporated into the sac.

Materials and Methods

Eight consecutive patients harboring wide-necked cerebral aneurysms with an incorporated, acute angle branch (mean, 30.4°) underwent coiling over an 18-month period. Dome-to-neck ratio ranged from 0.9 to 1.8 (mean, 1.2). Every procedure utilized BT, i.e., stent- or catheter-assisted coiling through the incorporated branch.

Results

Technical success was achieved in all cases. With the aim to avoid the risk of aneurysmal rupture during struggling intraaneurysmal wire navigation, a 'looping method' and retrograde approach of a preshaped 0.014' microcatheter (C or J) was used for branch access in five cases and a 'looping method' and antegrade approach in one case. In the remaining one, just the C-preshape was enough to directly enter the branch without intraaneurysmal wire navigation. Overall, stent-assisted coiling was performed in seven cases, while catheter-assisted coiling was undertaken in one. The only complication was thrombotic posterior inferior cerebellar artery occlusion in one case, which was recanalized after tirofiban infusion. New neurological deficits were not identified in any cases.

Conclusion

BT seems safe and feasible for wide-necked aneurysms with an acute angle branch incorporated into the sac. The looping method may offer safe access to the incorporated, acute angle branch and should be considered for replacement of the fearful intra-aneurysmal wire navigation.

Pulsatile tinnitus as the sole manifestation of an internal carotid artery aneurysm successfully treated by coil embolization

Pulsatile tinnitus is tinnitus that coincides with the patient's heartbeat. It constitutes a small portion of all tinnitus, but it is often the first or sole manifestation of a serious disease in the nervous system. Aneurysm of the internal carotid artery is known as a rare cause of pulsatile tinnitus and, in the main, aneurysms of the petrous portion have been reported as a cause of pulsatile tinnitus. We present an interesting case of pulsatile tinnitus that was caused by a paraclinoid aneurysm in this report and discuss clinical features and treatment of paraclinoid aneurysm.