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

Current Applications of the Three-Dimensional Printing Technology in Neurosurgery: A Review

BACKGROUND

 In the recent years, three-dimensional (3D) printing technology has emerged as a transformative tool, particularly in health care, offering unprecedented possibilities in neurosurgery. This review explores the diverse applications of 3D printing in neurosurgery, assessing its impact on precision, customization, surgical planning, and education.

METHODS

 A literature review was conducted using PubMed, Web of Science, Embase, and Scopus, identifying 84 relevant articles. These were categorized into spine applications, neurovascular applications, neuro-oncology applications, neuroendoscopy applications, cranioplasty applications, and modulation/stimulation applications.

RESULTS

 3D printing applications in spine surgery showcased advancements in guide devices, prosthetics, and neurosurgical planning, with patient-specific models enhancing precision and minimizing complications. Neurovascular applications demonstrated the utility of 3D-printed guide devices in intracranial hemorrhage and enhanced surgical planning for cerebrovascular diseases. Neuro-oncology applications highlighted the role of 3D printing in guide devices for tumor surgery and improved surgical planning through realistic models. Neuroendoscopy applications emphasized the benefits of 3D-printed guide devices, anatomical models, and educational tools. Cranioplasty applications showed promising outcomes in patient-specific implants, addressing biomechanical considerations.

DISCUSSION

 The integration of 3D printing into neurosurgery has significantly advanced precision, customization, and surgical planning. Challenges include standardization, material considerations, and ethical issues. Future directions involve integrating artificial intelligence, multimodal imaging fusion, biofabrication, and global collaboration.

CONCLUSION

 3D printing has revolutionized neurosurgery, offering tailored solutions, enhanced surgical planning, and invaluable educational tools. Addressing challenges and exploring future innovations will further solidify the transformative impact of 3D printing in neurosurgical care. This review serves as a comprehensive guide for researchers, clinicians, and policymakers navigating the dynamic landscape of 3D printing in neurosurgery.

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.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: neurosurgical and otolaryngologic conditions

BACKGROUND

Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG.

CONCLUSIONS

This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions.

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.

Computer-Assisted Microcatheter Shaping for Intracranial Aneurysm Embolization

BACKGROUND

This study investigates the accuracy, stability, and safety of computer-assisted microcatheter shaping for intracranial aneurysm coiling.

METHODS

Using the solid model, a microcatheter was shaped using computer-assisted techniques or manually to investigate the accuracy and delivery of microcatheter-shaping techniques in aneurysm embolization. Then, forty-eight patients were randomly assigned to the computer-assisted microcatheter-shaping (CAMS) group or the manual microcatheter-shaping (MMS) group, and the accuracy, stability, and safety of microcatheter in the patients were compared between the CAMS and MMS groups.

RESULTS

The speed of the successful microcatheter position was significantly faster in the CAMS group than in the MMS group (114.4 ± 23.99 s vs. 201.9 ± 24.54 s, p = 0.015) in vitro. In particular for inexperienced operators, the speed of the microcatheter position with the assistance of computer software is much faster than manual microcatheter shaping (93.6 ± 29.23 s vs. 228.9 ± 31.27 s, p = 0.005). In vivo, the time of the microcatheter position in the MMS group was significantly longer than that in the CAMS group (5.16 ± 0.46 min vs. 2.48 ± 0.32 min, p = 0.0001). However, the mRS score at discharge, the 6-month follow-up, and aneurysm regrowth at the 6-month follow-up were all similar between the groups.

CONCLUSIONS

Computer-assisted microcatheter shaping is a novel and safe method for microcatheter shaping that introduces higher accuracy in microcatheter shaping during the treatment of intracranial aneurysms.

SIGNIFICANT

Endovascular coiling of intracranial aneurysms can be truly revolutionized through computer assistance, which could improve the endovascular treatment of aneurysms.

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.

Clinical experience with the Bendit steerable microcatheter: a new paradigm for endovascular treatment

BACKGROUND

Vessel tortuosity poses a challenge during endovascular treatment of neurovascular lesions. Bendit Technologies (Petah Tikva, Israel) has developed flexible, steerable microcatheters designed with unique bending and torquing capabilities.

OBJECTIVE

To describe our first-in-human trial of Bendit21.

METHODS

Bendit21 was used in our exploratory, prospective, multicenter, open-label, single-arm clinical study, and in two compassionate use cases. Procedures were conducted at four centers in Austria, Germany, Israel, and the United States between May 2021 and March 2022, in patients with neurovascular conditions. The primary endpoints were device-related safety events, successful navigation through the neurovasculature, and, when intended, successful delivery of contrast or therapy.

RESULTS

Two patients with giant aneurysms were treated successfully under compassionate use approval. The clinical study included 25 patients (mean age: 63.4±11.8 years; 32.0% female). Fourteen patients (56.0%) had aneurysms, two had arteriovenous malformations/fistulas (8.0%), one had a stroke (4.0%), four (16.0%) had intracranial stenosis, and four (16.0%) had other conditions. Bendit21 was used without a guidewire in 12/25 (48.0%) procedures. Bendit21 was successfully navigated through the vasculature without delays or spasms in all cases (100%). Contrast was delivered as intended in 7/7 (100%) cases. Therapeutic devices were delivered successfully with Bendit as intended in 14/18 (77.8%) cases; four deficiencies occurred in three patients with aneurysms, in whom delivery of coils, an intrasaccular device, or a flow diverter was attempted. There were no device-related safety events or mortalities.

CONCLUSIONS

Our initial clinical experience with the Bendit21 microcatheter demonstrates its usefulness in achieving technical success in patients with challenging neurovascular conditions.

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.

New concept in neurovascular navigation: technical description and preclinical experience with the Bendit 17 and Bendit 21 microcatheters in a rabbit aneurysm model

BACKGROUND

Endovascular treatment of intracranial vascular diseases, such as aneurysms, is often challenged by unfavorable vascular anatomy. The Bendit Steerable Microcatheter (Bendit Technologies, Tel Aviv, Israel) has bending and torqueing capabilities designed to improve navigation and stability during device delivery, with or without a guidewire. We describe our preclinical experience with the Bendit 17 and Bendit 21 microcatheters in a rabbit aneurysm model.

METHODS

Bifurcation and side wall aneurysms were created surgically in six New Zealand rabbits. We attempted to navigate Bendit devices through the vasculature and enter the aneurysms without a guidewire. Various positions within the aneurysm were selectively explored. Angiographic imaging was used to visualize catheterization, navigation, vascular manipulations, and placement of coils, stents, and intrasaccular devices.

RESULTS

We successfully navigated the Bendit microcatheters to all aneurysms without a guidewire. We successfully recanalized a nearly occluded carotid artery and navigated the Bendit through a braided stent. In contrast, we were unable to navigate a comparator device with a guidewire as effectively as the Bendit. Coils were introduced at different locations within the aneurysm and could be pushed, pulled, and repositioned with the Bendit tip. Finally, we used the Bendit to deliver intrasaccular devices designed for terminal aneurysms to treat side wall aneurysms.

CONCLUSIONS

Bendit's bending and torqueing abilities, combined with its stability in the bent position, enable quick navigation and optimal deployment of devices. Clinical studies are necessary to determine whether these navigation advantages lead to more efficient treatment of intracranial and peripheral aneurysms.

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.

Three-Dimensional Modeling in Training, Simulation, and Surgical Planning in Open Vascular and Endovascular Neurosurgery: A Systematic Review of the Literature

BACKGROUND

The expanding use of three-dimensional (3D) printing in open vascular and endovascular neurosurgery presents a promising new tool in resident learning as well as operative planning. Recent studies have investigated the accuracy, efficacy, and practicality of 3D-printed models of patient-specific disease.

OBJECTIVE

To review the literature exploring 3D modeling in neurovascular and endovascular surgery for training, simulation, and surgical preparation.

METHODS

A systematic search of the PubMed database was conducted using keywords relating to 3D printing and neurovascular or endovascular surgery. Articles were manually screened to include those that focused on resident training, surgical simulation, or preoperative planning. Information on fabrication method, materials, cost, and validation measures was collected.

RESULTS

A total of 27 articles were identified that met inclusion criteria. Twenty-one studies used 3D printing to produce aneurysm models, 5 produced arteriovenous malformation models, and 1 produced aneurysm and arteriovenous malformation models. Stereolithography was the most common fabrication method used, with acrylonitrile butadiene styrene and VeroClearTangoPlus (Stratasys) being the most frequently used materials. The mean manufacturing cost per model was U.S. $624.83. Outcomes included model measurement accuracy, concordance of intraoperative devices with those selected preoperatively, and qualitative feedback.

CONCLUSIONS

Models generated by 3D printing are anatomically accurate and aid in resident learning as well as operative planning in open vascular and endovascular neurosurgery. As advancements in printing methods are made and manufacturing costs decrease, this tool may supplement training on a wider scale in a field in which direct exposure to cases is limited.

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.

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.

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.