Advanced 3D printed model of middle cerebral artery aneurysms for neurosurgery simulation

Design and Validation of a 3D Printed Cranio-Facial Simulator: A Novel Tool for Surgical Education

OBJECTIVE

To assess the ability of current 3D printing technology to generate a craniofacial bony and soft tissue anatomical model for use in simulating the performance of a fronto-orbital advancement (FOA) osteotomy and then to further assess the value of the model as an educational tool.

DESIGN

Anatomic models were designed with a process of serial anatomic segmentation/design, 3D printing, dissection, and device refinement. A validation study was conducted with 5 junior and 5 senior plastic surgery residents. The validation study incorporated a multiple-choice Knowledge Assessment test (KA), an Objective Structured Assessment of Technical skills (OSATs), a Global Rating Scale (GRS) and a Michigan Standard Simulation Experience Scale (MiSSES). We compared the scores of both the junior and senior residents and compared junior resident scores, before and after viewing a lecture/demonstration.

RESULTS

MiSSES showed high face validity with a score of 85.1/90, signifying high satisfaction with the simulator learning experience. Simulation and the lecture/demonstration improved the junior resident average KA score from 5.6/10 to 9.6/10 (P = .02), OSATs score from 32.4/66 to 64.4/66 (P < .001) and GRS score from 13.9/35 to 27.5/35 (P < .001). The senior residents OSATs score of 56.3/66 was higher than the pre-lecture juniors (32.4/66) (P < .001), but lower than the post-lecture juniors (64.4/66) (P < .001).

CONCLUSION

We have successfully fabricated a 3D printed craniofacial simulator capable of being used as an educational tool alongside traditional surgical training. Next steps would be improving soft tissue realism, inclusion of patient and disease specific anatomy and creation of models for other surgical specialties.

Shaping Perceptions and Inspiring Future Neurosurgeons: The Value of a Hands-On Simulated Aneurysm Clipping Workshops at a Student-Organized Neurosurgical Conference

Objective  Early exposure to niche specialities, like neurosurgery, is essential to inform decisions about future training in these specialities. This study assesses the impact of a hands-on simulated aneurysm clipping workshop on medical students' and junior doctors' perceptions of neurosurgery at a student-organized neurosurgical conference. Methods  Ninety-six delegates were sampled from a hands-on workshop involving hydrogel three-dimensional printed aneurysms clipping using surgical microscopes. Consultant neurosurgeons facilitated the workshop. Changes in delegates' perceptions of neurosurgery were collected using Likert scale and free-text responses postconference. Results  Postworkshop, 82% of participants reported a positive impact on their perception of neurosurgery. Thematic analysis revealed that delegates valued the hands-on experience, exposure to microsurgery, and interactions with consultant neurosurgeons. Thirty-six of the 96 delegates (37.5%) expressed that the workshop dispelled preconceived fears surrounding neurosurgery and improved understanding of a neurosurgeon's day-to-day tasks. Several delegates initially apprehensive about neurosurgery were now considering it as a career. Conclusion  Hands-on simulated workshops can effectively influence medical students' and junior doctors' perceptions of neurosurgery, providing valuable exposure to the specialty. By providing a valuable and immersive introduction to the specialty, these workshops can help to dispel misconceptions, fears, and apprehensions associated with neurosurgery, allowing them to consider the specialty to a greater degree than before. This study of a one-time workshop cannot effectively establish its long-term impact on said perceptions, however.

The Integration of 3D Virtual Reality and 3D Printing Technology as Innovative Approaches to Preoperative Planning in Neuro-Oncology

Our study explores the integration of three-dimensional (3D) virtual reality (VR) and 3D printing in neurosurgical preoperative planning. Traditionally, surgeons relied on two-dimensional (2D) imaging for complex neuroanatomy analyses, requiring significant mental visualization. Fortunately, nowadays advanced technology enables the creation of detailed 3D models from patient scans, utilizing different software. Afterwards, these models can be experienced through VR systems, offering comprehensive preoperative rehearsal opportunities. Additionally, 3D models can be 3D printed for hands-on training, therefore enhancing surgical preparedness. This technological integration transforms the paradigm of neurosurgical planning, ensuring safer procedures.

Training Cerebrovascular and Neuroendovascular Surgery Residents: A Systematic Literature Review and Recommendations

Background: The rapid evolution of neuroendovascular intervention has resulted in the inclusion of endovascular techniques as a core competency in neurosurgical residency training. Methods: We conducted a literature review of studies involving the training of neurosurgical residents in cerebrovascular and endovascular neurosurgery. We reviewed the evolution of cerebrovascular neurosurgery and the effects of these changes on residency, and we propose interventions to supplement contemporary training. Results: A total of 48 studies were included for full review. Studies evaluated trainee education and competency (29.2%, 14/48), neuroendovascular training models (20.8%, 10/48), and open cerebrovascular training models (52.1%, 25/48), with some overlap. We used a qualitative analysis of reviewed reports to generate a series of suggested training supplements to optimize cerebrovascular education. Conclusion: Cerebrovascular neurosurgery is at a crossroads where trainees must develop disparate skill sets with inverse trends in volume. Continued longitudinal exposure to both endovascular and open cerebrovascular surgical fields should be mandated in general resident education, and blended learning tactics using adjunct simulation systems and models should be incorporated with didactics to both optimize learning and alleviate restraints placed by decreased volume and autonomy.

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.

Medical 3D Printing Using Desktop Inverted Vat Photopolymerization: Background, Clinical Applications, and Challenges

Medical 3D printing is a complex, highly interdisciplinary, and revolutionary technology that is positively transforming the care of patients. The technology is being increasingly adopted at the Point of Care (PoC) as a consequence of the strong value offered to medical practitioners. One of the key technologies within the medical 3D printing portfolio enabling this transition is desktop inverted Vat Photopolymerization (VP) owing to its accessibility, high quality, and versatility of materials. Several reports in the peer-reviewed literature have detailed the medical impact of 3D printing technologies as a whole. This review focuses on the multitude of clinical applications of desktop inverted VP 3D printing which have grown substantially in the last decade. The principles, advantages, and challenges of this technology are reviewed from a medical standpoint. This review serves as a primer for the continually growing exciting applications of desktop-inverted VP 3D printing in healthcare.

Craniotomy Simulator with Force Myography and Machine Learning-Based Skills Assessment

Craniotomy is a fundamental component of neurosurgery that involves the removal of the skull bone flap. Simulation-based training of craniotomy is an efficient method to develop competent skills outside the operating room. Traditionally, an expert surgeon evaluates the surgical skills using rating scales, but this method is subjective, time-consuming, and tedious. Accordingly, the objective of the present study was to develop an anatomically accurate craniotomy simulator with realistic haptic feedback and objective evaluation of surgical skills. A CT scan segmentation-based craniotomy simulator with two bone flaps for drilling task was developed using 3D printed bone matrix material. Force myography (FMG) and machine learning were used to automatically evaluate the surgical skills. Twenty-two neurosurgeons participated in this study, including novices (n = 8), intermediates (n = 8), and experts (n = 6), and they performed the defined drilling experiments. They provided feedback on the effectiveness of the simulator using a Likert scale questionnaire on a scale ranging from 1 to 10. The data acquired from the FMG band was used to classify the surgical expertise into novice, intermediate and expert categories. The study employed naïve Bayes, linear discriminant (LDA), support vector machine (SVM), and decision tree (DT) classifiers with leave one out cross-validation. The neurosurgeons' feedback indicates that the developed simulator was found to be an effective tool to hone drilling skills. In addition, the bone matrix material provided good value in terms of haptic feedback (average score 7.1). For FMG-data-based skills evaluation, we achieved maximum accuracy using the naïve Bayes classifier (90.0 ± 14.8%). DT had a classification accuracy of 86.22 ± 20.8%, LDA had an accuracy of 81.9 ± 23.6%, and SVM had an accuracy of 76.7 ± 32.9%. The findings of this study indicate that materials with comparable biomechanical properties to those of real tissues are more effective for surgical simulation. In addition, force myography and machine learning provide objective and automated assessment of surgical drilling skills.

Real Stiffness and Vividness Reproduction of Anatomic Structures Into the 3D Printed Models Contributes to Improved Simulation and Training in Skull Base Surgery

BACKGROUND

Despite the advancement of 3-dimensional (3D) printing technology with medical application, its neurosurgical utility value has been limited to understanding the anatomy of bones, lesions, and their surroundings in the neurosurgical field.

OBJECTIVE

To develop a 3D printed model simulating the surgical technique applied in skull base surgery (SBS), especially to reproduce visually the surgical field together with the mechanical properties of tissues as perceived by the surgeon through procedures performance on a model.

METHODS

The Young modulus representing the degree of stiffness was measured for the tissues of anesthetized animals and printing materials. The stiffness and vividness of models were adjusted appropriately for each structure. Empty spaces were produced inside the models of brains, venous sinuses, and tumors. The 3D printed models were created in 7 cases of SBS planned patients and were used for surgical simulation.

RESULTS

The Young modulus of pig's brain ranged from 5.56 to 11.01 kPa and goat's brain from 4.51 to 13.69 kPa, and the dura of pig and goat values were 14.00 and 24.62 kPa, respectively. Although the softest printing material had about 20 times of Young modulus compared with animal brain, the hollow structure of brain model gave a soft sensation resembling the real organ and was helpful for bridging the gap between Young moduli values. A dura/tentorium-containing model was practical to simulate the real maneuverability at surgery.

CONCLUSION

The stiffness/vividness modulated 3D printed model provides an advanced realistic environment for training and simulation of a wide range of SBS procedures.

The Third Dimension: 3D Printed Replicas and Other Alternatives to Cadaver-Based Learning

Capturing the 'third dimension' of complex human form or anatomy has been an objective of artists and anatomists from the renaissance in the fifteenth and sixteenth centuries onwards. Many of these drawings, paintings, and sculptures have had a profound influence on medical teaching and the learning resources we took for granted until around 40 years ago. Since then, the teaching of human anatomy has undergone significant change, especially in respect of the technologies available to augment or replace traditional cadaver-based dissection instruction. Whilst resources such as atlases, wall charts, plastic models, and images from the Internet have been around for many decades, institutions looking to reduce the reliance on dissection-based teaching in medical or health professional training programmes have in more recent times increasingly had access to a range of other options for classroom-based instruction. These include digital resources and software programmes and plastinated specimens, although the latter come with a range of ethical and cost considerations. However, the urge to recapitulate the 'third dimension' of anatomy has seen the recent advent of novel resources in the form of 3D printed replicas. These 3D printed replicas of normal human anatomy dissections are based on a combination of radiographic imaging and surface scanning that captures critical 3D anatomical information. The final 3D files can either be augmented with false colour or made to closely resemble traditional prosections prior to printing. This chapter details the journey we and others have taken in the search for the 'third dimension'. The future of a haptically identical, anatomically accurate replica of human cadaver specimens for surgical and medical training is nearly upon us. Indeed, the need for hard copy replicas may eventually be superseded by the opportunities afforded by virtual reality (VR) and augmented reality (AR).

Fabrication of Compliant and Transparent Hollow Cerebral Vascular Phantoms for In Vitro Studies Using 3D Printing and Spin-Dip Coating

Endovascular surgery through flow diverters and coils is increasingly used for the minimally invasive treatment of intracranial aneurysms. To study the effectiveness of these devices, in vitro tests are performed in which synthetic vascular phantoms are typically used to reproduce in vivo conditions. In this paper, we propose a manufacturing process to obtain compliant and transparent hollow vessel replicas to assess the mechanical behaviour of endovascular devices and perform flow measurements. The vessel models were obtained in three main steps. First, a mould was 3D-printed in a water-soluble material; two techniques, fusion deposition modelling and stereolithography, were compared for this purpose. Then, the mould was covered with a thin layer of silicone through spin-dip coating, and finally, when the silicone layer solidified, it was dissolved in a hot water bath. The final models were tested in terms of the quality of the final results, the mechanical properties of the silicone, thickness uniformity, and transparency properties. The proposed approach makes it possible to produce models of different sizes and complexity whose transparency and mechanical properties are suitable for in vitro experiments. Its applicability is demonstrated through idealised and patient-specific cases.

Validation of three-dimensional printed models of intracranial aneurysms

INTRODUCTION

Three-dimensional (3D) printing has evolved for medical applications as it can produce customized 3D models of devices and implants that can improve patient care. In this study, we aimed to validate the geometrical accuracy of the 3D models of intracranial aneurysms printed using Stereolithography 3D printing technology.

MATERIALS AND METHODS

To compare the unruptured intracranial aneurysm mesh between the five patients and 3D printed models, we opened the DICOM files in the Sim&Size® simulation software, selected the region of interest, and performed the threshold check. We juxtaposed the 3D reconstructions and manually rotated the images to get the same orientation when needed and measured deviations at different nodes of the patient and 3D printed model meshes.

RESULTS

In the first patient, 80% of the nodes were separated by <0.56 mm and 0.17 mm. In the second patient, the deviations were below 0.17 mm for 80% of the meshes' nodes. In the next three patients, the deviations were below 0.21, 0.23, and 0.11 mm for 80% of the meshes' nodes. Finally, the overall deviation was below 0.21 mm for 80% of the mesh nodes of the five aneurysms.

CONCLUSIONS

3D printed models of intracranial aneurysms are accurate, having surfaces that resemble that of patients' angiographies with an 80% cumulative deviation below 0.21 mm.

Patient-Specific 3D-Print Extracranial Vascular Simulators and Infrared Imaging Platform for Diagnostic Cerebral Angiography Training

Tortuous aortic arch is always challenging for beginner neuro-interventionalists. Herein, we share our experience of using 3D-printed extracranial vascular simulators (VSs) and the infrared imaging platform (IRIP) in two training courses for diagnostic cerebral angiography in the past 4 years. A total of four full-scale patient-specific carotid-aortic-iliac models were fabricated, including one type I arch, one bovine variant, and two type III arches. With an angiography machine (AM) as the imaging platform for the practice and final test, the first course was held in March 2018 had 10 participants, including three first-year residents (R1), three second-year residents (R2), and four third-year residents (R3). With introduction of the IRIP as the imaging platform for practice, the second course in March 2022 had nine participants, including 3 R1s, 3 R2s, and 3 R3s. The total manipulation time (TMT) to complete type III aortic arch navigation was recorded. In the first course, the average TMT of the first trial was 13.1 min. Among 3 R1s and 3 R2s attending the second trial, the average TMT of the second trial was 3.4 min less than that of the first trial. In the second course using IRIP, the average TMT of the first and second trials was 6.7 min and 4.8 min, respectively. The TMT of the second trial (range 2.2~14.4 min; median 5.9 min) was significantly shorter than that of the first trial (range 3.6~18 min; median 8.7 min), regardless of whether AM or IRIP was used (p = 0.001). Compared with first trial, the TMT of the second trial was reduced by an average of 3.7 min for 6 R1s, which was significantly greater than the 1.7 min of R2 and R3 (p = 0.049). Patient-specific VSs with radiation-free IRIP could be a useful training platform for junior residents with little experience in neuroangiography.

Cerebrovascular modelling for the management of aneurysm embolization using an intrasaccular flow diverter made by 3D printing

PURPOSE

Using 3-dimensional (3D) printers, the creation of patient-specific models is possible before and after a therapeutic intervention. There are many articles about replicas for training and simulation of aneurysm clipping. However, no paper has focused on 3D replicas obtained from 3-tesla 3D time of flight (3D-TOF) MR angiography for intrasaccular flow diverter (WEB device) embolization of the cerebral aneurysms. In this paper, we aimed to investigate the feasibility of 3D printing models obtained from 3-tesla 3D-TOF data in the management and training of WEB-assisted embolization procedures.

CASE PRESENTATION

We presented a longitudinal case report with several 3D-TOF MRA prints over time. Three-tesla 3D-TOF data were converted into STL and G-code files using an open-source (3D-Slicer) program. We built patient-specific realistic 3D models of a patient with a middle cerebral artery trifurcation aneurysm, which were able to demonstrate the entire WEB device treatment procedure in the pre-intervention and post-intervention periods. The aneurysmatic segment was well displayed on the STL files and the 3D replicas. They allowed visualization of the aneurysmatic segment and changes within a 6-year follow-up period. We successfully showed the possibility of fast, cheap, and easy production of replicas for demonstration of the aneurysm, the parent vessels, and post-intervention changes in a simple way using an affordable 3D printer.

CONCLUSIONS

3D printing is useful for training the endovascular team and the patients, understanding the aneurysm/parent vessels, and choosing the optimal embolization technique/device. 3D printing will potentially lead to greater interventionalist confidence, decreased radiation dose, and improvements in patient safety.

Three-dimensional printing and 3D slicer powerful tools in understanding and treating neurosurgical diseases

With the development of the 3D printing industry, clinicians can research 3D printing in preoperative planning, individualized implantable materials manufacturing, and biomedical tissue modeling. Although the increased applications of 3D printing in many surgical disciplines, numerous doctors do not have the specialized range of abilities to utilize this exciting and valuable innovation. Additionally, as the applications of 3D printing technology have increased within the medical field, so have the number of printable materials and 3D printers. Therefore, clinicians need to stay up-to-date on this emerging technology for benefit. However, 3D printing technology relies heavily on 3D design. 3D Slicer can transform medical images into digital models to prepare for 3D printing. Due to most doctors lacking the technical skills to use 3D design and modeling software, we introduced the 3D Slicer to solve this problem. Our goal is to review the history of 3D printing and medical applications in this review. In addition, we summarized 3D Slicer technologies in neurosurgery. We hope this article will enable many clinicians to leverage the power of 3D printing and 3D Slicer.

3D-Printed Disease Models for Neurosurgical Planning, Simulation, and Training

Spatial insight into intracranial pathology and structure is important for neurosurgeons to perform safe and successful surgeries. Three-dimensional (3D) printing technology in the medical field has made it possible to produce intuitive models that can help with spatial perception. Recent advances in 3D-printed disease models have removed barriers to entering the clinical field and medical market, such as precision and texture reality, speed of production, and cost. The 3D-printed disease model is now ready to be actively applied to daily clinical practice in neurosurgical planning, simulation, and training. In this review, the development of 3D-printed neurosurgical disease models and their application are summarized and discussed.

Pre-Interventional 3D-Printing-Assisted Planning of Flow Disrupter Implantation for the Treatment of an Intracranial Aneurysm

Intrasaccular flow disrupter devices (ISFD) have opened up new ways to treat intracranial aneurysms but choosing the correct size of ISFD can be challenging. We describe the first use of 3D printing to assist in the choice of ISFD, and we report an illustrative case. We developed a technique that uses preoperative angiography to make a plastic model of the aneurysm. We tested the deployment of different sizes of intrasaccular flow disruptor on the 3D model under fluoroscopy. The best devices were then used as the first-line strategy to treat the patient. The preoperative 3D printing helped in the successful selection of a first-line ISFD, which was not the one recommended by the manufacturer. Three-dimensional printing can provide interesting information regarding the treatment of intracranial aneurysms using ISFD. Further studies are needed to fully assess its benefits.

A Minireview on Brain Models Simulating Geometrical, Physical, and Biochemical Properties of the Human Brain

There is a growing body of evidences that brain surrogates will be of great interest for researchers and physicians in the medical field. They are currently mainly used for education and training purposes or to verify the appropriate functionality of medical devices. Depending on the purpose, a variety of materials have been used with specific and accurate mechanical and biophysical properties, More recently they have been used to assess the biocompatibility of implantable devices, but they are still not validated to study the migration of leaching components from devices. This minireview shows the large diversity of approaches and uses of brain phantoms, which converge punctually. All these phantoms are complementary to numeric models, which benefit, reciprocally, of their respective advances. It also suggests avenues of research for the analysis of leaching components from implantable devices.

The Role of 3D Printing in Planning Complex Medical Procedures and Training of Medical Professionals-Cross-Sectional Multispecialty Review

Medicine is a rapidly-evolving discipline, with progress picking up pace with each passing decade. This constant evolution results in the introduction of new tools and methods, which in turn occasionally leads to paradigm shifts across the affected medical fields. The following review attempts to showcase how 3D printing has begun to reshape and improve processes across various medical specialties and where it has the potential to make a significant impact. The current state-of-the-art, as well as real-life clinical applications of 3D printing, are reflected in the perspectives of specialists practicing in the selected disciplines, with a focus on pre-procedural planning, simulation (rehearsal) of non-routine procedures, and on medical education and training. A review of the latest multidisciplinary literature on the subject offers a general summary of the advances enabled by 3D printing. Numerous advantages and applications were found, such as gaining better insight into patient-specific anatomy, better pre-operative planning, mock simulated surgeries, simulation-based training and education, development of surgical guides and other tools, patient-specific implants, bioprinted organs or structures, and counseling of patients. It was evident that pre-procedural planning and rehearsing of unusual or difficult procedures and training of medical professionals in these procedures are extremely useful and transformative.

Magnetic Resonance Imaging Manifestations of Pediatric Purulent Meningitis Based on Immune Clustering Algorithm

The purpose of this study was to analyze the diagnostic value of magnetic resonance imaging (MRI) based on the immune clustering algorithm (ICA) in children with purulent meningitis. In this study, 235 children with suspected pediatric purulent meningitis (PPM) were routinely scanned, and the artificial immune algorithm (AIA) and ICA were applied to image processing. In order to quantitatively analyze the accuracy and precision of the processed image, precision rate was introduced as the evaluation of accuracy, and the True Positive Vis Fox, False Negative Vis Fo, and False Positive Vis Fo were selected as the evaluation indicators. After comparison, the accuracy, sensitivity, and specificity of ICA detection were higher than those of AIA and conventional plain scanning, and the differences were statistically obvious (P < 0.05). Comparison on image display effects showed that compared with AIA, the image processed by the ICA algorithm constructed in this study showed the highest definition and contrast and the best denoising effect and image quality, showing a statistically obvious difference (P < 0.05). All in all, the display effect of MRI images of pediatric purulent meningitis based on ICA was more accurate and clearer than that of the traditional image processing, and it can provide a more accurate auxiliary basis in the diagnosis of lesion details. It also showed a higher clinical value for the development of a diagnosis and treatment plan for complicated PPM.

Engineering a 3D human intracranial aneurysm model using liquid-assisted injection molding and tuned hydrogels

Physiologically relevant intracranial aneurysm (IA) models are crucially required to facilitate testing treatment options for IA. Herein, we report the development of a new in vitro tissue-engineered platform, which recapitulates the microenvironment, structure, and cellular complexity of native human IA. A new modified liquid-assisted injection molding technique was developed to fabricate a three-dimensional hollow IA model with clinically relevant IA dimensions within a mechanically tuned Gelatin Methacryloyl (GelMA) hydrogel. An endothelium lining was created inside the IA model by culturing human umbilical vein endothelial cells over pre-cultured human brain vascular smooth muscle cells. These cellularized IA models were subjected to medium perfusion at flow rates between 6.3 and 15.75 mL/min for inducing biomimetic vessel wall shear stress (10-25 dyn/cm²) to the cells for ten days. Both cell types maintained their secretome profiles and showed more than 96% viability, demonstrating the biocompatibility of the hydrogel during perfusion cell culture at such flow rates. Based on the characterized viscoelastic properties of the GelMA hydrogel and with the aid of a fluid-structure interaction model, the capability of the IA model in predicting the response of the IA to different fluid flow profiles was mathematically shown. With physiologically relevant behavior, our developed in vitro human IA model could allow researchers to better understand the pathophysiology and treatment of IA. STATEMENT OF SIGNIFICANCE: A three-dimensional intracranial aneurysm (IA) tissue model recapitulating the microenvironment, structure, and cellular complexity of native human IA was developed. • An endothelium lining was created inside the IA model over pre-cultured human brain vascular smooth muscle cells over at least 10-day successful culture. • The cells maintained their secretome profiles, demonstrating the biocompatibility of hydrogel during a long-term perfusion cell culture. • The IA model showed its capability in predicting the response of IA to different fluid flow profiles. • The cells in the vessel region behaved differently from cells in the aneurysm region due to alteration in hemodynamic shear stress. • The IA model could allow researchers to better understand the pathophysiology and treatment options of IA.

Remote Training of Functional Endoscopic Sinus Surgery With Advanced Manufactured 3D Sinus Models and a Telemedicine System

Objective: Traditionally, cadaveric courses have been an important tool in surgical education for Functional Endoscopic Sinus Surgery (FESS). The recent COVID-19 pandemic, however, has had a significant global impact on such courses due to its travel restrictions, social distancing regulations, and infection risk. Here, we report the world-first remote (Functional Endoscopic Sinus Surgery) FESS training course between Japan and Australia, utilizing novel 3D-printed sinus models. We examined the feasibility and educational effect of the course conducted entirely remotely with encrypted telemedicine software.

Methods: Three otolaryngologists in Hokkaido, Japan, were trained to perform frontal sinus dissections on novel 3D sinus models of increasing difficulty, by two rhinologists located in Adelaide, South Australia. The advanced manufactured sinus models were 3D printed from the Computed tomography (CT) scans of patients with chronic rhinosinusitis. Using Zoom and the Quintree telemedicine platform, the surgeons in Adelaide first lectured the Japanese surgeons on the Building Block Concept for a three Dimensional understanding of the frontal recess. They in real time directly supervised the surgeons as they planned and then performed the frontal sinus dissections. The Japanese surgeons were asked to complete a questionnaire pertaining to their experience and the time taken to perform the frontal dissection was recorded. The course was streamed to over 200 otolaryngologists worldwide.

Results: All dissectors completed five frontal sinusotomies. The time to identify the frontal sinus drainage pathway (FSDP) significantly reduced from 1,292 ± 672 to 321 ± 267 s (p = 0.02), despite an increase in the difficulty of the frontal recess anatomy. Image analysis revealed the volume of FSDP was improved (2.36 ± 0.00 to 9.70 ± 1.49 ml, p = 0.014). Questionnaires showed the course's general benefit was 95.47 ± 5.13 in dissectors and 89.24 ± 15.75 in audiences.

Conclusion: The combination of telemedicine software, web-conferencing technology, standardized 3D sinus models, and expert supervision, provides excellent training outcomes for surgeons in circumstances when classical surgical workshops cannot be realized.

Application of nondestructive mechanical characterization testing for creating in vitro vessel models with material properties similar to human neurovasculature

Vessel models are a first step in developing endovascular medical devices. However, these models, often made from glass or silicone, do not accurately represent the mechanical properties of human vascular tissue, limiting their use to basic training and proof-of-concept testing. This study outlines methods to quantify human vascular tissue mechanical properties and synthetic biomaterials for creating representative vessel models. Human vascular tissue was assessed and compared to silicone and new UV-cured polymers (VC-A30) using the following eight mechanical tests: compressive, shear, tensile dynamic elastic modulus, Poisson's ratio, hardness, radial force, compliance, and lubricity. Half of these testing methods were nondestructive, allowing for multiple mechanical and histological characterizations of the same human tissue sample. Histological evaluation of the cellular and extracellular matrix of the human vessels verified that the dynamic moduli and Poison's ratio tests were nondestructive. Fluid absorption by VC-A30 showed statistically significant softening of mechanical properties, stabilizing after 4 days in phosphate-buffered saline (PBS). Human vasculature exhibited notably similar results to VC-A30 in five of eight mechanical tests (≤30% difference) versus two of eight for standard silicone (≤38% difference). Results show that VC-A30 provides a new option for 3D-printing translucent in vitro vascular models with anatomically relevant mechanical properties. These new vessel analogs may simulate patient-specific vessel disease states, improve surgical training models, accelerate new endovascular device developments, and ultimately reduce the need for animal models.

3D Printing of Physical Organ Models: Recent Developments and Challenges

Physical organ models are the objects that replicate the patient-specific anatomy and have played important roles in modern medical diagnosis and disease treatment. 3D printing, as a powerful multi-function manufacturing technology, breaks the limitations of traditional methods and provides a great potential for manufacturing organ models. However, the clinical application of organ model is still in small scale, facing the challenges including high cost, poor mimicking performance and insufficient accuracy. In this review, the mainstream 3D printing technologies are introduced, and the existing manufacturing methods are divided into "directly printing" and "indirectly printing", with an emphasis on choosing suitable techniques and materials. This review also summarizes the ideas to address these challenges and focuses on three points: 1) what are the characteristics and requirements of organ models in different application scenarios, 2) how to choose the suitable 3D printing methods and materials according to different application categories, and 3) how to reduce the cost of organ models and make the process simple and convenient. Moreover, the state-of-the-art in organ models are summarized and the contribution of 3D printed organ models to various surgical procedures is highlighted. Finally, current limitations, evaluation criteria and future perspectives for this emerging area are discussed.

Additive Fabrication of a Vascular 3D Phantom for Stereotactic Radiosurgery of Arteriovenous Malformations

In this study, an efficient methodology for manufacturing a realistic three-dimensional (3D) cerebrovascular phantom resembling a brain arteriovenous malformation (AVM) for applications in stereotactic radiosurgery is presented. The AVM vascular structure was 3D reconstructed from brain computed tomography (CT) data acquired from a patient. For the phantom fabrication, stereolithography was used to produce the AVM model and combined with silicone casting to mimic the brain parenchyma surrounding the vascular structure. This model was made with tissues-equivalent materials for radiology. The hollow vascular system of the phantom was filled with a contrast agent usually employed on patients for CT scans. The radiological response of the phantom was tested and compared with the one of the clinical case. The constructed model demonstrated to be a very accurate physical representation of the AVM and its vasculature and good morphological consistency was observed between the model and the patient-specific source anatomy. These results suggest that the proposed method has potential to be used to fabricate patient-specific phantoms for neurovascular radiosurgery applications and medical research.

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.

Three-dimensional printing applications in the neurosurgery: A pilot study

BACKGROUND: Three-dimensional (3D) printing is an evolving technology that has been used recently in a wide spectrum of applications. AIM: The objective is to evaluate the application of 3D printing in various neurosurgical practice. PATIENTS AND METHODS: This pilot study was conducted in the neurosurgical hospital in Baghdad/Iraq between July 2018 and July 2019. An X, Y, and Z printer was used. The working team included neurosurgeons, biomedical engineers, and bio-technicians. The procedure starts with obtaining Magnetic resonance imaging (MRI) or computed tomography (CT) scan in particular protocols. The MRI, and CT or angiography images were imported into a 3D programmer for DICOM images called 3D slice where these files converted into a 3D pictures. Next, the neurosurgeon determines the cut section he needs to print. The final required object is exported to the X, Y, Z printing software where the technician starts to print it out. The final prototype delivered to the neurosurgeon. He uses it intraoperatively to have an apparent actual size 3D representation of the actual lesion with nearby healthy tissues to have a good idea about the case they manages. RESULTS: This pilot study was applied in three major projects: brain tumors (ten cases), cerebral aneurysms (nine cases), and spine surgery (14 cases). CONCLUSION: Three-dimensional printing has excellent advantages in neurosurgical practice. It can replace many other recent modalities. It enables the neurosurgeon works with more precision, less time-consuming, less cost, and less radiation exposure.

The reproduction of human pathology specimens using three-dimensional (3D) printing technology for teaching purposes

The teaching of medical pathology has undergone significant change in the last 30-40 years, especially in the context of employing bottled specimens or 'pots' in classroom settings. The reduction in post-mortem based teaching in medical training programs has resulted in less focus being placed on the ability of students to describe the gross anatomical pathology of specimens. Financial considerations involved in employing staff to maintain bottled specimens, space constraints and concerns with health and safety of staff and student laboratories have meant that many institutions have decommissioned their pathology collections. This report details how full-colour surface scanning coupled with CT scanning and 3 D printing allows the digital archiving of gross pathological specimens and the production of reproductions or replicas of preserved human anatomical pathology specimens that obviates many of the above issues. With modern UV curable resin printing technology, it is possible to achieve photographic quality accurate replicas comparable to the original specimens in many aspects except haptic quality. Accurate 3 D reproductions of human pathology specimens offer many advantages over traditional bottled specimens including the capacity to generate multiple copies and their use in any educational setting giving access to a broader range of potential learners and users.

3D-printed anatomical models of the cystic duct and its variants, a low-cost solution for an in-house built simulator for laparoscopic surgery training

OBJECTIVES

To explore a method to create affordable anatomical models of the biliary tree that are adequate for training laparoscopic cholecystectomy with an in-house built simulator.

METHODS

We used a fused deposition modeling 3D printer to create molds of Acrylonitrile Butadiene Styrene (ABS) from Digital Imaging and Communication on Medicine (DICOM) images, and the molds were filled with silicone rubber. Thirteen surgeons with 4-5-year experience in the procedure evaluated the molds using a low-cost in-house built simulator utilizing a 5-point Likert-type scale.

RESULTS

Molds produced through this method had a consistent anatomical appearance and overall realism that evaluators agreed or definitely agreed (4.5/5). Evaluators agreed on recommending the mold for resident surgical training.

CONCLUSIONS

3D-printed molds created through this method can be applied to create affordable high-quality educational anatomical models of the biliary tree for training laparoscopic cholecystectomy.

Thrombus Imaging Using 3D Printed Middle Cerebral Artery Model and Preclinical Imaging Techniques: Application to Thrombus Targeting and Thrombolytic Studies

Diseases with the highest burden for society such as stroke, myocardial infarction, pulmonary embolism, and others are due to blood clots. Preclinical and clinical techniques to study blood clots are important tools for translational research of new diagnostic and therapeutic modalities that target blood clots. In this study, we employed a three-dimensional (3D) printed middle cerebral artery model to image clots under flow conditions using preclinical imaging techniques including fluorescent whole-body imaging, magnetic resonance imaging (MRI), and computed X-ray microtomography (microCT). Both liposome-based, fibrin-targeted, and non-targeted contrast agents were proven to provide a sufficient signal for clot imaging within the model under flow conditions. The application of the model for clot targeting studies and thrombolytic studies using preclinical imaging techniques is shown here. For the first time, a novel method of thrombus labeling utilizing barium sulphate (Micropaque^®) is presented here as an example of successfully employed contrast agents for in vitro experiments evaluating the time-course of thrombolysis and thus the efficacy of a thrombolytic drug, recombinant tissue plasminogen activator (rtPA). Finally, the proof-of-concept of in vivo clot imaging in a middle cerebral artery occlusion (MCAO) rat model using barium sulphate-labelled clots is presented, confirming the great potential of such an approach to make experiments comparable between in vitro and in vivo models, finally leading to a reduction in animals needed.

Reusable Low-Cost 3D Training Model for Aneurysm Clipping

BACKGROUND

Aneurysm clipping requires the proficiency of several skills, yet the traditional way of practicing them has been recently challenged, especially by the growth of endovascular techniques. The use of simulators could be an alternative educational tool, but some of them are cumbersome, expensive to implement, or lacking in realism. The aim of this study is to evaluate a reusable low-cost 3-dimensional printed training model we developed for aneurysm clipping.

METHODS

The simulator was designed to replicate the bone structure, arteries, and targeted aneurysms. Thirty-two neurosurgery residents performed a craniotomy and aneurysm clipping using the model and then filled out a survey. They were divided into Junior and Senior groups. Descriptive, exploratory, and confirmatory factor analysis was performed using IBM SPSS statistical software.

RESULTS

The overall residents' response was positive, with high scores to face validity and content validity questions. There was no significant statistical difference between the Junior and Senior groups. The confirmatory factor and internal consistency analysis confirmed that the evaluation was highly reliable. Globally, 97% of the residents found the model was useful and would repeat the simulator experience. The financial cost is $2500 USD for implementation and only $180 USD if further training sessions are required.

CONCLUSIONS

The main strengths of our training model are its highlighted realism, adaptability to trainees of different levels of expertise, sustainability, and low cost. Our data support the concept that it can be incorporated as a new training opportunity during professional specialty meetings and/or within residency academic programs.

A Novel 3-Dimensional Printing Fabrication Approach for the Production of Pediatric Airway Models

Pediatric airway models currently available for use in education or simulation do not replicate anatomy or tissue responses to procedures. Emphasis on mass production with sturdy but homogeneous materials and low-fidelity casting techniques diminishes these models’ abilities to realistically represent the unique characteristics of the pediatric airway, particularly in the infant and younger age ranges. Newer fabrication technologies, including 3-dimensional (3D) printing and castable tissue-like silicones, open new approaches to the simulation of pediatric airways with greater anatomical fidelity and utility for procedure training.

Cost-Effective Method for 3-Dimensional Printing Dynamic Multiobject and Patient-Specific Brain Tumor Models: Technical Note

BACKGROUND

Three-dimensional (3D) printing is a powerful tool for replicating patient-specific anatomic features for education and surgical planning. The advent of "desktop" 3D printing has created a cost-effective and widely available means for institutions with limited resources to implement a 3D-printing workflow into their clinical applications. The ability to physically manipulate the desired components of a "dynamic" 3D-printed model provides an additional dimension of anatomic understanding. There is currently a gap in the literature describing a cost-effective and time-efficient means of creating dynamic brain tumor 3D-printed models.

METHODS

Using free, open-access software (3D Slicer) for patient imaging to Standard Tessellation Language file conversion, as well as open access Standard Tessellation Language editing software (Meshmixer), both intraaxial and extraaxial brain tumor models of patient-specific pathology are created.

RESULTS

A step-by-step methodology and demonstration of the software manipulation techniques required for creating cost-effective, multidimensional brain tumor models for patient education and surgical planning are exhibited using a detailed written guide, images, and a video display.

CONCLUSIONS

In this technical note, we describe in detail the specific functions of free, open-access software and desktop 3D printing techniques to create dynamic and patient-specific brain tumor models for education and surgical planning.