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

3-Dimensional printing and bioprinting in neurological sciences: applications in surgery, imaging, tissue engineering, and pharmacology and therapeutics

The rapid evolution of three-dimensional printing (3DP) has significantly impacted the medical field. In neurology for instance, 3DP has been pivotal in personalized surgical planning and education. Additionally, it has facilitated the creation of implants, microfluidic devices, and optogenetic probes, offering substantial implications for medical and research applications. Additionally, 3D printed nasal casts are showing great promise for targeted brain drug delivery. 3DP has also aided in creating 3D "phantoms" aligning with advancements in neuroimaging, and in the design of intricate objects for investigating the neurobiology of sensory perception. Furthermore, the emergence of 3D bioprinting (3DBP), a fusion of 3D printing and cell biology, has created new avenues in neural tissue engineering. Effective and ethical creation of tissue-like biomimetic constructs has enabled mechanistic, regenerative, and therapeutic evaluations. While individual reviews have explored the applications of 3DP or 3DBP, a comprehensive review encompassing the success stories across multiple facets of both technologies in neurosurgery, neuroimaging, and neuro-regeneration has been lacking. This review aims to consolidate recent achievements of both 3DP and 3DBP across various neurological science domains to encourage interdisciplinary research among neurologists, neurobiologists, and engineers, in order to promote further exploration of 3DP and 3DBP methodologies to novel areas of neurological science research and practice.

Utility of Surgical Simulation for Tubular Retractor Surgery Using Three-Dimensional Printed Intraventricular Tumor Models: Case Series

OBJECTIVE

The utility of the tubular retractor for deep-seated tumors, including intraventricular tumors, has recently been reported. However, the surgical field's depth and narrowness can lead to blind spots, and it is crucial to prevent damage to the cortex and white matter fibers in eloquent areas. Therefore, preoperative simulation is critical for tubular retractor surgery. In this study, we investigated the benefits of threedimensional (3D)-printed intraventricular tumor models for tubular retractor surgery.

METHODS

Nine patients with intraventricular central neurocytoma who underwent tubular retractor surgery at our institution between March 2013 and August 2023 were retrospectively reviewed. Fusion images and 3D-printed intraventricular tumor models were developed from preoperative computed tomography (CT) and magnetic resonance imaging (MRI). The puncture points of the tubular retractor were simulated using fusion images and 3D-printed intraventricular tumor models by 11 neurosurgeons (3 experts in brain tumors, 2 experts in areas other than brain tumors, and 6 residents). The dispersion of puncture points among 8 neurosurgeons (excluding brain tumor experts) was compared in each simulation model.

RESULTS

These cases were categorized into two groups based on the dispersion of puncture points simulated by fusion images. Puncture point dispersion was markedly smaller in all cases when using 3D-printed intraventricular tumor models compared to simulations solely based on fusion images.

CONCLUSIONS

In intraventricular tumor surgery using a tubular retractor, 3D-printed intraventricular tumor models proved more beneficial in preoperative simulation compared to fusion images.

Application of 3D Printing Positioning Technology in Parasagittal Meningioma Surgery: A Single-center Retrospective Study

OBJECTIVE

To assess the utility of 3D printing positioning technology for resection of parasagittal meningioma.

METHODS

Information related to clinical history, application of 3D printing positioning technology, neuroimaging, surgical-related information, and postoperative hospital days of consecutive patients with parasagittal meningioma treated between January 2020 and December 2022 were retrospectively collected. Patients were divided into 2 groups based on whether the 3D printing positioning technology was applied. The values between groups were statistically compared.

RESULTS

A total of 41 patients were enrolled. In cases using 3D printing positioning technology (14 patients), the location of craniotomy was much better and the postoperative hospital stay was much shorter.

CONCLUSIONS

The application of 3D printing positioning technology in parasagittal meningioma surgery could improve the location of craniotomy, and reduce the postoperative hospital stay. It is a low-cost positioning technology, and has the potential to be applied to other superficial intracranial tumors.

Creation of a Novel Ex Vivo 3D Printed Ileal Conduit Task Trainer for Teaching Conduitoscopy Skills

OBJECTIVE

To perform endoscopy in patients with urinary diversions requires specific endoscopic skills, which can currently only be gained in clinical practice. We created a 3D-printed ex vivo ileal conduit model (stoma and conduit with ureters and 2 kidneys) to simulate "conduitoscopy" and evaluated the realism and limitations of the model.

METHODS

Accurate anatomical features were represented using an appropriate reusable design, realistic mechanical qualities with several material types, and 3D-printed components. Different models of bowel and ureters were assessed by the subject-matter experts (SME). The final ileal conduit model (Wallace 1 type anastomosis) was evaluated by 18 SMEs.

RESULTS

Most experts gave their approval to the view of the stoma, as well as the appearance of the bowel, ureteric, and pelvicalyceal systems. A total of 72.1% of SMEs approved the ureteric endoscopic view compared to about 66% who accepted the endoscopic examination of the bowel. The model's overall appearance was good for 61.1% and excellent for 38.8% of experts.

CONCLUSION

Conduitoscopy simulation training can now be facilitated using our novel and unique cutting-edge 3D-printed model. We created a model that is highly anatomically accurate and workable. In our study, anatomical and visual realism was demonstrated. The next step would be increasing the length of the conduit and conduct a validation study.

Implementation of 3D modelling to improve understanding and conceptualisation of arteriovenous malformation (AVM) morphology for the execution of safe microsurgical excision of complex paediatric AVMs

INTRODUCTION

Brain arteriovenous malformations (bAVMs) present complex challenges in neurosurgery, requiring precise pre-surgical planning. In this context, 3D printing technology has emerged as a promising tool to aid in understanding bAVM morphology and enhance surgical outcomes, particularly in pediatric patients. This study aims to assess the feasibility and effectiveness of using 3D AVM models in pediatric bAVM surgery.

METHODOLOGY

The study was conducted at Great Ormond Street Hospital, and cases were selected sequentially between October 2021 and February 2023. Eight pediatric bAVM cases with 3D models were compared to eight cases treated before the introduction of 3D printing models. The 3D modelling fidelity and clinical outcomes were assessed and compared between the two cohorts.

RESULTS

The study demonstrated excellent fidelity between 3D models and actual operative anatomy, with a median difference of only 0.31 mm. There was no statistically significant difference in angiographic cure rates or complications between the 3D model group and the non-3D model group. Surgical time showed a non-significant increase in cases involving 3D models. Furthermore, the 3D model cohort included higher-grade bAVMs, indicating increased surgical confidence.

CONCLUSION

This study demonstrates the feasibility and efficacy of utilizing 3D AVM models in pediatric bAVM surgery. The high fidelity between the models and actual operative anatomy suggests that 3D modelling can enhance pre-surgical planning and intraoperative guidance without significantly increasing surgical times or complications. Further research with larger cohorts is warranted to confirm and refine the application of 3D modelling in clinical practice.

Simulation to become a better neurosurgeon. An international prospective controlled trial: The Passion study

Introduction

Surgical training traditionally adheres to the apprenticeship paradigm, potentially exposing trainees to an increased risk of complications stemming from their limited experience. To mitigate this risk, augmented and virtual reality have been considered, though their effectiveness is difficult to assess.

Research question

The PASSION study seeks to investigate the improvement of manual dexterity following intensive training with neurosurgical simulators and to discern how surgeons' psychometric characteristics may influence their learning process and surgical performance.

Material and methods

Seventy-two residents were randomized into the simulation group (SG) and control group (CG). The course spanned five days, commencing with assessment of technical skills in basic procedures within a wet-lab setting on day 1. Over the subsequent core days, the SG engaged in simulated procedures, while the CG carried out routine activities in an OR. On day 5, all residents' technical competencies were evaluated. Psychometric measures of all participants were subjected to analysis.

Results

The SG demonstrated superior performance (p < 0.0001) in the brain tumour removal compared to the CG. Positive learning curves were evident in the SG across the three days of simulator-based training for all tumour removal tasks (all p-values <0.05). No significant differences were noted in other tasks, and no meaningful correlations were observed between performance and any psychometric parameters.

Discussion and conclusion

A brief and intensive training regimen utilizing 3D virtual reality simulators enhances residents' microsurgical proficiency in brain tumour removal models. Simulators emerge as a viable tool to expedite the learning curve of in-training neurosurgeons.

Tridimensional models and radiographic study of dorsal laminectomy and thoracolumbar hemilaminectomy in dogs

PURPOSE

To create three-dimensional anatomical models of the thoracic and lumbar portions of the canine spine that reproduce the vertebral surgical approaches of dorsal laminectomy and hemilaminectomy, and to perform the respective radiographic evaluations of each approach.

METHODS

In a digital archive of the canine spine, digitally replicate the dorsal laminectomy and hemilaminectomy in the thoracic and lumbar portions and, then, make tridimensional prints of the vertebral models and obtain radiographs in three dorsoventral, ventrodorsal and laterolateral projections.

RESULTS

The anatomical models of the surgical spinal canal accesses of the thoracic and lumbar portions showed great fidelity to the natural bones. The created accesses have the proper shape, location and size, and their radiographic images showed similar radiodensities.

CONCLUSIONS

The replicas of the dorsal laminectomy and hemilaminectomy developed in the anatomical models in the thoracic and lumbar portions are able to represent the technical recommendations of the specialized literature, as well as their respective radiographic images, which have certain radiological properties that allow to make a deep radiological study. Therefore, the models are useful for neurosurgical training.

3D printing as surgical planning and training in pediatric endoscopic skull base surgery - Systematic review and practical example

BACKGROUND

Pediatric endoscopic skull base surgery is challenging due to the intricate anatomy of the skull base and the presence of tumors with varied pathologies. The use of three-dimensional (3D) printing technologies in skull base surgeries has been found to be highly beneficial. A systematic review of the literature was performed to investigate the published studies that reported the effectiveness of 3D printing in pediatric endoscopic skull base surgery.

METHODS

Pub Med, Embase, Science Direct, The Cochrane Library, and Scopus were searched from January 01, 2000, until June 30, 2022. Original articles of any design reporting on the effectiveness of 3D printing in pediatric endoscopic skull base surgery were included. Information related to study population, conditions, models used, and key findings of study were extracted. Quality of included studies was evaluated using the Joanna Briggs Institute's (JBI) Critical Appraisal Checklist for Studies. To exemplify the use of 3D technology in this scenario, we report a complex clival chordoma case.

RESULTS

Six research articles were retrieved and included for qualitative analysis. Four of the six studies were conducted in the United States, followed by two in China. According to these studies, 3D reconstruction and printed models were more beneficial than CT/MRI images when discussing surgery with patients. In clinical training, these models were more helpful than 2D images in understanding the pathology when used in conjunction with image-guiding systems. It has been found that patient-specific 3D modeling, simulations, and rehearsal are the most efficient preoperative planning techniques, particularly in the pediatric population, for the treatment of complicated skull base surgeries. All the studies had a moderate risk of bias.

CONCLUSION

3D printing technologies assist in printing complex skull base tumors and the structures around them in three dimensions at the point of care and at the time needed, enabling the choice of the appropriate surgical strategy, thus minimizing surgery-related complications.