Current Applications and Future Perspectives of the Use of 3D Printing in Anatomical Training and Neurosurgery

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.

The Novel Impact of Augmented Reality and 3D Printing in the Diagnosis of Complex Acetabular Fractures: A Comparative Randomized Study in Orthopedic Residents

Augmented reality (AR) and 3D printing (3DP) are novel technologies in the orthopedic field. Over the past decade, enthusiasm for these new digital applications has driven new perspectives in improving diagnostic accuracy and sensitivity in the field of traumatology. Currently, however, it is still difficult to quantify their value and impact in the medical-scientific field, especially in the improvement of diagnostics in complex fractures. Acetabular fractures have always been a challenge in orthopedics, due to their volumetric complexity and low diagnostic reliability. Background/Objectives: The goal of this study was to determine whether these methods could improve the learning aspect and diagnostic accuracy of complex acetabular fractures compared to gold-standard CT (computed tomography). Methods: Orthopedic residents of our department were selected and divided into Junior (JUN) and Senior (SEN) groups. Associated fractures of acetabulum were included in the study, and details of these were provided as CT scans, 3DP models, and AR models displayed on a tablet screen. In a double-blind questionnaire, each resident classified every fracture. Diagnostic accuracy (DA), response time (RT), agreement (R), and confidence (C) were measured. Results: Twenty residents (JUN = 10, SEN = 10) classified five fractures. Overall DA was 26% (CT), 18% (3DP), and 29% (AR). AR-DA was superior to 3DP-DA (p = 0.048). DA means (JUN vs. SEN, respectively): CT-DA was 20% vs. 32% (p < 0.05), 3DP-DA was 12% vs. 24% (p = 0.08), and AR-DA was 28% vs. 30% (p = 0.80). Overall RT was 61.2 s (±24.6) for CT, 35.8 s (±20.1) for 3DP, and 46.7 s (±20.8) for AR. R was fairly poor between methods and groups. Overall, 3DPs had superior C (65%). Conclusions: AR had the same overall DA as CT, independent of experience, 3DP had minor differences in DA and R, but it was the fastest method and the one in which there was the most confidence. Intra- and inter-observer R between methods remained very poor in residents.

GRAVEN: a database of teaching method that applies gestures to represent the neurosurgical approach's blood vessels and nerves

BACKGROUND

In this era of rapid technological development, medical schools have had to use modern technology to enhance traditional teaching. Online teaching was preferred by many medical schools. However due to the complexity of intracranial anatomy, it was challenging for the students to study this part online, and the students were likely to be tired of neurosurgery, which is disadvantageous to the development of neurosurgery. Therefore, we developed this database to help students learn better neuroanatomy.

MAIN BODY

The data were sourced from Rhoton's Cranial Anatomy and Surgical Approaches and Neurosurgery Tricks of the Trade in this database. Then we designed many hand gesture figures connected with the atlas of anatomy. Our database was divided into three parts: intracranial arteries, intracranial veins, and neurosurgery approaches. Each section below contains an atlas of anatomy, and gestures represent vessels and nerves. Pictures of hand gestures and atlas of anatomy are available to view on GRAVEN ( www.graven.cn ) without restrictions for all teachers and students. We recruited 50 undergraduate students and randomly divided them into two groups: using traditional teaching methods or GRAVEN database combined with above traditional teaching methods. Results revealed a significant improvement in academic performance in using GRAVEN database combined with traditional teaching methods compared to the traditional teaching methods.

CONCLUSION

This database was vital to help students learn about intracranial anatomy and neurosurgical approaches. Gesture teaching can effectively simulate the relationship between human organs and tissues through the flexibility of hands and fingers, improving anatomy interest and education.

Exploring the Impact of Using Patient-Specific 3D Prints during Consent for Skull Base Neurosurgery

Objectives  Informed consent is fundamental to good practice. We hypothesized that a personalized three-dimensional (3D)-printed model of skull base pathology would enhance informed consent and reduce patient anxiety. Design  Digital images and communication in medicine (DICOM) files were 3D printed. After a standard pre-surgery consent clinic, patients completed part one of a two-part structured questionnaire. They then interacted with their personalized 3D printed model and completed part two. This explored their perceived involvement in decision-making, anxiety, concerns and also their understanding of lesion location and surgical risks. Descriptive statistics were used to report responses and text classification tools were used to analyze free text responses. Setting and Participants  In total,14 patients undergoing elective skull base surgery (with pathologies including skull base meningioma, craniopharyngioma, pituitary adenoma, Rathke cleft cyst, and olfactory neuroblastoma) were prospectively identified at a single unit. Results  After 3D model exposure, there was a net trend toward reduced patient-reported anxiety and enhanced patient-perceived involvement in treatment. Thirteen of 14 patients (93%) felt better about their operation and 13/14 patients (93%) thought all patients should have access to personalized 3D models. After exposure, there was a net trend toward improved patient-reported understanding of surgical risks, lesion location, and extent of feeling informed. Thirteen of 14 patients (93%) felt the model helped them understand the surgical anatomy better. Analysis of free text responses to the model found mixed sentiment: 47% positive, 35% neutral, and 18% negative. Conclusion  In the context of skull base neurosurgery, personalized 3D-printed models of skull base pathology can inform the surgical consent process, impacting the levels of patient understanding and anxiety.

Online anatomy education during the Covid-19 pandemic: Opinions of medical, speech therapy, and BSc Anatomy students

With the emergence of the Covid-19 pandemic in 2020, it was difficult to predict if the "cadaveric-based (golden) standard" of teaching anatomy would be possible in the unforeseeable future. This forced traditional anatomical teaching and learning practices to be transitioned to remote online platforms. This study explored the opinions of anatomy students (n = 51), on their online learning experience of anatomy during the Covid-19 pandemic. A mixed methods approach using a descriptive, exploratory study design was conducted, by use of an online survey. The survey consisted of a six-point Likert scale and was assembled into four sub-categories. Likert scale options ranged from; strongly disagree, to strongly agree, and not applicable. Results obtained seem to tally with expectations, indicating an adequate theoretical course component with room to improve practical online teaching. Most participants had a positive perception of the theoretical course content, duration, and platforms of communication. Virtual classes were simple to navigate with few technical difficulties experienced by the participants. Students also noted having access to sufficient study material, videos, and additional online material. Overall, more than half of all participants reported adapting well to the remote learning environment, however, the greatest challenge experienced highlighted a sense of deprivation from the lack of cadaver exposure and hands-on instruction. This research highlighted the effects of the pandemic on the modality of anatomy education and how it affected students. Although anatomy is multi-modal, it can be concluded that it is possible to achieve academic success by using online learning methods.

The Use of 3D Printed Models for Surgical Simulation of Cranioplasty in Craniosynostosis as Training and Education

BACKGROUND

The advance in imaging techniques is useful for 3D models and printing leading to a real revolution in many surgical specialties, in particular, neurosurgery.

METHODS

We report on a clinical study on the use of 3D printed models to perform cranioplasty in patients with craniosynostosis. The participants were recruited from various medical institutions and were divided into two groups: Group A (n = 5) received traditional surgical education (including cadaveric specimens) but without using 3D printed models, while Group B (n = 5) received training using 3D printed models.

RESULTS

Group B surgeons had the opportunity to plan different techniques and to simulate the cranioplasty. Group B surgeons reported that models provided a realistic and controlled environment for practicing surgical techniques, allowed for repetitive practice, and helped in visualizing the anatomy and pathology of craniosynostosis.

CONCLUSION

3D printed models can provide a realistic and controlled environment for neurosurgeons to develop their surgical skills in a safe and efficient manner. The ability to practice on 3D printed models before performing the actual surgery on patients may potentially improve the surgeons' confidence and competence in performing complex craniosynostosis surgeries.

Low-cost and open-source three-dimensional (3D) printing in neurosurgery: A pilot experiment using direct drive modification to produce multi-material neuroanatomical models

BACKGROUND

3-dimensional (3D) printing carries a genuine potential for pre-operative planning in neurosurgery. Entry-level 3D printers offer practicality in low resource settings, but are often limited by the range of filament materials as well as the capability of open-source segmentation software.

OBJECTIVE

We intended to demonstrate that 3D printing of neuroanatomical structures is possible using an entry-level 3D printer equipped with the direct drive (DD) modification, which supported flexible filaments, with the models segmented using an open-source software.

METHODS

A DD system was installed onto the Ender 3 Pro printer. An attempt to print neurosurgical models using a low-cost 3D printer was conducted, where four patient-based neuroanatomical models were printed: skull base-vasculature, skull base-tumour, cervical spine, and ventricular system. The results were discussed and compared to similar endeavours in past literature.

RESULTS

Although DD installation was challenging and led to vibration and longer print time, which ultimately warranted an inferior printing speed, DD system enabled the printing with thermoplastic polyurethane (TPU), a versatile elastomer; in addition to producing equal amount of detail to those printed with high-end printers and advanced image segmentation software. Fitting the frame well, changing infill type, and avoiding warping and stringing will improve print quality with the DD system.

CONCLUSION

3D printing with entry-level 3D printers equipped with DD system has been proven to be a reliable way of accurately reproducing patient-specific neuroanatomical constructs. Follow-up studies are necessary to implement 3D printing for neurosurgical planning in low-resource settings.

Anatomists' uses of human skeletons: Ethical issues associated with the India bone trade and anonymized archival collections

Concerns have recently been expressed about the continuing availability of human bones from India, obtained originally for educational purposes but lacking the requisite informed consent that would be expected today. More generally, a broader claim is being made, namely, that the practice of using any unconsented bones in educational settings is unethical and should cease. These calls, in turn, raise broader issues regarding the availability of anonymous archival collections in anatomy museums. Although this debate centers on undergraduate anatomy teaching, much anthropological research utilizes human remains of past populations for which there can have been no consent. A suggested alternative for undergraduate teaching is the use of 3D images of human bones, rather than the bones themselves. In addressing these issues, the background to the India bone trade is assessed, and the year 1985 is pinpointed as having significant ethical weight. The cultural and ethical interests inherent in studying archival anonymous skeletal material are weighed against indiscriminate reburial. Although any use of unconsented material represents ethical compromise, account should be taken of changing ethical expectations with time. It is concluded that: there is no justification for repatriation or disposal of all bones for which specific informed consent has not been obtained; continued use of anonymous archival human bones in a professional setting is acceptable, even in the absence of informed consent, with the proviso that there are no culturally relevant groups seeking repatriation; the continued existence of bones in long-standing private collections cannot be justified since it amounts to long-term storage with no identified goals; the notion that 3D images are an ethically superior alternative to actual human bones is unsustainable, since there is an intimate connection between the bones and the 3D images.

Three-Dimensional Printing Model Enhances Correct Identification and Understanding of Pelvic Fracture in Medical Students

OBJECTIVE

Understanding the anatomy behind a pelvic fracture can be a significant challenge to medical students. Recent advances in three-dimensional printing technology offers a novel approach to facilitate the learning of complex fracture. We have described here how the 3-dimension printing (3Dp) models can help medical students improve their understanding in and identification of pelvic fractures.

DESIGN

One hundred students were randomized into 2 teaching module groups (with or without 3Dp models). Prior to randomization assignment, a 50-minute didactic lecture covering elementary knowledge of anatomy, Young-Burgess classification, and traumatic mechanism of pelvic fracture was delivered to all students. The 3Dp group received X-rays, CT images, and 3Dp models of the eight pelvic fractures during presentation, while the students in the control group only obtained X-rays and CT scans of the same 8 pelvic fractures. Young-Burgess classification system and injury mechanism of pelvic fracture, time for evaluation, and subjective questions were conducted to assess the learning outcomes.

SETTING

A medical student program based in a LevelⅠtrauma center PARTICIPANTS: One hundred students in their 4th year of a 5-year clinical medicine program (for a medical bachelor degree) RESULTS: Students receiving 3Dp model had a higher rate of identifying the correct pelvic fracture via Young-Burgess identification compared to these without 3Dp model. Moreover, the accuracy of identifying the injury mechanism was significantly higher in the 3Dp group than that in group without 3Dp model. Participant in 3Dp group had faster assessment time compared to the control group. Subjective survey results suggested that 3Dp model would increase the learning interest and enhance the understanding of pelvic fracture. In addition, majority of students (83%) reported that they would like to use 3Dp model in other surgical course education.

CONCLUSIONS

3Dp model increased the perceived accuracy of pelvic fracture identification and understanding of injury mechanism. Moreover, 3Dp model promoted the subjective interest and motivation of students in pelvic fracture learning. Therefore, 3Dp model can be considered as a valuable educational tool for learning pelvic fracture in medical students.

Utility of 3D printed models as adjunct in acetabular fracture teaching for Orthopaedic trainees

OBJECTIVE

To evaluate the use of 3-D printed models as compared to didactic lectures in the teaching of acetabular fractures for Orthopaedic trainees.

METHODS

This was a randomised prospective study conducted in a tertiary hospital setting which consisted of 16 Orthopaedic residents. Ten different cases of acetabular fracture patterns were identified and printed as 3-D models. The baseline knowledge of orthopaedic residents regarding acetabular fracture classification and surgical approach was determined by an x-ray based pre-test. Trainees were then randomly assigned into two groups. Group I received only lectures. Group II were additionally provided with 3-D printed models during the lecture. Participants were then assessed for comprehension and retention of teaching.

RESULTS

Sixteen trainees participated in the trial. Both Group 1 and 2 improved post teaching with a mean score of 2.5 and 1.9 to 4.4 and 6 out of 10 respectively. The post test score for fracture classification and surgical approach were significantly higher for 3-D model group (p < 0.05). Trainees felt that the physical characteristics of the 3-D models were a good representation of acetabular fracture configuration, and should be used routinely for teaching and surgical planning.

CONCLUSION

3-D printed model of real clinical cases have significant educational impact compared to lecture-based learning towards improving young trainees' understanding of complex acetabular fractures.

Organizational and Supply Chain Impacts of 3D Printers Implementation in the Medical Sector

3D printing application extends to various sectors, such as aerospace, construction, art, domestic, up to healthcare. It is in this domain that its adoption could offer technological solutions aimed at improving the individual life and guaranteeing organizational effectiveness. The aim of this study is to understand the way in which the adoption of medical 3D printers has introduced economic-business changes at the supply chain, organizational and environmental level within business processes considering the point of view of 3D printer manufacturers. A multiple case study has been developed, through the administration of a semi-structured interview to 7 Italian companies that design, manufacture and sell 3D printers offering additive technological solutions to the medical sector. The results show how companies believe that the organizational impact related to the adoption of this technology is quite significant, highlighting how it leads to the definition of a new organizational culture. Secondly, it emerges that the adoption of 3D printers within the medical sector also leads to a change in procedures and production activities. Finally, it also emerges that the impact at the supply chain level particularly affects the reduction in the number of players in the supply chain and product time to market.

PMMA Cranioplasty Making by Using Оpen-Source CAD Software, PLA Printers, and Silicone Rubber Molds: Technical Note with Two Illustrative Cases

In this technical report, we discuss the design and production of polymethyl methacrylate (PMMA) implants, which we successfully applied in two patients using silicone molds, and a retrospective review of these patients at 1- and 6-month intervals. By using open-source computer-assisted design software, three-dimensional printers, and the patient's thin-sliced computed tomography data, we designed and produced the implant template and used it to make silicone rubber mоlds for intraoperative PMMA casting with good results. As a negative of the implant, we created a silicon mold, which can be autoclaved.

Two patients underwent PMMA cranioplasty using this method. Both implants were fitted into the defect without manipulation and good aesthetic аppеаrance of all patients was achieved. At follow-up 1 and 6 months after the operation, no complication was noted and the patients tolerated the cranioplasty platе wеll.

3D Printing for Complex Cranial Surgery Education: Technical Overview and Preliminary Validation Study

Background 3D printing—also known as additive manufacturing—has a wide range of applications. Reproduction of low-cost, high-fidelity, disease- or patient-specific models presents a key developmental area in simulation and education research for complex cranial surgery.

Methods Using cadaveric dissections as source materials, skull base models were created, printed, and tested for educational value in teaching complex cranial approaches. In this pilot study, assessments were made on the value of 3D printed models demonstrating the retrosigmoid and posterior petrosectomy approaches. Models were assessed and tested in a small cohort of neurosurgery resident subjects (n = 3) using a series of 10 radiographic and 2 printed case examples, with efficacy determined via agreement survey and approach selection accuracy.

Results All subjects indicated agreement or strong agreement for all study endpoints that 3D printed models provided significant improvements in understanding of neuroanatomic relationships and principles of approach selection, as compared to 2D dissections or patient cross-sectional imaging alone. Models were not superior to in-person hands-on teaching. Mean approach selection accuracy was 90% (±13%) for 10 imaging-based cases, or 92% (±7%) overall. Trainees strongly agreed that approach decision-making was enhanced by adjunctive use of 3D models for both radiographic and printed cases.

Conclusion 3D printed models incorporating skull base approaches and/or pathologies provide a compelling addition to the complex cranial education armamentarium. Based on our preliminary analysis, 3D printed models offer substantial potential for pedagogical value as dissection guides, adjuncts to preoperative study and case preparation, or tools for approach selection training and evaluation.

3D Printing Improve the Effectiveness of Fracture Teaching and Medical Learning: A Comprehensive Scientometric Assessment and Future Perspectives

Fractures of complex body parts are often serious and difficult to handle, and they have high technical and training requirements. However, the realistic situation is that there are few opportunities for the junior residents, trainee doctors, and especially medical students to contact enough clinical practice and see such fracture patients. Fortunately, with the rapid development and continuous progress of 3D printing and related technologies, this situation has gradually gotten better and better. In this research, we confirmed that 3D printing technology could improve the effectiveness of fracture teaching and medical learning from multiple dimensions. We comprehensively screened and assessed 223 papers from the Web of Science (WoS) Core Collection on October 3, 2021, with “((3D) AND ((printing) OR (printed)) AND (fracture)) AND ((education) OR (training) OR (teaching))” as the retrieval strategy. Additionally, we used the VOSviewer software to analyze the keywords and countries and the organizations of the publications, then a series of scientometric and visualized analyses were made based on the retrieval results. Afterward, multiple databases were retrieved according to our selection criteria, we selected eight studies for the extensive literature analysis. The extracted data contained information of authors, problems solved, participants, methods, assessments, results, and benefits/limitations. These intuitive and in-depth analyses further confirmed and appraised the advantages of 3D printing in complex fracture models more objectively. In conclusion, 3D printing could improve the effectiveness and extension of fracture teaching, as well as medical learning, by providing the powerful interaction with 3D effect, wakening students learning interest, and allowing the junior residents, trainee doctors to have as realistic a virtual practice experience as possible. Through this research, it is expected that more researchers could be attracted to conduct more comprehensive and thorough studies on the application of 3D printing for training and educational propose, to promote the development of 3D technology-based medical education practice and further deepen the reform of medical education and improve the quality of fracture education and learning.

3D printing technology in healthcare: applications, regulatory understanding, IP repository and clinical trial status

Mass consumerization of three-dimensional (3D) printing innovation has revolutionised admittance of 3D-printing in an expansive scope of ventures. When utilised predominantly for industrial manufacturing, 3D-printing strategies have rapidly attained acquaintance in different parts of health care industry. 3D-printing is a moderately new technology that has discovered promising applications in the medication conveyance and clinical areas. This review intends to explore different parts of 3D- printing innovation concerning pharmaceutical and clinical applications. Review on pharmaceutical products like tablets, caplets, films, polypills, microdots, biodegradable patches, medical devices (uterine and subcutaneous), patient specific implants, cardiovascular stents, etc. and prosthetics/anatomical structures, surgical models, organs and tissues created utilising 3D-printing is being presented. In addition, the regulatory understanding and current IP and clinical trial status pertaining to 3D fabricated products/medical applications have also been funnelled, garnering information from different web portals of regulatory agencies and databases. It is additionally certain that for such new innovations, there would be difficulties and questions before these are acknowledged as protected and viable. The circumstance demands purposeful and wary endeavours to acquire regulations which would at last prompt the accomplishment of this progressive innovation, thus various regulatory challenges faced have been conscientiously discussed.

Assessment of a 3D printed simulator of a lateral ventricular puncture in interns' surgical training

PURPOSE

In this study, a simulator for training lateral ventricular puncture (LVP) was developed using three-dimensional (3D) printing technology, and its function of improving the skills of LVP in young interns was evaluated.

METHODS

A virtual 3D craniocerebral simulator of a 51-year-old female patient with hydrocephalus was reconstructed with 3D printing technology. The anatomical and practical validity were assessed by all interns on a 13-item Likert scale. The usefulness of this simulator was evaluated once a week by two neurosurgeons, based on the performance of the interns, using the objective structured assessment of technical skills (OSATS) scale.

RESULTS

The Likert scale showed that all participants agreed with the overall appearance of the simulator. Also, the authenticity of the skull was the best, followed by the lateral ventricles, analog generation system of intraventricular pressure, cerebrum, and the scalp. This simulator could help the participants' learning about the anatomy of the lateral ventricle, effective training, and repeating the steps of LVP. During training, the interns' ratio of success in LVP elevated gradually. At each evaluation stage, all mean performance scores for each measure based on the OSATS scale were higher than the previous.

CONCLUSIONS

The 3D printed simulator for LVP training provided both anatomical and practical validity, and enabled young doctors to master the LVP procedures and skills.

Consensus statement from the international consensus meeting on post-traumatic cranioplasty

Background

Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach.

Methods

The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP.

Results

The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations.

Conclusions

This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

Accuracy evaluation of patient-specific 3D-printed aortic anatomy

INTRODUCTION

3D printing has a wide range of applications in medicine. In surgery, this technique can be used for preoperative planning of complex procedures, production of patient specific implants, as well as training. However, accuracy evaluations of 3D vascular models are rare.

OBJECTIVES

Aim of this study was to investigate the accuracy of patient-specific 3D-printed aortic anatomies.

METHODS

Patients suffering from aorto-iliac aneurysms and with indication for treatment were selected on the basis of different anatomy and localization of the aneurysm in the period from January 1st 2014 to May 27th 2016. Six patients with aorto-iliac aneurysms were selected out of the database for 3D-printing. Subsequently, computed tomography (CT) images of the printed 3D-models were compared with the original CT data sets.

RESULTS

The mean deviation of the six 3D-vascular models ranged between -0.73 mm and 0.14 mm compared to the original CT-data. The relative deviation of the measured values showed no significant difference between the 3D-vascular and the original patient CT-data.

CONCLUSION

Our results showed that 3D printing has the potential to produce patient-specific 3D vascular models with reliable accuracy. This enables the use of such models for the development of new endovascular procedures and devices.

Automatic segmentation of true color sectioned images using FMRIB Software Library: First trial in brain, gray matter, and white matter

Three-dimensional (3D) models of the brain made from magnetic resonance images (MRI) are used in various medical fields. 3D models assembled from grayscale color and low-resolution can be complemented with true color sectioned images of the Visible Korean. The purpose of this study is to apply the MRI automatic segmentation technique to the sectioned images. 3D models of the sectioned images, which have true color and high resolution, can be produced without manual segmentation. The Brain Extraction Tool and the Automated Segmentation Tool of the FMRIB Software Library (FSL) were chosen for automatic segmentation. Using those tools, true color sectioned images were reconstructed from gray 3D models of brain, gray matter, and white matter. Color 3D models of those structures were generated from the gray 3D models using MRIcroGL. The color 3D models made from the sectioned images revealed details of brain anatomy that could not be observed on the 3D models from MRI. This trial suggests that convergence of the MRI segmentation technique with color sectioned images is a time-efficient method for producing color 3D models of various structures. In future, the method of this study will be used for various sectioned images of cadavers. The resulting color sectioned images and 3D models will be made available to other researchers.

The Impact of Three-Dimensional Printed Anatomical Models on First-Year Student Engagement in a Block Mode Delivery

Student engagement is known to have several positive effects on learning outcomes and can impact a student's university experience. High levels of engagement in content-heavy subjects can be difficult to attain. Due to a major institutional restructure, the anatomy prosection laboratory time per subject was dramatically reduced. In response, the authors set out to redesign their anatomy units with a focus on engaging the learning activities that would increase time-on-task both within and outside of the classroom. One of these curriculum changes was the implementation of a suite of anatomy learning activities centered on sets of three-dimensional printed upper limb skeleton models. A two-part mixed-method sequential exploratory design was used to evaluate these activities. Part one was a questionnaire that evaluated the students' engagement with and perceptions of the models. Part two involved focus groups interviews, which were an extension of the survey questions in part one. The results of the study indicated that the majority of students found the models to be an engaging resource that helped improve their study habits. As a result, students strongly felt that the use of the models inspired greater academic confidence and overall better performance in their assessments. Overall, the models were an effective way of increasing the engagement and deep learning, and reinforced previous findings from the medical education research. Future research should investigate the effects of these models on student's grades within osteopathy and other allied health courses.

3D printing in pharmaceuticals: An emerging technology full of challenges

Although in its infancy, when compared with the other sectors, year 2005 marked the rapid evolution of 3 Dimensional printing (3DP) technologies in pharma sector with a huge potential in the dosage form designing and personalisation of the medication. 3DP is an innovative and highly promising way for the instant manufacturing in contrast with the tailored made conventional manufacturing. Various 3DP technologies are categorized into the various areas on the basis of the type of material used, deposition techniques and the solidification/fusion techniques. 3DP technologies have multiple pharmaceutical applications including formulation of the precise and unique dosage forms, medical research, personalization of medicine, tissues engineering and surgical application. In the present article, we have accentuated the comparative merits and demerits of various 3DP technologies used in the pharmaceutical sector. An insight in to the challenges, apropos availability and the choice of the excipients, as well as the printer, regulatory and safety concern of the product is provided.

3D-printed Titanium Prosthetic Reconstruction of the C2 Vertebra: Techniques and Outcomes of Three Consecutive Cases

STUDY DESIGN

Three patients were treated at our center with patient-specific three-dimensional (3D)-printed titanium prostheses for the reconstruction of structurally compromised C2 vertebrae.

OBJECTIVE

To describe our surgical and device design approach to these clinical scenarios and evaluate their outcomes.

SUMMARY OF BACKGROUND DATA

There are a limited but increasing number of case reports and series describing the use of 3D-printed prostheses for high cervical surgery.

METHODS

We have collated and reviewed three cases using patient-specific 3D-printed prostheses.

RESULTS

We report two cases arising from neoplastic destruction; one resulting from metastatic medullary thyroid carcinoma, and the other from multiple myeloma. We additionally describe a case of C2 compromise as a complication of rheumatoid arthritis. All patients included in this report achieved successful surgical outcomes and symptom relief without significant complication. Clinical and radiological follow-up has demonstrated good outcomes in all cases up to 14-months postprocedure.

CONCLUSIONS

These cases describe successful use of custom 3D-printed prostheses for reconstruction of the anterior vertebral column through C2, and add to the emerging body of literature detailing the use of custom prostheses for complex spinal surgery.

LEVEL OF EVIDENCE

4.

Investigation of a three-dimensional printed dynamic cervical spine model for anatomy and physiology education

INTRODUCTION

Three-dimensional (3D) printing of anatomical structures is a growing method of education for students and medical trainees. These models are generally produced as static representations of gross surface anatomy. In order to create a model that provides educators with a tool for demonstration of kinematic and physiologic concepts in addition to surface anatomy, a high-resolution segmentation and 3D-printingtechnique was investigated for the creation of a dynamic educational model.

METHODS

An anonymized computed tomography scan of the cervical spine with a diagnosis of ossification of the posterior longitudinal ligament was acquired. Using a high-resolution thresholding technique, the individual facet and intervertebral spaces were separated, and models of the C3-7 vertebrae were 3D-printed. The models were placed on a myelography simulator and subjected to flexion and extension under fluoroscopy, and measurements of the spinal canal diameter were recorded and compared to in-vivo measurements. The flexible 3D-printed model was then compared to a static 3D-printed model to determine the educational benefit of demonstrating physiologic concepts.

RESULTS

The canal diameter changes on the flexible 3D-printed model accurately reflected in-vivo measurements during dynamic positioning. The flexible model also was also more successful in teaching the physiologic concepts of spinal canal changes during flexion and extension than the static 3D-printed model to a cohort of learners.

CONCLUSIONS

Dynamic 3D-printed models can provide educators with a cost-effective and novel educational tool for not just instruction of surface anatomy, but also physiologic concepts through 3D ex-vivo modeling of case-specific physiologic and pathologic conditions.

The SpineBox: A Freely Available, Open-access, 3D-printed Simulator Design for Lumbar Pedicle Screw Placement

Background

The recent COVID-19 pandemic has demonstrated the need for innovation in cost-effective and easily produced surgical simulations for trainee education that are not limited by physical confines of location. This can be accomplished with the use of desktop three-dimensional (3D) printing technology. This study describes the creation of a low-cost and open-access simulation for anatomical learning and pedicle screw placement in the lumbar spine, which is termed the SpineBox.

Materials and methods

An anonymized CT scan of the lumbar spine was obtained and converted into 3D software files of the L1-L5 vertebral bodies. A computer-assisted design (CAD) software was used to assemble the vertebral models into a simulator unit in anatomical order to produce an easily prototyped simulator. The printed simulator was layered with foam in order to replicate soft tissue structures. The models were instrumented with pedicle screws using standard operative technique and examined under fluoroscopy.

Results

Ten SpineBoxes were created using a single desktop 3D printer, with accurate replication of the cortico-cancellous interface using previously validated techniques. The models were able to be instrumented with pedicle screws successfully and demonstrated quality representation of bony structures under fluoroscopy. The total cost of model production was under $10.

Conclusion

The SpineBox represents the first open-access simulator for the instruction of spinal anatomy and pedicle screw placement. This study aims to provide institutions across the world with an economical and feasible means of spine surgical simulation for neurosurgical trainees and to encourage other rapid prototyping laboratories to investigate innovative means of creating educational surgical platforms in the modern era.

Development of a three-dimensional printed heart from computed tomography images of a plastinated specimen for learning anatomy

Learning anatomy is commonly facilitated by use of cadavers, plastic models and more recently three-dimensional printed (3DP) anatomical models as they allow students to physically touch and hold the body segments. However, most existing models are limited to surface features of the specimen, with little opportunity to manipulate the structures. There is much interest in developing better 3DP models suitable for anatomy education. This study aims to determine the feasibility of developing a multi-material 3DP heart model, and to evaluate students' perceptions of the model. Semi-automated segmentation was performed on computed tomgoraphy plastinated heart images to develop its 3D digital heart model. Material jetting was used as part of the 3D printing process so that various colors and textures could be assigned to the individual segments of the model. Morphometric analysis was conducted to quantify the differences between the printed model and the plastinated heart. Medical students' opinions were sought using a 5-point Likert scale. The 3DP full heart was anatomically accurate, pliable and compressible to touch. The major vessels of the heart were color-coded for easy recognition. Morphometric analysis of the printed model was comparable with the plastinated heart. Students were positive about the quality of the model and the majority of them reported that the model was useful for their learning and that they would recommend their use for anatomical education. The successful feasibility study and students' positive views suggest that the development of multi-material 3DP models is promising for medical education.

Cranioplasty Following Decompressive Craniectomy

Cranioplasty (CP) after decompressive craniectomy (DC) for trauma is a neurosurgical procedure that aims to restore esthesis, improve cerebrospinal fluid (CSF) dynamics, and provide cerebral protection. In turn, this can facilitate neurological rehabilitation and potentially enhance neurological recovery. However, CP can be associated with significant morbidity. Multiple aspects of CP must be considered to optimize its outcomes. Those aspects range from the intricacies of the surgical dissection/reconstruction during the procedure of CP, the types of materials used for the reconstruction, as well as the timing of the CP in relation to the DC. This article is a narrative mini-review that discusses the current evidence base and suggests that no consensus has been reached about several issues, such as an agreement on the best material for use in CP, the appropriate timing of CP after DC, and the optimal management of hydrocephalus in patients who need cranial reconstruction. Moreover, the protocol-driven standards of care for traumatic brain injury (TBI) patients in high-resource settings are virtually out of reach for low-income countries, including those pertaining to CP. Thus, there is a need to design appropriate prospective studies to provide context-specific solid recommendations regarding this topic.

Neuroanatomy, the Achille's Heel of Medical Students. A Systematic Analysis of Educational Strategies for the Teaching of Neuroanatomy

Neuroanatomy has been deemed crucial for clinical neurosciences. It has been one of the most challenging parts of the anatomical curriculum and is one of the causes of "neurophobia," whose main implication is a negative influence on the choice of neurology in the near future. In the last decades, several educational strategies have been identified to improve the skills of students and to promote a deep learning. The aim of this study was to systematically review the literature to identify the most effective method/s to teach human neuroanatomy. The search was restricted to publications written in English language and to articles describing teaching tools in undergraduate medical courses from January 2006 through December 2017. The primary outcome was the observation of improvement of anatomical knowledge in undergraduate medical students. Secondary outcomes were the amelioration of long-term retention knowledge and the grade of satisfaction of students. Among 18 selected studies, 44.4% have used three-dimensional (3D) teaching tools, 16.6% near peer teaching tool, 5.55% flipped classroom tool, 5.55% applied neuroanatomy elective course, 5.55% equivalence-based instruction-rote learning, 5.55% mobile augmented reality, 5.55% inquiry-based clinical case, 5.55% cadaver dissection, and 5.55% Twitter. The high in-between study heterogeneity was the main issue to identify the most helpful teaching tool to improve neuroanatomical knowledge among medical students. Data from this study suggest that a combination of multiple pedagogical resources seems to be the more advantageous for teaching neuroanatomy.

Patient-specific 3-dimensionally printed models for neurosurgical planning and education

OBJECTIVE

Advances in 3-dimensional (3D) printing technology permit the rapid creation of detailed anatomical models. Integration of this technology into neurosurgical practice is still in its nascence, however. One potential application is to create models depicting neurosurgical pathology. The goal of this study was to assess the clinical value of patient-specific 3D printed models for neurosurgical planning and education.

METHODS

The authors created life-sized, patient-specific models for 4 preoperative cases. Three of the cases involved adults (2 patients with petroclival meningioma and 1 with trigeminal neuralgia) and the remaining case involved a pediatric patient with craniopharyngioma. Models were derived from routine clinical imaging sequences and manufactured using commercially available software and hardware.

RESULTS

Life-sized, 3D printed models depicting bony, vascular, and neural pathology relevant to each case were successfully manufactured. A variety of commercially available software and hardware were used to create and print each model from radiological sequences. The models for the adult cases were printed in separate pieces, which had to be painted by hand, and could be disassembled for detailed study, while the model for the pediatric case was printed as a single piece in separate-colored resins and could not be disassembled for study. Two of the models were used for patient education, and all were used for presurgical planning by the surgeon.

CONCLUSIONS

Patient-specific 3D printed models are useful to neurosurgical practice. They may be used as a visualization aid for surgeons and patients, or for education of trainees.

Identifying the Sources of Error When Using 3-Dimensional Printed Head Models with Surgical Navigation

OBJECTIVES

The evaluation of sources of error when preparing, printing, and using 3-dimensional (3D) printed head models for training purposes.

METHODS

Two 3D printed models were designed and fabricated using actual patient imaging data with reference marker points embedded artificially within these models that were then registered to a surgical navigation system using 3 different methods. The first method uses a conventional manual registration, using the actual patient's imaging data. The second method is done by directly scanning the created model using intraoperative computed tomography followed by registering the model to a new imaging dataset manually. The third is similar to the second method of scanning the model but eventually uses an automatic registration technique. The errors for each experiment were then calculated based on the distance of the surgical navigation probe from the respective positions of the embedded marker points.

RESULTS

Errors were found in the preparation and printing techniques, largely depending on the orientation of the printed segment and postprocessing, but these were relatively small. Larger errors were noted based on a couple of variables: if the models were registered using the original patient imaging data as opposed to using the imaging data from directly scanning the model (1.28 mm vs. 1.082 mm), and the accuracy was best using the automated registration techniques (0.74 mm).

CONCLUSION

Spatial accuracy errors occur consistently in every 3D fabricated model. These errors are derived from the fabrication process, the image registration process, and the surgical process of registration.

Effectiveness of personalized 3D printed models for patient education in degenerative lumbar disease

OBJECTIVE

Three-dimensional printing may play an important role in patients' education. The objective of this study was to assess the effectiveness of personalized 3D printed models for increasing patient understanding of their medical condition and surgical plan.

METHODS

Forty-five patients with degenerative lumbar diseases were randomized by block design into three groups: educational program presented by CT & MRI imaging (care-as-usual), 3D reconstructions, or personalized 3D printed models. Patients' level of understanding and satisfaction were evaluated by two questionnaires one day after education.

RESULTS

Patients educated with personalized 3D printed models demonstrated an expanded level of understanding than patients educated with CT & MRI imaging (care-as-usual) (P ＜ 0.05) and 3D reconstructions (P ＜ 0.05). Personalized 3D printed models also resulted in a higher degree of patient satisfaction (P ＜ 0.05).

CONCLUSIONS

Personalized 3D printed models and 3D reconstructions can simplify and enhance understanding of lumbar anatomy, physiology, and patients' disease and surgical plan. Personalized 3D printed models also enhance patients' subjective satisfaction.

PRACTICE IMPLICATIONS

Personalized 3D printed models for patient education are feasible and could be generalized for degenerative lumbar diseases.

Is This Mine to Keep? Three-dimensional Printing Enables Active, Personalized Learning in Anatomy

Understanding orbital anatomy is important for optometry students, but the learning resources available are often fragile, expensive, and accessible only during scheduled classes. Drawing on a constructivist, personalized approach to learning, this study investigated students' perceptions of an alternative learning resource: a three-dimensional (3D) printed model used in an active learning task. A human skull was three-dimensionally scanned and used to produce a 3D printed model for each student. Students actively participated in model creation by tracing suture lines and coloring individual orbital bones during a practical class, then keeping the model for future study. Students' perceptions of the 3D orbital model were examined through a questionnaire: the impact the model had on their learning; perceptions of the 3D orbit compared to traditional resources; and utility of having their own personalized model. The 3D orbit was well received by the student cohort. Participants (n = 69) preferred the 3D orbit as a resource for learning orbital bone anatomy compared to traditional learning resources, believing the model helped them to understand and visualize the spatial relationships of the bones, and that it increased their confidence to apply this knowledge. Overall, the participants liked that they co-created the model, could touch and feel it, and that they had access to it whenever they liked. Three-dimensional printing technology has the potential to enable the creation of effective learning resources that are robust, low-cost and readily accessible to students, and should be considered by anyone wishing to incorporate personalized resources to their multimodal teaching repertoire.

Beyond the Learning Curve: Comparison of Microscopic and Endoscopic Incidences of Internal Carotid Injury in a Series of Highly Experienced Operators

BACKGROUND

As the endoscopic endonasal approach (EEA) has gained popularity as an alternative to microsurgery (MS) for transsphenoidal resection (TSR), numerous studies have attempted to assess the differential risk of internal carotid artery (ICA) injury between the techniques, yet results have been equivocal and contradictory. The aim of this study was to evaluate ICA injury in MS versus EEA among highly experienced neurosurgeons.

METHODS

We performed a systematic literature review of publications from 2002-2017 reporting ICA injury outcomes in ≥250 cases using MS or EEA.

RESULTS

Seventeen series reporting 11,149 patients were included: 3 MS series, 13 EEA series, and 1 series with adequate samples for each. ICA injury incidences were 0.0%-1.6% in cohorts of 275-3000. MS series documented 5 ICA injuries in 2672 operations, for an overall incidence of 0.2% (range, 0.0%-0.4%), and EEA series reported 30 ICA injuries in 8477 operations, for a 0.4% injury rate (range, 0.0%-1.6%); the difference was nonsignificant (P = 0.25). Increased operative experience was associated with decreased incidence of ICA injury, a finding preserved in the overall study cohort and within discretely examined MS and EEA subgroups (overall r² = 0.08, MS r² = 0.23, EEA r² = 0.07).

CONCLUSIONS

ICA injury is the most serious complication of TSR of pituitary neoplasms. Operator inexperience may be a more important risk factor than choice of surgical technique, given the comparably low rates of injury obtained by highly experienced surgeons independent of technique. This emphasizes the need for consolidated care in pituitary centers of excellence, improvement of high-fidelity simulators, and skull base mentorship between senior and junior staff.

Three-dimensional Printing in Anatomy Education: Assessing Potential Ethical Dimensions

New technological developments have frequently had major consequences for anatomy education, and have raised ethical queries for anatomy educators. The advent of three-dimensional (3D) printing of human material is showing considerable promise as an educational tool that fits alongside cadaveric dissection, plastination, computer simulation, and anatomical models and images. At first glance its ethical implications appear minimal, and yet the more extensive ethical implications around clinical bioprinting suggest that a cautious approach to 3D printing in the dissecting room is in order. Following an overview of early groundbreaking studies into 3D printing of prosections, organs, and archived fetal material, it has become clear that their origin, using donated bodies or 3D files available on the Internet, has ethical overtones. The dynamic presented by digital technology raises questions about the nature of the consent provided by the body donor, reasons for 3D printing, the extent to which it will be commercialized, and its comparative advantages over other available teaching resources. In exploring questions like these, the place of 3D printing within a hierarchical sequence of value is outlined. Discussion centers on the significance of local usage of prints, the challenges created by regarding 3D prints as disposable property, the importance of retaining the human side to anatomy, and the unacceptability of obtaining 3D-printed material from unclaimed bodies. It is concluded that the scientific tenor of 3D processes represents a move away from the human person, so that efforts are required to prevent them accentuating depersonalization and commodification.

Acquisition of Volumetric Models of Skull Base Anatomy Using Endoscopic Endonasal Approaches: 3D Scanning of Deep Corridors Via Photogrammetry

OBJECTIVE

In this study we aim to evaluate the feasibility of creating volumetric models of highly intricate skull-base anatomy-previously not amenable to volumetric reconstruction-using endoscopic endonasal approaches.

METHODS

Ten human cadaveric heads were dissected through the nasal corridor to expose anterior, middle, and posterior cranial fossi structures and the pterygopalatine and infratemporal fossi. A rigid endoscope with a 30° lens was used to capture the images. Subsequently, a photogrammetry software was used to align, smooth, and texturize the images into a complete 3-dimensional model.

RESULTS

An average of 174 photographs were used to construct each model (n = 10). In the end, we achieved high-definition stereoscopic volumetric models of the nasal corridor; paranasal fossae; and anterior, middle and posterior fossae structures that preserved structural integrity. Strategic points of interests were labeled and animated for educational use.

CONCLUSIONS

Endoscopic volumetric models represent a new way to depict the anatomy of the skull base; their use with 3-dimensional technologies could potentially improve the visuospatial understanding of narrow surgical corridors for education and surgical-planning purposes.

Novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under subarachnoid hemorrhage conditions: technical note and timing study

OBJECTIVE

Sylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. The authors describe a novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions.

METHODS

A standardized microvascular anastomosis model comprising rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1- to 2-mm) soft-tissue debridement was conducted and followed by wound closure and delayed reexploration at intervals of 7, 14, and 28 days. Two residents dissected 1 rat each per time point (n = 6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed postprocedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales.

RESULTS

At all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point.

CONCLUSIONS

The authors’ experimental model of femoral vessel skeletonization, circumferential superficial soft-tissue injury, and delayed reexploration provides a novel approximation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal reexploration interval appears to be 7–14 days. To the authors’ knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.

Regulatory interfaces surrounding the growing field of additive manufacturing of medical devices and biologic products

Rapidly advancing technology often pulls the regulatory field along as it evolves to incorporate new concepts, better tools, and more finely honed equipment. When the area impacted by the technological advancement is regulated by the Food and Drug Administration (FDA), a gap develops between the technology and the guidelines that govern its application. Subsequently, there are challenges in determining appropriate regulatory pathways for evolving products at the initial research and developmental stages. Myriad factors necessitate several rounds of iterative review and the involvement of multiple divisions within the FDA. To better understand the regulatory science issues roiling around the area of additive manufacturing of medical products, a group of experts, led by a Clinical and Translational Science Award working group, convened the Regulatory Science to Advance Precision Medicine at the Fall Forum to discuss some of the current regulatory science roadblocks.

Use of 3D Printed Models in Resident Education for the Classification of Acetabulum Fractures

OBJECTIVE

To determine if three-dimensional (3D) printed models can be used to improve acetabular fracture pattern recognition and be a valuable adjunct in orthopedic resident education.

DESIGN

Fifteen randomized testing stations with each containing plain radiographs (XRs), two-dimensional computed tomography (CT) scans, or 3D model of an acetabular fracture.

SETTING

Two orthopedic residency programs based at Level 1 trauma centers.

PARTICIPANTS

Forty-one orthopedic residents, PGY 1-5.

RESULTS

Senior residents were superior to junior residents at correctly identifying the provided acetabular fracture pattern. Overall, use of CT scans or the 3D model improved fracture classification as compared to standard XRs, but there was no significant difference between use of the CT scans and 3D models. Subjective survey results indicated agreement among residents that 3D models were accurate representations of acetabular fractures and that models would be a desired educational modality.

CONCLUSIONS

3D models improved the accuracy of acetabular fracture identification compared to XR. In addition, trainees were able to use 3D models to obtain similar accuracy compared to CT scans despite not having previous exposure to the models. Interobserver agreement improved when comparing CT to 3D, but did not provide greater than a fair agreement indicating that fracture patterns were difficult to accurately classify even with the use of 3D models. Residents' subjective responses indicated a positive experience with the use of 3D models. We conclude that the incorporation of 3D models could be an important adjunct to orthopedic residency education for the evaluation complex fracture patterns, but is not significantly superior to identification with CT scans.

A High-fidelity Tactile Hand Simulator as a Training Tool to Develop Competency in Percutaneous Pinning in Residents

Introduction

We developed an economical three-dimensional printed and casted simulator of the hand for the training of percutaneous pinning. This simulator augments the traditional "See one, do one, teach one" training model.

Methods

To evaluate the simulator, five expert orthopaedic surgeons were recruited to perform percutaneous pinning on the simulator and then to complete a questionnaire on its realism and expected usefulness. Evaluation was based on responses to multiple-choice questions and a Likert-type scale.

Results

All subjects expressed that the tactile hand simulator is useful for residency training. They would recommend the simulator to their colleagues and indicated interest in testing future iterations. Subjects rated highly the realism of the material, the purchase of the pin, and the cortical-cancellous bone interface.

Conclusion

The learning of tactile skills in addition to visual cues on a tactile simulator is expected to benefit residents. It provides a low-cost and low-risk environment outside the operating room for residents to hone their skills.

The beneficial application of preoperative 3D printing for surgical stabilization of rib fractures

Objectives

The beneficial application of three-dimensional (3D) printing for surgical stabilization of rib fractures (SSRF) has never been proposed in the literature before. The aim of this study was to verify patients’ surgical outcomes when utilizing preoperative three-dimensional printing for SSRF.

Methods

We retrospectively reviewed the records of all consecutive patients who were treated at our hospital for SSRF from July 2015 to December 2017. The patients were divided into two groups according to whether or not 3D printing was utilized.

Results

Forty-eight patients who underwent SSRF at our hospital were enrolled. Of them, three patients underwent bilateral surgeries. The patients with application of preoperative 3D printing for SSRF had statistically significant associations with shorter operation time per fixed plate (p < 0.001), and a smaller incision length (p < 0.001).

Conclusions

We present an useful technique involving 3D printing for promoting SSRF significantly with shorter operation time and an appropriate incision length.

Efficacy of a Three-Dimensional-Printed Training Simulator for Endoscopic Biopsy in the Stomach

Background/Aims

We used three-dimensional (3D) printing technology to create a new biopsy simulator for the stomach and investigated its efficacy and realism in endoscopic biopsy training.

Methods

A novel stomach biopsy simulator, with 10 biopsy sites, was produced using a 3D printer. We enrolled 26 participants, including 10 residents, six first-year fellows, five second-year fellows, and five faculty members. We recorded and reviewed five training sessions and evaluated the simulator with questionnaires using a 7-point Likert scale.

Results

The mean completion time (seconds) was 244.8±11.5 for the residents, 107.9±33.4 for the first-year fellows, 106.8±20.1 for the second-year fellows, and 103.8±19.2 for the faculty members. The completion time became shorter with repetition and was significantly lower for residents by the fifth trial (first trial, 347.0±159.5; fifth trial, 169.6±57.7; p=0.007). The faculty members strongly agreed that the simulator realistically reflected endoscopic handling and was reasonable for endoscopic training (scores of 6.2±0.8 and 6.4±0.9, respectively). Importantly, experienced endoscopists reported that the difficulty levels of the 10 biopsy sites in the simulator were a realistic match for the actual stomach.

Conclusions

This endoscopic biopsy simulator created using a 3D printer is a realistic and useful method to improve the biopsy skills of trainee endoscopists.

A 3-Dimensional-Printed Spine Localizer: Introducing the Concept of Online Dissemination of Novel Surgical Instruments

Background/Aims

To date, applications of 3-dimensional (3D) printing in neurosurgery have been limited to the creation of anatomical models for training and simulation, fabrication of customized implants, and production of patient-specific surgical tool guides. We aim to demonstrate a new application of this technology for the online dissemination of novel surgical instrument designs across the world.

Methods

A link to a 3D printing file and instructions for assembly of a spine localizer are included in this article. This device was used to determine the optimal location of skin incision in lumbar microsurgery in 43 consecutive patients. Data regarding the accuracy of the surgeon's initial estimate of the target site based on palpation of anatomical landmarks and the accuracy of the localizer device in locating the target spine segment were prospectively collected.

Results

In 35 cases (81%), the surgeon’s initial estimate of the target site was correct. In the remaining 8 cases (19%), the initial estimate was off by 1 motion segment. Inaccuracy of the surgeon’s estimate was found to be associated with a higher body mass index and the presence of transitional lumbosacral anatomy, but not with age, sex, or location of the target segment. In all patients, the location of the incision guided by the localizer was found to overlie the target segment, yielding a device accuracy of 100%. There was no need to extend the incision or modify the surgical trajectory.

Conclusion

This 3D-printable localizer serves as an example of a device that can be disseminated online and printed at the point of use, thus promoting online tool-sharing by neurosurgeons.

Feasibility of Clinician-Facilitated Three-Dimensional Printing of Synthetic Cranioplasty Flaps

BACKGROUND

Integration of three-dimensional (3D) printing and stereolithography into clinical practice is in its nascence, and concepts may be esoteric to the practicing neurosurgeon. Currently, creation of 3D printed implants involves recruitment of offsite third parties. We explored a range of 3D scanning and stereolithographic techniques to create patient-specific synthetic implants using an onsite, clinician-facilitated approach.

METHODS

We simulated bilateral craniectomies in a single cadaveric specimen. We devised 3 methods of creating stereolithographically viable virtual models from removed bone. First, we used preoperative and postoperative computed tomography scanner-derived bony window models from which the flap was extracted. Second, we used an entry-level 3D light scanner to scan and render models of the individual bone pieces. Third, we used an arm-mounted, 3D laser scanner to create virtual models using a real-time approach.

RESULTS

Flaps were printed from the computed tomography scanner and laser scanner models only in a ultraviolet-cured polymer. The light scanner did not produce suitable virtual models for printing. The computed tomography scanner-derived models required extensive postfabrication modification to fit the existing defects. The laser scanner models assumed good fit within the defects without any modification.

CONCLUSIONS

The methods presented varying levels of complexity in acquisition and model rendering. Each technique required hardware at varying in price points from $0 to approximately $100,000. The laser scanner models produced the best quality parts, which had near-perfect fit with the original defects. Potential neurosurgical applications of this technology are discussed.

[Additive technologies in neurosurgery]

Modern achievements of technical progress, in particular additive technologies (ATs) and three-dimensional printing, have been increasingly introduced in neurosurgical practice. The increasing complexity of surgical interventions requires thorough planning of surgery and a high level of training of young neurosurgeons. Creation of full-scale three-dimensional models for planning of surgery enables visualization of the anatomical region of interest. Additive technologies are especially extensively used in reconstructive surgery of skull defects. ATs enable fast and efficient solving of the following tasks: - generation of accurate models of the skull and an implant; - development and fabrication of individual molds for intraoperative formation of implants from polymeric two-component materials (e.g., PMMA); - fabrication of individual implants from titanium alloys or polyetheretherketone (PEEK) for further use in surgery.

Evaluation by medical students of the educational value of multi-material and multi-colored three-dimensional printed models of the upper limb for anatomical education

For centuries, cadaveric material has been the cornerstone of anatomical education. For reasons of changes in curriculum emphasis, cost, availability, expertise, and ethical concerns, several medical schools have replaced wet cadaveric specimens with plastinated prosections, plastic models, imaging, and digital models. Discussions about the qualities and limitations of these alternative teaching resources are on-going. We hypothesize that three-dimensional printed (3DP) models can replace or indeed enhance existing resources for anatomical education. A novel multi-colored and multi-material 3DP model of the upper limb was developed based on a plastinated upper limb prosection, capturing muscles, nerves, arteries and bones with a spatial resolution of ∼1 mm. This study aims to examine the educational value of the 3DP model from the learner's point of view. Students (n = 15) compared the developed 3DP models with the plastinated prosections, and provided their views on their learning experience using 3DP models using a survey and focus group discussion. Anatomical features in 3DP models were rated as accurate by all students. Several positive aspects of 3DP models were highlighted, such as the color coding by tissue type, flexibility and that less care was needed in the handling and examination of the specimen than plastinated specimens which facilitated the appreciation of relations between the anatomical structures. However, students reported that anatomical features in 3DP models are less realistic compared to the plastinated specimens. Multi-colored, multi-material 3DP models are a valuable resource for anatomical education and an excellent adjunct to wet cadaveric or plastinated prosections. Anat Sci Educ 11: 54-64. © 2017 American Association of Anatomists.

Systematic review of 3D printing in spinal surgery: the current state of play

Three-dimensional printing (3DP), also known as "Additive Manufacturing", is a rapidly growing industry, particularly in the area of spinal surgery. Given the complex anatomy of the spine and delicate nature of surrounding structures, 3DP has the potential to aid surgical planning and procedural accuracy. We perform a systematic review of current literature on the applications of 3DP in spinal surgery. Six electronic databases were searched for original published studies reporting cases or outcomes for 3DP surgical models, guides or implants for spinal surgery. The findings of these studies were synthesized and summarized. These searches returned a combined 2,411 articles. Of these, 54 were included in this review. 3DP is currently used for surgical planning, intra-operative surgical guides, customised prostheses as well as "Off-the-Shelf" implants. The technology has the potential for enhanced implant properties, as well as decreased surgical time and better patient outcomes. The majority of the data thus far is from low-quality studies with inherent biases linked with the excitement of a new field. As the body of literature continues to expand, larger scale studies to evaluate advantages and disadvantages, and longer-term follow up will enhance our knowledge of the effect 3DP has in spinal surgery. In addition, issues such as financial impact, time to design and print, materials selection and bio-printing will evolve as this rapidly expanding field matures.