Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons

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.

That which is unseen: 3D printing for pediatric cerebrovascular education

INTRODUCTION

Pediatric cerebrovascular lesions are very rare and include aneurysms, arteriovenous malformations (AVM), and vein of Galen malformations (VOGM).

OBJECTIVE

To describe and disseminate a validated, reproducible set of 3D models for optimization of neurosurgical training with respect to pediatric cerebrovascular diseases METHODS: All pediatric cerebrovascular lesions treated at our institution with adequate imaging studies during the study period 2015-2020 were reviewed by the study team. Three major diagnostic groups were identified: aneurysm, AVM, and VOGM. For each group, a case deemed highly illustrative of the core diagnostic and therapeutic principles was selected by the lead and senior investigators for printing (CSG/JM). Files for model reproduction and free distribution were prepared for inclusion as Supplemental Materials.

RESULTS

Representative cases included a 7-month-old female with a giant left MCA aneurysm; a 3-day-old male with a large, complex, high-flow, choroidal-type VOGM, supplied from bilateral thalamic, choroidal, and pericallosal perforators, with drainage into a large prosencephalic vein; and a 7-year-old male with a left frontal AVM with one feeding arterial vessel from the anterior cerebral artery and one single draining vein into the superior sagittal sinus CONCLUSION: Pediatric cerebrovascular lesions are representative of rare but important neurosurgical diseases that require creative approaches for training optimization. As these lesions are quite rare, 3D-printed models and open source educational materials may provide a meaningful avenue for impactful clinical teaching with respect to a wide swath of uncommon or unusual neurosurgical diseases.

Artificial Intelligence in Gynaecological Malignancies: Perspectives of a Clinical Oncologist

Gynecological malignancies are treated with a multi-disciplinary approach. There are two important factors, the stage and Karnofsky performance status scale (KPS) of patients, which guide the treatment strategy by single or multiple modalities in terms of surgery, radiotherapy, or chemotherapy. Various aspects are included in the workflow of gynecological malignancies, like screening, diagnosis in each individual, treatment modalities, and finally, follow-up to see for outcomes leading to the development of new research protocols. The quality data plays an important role in every step. Artificial Intelligence (AI) will play an important role if it is developed in the above-mentioned steps. AI is already established partially in every aspect of the management of gynecological cancer. It needs to be strengthened and incorporated further in a more robust form. This needs an association between clinicians, software engineers, and stakeholders. This article reviews the role of AI in various steps of the workflow of gynecological malignancies and discusses a few clinical aspects that may be researched to find solutions by AI.

An overview of 3D printed metal implants in orthopedic applications: Present and future perspectives

With the ability to produce components with complex and precise structures, additive manufacturing or 3D printing techniques are now widely applied in both industry and consumer markets. The emergence of tissue engineering has facilitated the application of 3D printing in the field of biomedical implants. 3D printed implants with proper structural design can not only eliminate the stress shielding effect but also improve in vivo biocompatibility and functionality. By combining medical images derived from technologies such as X-ray scanning, CT, MRI, or ultrasonic scanning, 3D printing can be used to create patient-specific implants with almost the same anatomical structures as the injured tissues. Numerous clinical trials have already been conducted with customized implants. However, the limited availability of raw materials for printing and a lack of guidance from related regulations or laws may impede the development of 3D printing in medical implants. This review provides information on the current state of 3D printing techniques in orthopedic implant applications. The current challenges and future perspectives are also included.

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.

The Value of Three-Dimensional Printing Spine Model in Severe Spine Deformity Correction Surgery

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

We aimed to evaluate the value of 3-dimensional printing (3DP) spine model in the surgical treatment of severe spinal deformity since the prosperous development of 3DP technology.

METHODS

Severe scoliosis or hyper-kyphosis patients underwent posterior fixation and fusion surgery using the 3DP spine models were reviewed (3DP group). Spinal deformity surgeries operated by free-hand screw implantation during the same period were selected as the control group after propensity score matching (PSM). The correction rate, pedicle screw accuracy, and complications were analyzed. Class A and B screws were defined as accurate according to Gertzbein and Robbins criteria.

RESULTS

35 patients were enrolled in the 3DP group and 35 matched cases were included in the control group. The perioperative baseline data and deformity correction rate were similar between both groups (P > .05). However, the operation time and blood loss were significantly less in the 3DP group (296.14 ± 66.18 min vs. 329.43 ± 67.16 min, 711.43 ± 552.28 mL vs. 1322.29 ± 828.23 mL, P < .05). More three-column osteotomies (Grade 3-6) were performed in the 3DP group (30/35, 85.7% vs. 21/35, 60.0%. P = .016). The screw placement accuracy was significantly higher in the 3DP group (422/582, 72.51% vs. 397/575, 69.04%. P = .024). The screw misplacement related complication rate was significantly higher in the free-hand group (6/35 vs. 1/35, P = .046).

CONCLUSIONS

The study provided solid evidence that 3DP spine models can enhance surgeons' confidence in performing higher grade osteotomies and improve the safety and efficiency in severe spine deformity correction surgery. 3D printing technology has a good prospect in spinal deformity surgery.

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 application of three-dimensional printed patient-specific drilling templates for expansive open-door laminoplasty: A single-center, prospective randomized controlled study

Background

The choice of trough position in Expansive open-door laminoplasty (EOLP) mostly relied on bony landmarks and surgeons' experience. The present study was to validate the efficacy of the three-dimensional (3D) printed patient-specific drilling templates with the function of locating and depth control for EOLP.

Materials and Methods

A single-center, prospective randomized controlled study was conducted on the patients who underwent unilateral EOLP from August 2019 to December 2020. The 3D printed patient-specific drilling template was fabricated and used in the template group. All the EOLP were performed by a senior surgeon and a junior surgeon. The clinical outcomes and radiographic results were evaluated.

Results

A total of 37 patients who completed the 12-month follow-up were analyzed. The clinical outcomes were significantly improved after surgery in both groups (P < 0.05). The visual analogue scale (VAS) scores were significantly lower in the template group at 12 months postoperatively (P < 0.05). The anteroposterior diameter, Pavlov's ratio and Open angle were all higher in the template group than those in the control group at 3 days and 12 months postoperatively (P < 0.05). The satisfaction of the trough position on both sides and incomplete fracture rate on the hinge side were higher in the template group based on the CT scans taken 3 days after surgery (P < 0.05). To the junior surgeon, the satisfaction and the incomplete fracture rate were significantly higher in the template group compared with those in the control group (P < 0.05).

Conclusion

The application of 3D printed patient-specific drilling templates with the function of locating and depth control for EOLP could improve the outcome of neck pain relief and expand the decompression. It can also improve the satisfaction of the trough position on the open-door side and the hinge side and decrease the complete fracture rate on the hinge side, especially for the junior surgeon.

Advanced 3D Visualization and 3D Printing in Radiology

Since the discovery of X-rays in 1895, medical imaging systems have played a crucial role in medicine by permitting the visualization of internal structures and understanding the function of organ systems. Traditional imaging modalities including Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Ultrasound (US) present fixed two-dimensional (2D) images which are difficult to conceptualize complex anatomy. Advanced volumetric medical imaging allows for three-dimensional (3D) image post-processing and image segmentation to be performed, enabling the creation of 3D volume renderings and enhanced visualization of pertinent anatomic structures in 3D. Furthermore, 3D imaging is used to generate 3D printed models and extended reality (augmented reality and virtual reality) models. A 3D image translates medical imaging information into a visual story rendering complex data and abstract ideas into an easily understood and tangible concept. Clinicians use 3D models to comprehend complex anatomical structures and to plan and guide surgical interventions more precisely. This chapter will review the volumetric radiological techniques that are commonly utilized for advanced 3D visualization. It will also provide examples of 3D printing and extended reality technology applications in radiology and describe the positive impact of advanced radiological image visualization on patient care.

Investigating the effectiveness of three-dimensionally printed anatomical models compared with plastinated human specimens in learning cardiac and neck anatomy: A randomized crossover study

Three-dimensional printing (3DP) technology has been increasingly applied in health profession education. Yet, 3DP anatomical models compared with the plastinated specimens as learning scaffolds are unclear. A randomized-controlled crossover study was used to evaluate the objective outcomes of 3DP models compared with the plastinated specimens through an introductory lecture and team study for learning relatively simple (cardiac) and complex (neck) anatomies. Given the novel multimaterial and multicolored 3DP models are replicas of the plastinated specimens, it is hypothesized that 3DP models have the same educational benefits to plastinated specimens. This study was conducted in two phases in which participants were randomly assigned to 3DP (n = 31) and plastinated cardiac groups (n = 32) in the first phase, whereas same groups (3DP, n = 15; plastinated, n = 18) used switched materials in the second phase for learning neck anatomy. The pretest, educational activities and posttest were conducted for each phase. Miller's framework was used to assess the cognitive outcomes. There was a significant improvement in students' baseline knowledge by 29.7% and 31.3% for Phase 1; 31.7% and 31.3% for Phase 2 plastinated and 3DP models. Posttest scores for cardiac (plastinated, 3DP mean ± SD: 57.0 ± 13.3 and 60.8 ± 13.6, P = 0.27) and neck (70.3 ± 15.6 and 68.3 ± 9.9, P = 0.68) phases showed no significant difference. In addition, no difference observed when cognitive domains compared for both cases. These results reflect that introductory lecture plus either the plastinated or 3DP modes were effective for learning cardiac and neck anatomy.

Students' learning experiences of three-dimensional printed models and plastinated specimens: a qualitative analysis

BACKGROUND

Traditional cadaveric dissection is declining whilst plastinated and three-dimensional printed (3DP) models are increasingly popular as substitutes to the conventional anatomy teaching and learning methods. It is unclear about the pros and cons of these new tools and how they impact students' learning experiences of anatomy including humanistic values such as respect, care and empathy.  METHODS: Ninety-six students' views were sought immediately after a randomized cross-over study. Pragmatic design was used to investigate the learning experiences of using plastinated and 3DP models of cardiac (in Phase 1, n = 63) and neck (in Phase 2, n = 33) anatomy. Inductive thematic analysis was conducted based on 278 free text comments (related to strengths, weaknesses, things to improve), and focus group (n = 8) transcriptions in full verbatim about learning anatomy with these tools.

RESULTS

Four themes were found: perceived authenticity, basic understanding versus complexity, attitudes towards respect and care, and multimodality and guidance.

CONCLUSIONS

Overall, students perceived plastinated specimens as more real and authentic, thus perceived more respect and care than 3DP models; whereas 3DP models were easy to use and prefered for learning basic anatomy.

Thoracic Pedicle Screw Placement Utilizing Hands-On Training Session on Three-Dimensional Models

The utilization of three-dimensional (3D) models has been an important element of medical education. We demonstrate a three-dimensionally-printed (3DP) thoracic spine model for use in the teaching of freehand pedicle screw placement. Neurosurgical residents with varying years of experience practiced screw placement on these models. Residents were timed, and models were evaluated for medial and lateral breaches. Overall, this technical report describes the utility of 3D spine models in the training of thoracic pedicle screw placement. The tactile feedback from the 3D models was designed to represent both cortical and cancellous bones.

One-stage En bloc resection of thoracic spinal chondrosarcoma with huge paravertebral mass through the single posterior approach by dissociate longissimus thoracis

Study design

Retrospective case series.

Objective

To describe the technique details and therapeutic outcomes of 3-D printing model-guided en bloc resection of chondrosarcoma (CHS) with huge paravertebral mass via the combined posterior median and Wiltse approach.

Summary of background data

Total en bloc spondylectomy (TES) technique is conventionally based on the single posterior approach or combined anterior-posterior approach. However, the single posterior approach imposes a high technical demand on the surgeon due to the narrow field of vision, limited surgical space and the delicate spinal cord, while the combined anterior-posterior approach not only requires greater patient tolerance but is time consuming and runs the risk of more blood loss and injury to the visceral pleura and large blood vessels during surgery. In addition, it is difficult to completely remove the thoracic CHS with paravertebral mass through simple en bloc resection when it involves the aorta, vena cava, costa and lung.

Material and methods

Between August 2010 and January 2016, we performed a retrospective study to evaluate the clinical characteristics and outcomes of en bloc resection of thoracic spinal CHS with paravertebral mass through the combined posterior median and Wiltse approach. Postoperative recurrence-free survival (RFS) and overall survival (OS) were estimated by the Kaplan-Meier method. P values less than 0.05 were considered statistically significant.

Results

Altogether 15 patients received en bloc resection of thoracic spinal CHS with paravertebral mass through the combined posterior median and Wiltse approach. The mean age of these patients was 37.0 ± 12.8 years (median 36; range 15–64). This combination approach provided more extensive exposure and wider marginal resection of the tumor within a mean operation duration of 288 ± 96 min (median 280; range 140–480) and mean intraoperative blood loss of 1,966 ± 830 ml (median 2,000; range 300–3,000). Of the 15 patients, 5 experienced local recurrence of the disease; the mean time from surgery to recurrence was 22 ± 9.85 months (median 17, range 13–35). RFS in patients with recurrent CHS was significantly lower than that in patients with primary CHS on admission (p = 0.05).

Conclusions

The combined posterior median and Wiltse approach is a technically viable option for en bloc resection of thoracic spinal CHS with huge paravertebral mass, and can give a favorable local control of CHS.

Level of evidence

Level V.

Customized Multilevel 3D Printing Implant for Reconstructing Spine Tumor: A Retrospective Case Series Study in a Single Center

Objective

To investigate the clinical efficacy and safety of 3D printed artificial vertebral body for patients who underwent multilevel total en bloc spondylectomy (TES) and analyze whether it could reduce the incidence of implant subsidence.

Methods

This is a retrospective study. From January 2017 to May 2018, eight consecutive cases with spine tumor undergoing multilevel TES were analyzed. All patients underwent X‐ray and CT examinations to evaluate the stability of internal fixation during the postoperative follow‐up. Demographic, surgical details, clinical data, and perioperative complications was collected. Visual analog scale, Frankel score, and spinal instability neoplastic score (SINS) classification were also recorded.

Results

There were six cases of primary spinal tumor and two cases of metastatic spinal tumor. All patients achieved remarkable pain relief and improvement in neurological function. Five patients underwent operation through the posterior approach, one patient underwent operation through the anterior approach and the remaining two patients through a combined anterior and posterior approach. At the last follow‐up period, X‐rays showed that the 3D printed artificial vertebral body of all cases matched well, and the fixation was reliable. Hardware failure such as loosening, sinking, breaking, and displacement wasn't observed during the follow‐up period.

Conclusion

3D printed customized artificial vertebral body can provide satisfying good clinical and radiological outcomes for patients who have undergone multilevel TES.

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.

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.

The "springform" technique in cranioplasty: custom made 3D-printed templates for intraoperative modelling of polymethylmethacrylate cranial implants

Background

Manual moulding of cranioplasty implants after craniectomy is feasible, but does not always yield satisfying cosmetic results. In contrast, 3D printing can provide precise templates for intraoperative moulding of polymethylmethacrylate (PMMA) implants in cranioplasty. Here, we present a novel and easily implementable 3D printing workflow to produce patient-specific, sterilisable templates for PMMA implant moulding in cranioplastic neurosurgery.

Methods

3D printable templates of patients with large skull defects before and after craniectomy were designed virtually from cranial CT scans. Both templates — a mould to reconstruct the outer skull shape and a ring representing the craniectomy defect margins — were printed on a desktop 3D printer with biocompatible photopolymer resins and sterilised after curing. Implant moulding and implantation were then performed intraoperatively using the templates. Clinical and radiological data were retrospectively analysed.

Results

Sixteen PMMA implants were performed on 14 consecutive patients within a time span of 10 months. The median defect size was 83.4 cm² (range 57.8–120.1 cm²). Median age was 51 (range 21–80) years, and median operating time was 82.5 (range 52–152) min. No intraoperative complications occurred; PMMA moulding was uneventful and all implants fitted well into craniectomy defects. Excellent skull reconstruction could be confirmed in all postoperative computed tomography (CT) scans. In three (21.4%) patients with distinct risk factors for postoperative haematoma, revision surgery for epidural haematoma had to be performed. No surgery-related mortality or new and permanent neurologic deficits were recorded.

Conclusion

Our novel 3D printing-aided moulding workflow for elective cranioplasty with patient-specific PMMA implants proved to be an easily implementable alternative to solely manual implant moulding. The “springform” principle, focusing on reconstruction of the precraniectomy skull shape and perfect closure of the craniectomy defect, was feasible and showed excellent cosmetic results. The proposed method combines the precision and cosmetic advantages of computer-aided design (CAD) implants with the cost-effectiveness of manually moulded PMMA implants.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00701-021-05077-7.

Additive Manufacturing for Neurosurgery: Digital Light Processing of Individualized Patient-Specific Cerebral Aneurysms

This study aims at demonstrating the feasibility of reproducing individualized patient-specific three-dimensional models of cerebral aneurysms by using the direct light processing (DLP) 3D printing technique in a low-time and inexpensive way. Such models were used to help neurosurgeons understand the anatomy of the aneurysms together with the surrounding vessels and their relationships, providing, therefore, a tangible supporting tool with which to train and plan surgical operations. The starting 3D models were obtained by processing the computed tomography angiographies and the digital subtraction angiographies of three patients. Then, a 3D DLP printer was used to print the models, and, if acceptable, on the basis of the neurosurgeon’s opinion, they were used for the planning of the neurosurgery operation and patient information. All the models were printed within three hours, providing a comprehensive representation of the cerebral aneurysms and the surrounding structures and improving the understanding of their anatomy and simplifying the planning of the surgical operation.

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.

Artificial intelligence: A rapid case for advancement in the personalization of Gynaecology/Obstetric and Mental Health care

To evaluate and holistically treat the mental health sequelae and potential psychiatric comorbidities associated with obstetric and gynaecological conditions, it is important to optimize patient care, ensure efficient use of limited resources and improve health-economic models. Artificial intelligence applications could assist in achieving the above. The World Health Organization and global healthcare systems have already recognized the use of artificial intelligence technologies to address 'system gaps' and automate some of the more cumbersome tasks to optimize clinical services and reduce health inequalities. Currently, both mental health and obstetric and gynaecological services independently use artificial intelligence applications. Thus, suitable solutions are shared between mental health and obstetric and gynaecological clinical practices, independent of one another. Although, to address complexities with some patients who may have often interchanging sequelae with mental health and obstetric and gynaecological illnesses, 'holistically' developed artificial intelligence applications could be useful. Therefore, we present a rapid review to understand the currently available artificial intelligence applications and research into multi-morbid conditions, including clinical trial-based validations. Most artificial intelligence applications are intrinsically data-driven tools, and their validation in healthcare can be challenging as they require large-scale clinical trials. Furthermore, most artificial intelligence applications use rate-limiting mock data sets, which restrict their applicability to a clinical population. Some researchers may fail to recognize the randomness in the data generating processes in clinical care from a statistical perspective with a potentially minimal representation of a population, limiting their applicability within a real-world setting. However, novel, innovative trial designs could pave the way to generate better data sets that are generalizable to the entire global population. A collaboration between artificial intelligence and statistical models could be developed and deployed with algorithmic and domain interpretability to achieve this. In addition, acquiring big data sets is vital to ensure these artificial intelligence applications provide the highest accuracy within a real-world setting, especially when used as part of a clinical diagnosis or treatment.

Crisis Management Simulation: Review of Current Experience

Crisis management simulation is important in training the next generation of surgeons. In this review, we highlight our experiences with the cavernous carotid injury model. We then delve into other crisis simulation models available for the neurosurgical specialty. The discussion focuses upon how these trainings can continue to evolve. Much work is yet to be done in this exciting arena and we present several avenues for future discovery. Simulation continues to be an important training tool for the surgical learner.

Clinical application of patient-specific 3D printing brain tumor model production system for neurosurgery

The usefulness of 3-dimensional (3D)-printed disease models has been recognized in various medical fields. This study aims to introduce a production platform for patient-specific 3D-printed brain tumor model in clinical practice and evaluate its effectiveness. A full-cycle platform was created for the clinical application of a 3D-printed brain tumor model (3D-printed model) production system. Essential elements included automated segmentation software, cloud-based interactive communication tools, customized brain models with exquisite expression of brain anatomy in transparent material, adjunctive devices for surgical simulation, and swift process cycles to meet practical needs. A simulated clinical usefulness validation was conducted in which neurosurgeons assessed the usefulness of the 3D-printed models in 10 cases. We successfully produced clinically applicable patient-specific models within 4 days using the established platform. The simulated clinical usefulness validation results revealed the significant superiority of the 3D-printed models in surgical planning regarding surgical posture (p = 0.0147) and craniotomy design (p = 0.0072) compared to conventional magnetic resonance images. The benefit was more noticeable for neurosurgeons with less experience. We established a 3D-printed brain tumor model production system that is ready to use in daily clinical practice for neurosurgery.

3D Printing of Rapid, Low-Cost and Patient-Specific Models of Brain Vasculature for Use in Preoperative Planning in Clipping of Intracranial Aneurysms

We developed a practical and cost-effective method of production of a 3D-printed model of the arterial Circle of Willis of patients treated because of an intracranial aneurysm. We present and explain the steps necessary to produce a 3D model from medical image data, and express the significant value such models have in patient-specific pre-operative planning as well as education. A Digital Imaging and Communications in Medicine (DICOM) viewer is used to create 3D visualization from a patient’s Computed Tomography Angiography (CTA) images. After generating the reconstruction, we manually remove the anatomical components that we wish to exclude from the print by utilizing tools provided with the imaging software. We then export this 3D reconstructions file into a Standard Triangulation Language (STL) file which is then run through a “Slicer” software to generate a G-code file for the printer. After the print is complete, the supports created during the printing process are removed manually. The 3D-printed models we created were of good accuracy and scale. The median production time used for the models described in this manuscript was 4.4 h (range: 3.9–4.5 h). Models were evaluated by neurosurgical teams at local hospital for quality and practicality for use in urgent and non-urgent care. We hope we have provided readers adequate insight into the equipment and software they would require to quickly produce their own accurate and cost-effective 3D models from CT angiography images. It has become quite clear to us that the cost-benefit ratio in the production of such a simplified model is worthwhile.

Patient-centered oncosurgical planning with cancer models in subspecialty education

BACKGROUND

A fundamental aspect of oncosurgical planning in organ resections is the identification of feeder vessel details to preserve healthy organ tissue while fully resecting the tumors. The purpose of this study was to determine whether three-dimensional (3D) cancer case models of computed tomography (CT) images will assist resident-level trainees in making appropriate operative plans for organ resection surgery.

METHODS

This study was based on the perception of surgery residents who were presented with 5 different oncosurgical scenarios. A five-station carousel including cases of liver mass, stomach mass, annular pancreas, pelvic mass and mediastinal mass was formed for the study. The residents were required to compare their perception level of the cases with their CT images, and 3D models in terms of identifying the invasion of the mass, making differential diagnosis and preoperative planning stage.

RESULTS

All residents have given higher scores for models. 3D models provided better understanding of oncopathological anatomy and improved surgical planning. In all scenarios, 70-80% of the residents preferred the model for preoperative planning. For surgical choice, compared to the CT, the model provided a statistically significant difference in terms of visual assessment, such as tumor location, distal or proximal organotomy (p:0.009). In the evaluation of presacral mass, the perception of model was significantly better than the CT in terms of bone-foramen relationship of chondrosarcoma, its origin, geometric shape, localization, invasion, and surgical preference (p:0.004). The model statistically significantly provided help to evaluate and prepare the case together with the colleagues performing surgery (p:0.007). Commenting on the open-ended question, they stated that the tumor-vessel relationship was clearly demonstrated in the 3D model, which has been very useful.

CONCLUSIONS

With the help of 3D printing technology in this study, it is possible to implement and evaluate a well-structured real patient scenario setup in cancer surgery training. It can be used to improve the understanding of pathoanatomical changes of multidisciplinary oncologic cases. Namely, it is used in guiding the surgical strategy and determining whether patient-specific 3D models change pre-operative planning decisions made by surgeons in complex cancer mass surgical procedures.

CT-Based 3D Printing of the Glenoid Prior to Shoulder Arthroplasty: Bony Morphology and Model Evaluation

To demonstrate the 3D printed appearance of glenoid morphologies relevant to shoulder replacement surgery and to evaluate the benefits of printed models of the glenoid with regard to surgical planning. A retrospective review of patients referred for shoulder CT was performed, leading to a cohort of nine patients without arthroplasty hardware and exhibiting glenoid changes relevant to shoulder arthroplasty planning. Thin slice CT images were used to create both humerus-subtracted volume renderings of the glenoid, as well as 3D surface models of the glenoid, and 11 printed models were created. Volume renderings, surface models, and printed models were reviewed by a musculoskeletal radiologist for accuracy. Four fellowship-trained orthopaedic surgeons specializing in shoulder surgery reviewed each case individually as follows: First, the source CT images were reviewed, and a score for the clarity of the bony morphologies relevant to shoulder arthroplasty surgery was given. The volume rendering was reviewed, and the clarity was again scored. Finally, the printed model was reviewed, and the clarity again scored. Each printed model was also scored for morphologic complexity, expected usefulness of the printed model, and physical properties of the model. Mann-Whitney-Wilcoxon signed rank tests of the clarity scores were calculated, and the Spearman's ρ correlation coefficient between complexity and usefulness scores was computed. Printed models demonstrated a range of glenoid bony changes including osteophytes, glenoid bone loss, retroversion, and biconcavity. Surgeons rated the glenoid morphology as more clear after review of humerus-subtracted volume rendering, compared with review of the source CT images (p = 0.00903). Clarity was also better with 3D printed models compared to CT (p = 0.00903) and better with 3D printed models compared to humerus-subtracted volume rendering (p = 0. 00879). The expected usefulness of printed models demonstrated a positive correlation with morphologic complexity, with Spearman's ρ 0.73 (p = 0.0108). 3D printing of the glenoid based on pre-operative CT provides a physical representation of patient anatomy. Printed models enabled shoulder surgeons to appreciate glenoid bony morphology more clearly compared to review of CT images or humerus-subtracted volume renderings. These models were more useful as glenoid complexity increased.

Mimicking the Mechanical Properties of Aortic Tissue with Pattern-Embedded 3D Printing for a Realistic Phantom

3D printing technology has been extensively applied in the medical field, but the ability to replicate tissues that experience significant loads and undergo substantial deformation, such as the aorta, remains elusive. Therefore, this study proposed a method to imitate the mechanical characteristics of the aortic wall by 3D printing embedded patterns and combining two materials with different physical properties. First, we determined the mechanical properties of the selected base materials (Agilus and Dragonskin 30) and pattern materials (VeroCyan and TPU 95A) and performed tensile testing. Three patterns were designed and embedded in printed Agilus-VeroCyan and Dragonskin 30-TPU 95A specimens. Tensile tests were then performed on the printed specimens, and the stress-strain curves were evaluated. The samples with one of the two tested orthotropic patterns exceeded the tensile strength and strain properties of a human aorta. Specifically, a tensile strength of 2.15 ± 0.15 MPa and strain at breaking of 3.18 ± 0.05 mm/mm were measured in the study; the human aorta is considered to have tensile strength and strain at breaking of 2.0-3.0 MPa and 2.0-2.3 mm/mm, respectively. These findings indicate the potential for developing more representative aortic phantoms based on the approach in this study.

Clinical evaluation of rapid 3D print-formed implants for surgical reconstruction of large cranial defects

BACKGROUND

To clinically evaluate 3D print-formed implant process, using cranioplasty as a proof of concept, to examine its effectiveness and utility as a method of intraoperative implant fabrication.

METHODS

Twelve patients had a 3D print-formed template created for patient-specific implant manufacture. Of these patients, 10 received intraoperatively formed polymethylmethacrylate cranioplasty implants between 2013 and 2019. The 3D print-formed implant templates produced to manufacture these patient-specific implants were generated using patient computed tomography scans and 3D printed using fused deposition modelling technology. Cosmetic and functional results were determined by participating surgeons, in conjunction with a patient questionnaire.

RESULTS

The functional results and stability of the implants were deemed to be favourable by participating surgeons. Three of the 10 patients completed a post-cranioplasty survey, all of whom judged their cosmetic results as good or excellent. At time of writing, the rate of surgical revision was zero and without clinically adverse outcomes.

CONCLUSIONS

3D print-formed implants are an effective method of patient-specific implant formation.

Artificial intelligence and augmented reality in gynecology

PURPOSE OF REVIEW

Artificial intelligence and augmented reality have been progressively incorporated into our daily life. Technological advancements have resulted in the permeation of similar systems into medical practice.

RECENT FINDINGS

Both artificial intelligence and augmented reality are being increasingly incorporated into the practice of modern medicine to optimize decision making and ultimately improve patient outcomes.

SUMMARY

Artificial intelligence has already been incorporated into many areas of medical practice but has been slow to catch on in clinical gynecology. However, several applications of augmented reality are currently in use in gynecologic surgery. We present an overview of artificial intelligence and augmented reality and current use in medical practice with a focus on gynecology.

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.

Artificial Intelligence: A New Paradigm in Obstetrics and Gynecology Research and Clinical Practice

Artificial intelligence (AI) is growing exponentially in various fields, including medicine. This paper reviews the pertinent aspects of AI in obstetrics and gynecology (OB/GYN) and how these can be applied to improve patient outcomes and reduce the healthcare costs and workload for clinicians.

Herein, we will address current AI uses in OB/GYN, and the use of AI as a tool to interpret fetal heart rate (FHR) and cardiotocography (CTG) to aid in the detection of preterm labor, pregnancy complications, and review discrepancies in its interpretation between clinicians to reduce maternal and infant morbidity and mortality. AI systems can be used as tools to create algorithms identifying asymptomatic women with short cervical length who are at risk of preterm birth. Additionally, the benefits of using the vast data capacity of AI storage can assist in determining the risk factors for preterm labor using multiomics and extensive genomic data. In the field of gynecological surgery, the use of augmented reality helps surgeons detect vital structures, thus decreasing complications, reducing operative time, and helping surgeons in training to practice in a realistic setting. Using three-dimensional (3D) printers can provide materials that mimic real tissues and also helps trainees to practice on a realistic model. Furthermore, 3D imaging allows better depth perception than its two-dimensional (2D) counterpart, allowing the surgeon to create preoperative plans according to tissue depth and dimensions. Although AI has some limitations, this new technology can improve the prognosis and management of patients, reduce healthcare costs, and help OB/GYN practitioners to reduce their workload and increase their efficiency and accuracy by incorporating AI systems into their daily practice.

AI has the potential to guide practitioners in decision-making, reaching a diagnosis, and improving case management. It can reduce healthcare costs by decreasing medical errors and providing more dependable predictions. AI systems can accurately provide information on the large array of patients in clinical settings, although more robust data is required.

3D printed CT-based abdominal structure mannequin for enabling research

An anthropomorphic phantom is a radiologically accurate, tissue realistic model of the human body that can be used for research into innovative imaging and interventional techniques, education simulation and calibration of medical imaging equipment. Currently available CT phantoms are appropriate tools for calibration of medical imaging equipment but have major disadvantages for research and educational simulation. They are expensive, lacking the realistic appearance and characteristics of anatomical organs when visualized during X-ray based image scanning. In addition, CT phantoms are not modular hence users are not able to remove specific organs from inside the phantom for research or training purposes. 3D printing technology has evolved and can be used to print anatomically accurate abdominal organs for a modular anthropomorphic mannequin to address limitations of existing phantoms. In this study, CT images from a clinical patient were used to 3D print the following organ shells: liver, kidneys, spleen, and large and small intestines. In addition, fatty tissue was made using modelling beeswax and musculature was modeled using liquid urethane rubber to match the radiological density of real tissue in CT Hounsfield Units at 120kVp. Similarly, all 3D printed organ shells were filled with an agar-based solution to mimic the radiological density of real tissue in CT Hounsfield Units at 120kVp. The mannequin has scope for applications in various aspects of medical imaging and education, allowing us to address key areas of clinical importance without the need for scanning patients.

Current Practice in Preoperative Virtual and Physical Simulation in Neurosurgery

In brain tumor surgery, an appropriate and careful surgical planning process is crucial for surgeons and can determine the success or failure of the surgery. A deep comprehension of spatial relationships between tumor borders and surrounding healthy tissues enables accurate surgical planning that leads to the identification of the optimal and patient-specific surgical strategy. A physical replica of the region of interest is a valuable aid for preoperative planning and simulation, allowing the physician to directly handle the patient’s anatomy and easily study the volumes involved in the surgery. In the literature, different anatomical models, produced with 3D technologies, are reported and several methodologies were proposed. Many of them share the idea that the employment of 3D printing technologies to produce anatomical models can be introduced into standard clinical practice since 3D printing is now considered to be a mature technology. Therefore, the main aim of the paper is to take into account the literature best practices and to describe the current workflow and methodology used to standardize the pre-operative virtual and physical simulation in neurosurgery. The main aim is also to introduce these practices and standards to neurosurgeons and clinical engineers interested in learning and implementing cost-effective in-house preoperative surgical planning processes. To assess the validity of the proposed scheme, four clinical cases of preoperative planning of brain cancer surgery are reported and discussed. Our preliminary results showed that the proposed methodology can be applied effectively in the neurosurgical clinical practice both in terms of affordability and in terms of simulation realism and efficacy.

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.

3D printed anatomical (bio)models in spine surgery: clinical benefits and value to health care providers

The applications of three-dimensional printing (3DP) for clinical purposes have grown rapidly over the past decade. Recent advances include the fabrication of patient specific instrumentation, such as drill and cutting guides, patient specific/custom long term implants and 3DP of cellular scaffolds. Spine surgery in particular has seen enthusiastic early adoption of these applications. 3DP as a manufacturing method can be used to mass produce objects of the same design, but can also be used as a cost-effective method for manufacturing unique one-off objects, such as patient specific models and devices. Perhaps the first, and currently most widespread, application of 3DP for producing patient specific devices is the production of patient specific anatomical models, often termed biomodels. The present manuscript focuses on the current state of the art in anatomical (bio)models as used in spinal clinical practice. The biomodels shown and discussed include: translucent and coloured models to aid in identification of extent and margins of pathologies such as bone tumours; dynamic models for implant trial implantation and pre-operative sizing; models that can be disassembled to simulate surgical resection of diseased tissue and subsequent reconstruction. Biomodels can reduce risk to the patient by decreasing surgery time, reducing the probability of the surgical team encountering unexpected anatomy or relative positioning of structures and/or devices, and better pre-operative planning of the surgical workflow including ordered preparation of the necessary instrumentation for multi-step and revision procedures. Conversely, risks can be increased if biomodels are not accurate representations of the anatomy, which can occur if MRI/CT scan data is simply converted into 3DP format without interpretation of what the scan represents in terms of patient anatomy. A review and analysis of the cost-benefits of biomodels shows that biomodels can potentially reduce cost to health care providers if operating room time is reduced by 14 minutes or more.

Applications of three-dimensional printing in orbital diseases and disorders

PURPOSE OF REVIEW

To comprehensively review the applications of advanced three-dimensional printing technology in the management of orbital abnormalities.

RECENT FINDINGS

Three-dimensional printing has added value in the preoperative planning and manufacturing of patient-specific implants and surgical guides in the reconstruction of orbital trauma, congenital defects and tumor resection. In view of the costs and time, it is reserved as strategy for large and complex craniofacial cases, in particular those including the bony contour. There is anecdotal evidence of a benefit of three-dimensional printing in the manufacturing of prostheses for the exenterated and anophthalmic socket, and in the fabrication of patient-specific boluses, applicators and shielding devices for orbital radiation therapy. In addition, three-dimensional printed healthy and diseased orbits as phantom tangible models may augment the teaching and learning process of orbital surgery.

SUMMARY

Three-dimensional printing allows precision treatment tailored to the unique orbital anatomy of the patient. Advancement in technology and further research are required to support its wider use in orbital clinical practice.

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

Background

Neurosurgical residents are finding it more difficult to obtain experience as the primary operator in aneurysm surgery. The present study aimed to replicate patient-derived cranial anatomy, pathology and human tissue properties relevant to cerebral aneurysm intervention through 3D printing and 3D print-driven casting techniques. The final simulator was designed to provide accurate simulation of a human head with a middle cerebral artery (MCA) aneurysm.

Methods

This study utilized living human and cadaver-derived medical imaging data including CT angiography and MRI scans. Computer-aided design (CAD) models and pre-existing computational 3D models were also incorporated in the development of the simulator. The design was based on including anatomical components vital to the surgery of MCA aneurysms while focusing on reproducibility, adaptability and functionality of the simulator. Various methods of 3D printing were utilized for the direct development of anatomical replicas and moulds for casting components that optimized the bio-mimicry and mechanical properties of human tissues. Synthetic materials including various types of silicone and ballistics gelatin were cast in these moulds. A novel technique utilizing water-soluble wax and silicone was used to establish hollow patient-derived cerebrovascular models.

Results

A patient-derived 3D aneurysm model was constructed for a MCA aneurysm. Multiple cerebral aneurysm models, patient-derived and CAD, were replicated as hollow high-fidelity models. The final assembled simulator integrated six anatomical components relevant to the treatment of cerebral aneurysms of the Circle of Willis in the left cerebral hemisphere. These included models of the cerebral vasculature, cranial nerves, brain, meninges, skull and skin. The cerebral circulation was modeled through the patient-derived vasculature within the brain model. Linear and volumetric measurements of specific physical modular components were repeated, averaged and compared to the original 3D meshes generated from the medical imaging data. Calculation of the concordance correlation coefficient (ρ_c: 90.2%–99.0%) and percentage difference (≤0.4%) confirmed the accuracy of the models.

Conclusions

A multi-disciplinary approach involving 3D printing and casting techniques was used to successfully construct a multi-component cerebral aneurysm surgery simulator. Further study is planned to demonstrate the educational value of the proposed simulator for neurosurgery residents.

4D printing and stimuli-responsive materials in biomedical aspects

Three-dimensional (3D) printing has revolutionized the world manufacturing production. In biomedical applications, however, 3D printed constructs fell short of expectations mainly due to their inability to adequately mimic the dynamic human tissues. To date, most of the 3D printed biomedical structures are largely static and inanimate as they lack the time-dependant dimension. To adequately address the dynamic healing and regeneration process of human tissues, 4D printing emerges as an important development where "time" is incorporated into the conventional concept of 3D printing as the fourth dimension. As such, additive manufacturing (AM) evolves from 3D to 4D printing and in the process putting stimulus-responsive materials in the limelight. In this review, the state-of-the-art efforts in integrating the time-dependent behaviour of stimulus-responsive materials in 4D printing will be discussed. In addition, current literatures on the interactions between various types of stimuli (categorized under physical, chemical and biological signals) with the associated stimulus-responsive materials will be the major focus in this review. Lastly, potential usage of 4D printing in biomedical applications will also be discussed, followed by technical considerations as well as outlook for future discoveries. STATEMENT OF SIGNIFICANCE: In this Review, we have demonstrated the significance of 4D printing in biomedical applications, in which "time" has been incorporated into the conventional concept of 3D printing as the 4th dimension. As such, 4D printing differentiates and evolves from 3D printing using stimulus-responsive materials which can actively respond to external stimuli and more sophisticated "hardware"-printer which can achieve multi-printing via mathematical-predicted designs that are programmed to consider the transformation of 3D constructs over time. The emphasize will be on the interactions between various types of stimuli (categorized under physical, chemical and biological signals) with the associated stimulus-responsive materials, followed by technical considerations as well as outlook for future discoveries.

Multi-material three dimensional printed models for simulation of bronchoscopy

Background

Bronchoscopy involves exploration of a three-dimensional (3D) bronchial tree environment using just two-dimensional (2D) images, visual cues and haptic feedback. Sound knowledge and understanding of tracheobronchial anatomy as well as ample training experience is mandatory for technical mastery. Although simulated modalities facilitate safe training for inexperienced operators, current commercial training models are expensive or deficient in anatomical accuracy, clinical fidelity and patient representation. The advent of Three-dimensional (3D) printing technology may resolve the current limitations with commercial simulators. The purpose of this report is to develop and test the novel multi-material three-dimensional (3D) printed airway models for bronchoscopy simulation.

Methods

Using material jetting 3D printing and polymer amalgamation, human airway models were created from anonymized human thoracic computed tomography images from three patients: one normal, a second with a tumour obstructing the right main bronchus and third with a goitre causing external tracheal compression. We validated their efficacy as airway trainers by expert bronchoscopists. Recruited study participants performed bronchoscopy on the 3D printed airway models and then completed a standardized evaluation questionnaire.

Results

The models are flexible, life size, anatomically accurate and patient specific. Five expert respiratory physicians participated in validation of the airway models. All the participants agreed that the models were suitable for training bronchoscopic anatomy and access. Participants suggested further refinement of colour and texture of the internal surface of the airways. Most respondents felt that the models are suitable simulators for tracheal pathology, have a learning value and recommend it to others for use in training.

Conclusion

Using material jetting 3D printing to create patient-specific anatomical models is a promising modality of simulation training. Our results support further evaluation of the printed airway model as a bronchoscopic trainer, and suggest that pathological airways may be simulated using this technique.

Can Preoperative 3D Printing Change Surgeon's Operative Plan for Distal Tibia Fracture?

This study aimed to determine if 3D printing can affect surgeon's selection of plate for distal tibia fracture surgery and to find out whether orthopedic surgeons consider this technology necessary and would use it in their practice. A total of 102 orthopedic surgeons were asked to choose anatomically contoured locking plates among 5 most commonly used types for one simple and one complex distal tibia fracture based on X-ray and CT images. Next, they were provided real-size 3D printed models of the same fractures, allowed to apply each of the 5 plates to these models, and asked if they would change their choice of plate. A 10-point numeric rating scale was provided to measure the extent of the help that 3D printing provided on preoperative planning. Finally, we asked the surgeons if they would use 3D printing in their practice. Seventy-four percent of inexperienced surgeons changed their selection of plate after using 3D printed models for the complex fracture. In contrast, only 9% of experienced surgeons changed their selection of plate for the simple fracture. Surgeons rated the extent of usefulness of the 3D models in preoperative planning as a mean of 4.84 ± 2.54 points for the simple fracture and 6.63 ± 2.54 points for the complex fracture. The difference was significant (p < 0.001). Eighty-six percent of inexperienced surgeons wanted to use 3D models for complex fractures. However, only 18% of experienced surgeons wanted to use 3D printed models for simple fractures. The use of a real-size 3D-printed model often changed surgeon's preoperative selection of locking plates, especially when inexperienced surgeons evaluated a complex fracture. However, experienced surgeons did not find 3D models very useful when assessing simple fractures. Future applications of 3D models should focus on training beginners in fracture surgery, especially when complex fractures are concerned.

Three-Dimensional Printing of Archived Human Fetal Material for Teaching Purposes

The practical aspect of human developmental biology education is often limited to the observation and use of animal models to illustrate developmental anatomy. This is due in part to the difficulty of accessing human embryonic and fetal specimens, and the sensitivity inherent to presenting these specimens as teaching materials. This report presents a new approach using three-dimensional (3D) printed replicas of actual human materials in practical classes, thus allowing for the inclusion of accurate examples of human developmental anatomy in the educational context. A series of 3D prints have been produced from digital data collected by computed tomography (CT) imaging of an archived series of preserved human embryonic and fetal specimens. The final versions of 3D prints have been generated in a range of single or multiple materials to illustrate the progression of human development, including the development of internal anatomy. Furthermore, multiple copies of each replica have been printed for large group teaching. In addition to the educational benefit of examining accurate 3D replicas, this approach lessens the potential for adverse student reaction (due to cultural background or personal experience) to observing actual human embryonic/fetal anatomical specimens, and reduces the potential of damage or loss of original specimens. This approach, in combination with ongoing improvements in the management and analysis of digital data and advances in scanning technology, has enormous potential to allow embryology students access to both local and international collections of human gestational material. Anat Sci Educ 00: 000-000. © 2018 American Association of Anatomists.

Construct validity of a low-cost medium-fidelity endoscopic sinus surgery simulation model

OBJECTIVE

Assess construct validity of a low-cost medium-fidelity silicone injection molded model task trainer for endoscopic sinus surgery (ESS) training.

METHODS

Fellowship-trained rhinologists, otolaryngology attendings, and otolaryngology residents at various levels of training performed sinus endoscopy and seven procedures on the model. Construct validity was evaluated by comparing novice to various levels of experienced performance using a validated checklist.

RESULTS

Thirty-two subjects participated in this study. Otolaryngology attendings and postgraduate year (PGY) 3 to 5 otolaryngology residents significantly outperformed PGY 1 to 2 otolaryngology residents on most tasks in the task-specific checklist.

CONCLUSIONS

This study demonstrated the construct validity of the low-cost medium-fidelity ESS model.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:1505-1509, 2019.

Three-dimensionally printed vertebrae with different bone densities for surgical training

PURPOSE

To evaluate whether 3D-printed vertebrae offer realistic haptic simulation of posterior pedicle screw placement and decompression surgery with normal to osteoporotic-like properties.

METHODS

A parameterizable vertebra model was developed, adjustable in cortical and cancellous bone thicknesses. Based on this model, five different L3 vertebra types (α, β, γ1, γ2, and γ3) were designed and fourfold 3D-printed. Four spine surgeons assessed each vertebra type and a purchasable L3 Sawbones vertebra. Haptic behavior of six common steps in posterior spine surgery was rated from 1 to 10: 1-2: too soft, 3-4: osteoporotic, 5-6: normal, 7-8: hard, and 9-10: too hard. Torques were measured during pedicle screw insertion.

RESULTS

In total, 24 vertebrae (six vertebra types times four examiners) were evaluated. Mean surgical assessment scores were: α 3.2 ± 0.9 (osteoporotic), β 1.9 ± 0.7 (too soft), γ1 4.7 ± 0.9 (osteoporotic-normal), γ2 6.3 ± 1.1 (normal), and γ3 7.5 ± 1.1 (hard). All surgeons considered the 3D-printed vertebrae α, γ1, and γ2 as more realistic than Sawbones vertebrae, which were rated with a mean score of 4.1 ± 1.7 (osteoporotic-normal). Mean pedicle screw insertion torques (Ncm) were: α 32 ± 4, β 12 ± 3, γ1 74 ± 4, γ2 129 ± 13, γ3 196 ± 34 and Sawbones 90 ± 11.

CONCLUSIONS

In this pilot study, 3D-printed vertebrae displayed haptically and biomechanically realistic simulation of posterior spinal procedures and outperformed Sawbones. This approach enables surgical training on bone density-specific vertebrae and provides an outlook toward future preoperative simulation on patient-specific spine replicas. These slides can be retrieved under Electronic Supplementary Material.

What we have achieved in the design of 3D printed metal implants for application in orthopedics? Personal experience and review

Purpose

This paper aims to review the latest applications in terms of three-dimensional printed (3DP) metal implants in orthopedics, and, importantly, the design of 3DP metal implants through a series of cases operated at The Second Hospital of Jilin University were presented.

Design/methodology/approach

This paper is available to practitioners who are use 3DP implants in orthopedics. This review began with the deficiency of traditional prostheses and basic concepts of 3DP implants. Then, representative 3DP clinical cases were summarized and compared, and the experiences using customized prostheses and directions for future potential development are also shown.

Findings

The results obtained from the follow-up of clinical applications of 3DP implants show that the 3D designed and printed metal implants could exhibit good bone defect matching, quick and safe joint functional rehabilitation as well as saving time in surgery, which achieved high patient satisfaction collectively.

Originality/value

Single center experiences of 3DP metal implants design were shared and the detailed technical points between various regions were compared and analyzed. In conclusion, the 3DP technology is infusive and will present huge potential to reform future orthopedic practice.

Three-Dimensional Printed Model Used to Teach Skull Base Anatomy Through a Transsphenoidal Approach for Neurosurgery Residents

BACKGROUND

Skull base anatomy through a transsphenoidal approach is challenging for the neurosurgical resident to conquer.

OBJECTIVE

To demonstrate that stereolithography, or 3-dimensional (3-D) printing, is a useful educational tool for neurosurgery residents to learn skull base anatomy.

METHODS

Before any formal teaching, residents were brought into the operating room where they were asked to identify key structures seen through an endoscopic transsphenoidal approach. Scoring was based on correctly naming the anatomical structures. After the initial testing, all residents participated in a didactic lecture reviewing this anatomy by using 2-dimensional pictures. Residents were then divided into 2 groups: A and B. Group B residents were additionally taught through neurosurgical simulation using a 3-D printed model and an endoscope. Following all formal teaching, residents were retested in the operating room.

RESULTS

A maximum score of 8 points was possible if all structures were identified correctly. Group A had mean scores of 2.75 on initial testing compared with 5 after the lecture (P = .041 using 2-tailed t test). Group B had mean scores of 2.75 on initial testing compared with 7.5 after the lecture and 3-D model simulation (P = .002). When comparing mean scores after formal teaching in groups A and B, 5 vs 7.5 were obtained for lecture only vs lecture and 3-D model simulation, respectively (P = .031).

CONCLUSION

Three-dimensional models used in neurosurgical simulation to teach skull base anatomy through a transsphenoidal approach showed objective and subjective improvement in testing scores in neurosurgery residents. This study confirms that 3-D models are a useful educational tool.

3D surgical printing for preoperative planning of trabecular augments in acetabular fracture sequel

We describe the methodical and possibilities of 3D surgical printing in preoperative planning for a total hip arthroplasty in acetabular deformity after acetabular fractures, showing a case of a 43-year-old with posttraumatic arthritis after both column fracture of the left acetabulum that was treated non operatively, supporting the do it yourself mode.