Injecting realism in surgical training-initial simulation experience with custom 3D models

Application of 3D Printing in Cleft Lip and Palate Repair

This manuscript reviews the transformative impact of 3-dimensional (3D) printing technologies in the treatment and management of cleft lip and palate (CLP), highlighting its application across presurgical planning, surgical training, implantable scaffolds, and postoperative care. By integrating patient-specific data through computer-aided design and manufacturing, 3D printing offers tailored solutions that improve surgical outcomes, reduce operation times, and enhance patient care. The review synthesizes current research findings, technical advancements, and clinical applications, illustrating the potential of 3D printing to revolutionize CLP treatment. Further, it discusses the future directions of combining 3D printing with other innovative technologies like artificial intelligence, 4D printing, and in situ bioprinting for more comprehensive care strategies. This paper underscores the necessity for multidisciplinary collaboration and further research to overcome existing challenges and fully utilize the capabilities of 3D printing in CLP repair.

Impact of patient-specific three-dimensional printed liver models on hepatic surgery safety: a pilot study

BACKGROUND

Simulation and navigation technologies in hepatobiliary surgery have been developed recently. In this prospective clinical trial, we evaluated the accuracy and utility of our patient-specific three dimensional (3D)-printed liver models as an intraoperative navigation system to ensure surgical safety.

METHOD

Patients requiring advanced hepatobiliary surgeries during the study period were enrolled. Three cases were selected for comparison of the computed tomography (CT) scan data of the models with the patients' original data. Questionnaires were completed after surgeries to evaluate the utility of the models. Psychological stress was used as subjective data and operation time and blood loss as objective data.

RESULTS

Thirteen patients underwent surgery using the patient-specific 3D liver models. The difference between patient-specific 3D liver models and the original data was less than 0.6 mm in the 90% area. The 3D model assisted with intra-liver hepatic vein recognition and the definition of the cutting line. According to the post-operative subjective evaluation, surgeons found the models improved safety and reduced psychological stress during operations. However, the models did not reduce operative time or blood loss.

CONCLUSION

The patient-specific 3D-printed liver models accurately reflected patients' original data and were an effective intraoperative navigation tool for meticulously difficult liver surgeries.

CLINICAL TRIAL REGISTRATION

This study was registered in the UMIN Clinical Trial Registry (UMIN000025732).

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.

Using 3D Printing to Improve Student Education of Complex Anatomy: a Systematic Review and Meta-analysis

Objective

Additive manufacturing has played an increasingly important role in the field of health care. One of the most recent applications has been the development of 3D printed anatomical models specifically to improve student education. The purpose of this review was to assess the potential for 3D printed models to improve understanding of complex anatomy in undergraduate and medical/professional students.

Methods

A systematic review was performed to investigate the different implementations of 3D printed anatomical models in educational curricula. In addition, a meta-analysis was conducted to assess the differences in comprehension between students who received 3D printed models as part of their instruction and those taught with traditional methods.

Results

Of the 10 groups included in the meta-analysis, students whose educational experience included a 3D printed model scored roughly 11% better on objective assessments compared to students who did not use such models (Hedge's g = 0.742, p < 0.001).

Conclusion

Based on these findings, the use of 3D printed anatomical models as a method of education is likely to improve students' understanding of complex anatomical structures.

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.

Heat Sterilization Effects on Polymeric, FDM-Optimized Orthopedic Cutting Guide for Surgical Procedures

Improvements in software for image analysis have enabled advances in both medical and engineering industries, including the use of medical analysis tools to recreate internal parts of the human body accurately. A research analysis found that FDM-sourced elements have shown viability for a customized and reliable approach in the orthopedics field. Three-dimensional printing has allowed enhanced accuracy of preoperative planning, leading to reduced surgery times, fewer unnecessary tissue perforations, and fewer healing complications. Furthermore, using custom tools chosen for each procedure has shown the best results. Bone correction-related surgeries require customized cutting guides for a greater outcome. This study aims to assess the biopolymer-based tools for surgical operations and their ability to sustain a regular heat-sterilization cycle without compromising the geometry and fit characteristics for a proper procedure. To achieve this, a DICOM and FDM methodology is proposed for fast prototyping of the cutting guide by means of 3D engineering. A sterilization test was performed on HTPLA, PLA, and nylon polymers. As a result, the unique characteristics within the regular autoclave sterilization process allowed regular supplied PLA to show there were no significant deformations, whilst annealed HTPLA proved this material’s capability of sustaining repeated heat cycles due to its crystallization properties. Both of these proved that the sterilization procedures do not compromise the reliability of the part, nor the safety of the procedure. Therefore, prototypes made with a similar process as this proposal could be safely used in actual surgery practices, while nylon performed poorly because of its hygroscopic properties.

Hybrid Additive Fabrication of a Transparent Liver with Biosimilar Haptic Response for Preoperative Planning

Due to the complexity of liver surgery, the interest in 3D printing is constantly increasing among hepatobiliary surgeons. The aim of this study was to produce a patient-specific transparent life-sized liver model with tissue-like haptic properties by combining additive manufacturing and 3D moulding. A multistep pipeline was adopted to obtain accurate 3D printable models. Semiautomatic segmentation and registration of routine medical imaging using 3D Slicer software allowed to obtain digital objects representing the structures of interest (liver parenchyma, vasculo-biliary branching, and intrahepatic lesion). The virtual models were used as the source data for a hybrid fabrication process based on additive manufacturing using soft resins and casting of tissue-mimicking silicone-based blend into 3D moulds. The model of the haptic liver reproduced with high fidelity the vasculo-biliary branching and the relationship with the intrahepatic lesion embedded into the transparent parenchyma. It offered high-quality haptic perception and a remarkable degree of surgical and anatomical information. Our 3D transparent model with haptic properties can help surgeons understand the spatial changes of intrahepatic structures during surgical manoeuvres, optimising preoperative surgical planning.

3D printing in oral and maxillofacial surgery: a nationwide survey among university and non-university hospitals and private practices in Germany

OBJECTIVES

Oral and maxillofacial surgery (OMFS) has undergone pioneering progress through the development of three-dimensional (3D) printing technologies. The aim of this study was to evaluate the use of 3D printing at OMFS university and non-university hospitals and private practices in Germany.

MATERIALS AND METHODS

For explorative assessment, a dynamic online questionnaire containing 10-22 questions about the current use of 3D printing and the reasons behind it was sent to OMFS university and non-university hospitals and private practices in Germany by the study group from the German Association of Oral and Maxillofacial Surgery (DGMKG).

RESULTS

In total, 156 participants responded from university (23 [14.7%]) and non-university hospitals (19 [12.2%]) and private practices without (85 [50.5%]) and with 29 (18.6%) inpatient treatment facility. Highest applications of 3D printing were in implantology (57%), microvascular bone reconstructions (25.6%), and orthognathics (21.1%). Among the participants, 37.8% reportedly were not using 3D printing. Among the hospitals and private practices, 21.1% had their own 3D printer, and 2.5% shared it with other departments. The major reason for not having a 3D printer was poor cost efficiency (37.6%). Possessing a 3D printer was motivated by independence from external providers (91.3%) and rapid template production (82.6%). The preferred printing methods were stereolithography (69.4 %) and filament printing (44.4%).

CONCLUSIONS

OMFS 3D printing is established in Germany with a wide range of applications.

CLINICAL RELEVANCE

The prevalence of 3D printing in hospitals and private practices is moderate. This may be enhanced by future innovations including improved cost efficiency.

A direct slicing technique for the 3D printing of implicitly represented medical models

In conventional medical image printing methods, volumetric medical data needs to be conversed into STereo Lithography (STL) format, the most commonly used format for representing geometric models for 3D printing. However, this STL conversion process is not only time consuming, but more importantly, it often leads to the loss of accuracy. It has become a critical factor hindering the printing efficiency and precision of organ models. By examining the key characteristics of discrete medical volume data, this paper proposes a direct slicing technique for printing implicitly represented 3D medical models. The proposed method mainly consists of three algorithms: (1) A layer-based contour extraction algorithm for discrete volume data; (2) An inner shell construction algorithm based on discrete point differential indentation; (3) An infill generation algorithm based on the constructed virtual contour and scan lines. The proposed method has been applied to the slicing of several organ models for experiments, and the ratios of time cost and memory cost between the conventional method and the proposed method are about 4-100 and 1.1 to 1.4 respectively, which demonstrate that the proposed method has a great improvement in both time and space performance when compared with the conventional STL-based method. Our technique extends the direct input format of geometric models for additive manufacturing. That is, discrete volume data can be used as a direct input for additive manufacturing without conversion to STL format.

3D printed rodent skin-skull-brain model: A novel animal-free approach for neurosurgical training

In neuroscience, stereotactic brain surgery is a standard yet challenging technique for which laboratory and veterinary personnel must be sufficiently and properly trained. There is currently no animal-free training option for neurosurgeries; stereotactic techniques are learned and practiced on dead animals. Here we have used three-dimensional (3D) printing technologies to create rat and mouse skin-skull-brain models, specifically conceived for rodent stereotaxic surgery training. We used 3D models obtained from microCT pictures and printed them using materials that would provide the most accurate haptic feedback for each model—PC-ABS material for the rat and Durable resin for the mouse. We filled the skulls with Polyurethane expanding foam to mimic the brain. In order to simulate rodent skin, we added a rectangular 1mm thick clear silicone sheet on the skull. Ten qualified rodent neurosurgeons then performed a variety of stereotaxic surgeries on these rat and mouse 3D printed models. Participants evaluated models fidelity compared to cadaveric skulls and their appropriateness for educational use. The 3D printed rat and mouse skin-skull-brain models received an overwhelmingly positive response. They were perceived as very realistic, and considered an excellent alternative to cadaveric skulls for training purposes. They can be made rapidly and at low cost. Our real-size 3D printed replicas could enable cost- and time-efficient, animal-free neurosurgery training. They can be absolute replacements for stereotaxic surgery techniques practice including but not limited to craniotomies, screw placement, brain injections, implantations and cement applications. This project is a significant step forward in implementing the replacement, reduction, and refinement (3Rs) principles to animal experimentation. These 3D printed models could lead the way to the complete replacement of live animals for stereotaxic surgery training in laboratories and veterinary studies.

[Comprehensive review of 3D printing use in medicine: Comparison with practical applications in urology]

INTRODUCTION

Over the past few years, 3D printing has evolved rapidly. This has resulted in an increasing number of scientific publications reporting on the medical use of 3D printing. These applications can range from patient information, preoperative planning, education, or 3D printing of patient-specific surgical implants. The objective of this review was to give an overview of the different applications in urology and other disciplines based on a selection of publications.

METHODS

In the current narrative review the Medline database was searched to identify all the related reports discussing the use of 3D printing in the medical field and more specifically in Urology. 3D printing applications were categorized so they could be searched more thoroughly within the Medline database.

RESULTS

Three-dimensional printing can help improve pre-operative patient information, anatomy and medical trainee education. The 3D printed models may assist the surgeon in preoperative planning or become patient-specific surgical simulation models. In urology, kidney cancer surgery is the most concerned by 3D printing-related publications, for preoperative planning, but also for surgical simulation and surgical training.

CONCLUSION

3D printing has already proven useful in many medical applications, including urology, for patient information, education, pre-operative planning and surgical simulation. All areas of urology are involved and represented in the literature. Larger randomized controlled studies will certainly allow 3D printing to benefit patients in routine clinical practice.

Transcatheter Mitral Valve Repair Simulator Equipped with Eye Tracking Based Performance Assessment Capabilities: A Pilot Study

Background

The increase in cardiovascular disease cases that require minimally invasive treatment is inducing a new need to train physicians to perform them safely and effectively. Nevertheless, adaptation to simulation-based training has been slow, especially for complex procedures.

Objectives

We describe a newly developed mitral valve repair (MVR) simulator, equipped with new objective performance assessment methods, with an emphasis on its use for training the MitraClip™ procedure.

Methods

The MVR contains phantoms of all anatomical structures encountered during mitral valve repair with a transvenous, transseptal approach. In addition, several cameras, line lasers, and ultraviolet lights are used to mimic echocardiographic and fluoroscopic imaging and with a remote eye tracker the cognitive behaviour of the operator is recorded. A pilot study with a total of 9 interventional cardiologists, cardiac surgeons and technical experts was conducted. All participants performed the MitraClip procedure on the MVR simulator using standard interventional tools. Subsequently, each participant completed a structured questionnaire to assess the simulator.

Results

The simulator functioned well, and the implemented objective performance assessment methods worked reliably. Key performance metrics such as x-ray usage were comparable with results from studies assessing these metrics in real interventions. Fluoroscopy imaging is realistic for the transseptal puncture but reaches its limits during the final steps of the procedure.

Conclusion

The functionality and objective performance assessment of the MVR simulator were demonstrated. Especially for complex procedures such as the MitraClip procedure, this simulator offers a suitable platform for risk-free training and education.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13239-021-00549-4.

The utilisation of 3D printing in paediatric neurosurgery

3D printing technology has evolved over the years and there is a growing interest in its application in paediatric neurosurgery. Modern 3D printers have enabled the development of patient-specific 3D models that provide a realistic representation of complex anatomies and will aid in planning complex procedures. Paediatric neurosurgical operations are challenging and hands-on training is restricted. Surgical simulation training with biomodel has provided a new paradigm for trainees to master their surgical skills before encountering similar scenarios in real-life environment. This paper reviews the aspects of 3D printing for preoperative planning and simulation-based surgical training in paediatric neurosurgery.

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.

The effect of three-dimensional (3D) printing on quantitative and qualitative outcomes in paediatric orthopaedic osteotomies: a systematic review

Three-dimensional (3D) printing technology is increasingly being utilized in various surgical specialities. In paediatric orthopaedics it has been applied in the pre-operative and intra-operative stages, allowing complex deformities to be replicated and patient-specific instrumentation to be used. This systematic review analyses the literature on the effect of 3D printing on paediatric orthopaedic osteotomy outcomes.A systematic review of several databases was conducted according to PRISMA guidelines. Studies evaluating the use of 3D printing technology in orthopaedic osteotomy procedures in children (aged ≤ 16 years) were included. Spinal and bone tumour surgery were excluded. Data extracted included demographics, disease pathology, target bone, type of technology, imaging modality used, qualitative/quantitative outcomes and follow-up. Articles were further categorized as either 'pre-operative' or 'intra-operative' applications of the technology.Twenty-two articles fitting the inclusion criteria were included. The reported studies included 212 patients. There were five articles of level of evidence 3 and 17 level 4.A large variety of outcomes were reported with the most commonly used being operating time, fluoroscopic exposure and intra-operative blood loss.A significant difference in operative time, fluoroscopic exposure, blood loss and angular correction was found in the 'intra-operative' application group. No significant difference was found in the 'pre-operative' category.Despite a relatively low evidence base pool of studies, our aggregate data demonstrate a benefit of 3D printing technology in various deformity correction applications, especially when used in the 'intra-operative' setting. Further research including paediatric-specific core outcomes is required to determine the potential benefit of this novel addition. Cite this article: EFORT Open Rev 2021;6:130-138. DOI: 10.1302/2058-5241.6.200092.

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.

Neurosurgical simulator for training aneurysm microsurgery-a user suitability study involving neurosurgeons and residents

BACKGROUND

Due to its complexity and to existing treatment alternatives, exposure to intracranial aneurysm microsurgery at the time of neurosurgical residency is limited. The current state of the art includes training methods like assisting in surgeries, operating under supervision, and video training. These approaches are labor-intensive and difficult to fit into a timetable limited by the new work regulations. Existing virtual reality (VR)-based training modules lack patient-specific exercises and haptic properties and are thus inferior to hands-on training sessions and exposure to real surgical procedures.

MATERIALS AND METHODS

We developed a physical simulator able to reproduce the experience of clipping an intracranial aneurysm based on a patient-specific 3D-printed model of the skull, brain, and arteries. The simulator is made of materials that not only imitate tissue properties including arterial wall patency, thickness, and elasticity but also able to recreate a pulsatile blood flow. A sample group of 25 neurosurgeons and residents (n = 16: early residency with less than 4 years of neurosurgical exposure; n = 9: late residency and board-certified neurosurgeons, 4-15 years of neurosurgical exposure) took part to the study. Participants evaluated the simulator and were asked to answer questions about surgical simulation anatomy, realism, haptics, tactility, and general usage, scored on a 5-point Likert scale. In order to evaluate the feasibility of a future validation study on the role of the simulator in neurosurgical postgraduate training, an expert neurosurgeon assessed participants' clipping performance and a comparison between groups was done.

RESULTS

The proposed simulator is reliable and potentially useful for training neurosurgical residents and board-certified neurosurgeons. A large majority of participants (84%) found it a better alternative than conventional neurosurgical training methods.

CONCLUSION

The integration of a new surgical simulator including blood circulation and pulsatility should be considered as part of the future armamentarium of postgraduate education aimed to ensure high training standards for current and future generations of neurosurgeons involved in intracranial aneurysm surgery.

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.

Use of 3D Printing in Model Manufacturing for Minor Surgery Training of General Practitioners in Primary Care

In order to increase the efficiency of the Spanish health system, minor surgery programs are currently carried out in primary care centers. This organizational change has led to the need to train many general practitioners (GPs) in this discipline on a practical level. Due to the cost of the existing minor surgery training models in the market, pig’s feet or chicken thighs are used to practice the removal of figured lesions and the suture of wounds. In the present work, the use of 3D printing is proposed, to manufacture models that reproduce in a realistic way the most common lesions in minor surgery practice, and that allow doctors to be trained in an adequate way. Four models with the most common dermal lesions have been designed and manufactured, and then evaluated by a panel of experts. Face validity was demonstrated with four items on a five-point Likert scale that was completed anonymously. The models have obtained the following results: aesthetic recreation, 4.6 ± 0.5; realism during anesthesia infiltration, 4.8 ± 0.4; realism during lesion removal, 2.8 ± 0.4; realism during surgical wound closure, 1.2 ± 0.4. The score in this last section could be improved if a more elastic skin-colored filament were found on the market.

A Systematic Review of Three-Dimensional Printing in Liver Disease

The purpose of this review is to analyse current literature related to the clinical applications of 3D printed models in liver disease. A search of the literature was conducted to source studies from databases with the aim of determining the applications and feasibility of 3D printed models in liver disease. 3D printed model accuracy and costs associated with 3D printing, the ability to replicate anatomical structures and delineate important characteristics of hepatic tumours, and the potential for 3D printed liver models to guide surgical planning are analysed. Nineteen studies met the selection criteria for inclusion in the analysis. Seventeen of them were case reports and two were original studies. Quantitative assessment measuring the accuracy of 3D printed liver models was analysed in five studies with mean difference between 3D printed models and original source images ranging from 0.2 to 20%. Fifteen studies provided qualitative assessment with results showing the usefulness of 3D printed models when used as clinical tools in preoperative planning, simulation of surgical or interventional procedures, medical education, and training. The cost and time associated with 3D printed liver model production was reported in 11 studies, with costs ranging from US$13 to US$2000, duration of production up to 100 h. This systematic review shows that 3D printed liver models demonstrate hepatic anatomy and tumours with high accuracy. The models can assist with preoperative planning and may be used in the simulation of surgical procedures for the treatment of malignant hepatic tumours.

Assessment of a Patient-Specific, 3-Dimensionally Printed Endoscopic Sinus and Skull Base Surgical Model

Importance

Three-dimensional (3D) printing is an emerging tool in the creation of anatomical models for simulation and preoperative planning. Its use in sinus and skull base surgery has been limited because of difficulty in replicating the details of sinus anatomy.

Objective

To describe the development of 3D-printed sinus and skull base models for use in endoscopic skull base surgery.

Design, Setting, and Participants

In this single-center study performed from April 1, 2017, through June 1, 2017, a total of 7 otolaryngology residents and 2 attending physicians at a tertiary academic center were recruited to evaluate the procedural anatomical accuracy and haptic feedback of the printed model.

Interventions

A 3D model of sinus and skull base anatomy with high-resolution, 3D printed material (VeroWhite) was printed using a 3D printer. Anatomical accuracy was assessed by comparing a computed tomogram of the original patient with that of the 3D model across set anatomical landmarks (eg, depth of cribriform plate). Image-guided navigation was also used to evaluate accuracy of 13 surgical landmarks. Likert scale questionnaires (1 indicating strongly disagree; 2, disagree; 3, neutral; 4, agree; and 5, strongly agree) were administered to 9 study participants who each performed sinus and skull base dissections on the 3D-printed model to evaluate anatomical accuracy and haptic feedback.

Main Outcomes and Measures

Main outcomes of the study include objective anatomical accuracy through imaging and navigation and haptic evaluation by the study participants.

Results

Seven otolaryngology residents (3 postgraduate year [PGY]-5 residents, 2 PGY-4 residents, 1 PGY-3 resident, and 1 PGY-2 resident) and 2 attending physicians evaluated the haptic feedback of the 3D model. Computed tomographic comparison demonstrated a less than 5% difference between patient and 3D model measurements. Image-guided navigation confirmed accuracy of 13 landmarks to within 1 mm. Likert scores were a mean (SD) of 4.00 (0.71) for overall procedural anatomical accuracy and 4.67 (0.5) for haptic feedback.

Conclusions and Relevance

This study shows that high-resolution, 3D-printed sinus and skull base models can be generated with anatomical and haptic accuracy. This technology has the potential to be useful in surgical training and preoperative planning and as a supplemental or alternative simulation or training platform to cadaveric dissection.

[3D printing in orthopedic and trauma surgery education and training : Possibilities and fields of application]

The 3D printing technology enables precise fracture models to be generated from volumetric digital imaging and communications in medicine (DICOM) computed tomography (CT) data. Apart from patient treatment, in the future this technology could potentially play a significant role in education and training in the field of orthopedic and trauma surgery. Preliminary results show that the understanding and classification of fractures can be improved when teaching medical students. The use of life-size and haptic models of real fractures for education is particularly interesting. Even experienced surgeons show an improved classification and treatment planning with the help of 3D printed models when compared to plain CT data. Especially for complex articular fractures, such as those of the acetabulum and tibial plateau, initial evidence shows patient benefits in terms of reduced surgery time and blood loss with the help of 3D models. The use of 3D printing on-site at the hospital is of particular interest in orthopedic and trauma surgery as it promises to provide products within a short time. The low investment and running costs and the increasing availability of convenient software solutions will spur increasing dissemination of this technology in the coming years.

Developing a 3D composite training model for cranial remodeling

OBJECTIVE

Craniosynostosis correction, including cranial vault remodeling, fronto-orbital advancement (FOA), and endoscopic suturectomy, requires practical experience with complex anatomy and tools. The infrequent exposure to complex neurosurgical procedures such as these during residency limits extraoperative training. Lack of cadaveric teaching tools given the pediatric nature of synostosis compounds this challenge. The authors sought to create lifelike 3D printed models based on actual cases of craniosynostosis in infants and incorporate them into a practical course for endoscopic and open correction. The authors hypothesized that this training tool would increase extraoperative facility and familiarity with cranial vault reconstruction to better prepare surgeons for in vivo procedures.

METHODS

The authors utilized representative craniosynostosis patient scans to create 3D printed models of the calvaria, soft tissues, and cranial contents. Two annual courses implementing these models were held, and surveys were completed by participants (n = 18, 5 attending physicians, 4 fellows, 9 residents) on the day of the course. These participants were surveyed during the course and 1 year later to assess the impact of this training tool. A comparable cohort of trainees who did not participate in the course (n = 11) was also surveyed at the time of the 1-year follow-up to assess their preparation and confidence with performing craniosynostosis surgeries.

RESULTS

An iterative process using multiple materials and the various printing parameters was used to create representative models. Participants performed all major surgical steps, and we quantified the fidelity and utility of the model through surveys. All attendees reported that the model was a valuable training tool for open reconstruction (n = 18/18 [100%]) and endoscopic suturectomy (n = 17/18 [94%]). In the first year, 83% of course participants (n = 14/17) agreed or strongly agreed that the skin and bone materials were realistic and appropriately detailed; the second year, 100% (n = 16/16) agreed or strongly agreed that the skin material was realistic and appropriately detailed, and 88% (n = 14/16) agreed or strongly agreed that the bone material was realistic and appropriately detailed. All participants responded that they would use the models for their own personal training and the training of residents and fellows in their programs.

CONCLUSIONS

The authors have developed realistic 3D printed models of craniosynostosis including soft tissues that allow for surgical practice simulation. The use of these models in surgical simulation provides a level of preparedness that exceeds what currently exists through traditional resident training experience. Employing practical modules using such models as part of a standardized resident curriculum is a logical evolution in neurosurgical education and training.

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.

Low-cost sensor-integrated 3D-printed personalized prosthetic hands for children with amniotic band syndrome: A case study in sensing pressure distribution on an anatomical human-machine interface (AHMI) using 3D-printed conformal electrode arrays

Interfacing anatomically conformal electronic components, such as sensors, with biology is central to the creation of next-generation wearable systems for health care and human augmentation applications. Thus, there is a need to establish computer-aided design and manufacturing methods for producing personalized anatomically conformal systems, such as wearable devices and human-machine interfaces (HMIs). Here, we show that a three-dimensional (3D) scanning and 3D printing process enabled the design and fabrication of a sensor-integrated anatomical human-machine interface (AHMI) in the form of personalized prosthetic hands that contain anatomically conformal electrode arrays for children affected by amniotic band syndrome, a common birth defect. A methodology for identifying optimal scanning parameters was identified based on local and global metrics of registered point cloud data quality. This method identified an optimal rotational angle step size between adjacent 3D scans. The sensitivity of the optimization process to variations in organic shape (i.e., geometry) was examined by testing other anatomical structures, including a foot, an ear, and a porcine kidney. We found that personalization of the prosthetic interface increased the tissue-prosthesis contact area by 408% relative to the non-personalized devices. Conformal 3D printing of carbon nanotube-based polymer inks across the personalized AHMI facilitated the integration of electronic components, specifically, conformal sensor arrays for measuring the pressure distribution across the AHMI (i.e., the tissue-prosthesis interface). We found that the pressure across the AHMI exhibited a non-uniform distribution and became redistributed upon activation of the prosthetic hand's grasping action. Overall, this work shows that the integration of 3D scanning and 3D printing processes offers the ability to design and fabricate wearable systems that contain sensor-integrated AHMIs.

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.

The potential for machine learning algorithms to improve and reduce the cost of 3-dimensional printing for surgical planning

INTRODUCTION

3D-printed anatomical models play an important role in medical and research settings. The recent successes of 3D anatomical models in healthcare have led many institutions to adopt the technology. However, there remain several issues that must be addressed before it can become more wide-spread. Of importance are the problems of cost and time of manufacturing. Machine learning (ML) could be utilized to solve these issues by streamlining the 3D modeling process through rapid medical image segmentation and improved patient selection and image acquisition. The current challenges, potential solutions, and future directions for ML and 3D anatomical modeling in healthcare are discussed.

AREAS COVERED

This review covers research articles in the field of machine learning as related to 3D anatomical modeling. Topics discussed include automated image segmentation, cost reduction, and related time constraints.

EXPERT COMMENTARY

ML-based segmentation of medical images could potentially improve the process of 3D anatomical modeling. However, until more research is done to validate these technologies in clinical practice, their impact on patient outcomes will remain unknown. We have the necessary computational tools to tackle the problems discussed. The difficulty now lies in our ability to collect sufficient data.

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 printing for preoperative planning and surgical training: a review

Surgeons typically rely on their past training and experiences as well as visual aids from medical imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) for the planning of surgical processes. Often, due to the anatomical complexity of the surgery site, two dimensional or virtual images are not sufficient to successfully convey the structural details. For such scenarios, a 3D printed model of the patient's anatomy enables personalized preoperative planning. This paper reviews critical aspects of 3D printing for preoperative planning and surgical training, starting with an overview of the process-flow and 3D printing techniques, followed by their applications spanning across multiple organ systems in the human body. State of the art in these technologies are described along with a discussion of current limitations and future opportunities.

Ophthalmic gels: Past, present and future

Aqueous gels formulated using hydrophilic polymers (hydrogels) along with those based on stimuli responsive polymers (in situ gelling or gel forming systems) continue to attract increasing interest for various eye health-related applications. They allow the incorporation of a variety of ophthalmic pharmaceuticals to achieve therapeutic levels of drugs and bioactives at target ocular sites. The integration of sophisticated drug delivery technologies such as nanotechnology-based ones with intelligent and environment responsive systems can extend current treatment duration to provide more clinically relevant time courses (weeks and months instead of hours and days) which will inevitably reduce dose frequency, increase patient compliance and improve clinical outcomes. Novel applications and design of contact lenses and intracanalicular delivery devices along with the move towards integrating gels into various drug delivery devices like intraocular pumps, injections and implants has the potential to reduce comorbidities caused by glaucoma, corneal keratopathy, cataract, diabetic retinopathies and age-related macular degeneration. This review describes ophthalmic gelling systems with emphasis on mechanism of gel formation and application in ophthalmology. It provides a critical appraisal of the techniques and methods used in the characterization of ophthalmic preformed gels and in situ gelling systems along with a thorough insight into the safety and biocompatibility of these systems. Newly developed ophthalmic gels, hydrogels, preformed gels and in situ gelling systems including the latest in the area of stimuli responsive gels, molecularly imprinted gels, nanogels, 3D printed hydrogels; 3D printed devices comprising ophthalmic gels are covered. Finally, new applications of gels in the production of artificial corneas, corneal wound healing and hydrogel contact lenses are described.

Systematic Review of Patient-Specific Surgical Simulation: Toward Advancing Medical Education

OBJECTIVE

Simulation-based education has been shown to be an effective tool to teach foundational technical skills in various surgical specialties. However, most of the current simulations are limited to generic scenarios and do not allow continuation of the learning curve beyond basic technical skills to prepare for more advanced expertise, such as patient-specific surgical planning. The objective of this study was to evaluate the current medical literature with respect to the utilization and educational value of patient-specific simulations for surgical training.

METHODS

We performed a systematic review of the literature using Pubmed, Embase, and Scopus focusing on themes of simulation, patient-specific, surgical procedure, and education. The study included randomized controlled trials, cohort studies, and case-control studies published between 2005 and 2016. Two independent reviewers (W.H.R. and N.D) conducted the study appraisal, data abstraction, and quality assessment of the studies.

RESULTS

The search identified 13 studies that met the inclusion criteria; 7 studies employed computer simulations and 6 studies used 3-dimensional (3D) synthetic models. A number of surgical specialties evaluated patient-specific simulation, including neurosurgery, vascular surgery, orthopedic surgery, and interventional radiology. However, most studies were small in size and primarily aimed at feasibility assessments and early validation.

CONCLUSIONS

Early evidence has shown feasibility and utility of patient-specific simulation for surgical education. With further development of this technology, simulation-based education may be able to support training of higher-level competencies outside the clinical settingto aid learners in their development of surgical skills.

Robotic Pancreatoduodenectomy Biotissue Curriculum has Validity and Improves Technical Performance for Surgical Oncology Fellows

OBJECTIVE

Obtaining the proficiency on the robotic platform necessary to safely perform a robotic pancreatoduodenectomy is particularly challenging. We hypothesize that by instituting a proficiency-based robotic training curriculum we can enhance novice surgeons' skills outside of the operating room, leading to a shorter learning curve.

DESIGN

A biotissue curriculum was designed consisting of sewing artificial organs to simulate a hepaticojejunostomy (HJ), gastrojejunostomy (GJ), and pancreaticojejunostomy (PJ). Three master robotic surgeons performed each biotissue anastomosis to assess validity. Using video review, trainee performance on biotissue drills was evaluated for time, errors and objective structured assessment of technical skills (OSATS) by 2 blinded graders.

SETTING

This study is conducted at the University of Pittsburgh Medical Center (Pittsburgh, PA), a tertiary care academic teaching hospital.

PARTICIPANTS

In total, 14 surgical oncology fellows completed the biotissue curriculum.

RESULTS

Fourteen fellows performed 196 anastomotic drills during the first year: 66 (HJ), 64 (GJ), and 66 (PJ). The fellows' performances were analyzed as a group by attempt. The attendings' first attempt outperformed the fellows' first attempt in all metrics for every drill (all p < 0.05). More than 5 analyzed attempts of the HJ, there was improvement in time, errors, and OSATS (all p < 0.01); however, no metric reached attending performance. For the GJ, time, errors, and OSATS all improved more than 5 attempts (all p < 0.01), whereas only errors and OSATS reached proficiency. For the PJ, errors and OSATS both improved over attempts (p < 0.01) and reached proficiency; however, time did not statistically improve nor reach proficiency. The graders scoring correlated for errors and OSATS (p < 0.0001).

CONCLUSION

A pancreatoduodenectomy biotissue curriculum has face and construct validity. The curriculum is feasible and improves errors and technical performance. Time is the most difficult technical parameter to improve. This curriculum is a valid tool for teaching robotic pancreatoduodenectomies with established milestones for reaching optimum performance.

Preparation and fabrication of a full-scale, sagittal-sliced, 3D-printed, patient-specific radiotherapy phantom

Purpose

Patient‐specific 3D‐printed phantoms have many potential applications, both research and clinical. However, they have been limited in size and complexity because of the small size of most commercially available 3D printers as well as material warping concerns. We aimed to overcome these limitations by developing and testing an effective 3D printing workflow to fabricate a large patient‐specific radiotherapy phantom with minimal warping errors. In doing so, we produced a full‐scale phantom of a real postmastectomy patient.

Methods

We converted a patient's clinical CT DICOM data into a 3D model and then sliced the model into eleven 2.5‐cm‐thick sagittal slices. The slices were printed with a readily available thermoplastic material representing all body tissues at 100% infill, but with air cavities left open. Each slice was printed on an inexpensive and commercially available 3D printer. Once the printing was completed, the slices were placed together for imaging and verification. The original patient CT scan and the assembled phantom CT scan were registered together to assess overall accuracy.

Results

The materials for the completed phantom cost $524. The printed phantom agreed well with both its design and the actual patient. Individual slices differed from their designs by approximately 2%. Registered CT images of the assembled phantom and original patient showed excellent agreement.

Conclusions

Three‐dimensional printing the patient‐specific phantom in sagittal slices allowed a large phantom to be fabricated with high accuracy. Our results demonstrate that our 3D printing workflow can be used to make large, accurate, patient‐specific phantoms at 100% infill with minimal material warping error.

Training in Cerebral Aneurysm Clipping Using Self-Made 3-Dimensional Models

INTRODUCTION

Recently, there have been increasingly fewer opportunities for junior surgeons to receive on-the-job training. Therefore, we created custom-built three-dimensional (3D) surgical simulators for training in connection with cerebral aneurysm clipping.

METHODS

Three patient-specific models were composed of a trimmed skull, retractable brain, and a hollow elastic aneurysm with its parent artery. The brain models were created using 3D printers via a casting technique. The artery models were made by 3D printing and a lost-wax technique. Four residents and 2 junior neurosurgeons attended the training courses. The trainees retracted the brain, observed the parent arteries and aneurysmal neck, selected the clip(s), and clipped the neck of an aneurysm. The duration of simulation was recorded. A senior neurosurgeon then assessed the trainee's technical skill and explained how to improve his/her performance for the procedure using a video of the actual surgery. Subsequently, the trainee attempted the clipping simulation again, using the same model. After the course, the senior neurosurgeon assessed each trainee's technical skill. The trainee critiqued the usefulness of the model and the effectiveness of the training course.

RESULTS

Trainees succeeded in performing the simulation in line with an actual surgery. Their skills tended to improve upon completion of the training.

CONCLUSION

These simulation models are easy to create, and we believe that they are very useful for training junior neurosurgeons in the surgical techniques needed for cerebral aneurysm clipping.

Creation of a novel simulator for minimally invasive neurosurgery: fusion of 3D printing and special effects

OBJECTIVE Recent advances in optics and miniaturization have enabled the development of a growing number of minimally invasive procedures, yet innovative training methods for the use of these techniques remain lacking. Conventional teaching models, including cadavers and physical trainers as well as virtual reality platforms, are often expensive and ineffective. Newly developed 3D printing technologies can recreate patient-specific anatomy, but the stiffness of the materials limits fidelity to real-life surgical situations. Hollywood special effects techniques can create ultrarealistic features, including lifelike tactile properties, to enhance accuracy and effectiveness of the surgical models. The authors created a highly realistic model of a pediatric patient with hydrocephalus via a unique combination of 3D printing and special effects techniques and validated the use of this model in training neurosurgery fellows and residents to perform endoscopic third ventriculostomy (ETV), an effective minimally invasive method increasingly used in treating hydrocephalus. METHODS A full-scale reproduction of the head of a 14-year-old adolescent patient with hydrocephalus, including external physical details and internal neuroanatomy, was developed via a unique collaboration of neurosurgeons, simulation engineers, and a group of special effects experts. The model contains "plug-and-play" replaceable components for repetitive practice. The appearance of the training model (face validity) and the reproducibility of the ETV training procedure (content validity) were assessed by neurosurgery fellows and residents of different experience levels based on a 14-item Likert-like questionnaire. The usefulness of the training model for evaluating the performance of the trainees at different levels of experience (construct validity) was measured by blinded observers using the Objective Structured Assessment of Technical Skills (OSATS) scale for the performance of ETV. RESULTS A combination of 3D printing technology and casting processes led to the creation of realistic surgical models that include high-fidelity reproductions of the anatomical features of hydrocephalus and allow for the performance of ETV for training purposes. The models reproduced the pulsations of the basilar artery, ventricles, and cerebrospinal fluid (CSF), thus simulating the experience of performing ETV on an actual patient. The results of the 14-item questionnaire showed limited variability among participants' scores, and the neurosurgery fellows and residents gave the models consistently high ratings for face and content validity. The mean score for the content validity questions (4.88) was higher than the mean score for face validity (4.69) (p = 0.03). On construct validity scores, the blinded observers rated performance of fellows significantly higher than that of residents, indicating that the model provided a means to distinguish between novice and expert surgical skills. CONCLUSIONS A plug-and-play lifelike ETV training model was developed through a combination of 3D printing and special effects techniques, providing both anatomical and haptic accuracy. Such simulators offer opportunities to accelerate the development of expertise with respect to new and novel procedures as well as iterate new surgical approaches and innovations, thus allowing novice neurosurgeons to gain valuable experience in surgical techniques without exposing patients to risk of harm.

Fabrication of cerebral aneurysm simulator with a desktop 3D printer

Now, more and more patients are suffering cerebral aneurysm. However, long training time limits the rapid growth of cerebrovascular neurosurgeons. Here we developed a novel cerebral aneurysm simulator which can be better represented the dynamic bulging process of cerebral aneurysm The proposed simulator features the integration of a hollow elastic vascular model, a skull model and a brain model, which can be affordably fabricated at the clinic (Fab@Clinic), under $25.00 each with the help of a low-cost desktop 3D printer. Moreover, the clinical blood flow and pulsation pressure similar to the human can be well simulated, which can be used to train the neurosurgical residents how to clip aneurysms more effectively.

New Generation of Three-Dimensional Tools to Learn Anatomy

We present a new generation tool based of interactive 3D models. This models are based on the radiological two-dimensional images by computed tomography imaging. Our article focuses on the anatomical region of the skull base. These new three-dimensional models offer a wide field of application in the learning, as they offer multiple visualization tools (rotation, scrolling, zoom…). In this way, understanding of the anatomical region is facilitated. A feature to be dismissed is that a professional workstation is not required to work with three-dimensional models, since a personal computer can be viewed and interacted with the models. Educational and clinical applications are also discussed.

Using 3D printed models for planning and guidance during endovascular intervention: a technical advance

Three-dimensional (3D) printing applications in medicine have been limited due to high cost and technical difficulty of creating 3D printed objects. It is not known whether patient-specific, hollow, small-caliber vascular models can be manufactured with 3D printing, and used for small vessel endoluminal testing of devices. Manufacture of anatomically accurate, patient-specific, small-caliber arterial models was attempted using data from a patient's CT scan, free open-source software, and low-cost Internet 3D printing services. Prior to endovascular treatment of a patient with multiple splenic artery aneurysms, a 3D printed model was used preoperatively to test catheter equipment and practice the procedure. A second model was used intraoperatively as a reference. Full-scale plastic models were successfully produced. Testing determined the optimal puncture site for catheter positioning. A guide catheter, base catheter, and microcatheter combination selected during testing was used intraoperatively with success, and the need for repeat angiograms to optimize image orientation was minimized. A difficult and unconventional procedure was successful in treating the aneurysms while preserving splenic function. We conclude that creation of small-caliber vascular models with 3D printing is possible. Free software and low-cost printing services make creation of these models affordable and practical. Models are useful in preoperative planning and intraoperative guidance.

Development and validation of a septoplasty training model using 3-dimensional printing technology

BACKGROUND

Providing alternative training modalities may improve trainees' ability to perform septoplasty. Three-dimensional printing has been shown to be a powerful tool in surgical training. The objectives of this study were to explain the development of our 3-dimensional (3D) printed septoplasty training model, to assess its face and content validity, and to present evidence supporting its ability to distinguish between levels of surgical proficiency.

METHODS

Imaging data of a patient with a nasal septal deviation was selected for printing. Printing materials reproducing the mechanical properties of human tissues were selected based on literature review and prototype testing. Eight expert rhinologists, 6 senior residents, and 6 junior residents performed endoscopic septoplasties on the model and completed a postsimulation survey. Performance metrics in quality (final product analysis), efficiency (time), and safety (eg, perforation length, nares damage) were recorded and analyzed in a study-blind manner.

RESULTS

The model was judged to be anatomically correct and the steps performed realistic, with scores of 4.05 ± 0.82 and 4.2 ± 1, respectively, on a 5-point Likert scale. Ninety-two percent of residents desired the simulator to be integrated into their teaching curriculum. There was a significant difference (p < 0.05) between the expert, intermediate, and novice groups in time taken and nares cuts, whereas other performance metrics showed no significant difference.

CONCLUSION

To our knowledge, there are no other simulator training models for septoplasty. Our model incorporates 2 different materials mixed into the 3 relevant consistencies necessary to simulate septoplasty. Our findings provide evidence supporting the validity of the model.

3D printing in neurosurgery: A systematic review

BACKGROUND

The recent expansion of three-dimensional (3D) printing technology into the field of neurosurgery has prompted a widespread investigation of its utility. In this article, we review the current body of literature describing rapid prototyping techniques with applications to the practice of neurosurgery.

METHODS

An extensive and systematic search of the Compendex, Scopus, and PubMed medical databases was conducted using keywords relating to 3D printing and neurosurgery. Results were manually screened for relevance to applications within the field.

RESULTS

Of the search results, 36 articles were identified and included in this review. The articles spanned the various subspecialties of the field including cerebrovascular, neuro-oncologic, spinal, functional, and endoscopic neurosurgery.

CONCLUSIONS

We conclude that 3D printing techniques are practical and anatomically accurate methods of producing patient-specific models for surgical planning, simulation and training, tissue-engineered implants, and secondary devices. Expansion of this technology may, therefore, contribute to advancing the neurosurgical field from several standpoints.

New approach for predictive measurement of knee cartilage defects with three-dimensional printing based on CT-arthrography: A feasibility study

PURPOSE

The aim was to prove the possibility of creating an exact module of knee cartilage defects using 3D printing.

METHODS

Defects were created in cadaver knees. CT-arthrography and 3-Tesla MRI were performed. Based on CTA images a model of the cartilage was created using 3D printing. Defect-sizes in the imaging modalities were compared.

RESULTS

Estimated lesion area in 3D model differed approximately 5% comparing to the defect sizes in knees. MRI underestimated the defect on average of 12%, whereas the CTA overestimated the defect about 3%.

CONCLUSIONS

We proved the feasibility of creating an accurate module of knee cartilage.

3D Printed Models of Cleft Palate Pathology for Surgical Education

To explore the potential viability and limitations of 3D printed models of children with cleft palate deformity.

BACKGROUND

The advantages of 3D printed replicas of normal anatomical specimens have previously been described. The creation of 3D prints displaying patient-specific anatomical pathology for surgical planning and interventions is an emerging field. Here we explored the possibility of taking rare pediatric radiographic data sets to create 3D prints for surgical education.

METHODS

Magnetic resonance imaging data of 2 children (8 and 14 months) were segmented, colored, and anonymized, and stereolothographic files were prepared for 3D printing on either multicolor plastic or powder 3D printers and multimaterial 3D printers.

RESULTS

Two models were deemed of sufficient quality and anatomical accuracy to print unamended. One data set was further manipulated digitally to artificially extend the length of the cleft. Thus, 3 models were printed: 1 incomplete soft-palate deformity, 1 incomplete anterior palate deformity, and 1 complete cleft palate. All had cleft lip deformity. The single-material 3D prints are of sufficient quality to accurately identify the nature and extent of the deformities. Multimaterial prints were subsequently created, which could be valuable in surgical training.

CONCLUSION

Improvements in the quality and resolution of radiographic imaging combined with the advent of multicolor multiproperty printer technology will make it feasible in the near future to print 3D replicas in materials that mimic the mechanical properties and color of live human tissue making them potentially suitable for surgical training.

3D haptic modelling for preoperative planning of hepatic resection: A systematic review

Introduction and background

Three dimensional (3D) printing has gained popularity in the medical field because of increased research in the field of haptic 3D modeling. We review the role of 3D printing with specific reference to liver directed applications.

Methods

A literature search was performed using the scientific databases Medline and PubMed. We performed this in-line with the PRISMA [20] statement. We only included articles in English, available in full text, published about adults, about liver surgery and published between 2005 and 2015. The 3D model of a patient's liver venous vasculature and metastasis was prepared from a CT scan using Osirix software (Pixmeo, Gineva, Switzerland) and printed using our 3D printer (MakerBot Replicator Z18, US). To validate the model, measurements from the inferior vena cava (IVC) were compared between the CT scan and the 3D printed model.

Results

A total of six studies were retrieved on 3D printing directly related to a liver application. While stereolithography (STL) remains the gold standard in medical additive manufacturing, Fused Filament Fabrication (FFF), is cheaper and may be more applicable. We found our liver 3D model made by FFF had a 0.1 ± 0.06 mm margin of error (mean ± standard deviation) compared with the CT scans.

Conclusion

3D printing in general surgery is yet to be thoroughly exploited. The most relevant feature of interest with regard to liver surgery is the ability to view the 3D dimensional relationship of the various hepatic and portal veins with respect to tumor deposits when planning hepatic resection.

Systematic review registration number: researchregistry1348.

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3D printing allows a fast, accurate and inexpensive production of a 3D liver model.

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A 3D printed model is excellent for education of junior staff as it offers insight to a patient's unique anatomy.

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3D printed models could also aid in patient education and facilitate surgery by obtaining informed consent.