Training for Skull Base Surgery with a Colored Temporal Bone Model Created by Three-Dimensional Printing Technology

3D printing materials and 3D printed surgical devices in oral and maxillofacial surgery: design, workflow and effectiveness

Oral and maxillofacial surgery is a specialized surgical field devoted to diagnosing and managing conditions affecting the oral cavity, jaws, face and related structures. In recent years, the integration of 3D printing technology has revolutionized this field, offering a range of innovative surgical devices such as patient-specific implants, surgical guides, splints, bone models and regenerative scaffolds. In this comprehensive review, we primarily focus on examining the utility of 3D-printed surgical devices in the context of oral and maxillofacial surgery and evaluating their efficiency. Initially, we provide an insightful overview of commonly utilized 3D-printed surgical devices, discussing their innovations and clinical applications. Recognizing the pivotal role of materials, we give consideration to suitable biomaterials and printing technology of each device, while also introducing the emerging fields of regenerative scaffolds and bioprinting. Furthermore, we delve into the transformative impact of 3D-printed surgical devices within specific subdivisions of oral and maxillofacial surgery, placing particular emphasis on their rejuvenating effects in bone reconstruction, orthognathic surgery, temporomandibular joint treatment and other applications. Additionally, we elucidate how the integration of 3D printing technology has reshaped clinical workflows and influenced treatment outcomes in oral and maxillofacial surgery, providing updates on advancements in ensuring accuracy and cost-effectiveness in 3D printing-based procedures.

Developing a production workflow for 3D-printed temporal bone surgical simulators

INTRODUCTION

3D-printed temporal bone models enable the training and rehearsal of complex otological procedures. To date, there has been no consolidation of the literature regarding the developmental process of 3D-printed temporal bone models. A brief review of the current literature shows that many of the key surgical landmarks of the temporal bone are poorly represented in models. This study aims to propose a novel design and production workflow to produce high-fidelity 3D-printed temporal bone models for surgical simulation.

METHODS

Developmental phases for data extraction, 3D segmentation and Computer Aided Design (CAD), and fabrication are outlined. The design and fabrication considerations for key anatomical regions, such as the mastoid air cells and course of the facial nerve, are expounded on with the associated strategy and design methods employed. To validate the model, radiological measurements were compared and a senior otolaryngologist performed various surgical procedures on the model.

RESULTS

Measurements between the original scans and scans of the model demonstrate sub-millimetre accuracy of the model. Assessment by the senior otologist found that the model was satisfactory in simulating multiple surgical procedures.

CONCLUSION

This study offers a systematic method for creating accurate 3D-printed temporal bone models for surgical training. Results show high accuracy and effectiveness in simulating surgical procedures, promising improved training and patient outcomes.

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.

A Three-Dimensional Anterior and Middle Cranial Fossa Model for Skull Base Surgical Training with Two Layers of the Colored Dura Mater

BACKGROUND

Adequate epidural procedures and anatomical knowledge are essential for the technical success of skull base surgery. We evaluated the usefulness of our three-dimensional (3D) model of the anterior and middle cranial fossa as a learning tool in improving knowledge of anatomy and surgical approaches, including skull base drilling and dura matter peeling techniques.

METHODS

Using a 3D printer, a bone model of the anterior and middle cranial fossa was created based on multi-detector row computed tomography data, incorporating artificial cranial nerves, blood vessels, and dura mater. The artificial dura mater was painted using different colors, with 2 pieces glued together to allow for the simulation of peeling the temporal dura propria from the lateral wall of the cavernous sinus. Two experts in skull base surgery and 1 trainee surgeon operated on this model and 12 expert skull base surgeons watched the operation video to evaluate this model subtlety on a scale of 1 to 5.

RESULTS

A total of 15 neurosurgeons, 14 of whom were skull base surgery expert, evaluated, scoring 4 or higher on most of the items. The experience of dural dissection and 3D positioning of important structures, including cranial nerves and blood vessels, was similar to that in actual surgery.

CONCLUSIONS

This model was designed to facilitate teaching anatomical knowledge and essential epidural procedure-related skills. It was shown to be useful for teaching essential elements of skull-base surgery.

3D printing method for bone tissue engineering scaffold

3D printing technology is an emerging technology. It constructs solid bodies by stacking materials layer by layer, and can quickly and accurately prepare bone tissue engineering scaffolds with specific shapes and structures to meet the needs of different patients. The field of life sciences has received a great deal of attention. However, different 3D printing technologies and materials have their advantages and disadvantages, and there are limitations in clinical application. In this paper, the technology, materials and clinical applications of 3D printed bone tissue engineering scaffolds are reviewed, and the future development trends and challenges in this field are prospected.

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.

Properties and Characteristics of Three-Dimensional Printed Head Models Used in Simulation of Neurosurgical Procedures: A Scoping Review

BACKGROUND

Intracranial surgery can be complex and high risk. Safety, ethical and financial factors make training in the area challenging. Head model 3-dimensional (3D) printing is a realistic training alternative to patient and traditional means of cadaver and animal model simulation.

OBJECTIVE

To describe important factors relating to the 3D printing of human head models and how such models perform as simulators.

METHODS

Searches were performed in PubMed, the Cochrane Library, Scopus, and Web of Science. Articles were screened independently by 3 reviewers using Covidence software. Data items were collected under 5 categories: study information; printers and processes; head model specifics; simulation and evaluations; and costs and production times.

RESULTS

Forty articles published over the last 10 years were included in the review. A range of printers, printing methods, and substrates were used to create head models and tissue types. Complexity of the models ranged from sections of single tissue type (e.g., bone) to high-fidelity integration of multiple tissue types. Some models incorporated disease (e.g., tumors and aneurysms) and artificial physiology (e.g., pulsatile circulation). Aneurysm clipping, bone drilling, craniotomy, endonasal surgery, and tumor resection were the most commonly practiced procedures. Evaluations completed by those using the models were generally favorable.

CONCLUSIONS

The findings of this review indicate that those who practice surgery and surgical techniques on 3D-printed head models deem them to be valuable assets in cranial surgery training. Understanding how surgical simulation on such models affects surgical performance and patient outcomes, and considering cost-effectiveness, are important future research endeavors.

Training in temporal bone drilling

Acquiring surgical experience in the operating room is increasingly difficult. Simulation of temporal bone drilling is therefore essential, and more and more widely used. The aim of this review is to clarify the limitations of classical surgical training, and to describe the different types of simulation available for temporal bone drilling. Systematic Medline search used the terms: "temporal bone" and training and surgery; "temporal bone" and training and drilling. Seventy-one of the 467 articles identified were relevant for this review. Various temporal bone simulators have been created to get around the limitations (ethical, financial, cultural, working time) of temporal bone drilling. They can be classified as cadaver, animal, physical or virtual models. The main advantages of physical and virtual prototyping are their ease of access, the possibility of repeating gestures on a standardised model, and the absence of ethical issues. Validation is essential before these simulators can be included in the curriculum, to ensure efficacy and thus improve patient safety in the operating room.

3D-Printed Models for Temporal Bone Surgical Training: A Systematic Review

OBJECTIVE

3D-printed models hold great potential for temporal bone surgical training as a supplement to cadaveric dissection. Nevertheless, critical knowledge on manufacturing remains scattered, and little is known about whether use of these models improves surgical performance. This systematic review aims to explore (1) methods used for manufacturing and (2) how educational evidence supports using 3D-printed temporal bone models.

DATA SOURCES

PubMed, Embase, the Cochrane Library, and Web of Science.

REVIEW METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, relevant studies were identified and data on manufacturing and validation and/or training extracted by 2 reviewers. Quality assessment was performed using the Medical Education Research Study Quality Instrument tool; educational outcomes were determined according to Kirkpatrick's model.

RESULTS

The search yielded 595 studies; 36 studies were found eligible and included for analysis. The described 3D-printed models were based on computed tomography scans from patients or cadavers. Processing included manual segmentation of key structures such as the facial nerve; postprocessing, for example, consisted of removal of print material inside the model. Overall, educational quality was low, and most studies evaluated their models using only expert and/or trainee opinion (ie, Kirkpatrick level 1). Most studies reported positive attitudes toward the models and their potential for training.

CONCLUSION

Manufacturing and use of 3D-printed temporal bones for surgical training are widely reported in the literature. However, evidence to support their use and knowledge about both manufacturing and the effects on subsequent surgical performance are currently lacking. Therefore, stronger educational evidence and manufacturing knowhow are needed for widespread implementation of 3D-printed temporal bones in surgical curricula.

Application of 3-dimensional printing technology combined with guide plates for thoracic spinal tuberculosis

BACKGROUND

To explore the accuracy and security of 3-dimensional (3D) printing technology combined with guide plates in the preoperative planning of thoracic tuberculosis and the auxiliary placement of pedicle screws during the operation.

METHODS

Retrospective analysis was performed on the data of 60 cases of thoracic tuberculosis patients treated with 1-stage posterior debridement, bone graft fusion, and pedicle screw internal fixation in the Department of Orthopedics, Zhejiang Chinese Medicine and Western Medicine Integrated Hospital from March 2017 to February 2019. There were 31 males and 29 females; age: 41 to 52 years old, with an average of (46.6 ± 2.0) years old. According to whether 3D printing personalized external guide plates are used or not, they are divided into 2 groups: 30 cases in 3D printing group (observation group), and 30 cases in pedicle screw placement group (control group). A 1:1 solid model of thoracic spinal tuberculosis and personalized pedicle guide plates was created using the 3D printing technology combined with guide plates in the observation group. Stability and accuracy tests were carried out in vitro and in vivo. 30 patients in the control group used conventional nail placement with bare hands. The amount of blood loss, the number of fluoroscopy, the operation time, and the occurrence of adverse reactions related to nail placement were recorded. After the operation, the patients were scanned by computed tomography to observe the screw position and grade the screw position to evaluate the accuracy of the navigation template. All patients were followed up for more than 1 year. Visual Analogue Scale scores, erythrocyte sedimentation rate, and C-reactive protein were evaluated before surgery, 6 months after surgery, and 12 months after surgery.

RESULTS

Sixty patients were followed up for 6 to 12 months after surgery. One hundred seventy-five and 177 screws were placed in the 3D printing group and the free-hand placement group, respectively. The rate of screw penetration was only 1.14% in the 3D-printed group (all 3 screws were grade 1) and 6.78% in the free-hand nail placement group (12 screws, 9 screws were grade 1 and 3 screws were grade 2). The difference was statistically significant (P = .047). The operation time of the 3D printing group ([137.67 ± 9.39] minutes), the cumulative number of intraoperative fluoroscopy ([4.67 ± 1.03] times), and the amount of intraoperative blood loss ([599.33 ± 83.37] mL) were significantly less than those in the manual nail placement group ([170.00 ± 20.48] minutes, [9.38 ± 1.76] times, [674.6 ± 83.61] mL). The differences were statistically significant (P < .05). There was no significant difference in VAS score and Oswestry disability index score between the 2 groups of patients before operation, 3 and 6 months after operation (P > .05).

CONCLUSION

The 3D printing technology combined with guide plate is used in thoracic spinal tuberculosis surgery to effectively reduce the amount of bleeding, shorten the operation time, and increase the safety and accuracy of nail placement.

Additive manufacturing pertaining to bone: Hopes, reality and future challenges for clinical applications

For the past 20 years, the democratization of additive manufacturing (AM) technologies has made many of us dream of: low cost, waste-free, and on-demand production of functional parts; fully customized tools; designs limited by imagination only, etc. As every patient is unique, the potential of AM for the medical field is thought to be considerable: AM would allow the division of dedicated patient-specific healthcare solutions entirely adapted to the patients' clinical needs. Pertinently, this review offers an extensive overview of bone-related clinical applications of AM and ongoing research trends, from 3D anatomical models for patient and student education to ephemeral structures supporting and promoting bone regeneration. Today, AM has undoubtably improved patient care and should facilitate many more improvements in the near future. However, despite extensive research, AM-based strategies for bone regeneration remain the only bone-related field without compelling clinical proof of concept to date. This may be due to a lack of understanding of the biological mechanisms guiding and promoting bone formation and due to the traditional top-down strategies devised to solve clinical issues. Indeed, the integrated holistic approach recommended for the design of regenerative systems (i.e., fixation systems and scaffolds) has remained at the conceptual state. Challenged by these issues, a slower but incremental research dynamic has occurred for the last few years, and recent progress suggests notable improvement in the years to come, with in view the development of safe, robust and standardized patient-specific clinical solutions for the regeneration of large bone defects.

3D printed bone models in oral and cranio-maxillofacial surgery: a systematic review

AIM

This systematic review aimed to evaluate the use of three-dimensional (3D) printed bone models for training, simulating and/or planning interventions in oral and cranio-maxillofacial surgery.

MATERIALS AND METHODS

A systematic search was conducted using PubMed® and SCOPUS® databases, up to March 10, 2019, by following the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol. Study selection, quality assessment (modified Critical Appraisal Skills Program tool) and data extraction were performed by two independent reviewers. All original full papers written in English/French/Italian and dealing with the fabrication of 3D printed models of head bone structures, designed from 3D radiological data were included. Multiple parameters and data were investigated, such as author's purpose, data acquisition systems, printing technologies and materials, accuracy, haptic feedback, variations in treatment time, differences in clinical outcomes, costs, production time and cost-effectiveness.

RESULTS

Among the 1157 retrieved abstracts, only 69 met the inclusion criteria. 3D printed bone models were mainly used as training or simulation models for tumor removal, or bone reconstruction. Material jetting printers showed best performance but the highest cost. Stereolithographic, laser sintering and binder jetting printers allowed to create accurate models with adequate haptic feedback. The cheap fused deposition modeling printers exhibited satisfactory results for creating training models.

CONCLUSION

Patient-specific 3D printed models are known to be useful surgical and educational tools. Faced with the large diversity of software, printing technologies and materials, the clinical team should invest in a 3D printer specifically adapted to the final application.

Three-Dimensional Printed Models for Lateral Skull Base Surgical Training: Anatomy and Simulation of the Transtemporal Approaches

BACKGROUND

Three-dimensional (3D) printing holds great potential for lateral skull base surgical training; however, studies evaluating the use of 3D-printed models for simulating transtemporal approaches are lacking.

OBJECTIVE

To develop and evaluate a 3D-printed model that accurately represents the anatomic relationships, surgical corridor, and surgical working angles achieved with increasingly aggressive temporal bone resection in lateral skull base approaches.

METHODS

Cadaveric temporal bones underwent thin-slice computerized tomography, and key anatomic landmarks were segmented using 3D imaging software. Corresponding 3D-printed temporal bone models were created, and 4 stages of increasingly aggressive transtemporal approaches were performed (40 total approaches). The surgical exposure and working corridor were analyzed quantitatively, and measures of face validity, content validity, and construct validity in a cohort of 14 participants were assessed.

RESULTS

Stereotactic measurements of the surgical angle of approach to the mid-clivus, residual bone angle, and 3D-scanned infill volume demonstrated comparable changes in both the 3D temporal bone models and cadaveric specimens based on the increasing stages of transtemporal approaches (PANOVA <.003, <.007, and <.007, respectively), indicating accurate representation of the surgical corridor and working angles in the 3D-printed models. Participant assessment revealed high face validity, content validity, and construct validity.

CONCLUSION

The 3D-printed temporal bone models highlighting key anatomic structures accurately simulated 4 sequential stages of transtemporal approaches with high face validity, content validity, and construct validity. This strategy may provide a useful educational resource for temporal bone anatomy and training in lateral skull base approaches.

3D-printed pediatric temporal bone models for surgical training: a patient-specific and low-cost alternative

Aim: To determine the usefulness of low-cost 3D-printed pediatric temporal bone models and to define if they could be used as a tool for large-scale surgical training based on their affordability. Materials & methods: Prototypes of a pediatric temporal bone were printed using fused deposition modeling 3D printing technique. The prototypes were drilled. The surgical simulation experience was registered by means of a Likert scale questionnaire. Results: The prototypes adequately simulated a cadaveric temporal bone. The costs associated with production were low compared with other commercial models making it a cost-effective alternative for a temporal bone laboratory. Conclusion: Printed temporal bones created by means of fused deposition modeling are useful for surgical simulation and training in otolaryngology, and it is possible to achieve detailed low-cost models.

Virtual, 3-Dimensional Temporal Bone Model and Its Educational Value for Neurosurgical Trainees

OBJECTIVE

Learning complex neuroanatomy is an arduous yet important task for every neurosurgical trainee. As technology has advanced, various modalities have been created to aid our understanding of anatomy. This study sought to assess the educational value of a virtual, 3-dimensional (3D) temporal bone model.

METHODS

The 3D temporal bone model was created with assistance of computer graphic designers and published online. Its educational value as a teaching was tool was assessed by querying 73 neurosurgery residents at 4 institutions and was compared with that of a standard, 2-dimensional (2D) temporal bone resource. Data were collected via a survey, and significance among responses was analyzed via a univariate chi-square test.

RESULTS

The survey response rate was 37%. Greater than 90% of residents preferred to study with the 3D model compared with the 2D resource and felt that the 3D model allowed them understand the anatomy more realistically (P = 0.001). Moreover, >90% of residents believed that reviewing the 3D model before an actual surgery could lead to improved operative efficiency and safety (P = 0.001).

CONCLUSIONS

This study demonstrates the utility of a novel, 3D temporal bone model as a teaching tool for neurosurgery residents. The model contains accurate anatomic structures and allows user interaction via a virtual, immersive environment.

Augmented Reality, Surgical Navigation, and 3D Printing for Transcanal Endoscopic Approach to the Petrous Apex

Otolaryngologists increasingly use patient-specific 3-dimensional (3D)–printed anatomic physical models for preoperative planning. However, few reports describe concomitant use with virtual models. Herein, we aim to (1) use a 3D-printed patient-specific physical model with lateral skull base navigation for preoperative planning, (2) review anatomy virtually via augmented reality (AR), and (3) compare physical and virtual models to intraoperative findings in a challenging case of a symptomatic petrous apex cyst. Computed tomography (CT) imaging was manually segmented to generate 3D models. AR facilitated virtual surgical planning. Navigation was then coupled to 3D-printed anatomy to simulate surgery using an endoscopic approach. Intraoperative findings were comparable to simulation. Virtual and physical models adequately addressed details of endoscopic surgery, including avoidance of critical structures. Complex lateral skull base cases may be optimized by surgical planning via 3D-printed simulation with navigation. Future studies will address whether simulation can improve patient outcomes.

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

Background/Aims

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

Methods

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

Results

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

Conclusion

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

3D Printed Surgical Simulation Models as educational tool by maxillofacial surgeons

INTRODUCTION

The aim of this study was to evaluate whether inexpensive 3D models can be suitable to train surgical skills to dental students or oral and maxillofacial surgery residents. Furthermore, we wanted to know which of the most common filament materials, acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), can better simulate human bone according to surgeons' subjective perceptions.

MATERIALS AND METHODS

Upper and lower jaw models were produced with common 3D desktop printers, ABS and PLA filament and silicon rubber for soft tissue simulation. Those models were given to 10 blinded, experienced maxillofacial surgeons to perform sinus lift and wisdom teeth extraction. Evaluation was made using a questionnaire.

RESULTS

Because of slightly different density and filament prices, each silicon-covered model costs between 1.40-1.60 USD (ABS) and 1.80-2.00 USD (PLA) based on 2017 material costs. Ten experienced raters took part in the study. All raters deemed the models suitable for surgical education. No significant differences between ABS and PLA were found, with both having distinct advantages.

CONCLUSION

The study demonstrated that 3D printing with inexpensive printing filaments is a promising method for training oral and maxillofacial surgery residents or dental students in selected surgical procedures. With a simple and cost-efficient manufacturing process, models of actual patient cases can be produced on a small scale, simulating many kinds of surgical procedures.

Clinical 3D printing: A protected health information (PHI) and compliance perspective

Advanced manufacturing techniques such as 3-dimensional (3D) printing, while mature in other industries, are starting to become more commonplace in clinical care. Clinicians are producing physical objects based on patient clinical data for use in planning care and educating patients, all of which should be managed like any other healthcare system data, except it exists in the "real" world. There are currently no provisions in the Health Insurance Portability and Accountability Act (HIPAA) either in its original 1996 form or in more recent updates that address the nature of physical representations of clinical data. We submit that if we define the source data as protected health information (PHI), then the objects 3D printed from that data need to be treated as both (PHI), and if used clinically, part of the clinical record, and propose some basic guidelines for quality and privacy like all documentation until regulatory frameworks can catch up to this technology. Many of the mechanisms designed in the paper and film chart era will work well with 3D printed patient data.

European status on temporal bone training: a questionnaire study

PURPOSE

In otorhinolaryngology training, introduction to temporal bone surgery through hands-on practice on cadaveric human temporal bones is the gold-standard training method before commencing supervised surgery. During the recent decades, the availability of such specimens and the necessary laboratory facilities for training seems to be decreasing. Alternatives to traditional training can consist of drilling artificial models made of plaster or plastic but also virtual reality (VR) simulation. Nevertheless, the integration and availability of these alternatives into specialist training programs remain unknown.

METHODS

We conducted a questionnaire study mapping current status on temporal bone training and included responses from 113 departments from 23 countries throughout Europe.

RESULTS

In general, temporal bone training during residency in ORL is organized as in-house training, or as participation in national or international temporal bone courses or some combination hereof. There are considerable differences in the availability of training facilities for temporal bone surgery and the number of drillings each ORL trainee can perform. Cadaveric dissection is still the most commonly used training modality.

CONCLUSIONS

VR simulation and artificial models are reported to be used at many leading training departments already. Decreasing availability of cadavers, lower costs of VR simulation and artificial models, in addition to established evidence for a positive effect on the trainees' competency, were reported as the main reasons. Most remaining departments expect to implement VR simulation and artificial models for temporal bone training into their residency programs in the near future.

Surgical applications of three-dimensional printing: a review of the current literature & how to get started

Three dimensional (3D) printing involves a number of additive manufacturing techniques that are used to build structures from the ground up. This technology has been adapted to a wide range of surgical applications at an impressive rate. It has been used to print patient-specific anatomic models, implants, prosthetics, external fixators, splints, surgical instrumentation, and surgical cutting guides. The profound utility of this technology in surgery explains the exponential growth. It is important to learn how 3D printing has been used in surgery and how to potentially apply this technology. PubMed was searched for studies that addressed the clinical application of 3D printing in all surgical fields, yielding 442 results. Data was manually extracted from the 168 included studies. We found an exponential increase in studies addressing surgical applications for 3D printing since 2011, with the largest growth in craniofacial, oromaxillofacial, and cardiothoracic specialties. The pertinent considerations for getting started with 3D printing were identified and are discussed, including, software, printing techniques, printing materials, sterilization of printing materials, and cost and time requirements. Also, the diverse and increasing applications of 3D printing were recorded and are discussed. There is large array of potential applications for 3D printing. Decreasing cost and increasing ease of use are making this technology more available. Incorporating 3D printing into a surgical practice can be a rewarding process that yields impressive results.