Endoscopic skull base training using 3D printed models with pre-existing pathology

Pilot Validation of a 3-Dimensional Printed Pituitary Adenoma, Vascular Injury, and Cerebrospinal Fluid Leak Surgical Simulator

BACKGROUND AND OBJECTIVES

Endoscopic skull base surgery is a subspecialty field which would benefit significantly from high-fidelity surgical simulators. Giving trainees the opportunity to flatten their learning curve by practicing a variety of procedures on surgical simulators will inevitably improve patient outcomes.

METHODS

Four neurosurgeons, 8 otolarynologists, and 6 expert course faculty agreed to participate. All participants were asked to perform a transsphenoidal exposure and resection of a pituitary adenoma, repair a cerebrospinal fluid (CSF) leak, control a carotid injury, and repair a skull base defect. The content, face, and construct validity of the 3-dimensional printed model was examined.

RESULTS

The heart rate of the participants significantly increased from baseline when starting the carotid injury simulation (mean 90 vs 121, P = .029) and significantly decreased once the injury was controlled (mean 121 vs 110, P = .033, respectively). The participants reported a significant improvement in anxiety in facing a major vascular injury, as well as an increase in their confidence in management of major vascular injury, resecting a pituitary adenoma and repair of a CSF leak using a 5-point Likert scale (mean 4.42 vs 3.58 P = .05, 2 vs 3.25 P < .001, 2.36 vs 4.27 P < .001 and 2.45 vs 4.0 P = .001, respectively). The mean Objective Structured Assessment of Technical Skills score for experienced stations was 4.4, significantly higher than the Objective Structured Assessment of Technical Skills score for inexperienced stations (mean 3.65, P = .016).

CONCLUSION

We have demonstrated for the first time a validated 3-dimensional printed surgical simulator for endoscopic pituitary surgery that allows surgeons to practice a transsphenoidal approach, surgical resection of a pituitary adenoma, repair of a CSF leak in the diaphragma sellae, control of a carotid injury, and repair of skull base defect.

Successful use of a patient specific 3D-printed biomodel as surgical guide for excision of juvenile nasopharyngeal angiofibroma extending to skull base: A case report

Background

3-Dimensional (3D) printing has proven its role in various fields. Recently, 3D printing has also been introduced in the otolaryngology domain. The nasopharynx, paranasal sinuses, and the anterior skull base have a complex anatomy. Critical structures must be delicately protected and preserved during a surgical procedure. It is, therefore, very important for the surgeon to have an excellent spatial understanding of the complex surgical field that is being traversed.

Case Description

Our case is of a 19-year-old male with a 2-month history of recurrent epistaxis, nasal blockage, and headache. Based on the computed tomography scan and the clinical presentation, the patient was diagnosed with juvenile nasopharyngeal angiofibroma. The patient underwent angioembolization of the tumor followed by endoscopic surgical resection. The patient remained stable postoperatively and demonstrated a good recovery in the follow-up visit with no signs of cranial deficits. This case report highlights the use of a patient-specific 3D-printed biomodel to visualize this rare tumor of the nasopharynx. The benefits of using the model in surgical planning, patient education, and resident training are reported. We found that the ability to visualize the tumor on a tangible model, viewing its actual size in relation to the adjacent anatomy and all the structures associated with it, greatly enhances the surgeon's capacity to tackle such a difficult tumor endoscopically.

Conclusion

Incorporating 3D-printed biomodels in surgical practice should result in improved outcomes for the patients.

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.

Training models and simulators for endoscopic transsphenoidal surgery: a systematic review

Endoscopic transsphenoidal surgery is a novel surgical technique requiring specific training. Different models and simulators have been recently suggested for it, but no systematic review is available. To provide a systematic and critical literature review and up-to-date description of the training models or simulators dedicated to endoscopic transsphenoidal surgery. A search was performed on PubMed and Scopus databases for articles published until February 2023; Google was also searched to document commercially available. For each model, the following features were recorded: training performed, tumor/arachnoid reproduction, assessment and validation, and cost. Of the 1199 retrieved articles, 101 were included in the final analysis. The described models can be subdivided into 5 major categories: (1) enhanced cadaveric heads; (2) animal models; (3) training artificial solutions, with increasing complexity (from "box-trainers" to multi-material, ct-based models); (4) training simulators, based on virtual or augmented reality; (5) Pre-operative planning models and simulators. Each available training model has specific advantages and limitations. Costs are high for cadaver-based solutions and vary significantly for the other solutions. Cheaper solutions seem useful only for the first stages of training. Most models do not provide a simulation of the sellar tumor, and a realistic simulation of the suprasellar arachnoid. Most artificial models do not provide a realistic and cost-efficient simulation of the most delicate and relatively common phase of surgery, i.e., tumor removal with arachnoid preservation; current research should optimize this to train future neurosurgical generations efficiently and safely.

Efficacy of three-dimensional models for medical education: A systematic scoping review of randomized clinical trials

To estimate the efficacy of three-dimensional (3D) models for medical education.

METHODS

A systematic scoping review was performed containing diverse databases such as SCOPUS, PubMed/MEDLINE, SCIELO, and LILACS. MeSH terms and keywords were stipulated to explore randomized clinical trials (RCTs) in all languages. Solely RCTs that accomplished the eligibility criteria were admitted.

RESULTS

Fifteen RCTs including 1659 medical students were chosen. Five RCTs studied heart models, 3 RCTs explored facial, spinal and bone fractures and the rest of the trials investigated eye, arterial, pelvic, hepatic, chest, skull, and cleft lip and palate models. Regarding the efficacy of 3D models, in terms of learning skills and knowledge gained by medical students, most RCTs reported higher scores. Considering the test-taking times, the results were variable. Two RCTs showed less time for the 3D group, another RCT indicated variable results in the response times of the test depending on the anatomical zone evaluated, while another described that the students in the 3D group were slightly quicker to answer all questions when compared with the traditional group, but without statistical significance. The other 11 experiments did not present results about test-taking times. Most students in all RCTs indicated satisfaction, enjoyment, and interest in utilizing the 3D systems, and recognized that their abilities were enhanced.

CONCLUSIONS

Higher efficacy in terms of learning skills and knowledge gained was observed when the 3D systems were used by medical students. Undergraduates also expressed great satisfaction with the use of these technologies. Regarding the test-taking times, the results favored the 3D group.

High fidelity simulation of the endoscopic transsphenoidal approach: Validation of the UpSurgeOn TNS Box

Objective

Endoscopic endonasal transsphenoidal surgery is an established technique for the resection of sellar and suprasellar lesions. The approach is technically challenging and has a steep learning curve. Simulation is a growing training tool, allowing the acquisition of technical skills pre-clinically and potentially resulting in a shorter clinical learning curve. We sought validation of the UpSurgeOn Transsphenoidal (TNS) Box for the endoscopic endonasal transsphenoidal approach to the pituitary fossa.

Methods

Novice, intermediate and expert neurosurgeons were recruited from multiple centres. Participants were asked to perform a sphenoidotomy using the TNS model. Face and content validity were evaluated using a post-task questionnaire. Construct validity was assessed through post-hoc blinded scoring of operative videos using a Modified Objective Structured Assessment of Technical Skills (mOSAT) and a Task-Specific Technical Skill scoring system.

Results

Fifteen participants were recruited of which n = 10 (66.6%) were novices and n = 5 (33.3%) were intermediate and expert neurosurgeons. Three intermediate and experts (60%) agreed that the model was realistic. All intermediate and experts (n = 5) strongly agreed or agreed that the TNS model was useful for teaching the endonasal transsphenoidal approach to the pituitary fossa. The consensus-derived mOSAT score was 16/30 (IQR 14-16.75) for novices and 29/30 (IQR 27-29) for intermediate and experts (p < 0.001, Mann-Whitney U). The median Task-Specific Technical Skill score was 10/20 (IQR 8.25-13) for novices and 18/20 (IQR 17.75-19) for intermediate and experts (p < 0.001, Mann-Whitney U). Interrater reliability was 0.949 (CI 0.983-0.853) for OSATS and 0.945 (CI 0.981-0.842) for Task-Specific Technical Skills. Suggested improvements for the model included the addition of neuro-vascular anatomy and arachnoid mater to simulate bleeding vessels and CSF leak, respectively, as well as improvement in materials to reproduce the consistency closer to that of human tissue and bone.

Conclusion

The TNS Box simulation model has demonstrated face, content, and construct validity as a simulator for the endoscopic endonasal transsphenoidal approach. With the steep learning curve associated with endoscopic approaches, this simulation model has the potential as a valuable training tool in neurosurgery with further improvements including advancing simulation materials, dynamic models (e.g., with blood flow) and synergy with complementary technologies (e.g., artificial intelligence and augmented reality).

Construct and Validation of a Three-Dimensional Physical Model for Training in Transnasal Office Procedures

Most simulation models in rhinology are costly and are primarily meant to enhance endoscopic surgical skills. The present study aimed to construct a 3-dimensional model of the nose which is easily constructible with commonly available low cost plaster of Paris (POP) and assess its usefulness in training residents in basic transnasal procedures. A nose model was created using plaster of Paris and assessed for face and content validity by experts in rhinology while a construct validation was performed on five specified tasks by residents. All experts agreed with the resemblance of 10 of the 13 anatomical landmarks in the POP model and its utility in teaching basic transnasal procedures. There was a statistically significant difference in the time taken by I and III year residents in performing a diagnostic nasal endoscopy (p = 0.007), anterior nasal packing with polyvinyl alcohol tampon (p = 0.007), posterior nasal packing with Foley's catheter (p = 0) and nasopharyngeal swabbing (p = 0.025). This study demonstrates the construct of a low cost 3-dimensional POP model and validates its utility in training residents in routine transnasal rhinological procedures. Face and content validation showed a high degree of resemblance to human anatomy with good agreement that this model could increase resident competency. The significant difference in time taken by residents at various levels of experience in performing rhinological procedures also confirmed a reliable construct validity. The described model could be an affordable and easily constructible alternative tool to other simulation models in otorhinolaryngology residency programs especially in developing countries.

Development of 3-dimensional printed simulation surgical training models for endoscopic endonasal and transorbital surgery

Background

Endoscopic skull base surgery (ESBS) is complex, requiring methodical and unremitting surgical training. Herein, we describe the development and evaluation of a novel three-dimensional (3D) printed simulation model for ESBS. We further validate the efficacy of this model as educational support in neurosurgical training.

Methods

A patient-specific 3D printed simulation model using living human imaging data was established and evaluated in a task-based hands-on dissection program. Endoscopic endonasal and transorbital procedures were simulated on the model by neurosurgeons and otorhinolaryngology surgeons of varying experience. All procedures were recorded using a high-definition camera coupled with digital video recorder system. The participants were asked to complete a post-procedure questionnaire to validate the efficacy of the model.

Results

Fourteen experts and 22 trainees participated in simulations, and the 32 participants completed the post-procedure survey. The anatomical realism was scored as 4.0/5.0. The participants rated the model as helpful in hand-eye coordination training (4.7/5.0) and improving surgical skills (4.6/5.0) for ESBS. All participants believed that the model was useful as educational support for trainees (4.7 [ ± 0.5]). However, the color (3.6/5.0) and soft tissue feedback parameters (2.8/5) scored low.

Conclusion

This study shows that high-resolution 3D printed skull base models for ESBS can be generated with high anatomical accuracy and acceptable haptic feedback. The simulation program of ESBS using this model may be supplemental or provide an alternative training platform to cadaveric dissection.

Computer assisted skull base surgery: a contemporary review

Skull base surgery has evolved significantly since Harvey Cushing‘s first descriptions in the early 1900s. Computer aided surgery (CAS) applications continue to expand; they include virtual surgical planning, augmented and virtual reality, 3D printing of models/cutting guides/implants, surgical navigation, and intraoperative imaging. The authors will review the current skull base CAS literature and propose a computer aided surgical workflow categorizing these applications into 3 phases: 1) Virtual planning, 2) Surgical execution, 3) Intraoperative verification.

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.

Systematic review and meta-analysis of 3D-printing in otolaryngology education

INTRODUCTION

Three-dimensional (3D) printing has received increased attention in recent years and has many applications. In the field of otolaryngology surgery, 3D-printed models have shown potential educational value and a high fidelity to actual tissues. This provides an opportunity for trainees to gain additional exposure, especially as conventional educational tools, such as cadavers, are expensive and in limited supply. The purpose of this study was to perform a meta-analysis of the uses of 3D-printing in otolaryngology education. The primary outcomes of investigation were surgical utility, anatomical similarity, and educational value of 3D-printed models. Secondary outcomes of interest included country of implementation, 3D-printer materials and costs, types of surgical simulators, and the levels of training of participants.

METHODS

MEDLINE, Embase, Web of Science, Google Scholar and previous reviews were searched from inception until June 2021 for eligible articles. Title, abstract, and data extraction were performed in duplicate. Data were analyzed using random-effects models. The National Institute of Health Quality Assessment Tool was used to rate the quality of the evidence.

RESULTS

A total of 570 abstracts were identified and screened by 2 independent reviewers. Of the 274 articles reviewed in full text, 46 articles met the study criteria and were included in the meta-analysis. Surgical skill utility was reported in 42 studies (563 participants) and had a high degree of acceptance (84.8%, 95% CI: 81.1%-88.4%). The anatomical similarity was reported in 39 studies (484 participants) and was received positively at 80.6% (95% CI: 77.0%-84.2%). Educational value was described in 36 studies (93 participants) and had the highest approval rating by participants at 90.04% (87.20%-92.88%). A subgroup analysis by year of publication demonstrated that studies published after 2015 had higher ratings across all outcomes compared to those published prior to 2015.

CONCLUSION

This study found that 3D-printing interventions in otolaryngology demonstrated surgical, anatomical, and educational value. In addition, the approval ratings of 3D-printed models indicate a positive trend over time. Future educational programs may consider implementing 3D-printing on a larger scale within the medical curriculum to enhance exposure to otolaryngology.

Simulation training in endoscopic skull base surgery: A scoping review

Objective

Methods

Results

Conclusions

Designing a 3D Printed Model of the Skull-Base: A Collaboration Between Clinicians and Industry

INTRODUCTION

The role of three dimensional (3D) printing in neurosurgical education is becoming increasingly common. Notably, 3D printing can simulate complex anatomical pathways that may be difficult to regularly and accurately reproduce in cadavers. One such example is the course of the facial nerve within the temporal bone and its relation to the labyrinth. This can aid pre-surgical planning and minimise surgical complications. Here we aim to develop a novel anatomically accurate model of the skull base which demonstrates key neuro vascular components and the course of the facial nerve within the temporal bone by developing a 3D printed model of the skull-base that can be used for medical education and pre-surgical planning.

MATERIALS AND METHODS

We utilised a combination of Computed Tomography (CT) and angiography scans to reconstruct the skull base and its vascular contents. Neural components were digitally incorporated under the guidance of the Oxford neurosurgical team and the anatomy department. The model was integrated and printed using polymer jetting.

RESULTS

The model was successfully printed, with all neurovascular components included. Notably we were able to highlight the intra-temporal course of the facial nerve by creating a bony window within the temporal bone.

CONCLUSION

Through a collaboration with industry and a multidisciplinary team, we were able to reproduce the base of the skull from patient neuro-imaging. Our model is both cost-effective, reproducible and can aid both medical students and neurosurgical trainees in their training/education.

Remote Training of Functional Endoscopic Sinus Surgery With Advanced Manufactured 3D Sinus Models and a Telemedicine System

Objective: Traditionally, cadaveric courses have been an important tool in surgical education for Functional Endoscopic Sinus Surgery (FESS). The recent COVID-19 pandemic, however, has had a significant global impact on such courses due to its travel restrictions, social distancing regulations, and infection risk. Here, we report the world-first remote (Functional Endoscopic Sinus Surgery) FESS training course between Japan and Australia, utilizing novel 3D-printed sinus models. We examined the feasibility and educational effect of the course conducted entirely remotely with encrypted telemedicine software.

Methods: Three otolaryngologists in Hokkaido, Japan, were trained to perform frontal sinus dissections on novel 3D sinus models of increasing difficulty, by two rhinologists located in Adelaide, South Australia. The advanced manufactured sinus models were 3D printed from the Computed tomography (CT) scans of patients with chronic rhinosinusitis. Using Zoom and the Quintree telemedicine platform, the surgeons in Adelaide first lectured the Japanese surgeons on the Building Block Concept for a three Dimensional understanding of the frontal recess. They in real time directly supervised the surgeons as they planned and then performed the frontal sinus dissections. The Japanese surgeons were asked to complete a questionnaire pertaining to their experience and the time taken to perform the frontal dissection was recorded. The course was streamed to over 200 otolaryngologists worldwide.

Results: All dissectors completed five frontal sinusotomies. The time to identify the frontal sinus drainage pathway (FSDP) significantly reduced from 1,292 ± 672 to 321 ± 267 s (p = 0.02), despite an increase in the difficulty of the frontal recess anatomy. Image analysis revealed the volume of FSDP was improved (2.36 ± 0.00 to 9.70 ± 1.49 ml, p = 0.014). Questionnaires showed the course's general benefit was 95.47 ± 5.13 in dissectors and 89.24 ± 15.75 in audiences.

Conclusion: The combination of telemedicine software, web-conferencing technology, standardized 3D sinus models, and expert supervision, provides excellent training outcomes for surgeons in circumstances when classical surgical workshops cannot be realized.

Three-dimensional printing in otolaryngology education: a systematic review

PURPOSE

The progressive expansion of the technology that facilitates the development of three-dimensional (3D) printing within the field of otorhinolaryngology has opened up a new study front in medicine. The objective of this study is to systematically review scientific publications describing the development of 3D models having applications in otorhinolaryngology, with emphasis on subareas with a large number of publications, as well as the countries in which the publications are concentrated.

METHODS

In this literature review, specific criteria were used to search for publications on 3D models. The review considered articles published in English on the development of 3D models to teach otorhinolaryngology. The studies with presurgical purposes or without validation of the task by surgeons were excluded from this review.

RESULTS

This review considered 39 articles published in 10 countries between 2012 and 2021. The works published prior to 2012 were not considered as per the inclusion criteria for the research. Among the 39 simulators selected for review, otology models comprised a total of 15 publications (38%); they were followed by rhinology, with 12 (31%); laryngology, with 8 (21%); and head and neck surgery, with 4 publications (10%).

CONCLUSION

The use of 3D technology and printing is well established in the context of surgical education and simulation models. The importance of developing new technological tools to enhance 3D printing and the current limitations in obtaining appropriate animal and cadaver models signify the necessity of investing more in 3D models.

Crisis Management Simulation: The Value of Interdisciplinary Debriefing

OBJECTIVE

Simulation offers an important avenue for surgical and anesthesia training. This is especially important for crisis management scenarios where individuals need to act quickly and efficiently for optimal patient care. Practice based performance can be measured and real time feedback provided during debriefing scenarios.

METHODS

In this paper, we highlight a dual anesthesia and otolaryngology cavernous carotid injury scenario. The trials were run three different times with inter-trial debriefing.

RESULTS

The focused debriefing improved resident performance in terms of blood loss on subsequent trials. Furthermore, the learners provided important feedback regarding the utility of training and how it improved their ability to handle crisis management scenarios in the future.

CONCLUSION

Debriefing for crisis management in a simulation trial improves performance and trainee confidence. Follow up studies will evaluate real world effectiveness over a longer follow up period.

Advanced Magnetic Resonance Imaging of the Skull Base

Magnetic resonance (MR) imaging is a crucial tool for evaluation of the skull base, enabling characterization of complex anatomy by utilizing multiple image contrasts. Recent technical MR advances have greatly enhanced radiologists' capability to diagnose skull base pathology and help direct management. In this paper, we will summarize cutting-edge clinical and emerging research MR techniques for the skull base, including high-resolution, phase-contrast, diffusion, perfusion, vascular, zero echo-time, elastography, spectroscopy, chemical exchange saturation transfer, PET/MR, ultra-high-field, and 3D visualization. For each imaging technique, we provide a high-level summary of underlying technical principles accompanied by relevant literature review and clinical imaging examples.

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.

Multimaterial and multicolor 3D-printed model in training of transnasal endoscopic surgery for pituitary adenoma

OBJECTIVE

The aim of the present study was to investigate the practical value of a multimaterial and multicolor 3D-printed model in anatomical teaching, surgical training, and preoperative planning of transnasal endoscopic surgery for pituitary adenoma.

METHODS

Multimodality neuroimaging data were obtained in a 42-year-old healthy male volunteer and a 40-year-old female patient with an invasive nonfunctional pituitary adenoma. Three 3D-printed models were produced: a monomaterial and monocolor model, a monomaterial and multicolor model, and a multimaterial and multicolor model. The effects on anatomical teaching and surgical training for exposing the vidian nerve were assessed by 12 residents, and the training effect was validated on cadavers. The practical values for preoperative planning were evaluated by 6 experienced neurosurgeons. All evaluations were based on 5-point Likert questionnaires.

RESULTS

The multimaterial and multicolor model was superior to the monomaterial models in surgical training for exposing the vidian nerve (Fisher test; p < 0.05). In addition, the multimaterial and multicolor model was superior to the monomaterial models in anatomical teaching and preoperative planning (Friedman test; p < 0.05).

CONCLUSIONS

Multimaterial and multicolor 3D printing technology makes it convenient and efficient to produce a practical model for simulating individualized and complex anatomical structures in the sellar region. Furthermore, the multimaterial model can provide a more realistic manipulative experience for surgical training and facilitate the preoperative planning.

The Wooden Skull: An Innovation through the Use of Local Materials and Technology to Promote the Teaching and Learning of Human Anatomy

Skeleton models are important in facilitating a student's easy retention and recollection of information in the future. These may assist students carry out hands-on practice in order to acquire and practice new skills that are relevant to first aid. The increasing number of medical institutions and medical students attracts the challenge of inadequate facilitation of the teaching and learning processes. This warrants a study and/or an exploration of an alternative solution such as wooden models in order to solve the problem of scarce and ethically restricted human teaching aids. Wooden pieces (50 cm length × 20 cm diameter) from a Jacaranda mimosifolia tree were prepared for the carving process, and wooden replicas of human skulls were made. Two experimental groups of randomly selected medical students (60: active and 60: control) were separately taught using wooden and natural skull models, respectively. The two groups were assessed and evaluated using the natural skull models to compare their understanding of the anatomy of the skull. Additionally, opinion statements were collected from participants in the active group during the oral examination. Six (6) wooden skull models were produced and used for experimental study. Comparisons of academic scores (mean and median) between active (students using the wooden skull) and control (students using natural skull) groups showed no statistically significant difference (P ≥ 0.05). Concerning the enhancement of learning skills, the wooden model was constructed in a way that would be able to enhance learning as it would be the natural skull. The wooden skull model, with more improvement in structural formation, can adequately facilitate the teaching and learning of anatomy of the human skull. This project and the experimental study about utilization of the wooden skull model provide a good potential of using the wooden models to supplement the use of the natural human skull.

Rhinology: Simulation Training (Part 2)

Purpose of Review

Recently, there has been an expansion of novel technologies in simulation training. The aim of this review was to examine existing evidence about training simulators in rhinology, their incorporation into real training programmes and translation of these skills into the operating room. The first part focuses on the virtual and augmented reality simulators. The second part describes the role of physical (i.e. non-computer-based) models of endoscopic sinus surgery.

Recent Findings

We learned that an ideal sinus surgery model would score highly in all standard measures of validity whilst maintaining an attainable cost. This is a challenging goal that is worthy of pursuit given that simulation training has been shown to be cost-effective option in other domains. Non-AR or VR models are attractive ways to fill gaps in simulation training whilst reducing compared with computer-based models.

Summary

In an era of improved computer technology and improved 3D printing, it will be increasingly important to focus on both the manufacture and validation process. One area that will benefit from further technological advancement is the realistic simulation of bleeding as this would obviate the need for animal models. Future studies on ESS simulation will also need to robustly demonstrate the validity of each model with the emphasis on the ability of a model to predict performance in operative environment.

A Review of Physical Simulators for Neuroendoscopy Skills Training

BACKGROUND

Minimally invasive neurosurgical approaches reduce patient morbidity by providing the surgeon with better visualization and access to complex lesions, with minimal disruption to normal anatomy. The use of rigid or flexible neuroendoscopes, supplemented with a conventional stereoscopic operating microscope, has been integral to the adoption of these techniques. Neurosurgeons commonly use neuroendoscopes to perform the ventricular and endonasal approaches. It is challenging to learn neuroendoscopy skills from the existing apprenticeship model of surgical education. The training methods, which use simulation-based systems, have achieved wide acceptance. Physical simulators provide anatomic orientation and hands-on experience with repeatability. Our aim is to review the existing physical simulators on the basis of the skills training of neuroendoscopic procedures.

METHODS

We searched Scopus, Google Scholar, PubMed, IEEE Xplore, and dblp. We used the following keywords "neuroendoscopy," "training," "simulators," "physical," and "skills evaluation." A total of 351 articles were screened based on development methods, evaluation criteria, and validation studies on physical simulators for skills training in neuroendoscopy.

RESULTS

The screening of the articles resulted in classifying the physical training methods developed for neuroendoscopy surgical skills into synthetic simulators and box trainers. The existing simulators were compared based on their design, fidelity, trainee evaluation methods, and validation studies.

CONCLUSIONS

The state of simulation systems demands collaborative initiatives among translational research institutes. They need improved fidelity and validation studies for inclusion in the surgical educational curriculum. Learning should be imparted in stages with standardization of performance metrics for skills evaluation.

Three-dimensional printing as a tool in otolaryngology training: a systematic review

OBJECTIVE

Three-dimensional printing is a revolutionary technology that is disrupting the status quo in surgery. It has been rapidly adopted by otolaryngology as a tool in surgical simulation for high-risk, low-frequency procedures. This systematic review comprehensively evaluates the contemporary usage of three-dimensional printed otolaryngology simulators.

METHOD

A systematic review of the literature was performed with narrative synthesis.

RESULTS

Twenty-two articles were identified for inclusion, describing models that span a range of surgical tasks (temporal bone dissection, airway procedures, functional endoscopic sinus surgery and endoscopic ear surgery). Thirty-six per cent of articles assessed construct validity (objective measures); the other 64 per cent only assessed face and content validity (subjective measures). Most studies demonstrated positive feedback and high confidence in the models' value as additions to the curriculum.

CONCLUSION

Whilst further studies supported with objective metrics are merited, the role of three-dimensional printed otolaryngology simulators is poised to expand in surgical training given the enthusiastic reception from trainees and experts alike.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Three-Dimensional Printing: Current Use in Rhinology and Endoscopic Skull Base Surgery

Background

In the discipline of rhinology and endoscopic skull base surgery (ESBS), 3-dimensional (3D) printing has found meaningful application in areas including preoperative surgical planning as well as in surgical education. However, its scope of use may be limited due to the perception among surgeons that there exists a prohibitively high initial investment in resources and time to acquire the requisite technical expertise. Nevertheless, given the ever decreasing cost of advancing technology coupled with the need to understand the complex spatial relationships of the paranasal sinuses and skull base, the use of 3D printing in rhinology and ESBS is poised to blossom.

Objective

Help the reader identify current or potential future uses of 3D printing technology relevant to their rhinologic clinical or educational practice.

Methods

A review of published literature relating to 3D printing in rhinology and ESBS was performed.

Results

Results were reviewed and organized into 5 overarching categories including an overview of the 3D printing process as well as applications of 3D printing including (1) surgical planning, (2) custom prosthetics and implants, (3) patient education, and (4) surgical teaching and assessment.

Conclusion

In the discipline of rhinology and ESBS, 3D printing finds use in the areas of presurgical planning, patient education, prosthesis creation, and trainee education. As this technology moves forward, these products will be more broadly available to providers in the clinical and educational setting. The possible applications are vast and have great potential to positively impact surgical training, patient satisfaction, and most importantly, patient outcomes.

Watertight Robust Osteoconductive Barrier for Complex Skull Base Reconstruction: An Expanded-endoscopic Endonasal Experimental Study

Endoscopic skull base reconstruction (ESBR) following expanded-endoscopic endonasal approaches (EEA) in high-risk non-ideal endoscopic reconstructive candidates remains extremely challenging, and further innovations are still necessary. Here, the aim is to study the reconstructive knowledge gap following expanded-EEA and to introduce the watertight robust osteoconductive (WRO)-barrier as an alternative durable option. Distinctively, we focused on 10 clinical circumstances. A 3D-skull base-water system model was innovated to investigate the ESBR under realistic conditions. A large-irregular defect (31 × 89 mm) extending from the crista galli to the mid-clivus was achieved. Then, WRO-barrier was fashioned and its tolerance was evaluated under stressful settings, including an exceedingly high (55 cmH₂O) pressure, with radiological assessment. Next, the whole WRO-barrier was drilled to examine its practical-safe removal (simulating redo-EEA) and the whole experiment was repeated. Finally, WRO-barrier was kept into place to value its 18-month long-term high-tolerance. Results in all experiments of WRO-barriers were satisfactorily fashioned to conform the geometry of the created defect under realistic circumstances via EEA, tolerated an exceedingly high pressure without evidence of leak even under stressful settings, resisted sudden-elevated pressure, and remained in its position to maintain long-term watertight seal (18 months), efficiently evaluated with neuroimaging and simply removed-and-reconstructed when redo-EEA is needed. In conclusion, WRO-barrier as an osteoconductive watertight robust design for cranial base reconstruction possesses several distinct qualities that might be beneficial for patients with complex skull base tumours.

3D Printed lattice microstructures to mimic soft biological materials

OBJECTIVE

Our group has developed a method for 3D printing mechanically-realistic soft tissue, as a building block towards developing anatomically realistic 3D-printed biomechanical testbed models.

METHODS

A Polyjet 3D printer was used to print lattice microstructures, which were tested in compression to evaluate the elastic profile. Lattice properties including element diameter, element spacing (ES), element cross-sectional geometry, element arrangement, and lattice rotation were varied to determine their effect on the stress-strain curve. As a case study, a single 3D printed sample was tuned such that its elastic profile matched plantar fat.

RESULTS

Element diameter and ES had the largest effect on the stress-strain profile, and rotating the lattice microstructure tends to linearize the curves. A simple cubic lattice microstructure of cylindrical elements, with 0.5 mm diameter columns and 1.2 mm spacing had a stress-strain curve the was closest to plantar fat. The elastic modulus at 10, 30, and 50% strain was 7.55, 9.50, and 252 kPa respectively. Physiologic plantar fat at the same strain values has moduli values of 1.08, 7.13, and 188 kPa.

SIGNIFICANCE

We demonstrated that lattice microstructures can decrease the young's modulus of soft 3D printed materials by three orders of magnitude. By creating a method for fine-tuning the elastic profile of 3D-printed materials to behave like human soft tissue, we provide an attractive alternative to more exotic and time-consuming techniques such as molding and casting.

New frontiers and emerging applications of 3D printing in ENT surgery: a systematic review of the literature

3D printing systems have revolutionised prototyping in the industrial field by lowering production time from days to hours and costs from thousands to just a few dollars. Today, 3D printers are no more confined to prototyping, but are increasingly employed in medical disciplines with fascinating results, even in many aspects of otorhinolaryngology. All publications on ENT surgery, sourced through updated electronic databases (PubMed, MEDLINE, EMBASE) and published up to March 2017, were examined according to PRISMA guidelines. Overall, 121 studies fulfilled specific inclusion criteria and were included in our systematic review. Studies were classified according to the specific field of application (otologic, rhinologic, head and neck) and area of interest (surgical and preclinical education, customised surgical planning, tissue engineering and implantable prosthesis). Technological aspects, clinical implications and limits of 3D printing processes are discussed focusing on current benefits and future perspectives.

Nerves of Steel: a Low-Cost Method for 3D Printing the Cranial Nerves

Steady-state free precession (SSFP) magnetic resonance imaging (MRI) can demonstrate details down to the cranial nerve (CN) level. High-resolution three-dimensional (3D) visualization can now quickly be performed at the workstation. However, we are still limited by visualization on flat screens. The emerging technologies in rapid prototyping or 3D printing overcome this limitation. It comprises a variety of automated manufacturing techniques, which use virtual 3D data sets to fabricate solid forms in a layer-by-layer technique. The complex neuroanatomy of the CNs may be better understood and depicted by the use of highly customizable advanced 3D printed models. In this technical note, after manually perfecting the segmentation of each CN and brain stem on each SSFP-MRI image, initial 3D reconstruction was performed. The bony skull base was also reconstructed from computed tomography (CT) data. Autodesk 3D Studio Max, available through freeware student/educator license, was used to three-dimensionally trace the 3D reconstructed CNs in order to create smooth graphically designed CNs and to assure proper fitting of the CNs into their respective neural foramina and fissures. This model was then 3D printed with polyamide through a commercial online service. Two different methods are discussed for the key segmentation and 3D reconstruction steps, by either using professional commercial software, i.e., Materialise Mimics, or utilizing a combination of the widely available software Adobe Photoshop, as well as a freeware software, OsiriX Lite.

Optimization of 3D Print Material for the Recreation of Patient-Specific Temporal Bone Models

Objective:

Identify the 3D printed material that most accurately recreates the visual, tactile, and kinesthetic properties of human temporal bone

Subjects and Methods:

Fifteen study participants with an average of 3.6 years of postgraduate training and 56.5 temporal bone (TB) procedures participated. Each participant performed a mastoidectomy on human cadaveric TB and five 3D printed TBs of different materials. After drilling each unique material, participants completed surveys to assess each model’s appearance and physical likeness on a Likert scale from 0 to 10 (0 = poorly representative, 10 = completely life-like). The 3D models were acquired by computed tomography (CT) imaging and segmented using 3D Slicer software.

Results:

Polyethylene terephthalate (PETG) had the highest average survey response for haptic feedback (HF) and appearance, scoring 8.3 (SD = 1.7) and 7.6 (SD = 1.5), respectively. The remaining plastics scored as follows for HF and appearance: polylactic acid (PLA) averaged 7.4 and 7.6, acrylonitrile butadiene styrene (ABS) 7.1 and 7.2, polycarbonate (PC) 7.4 and 3.9, and nylon 5.6 and 6.7.

Conclusion:

A PETG 3D printed temporal bone models performed the best for realistic appearance and HF as compared with PLA, ABS, PC, and nylon. The PLA and ABS were reliable alternatives that also performed well with both measures.

Three-Dimensional Printed Skull Base Simulation for Transnasal Endoscopic Surgical Training

OBJECTIVE

Transnasal endoscopic skull base surgery (SBS) presents a major challenge for inexperienced neurosurgeons because of the complicated anatomic structures, 2-dimensional endoscopic view, limited operative field, and required skills. We designed a personalized multimaterial and multicolor three-dimensional (3D)-printed SBS simulation to reproduce the complex anatomy of the skull base. The fidelity and feasibility for anatomic education and surgical training were assessed.

METHODS

Two-dimensional computer tomography and magnetic resonance images were collected from a 42-year-old healthy male volunteer. After 3D modeling and spatial alignment, personalized SBS simulations were produced using a multimaterial 3D printer. The fidelity of the models was assessed by 3 experienced neurosurgeons, and the effects for anatomic education and surgical training were evaluated by 10 resident trainees. Both evaluations were based on 5-point Likert questionnaires.

RESULTS

The mean scores for fidelity of tissue structure ranged from 3.7 to 4.7, and scores for aid in anatomic education and surgical training ranged from 3.5 to 4.9.

CONCLUSION

The 3D-printed SBS simulation is a practical, economical, high-fidelity model. It has great potential for anatomic education and operative training in transnasal endoscopic surgery.

Using simulators to teach pediatric airway procedures in an international setting

INTRODUCTION

There has been a growing shift towards endoscopic management of laryngeal procedures in pediatric otolaryngology. There still appears to be a shortage of pediatric otolaryngology programs and children's hospitals worldwide where physicians can learn and practice these skills. Laryngeal simulation models have the potential to be part of the educational training of physicians who lack exposure to relatively uncommon pediatric otolaryngologic pathology.

OBJECTIVES

The objective of this study was to assess the utility of pediatric laryngeal models to teach laryngeal pathology to physicians at an international meeting.

METHODS

Pediatric laryngeal models were assessed by participants at an international pediatric otolaryngology meeting. Participants provided demographic information and previous experience with pediatric airways. Participants then performed simulated surgery on these models and evaluated them using both a previously validated Tissue Likeness Scale and a pre-simulation to post-simulation confidence scale.

RESULTS

Participants reported significant subjective improvement in confidence level after use of the simulation models (p < 0.05). Participants reported realistic representations of human anatomy and pathology. The models' tissue mechanics were adequate to practice operative technique including the ability to incise, suture, and suspend models.

CONCLUSION

The pediatric laryngeal models demonstrate high quality anatomy, which is easy manipulated with surgical instruments. These models allow both trainees and surgeons to practice time-sensitive airway surgeries in a safe and controlled environment.

Systematic Review of the Use of 3-Dimensional Printing in Surgical Teaching and Assessment

OBJECTIVE

The use of 3-dimensional (3D) printing in medicine has rapidly expanded in recent years as the technology has developed. The potential uses of 3D printing are manifold. This article provides a systematic review of the uses of 3D printing within surgical training and assessment.

METHODS

A structured literature search of the major literature databases was performed in adherence to PRISMA guidelines. Articles that met predefined inclusion and exclusion criteria were appraised with respect to the key objectives of the review and sources of bias were analysed.

RESULTS

Overall, 49 studies were identified for inclusion in the qualitative analysis. Heterogeneity in study design and outcome measures used prohibited meaningful meta-analysis. 3D printing has been used in surgical training across a broad range of specialities but most commonly in neurosurgery and otorhinolaryngology. Both objective and subjective outcome measures have been studied, demonstrating the usage of 3D printed models in training and education. 3D printing has also been used in anatomical education and preoperative planning, demonstrating improved outcomes when compared to traditional educational methods and improved patient outcomes, respectively.

CONCLUSIONS

3D printing technology has a broad range of potential applications within surgical education and training. Although the field is still in its relative infancy, several studies have already demonstrated its usage both instead of and in addition to traditional educational methods.

Endoscopic Endonasal Transclival Approach versus Dual Transorbital Port Technique for Clip Application to the Posterior Circulation: A Cadaveric Anatomical and Cerebral Circulation Simulation Study

Purpose  Simulation training offers a useful opportunity to appreciate vascular anatomy and develop the technical expertise required to clip intracranial aneurysms of the posterior circulation. Materials and Methods  In cadavers, a comparison was made between the endoscopic transclival approach (ETA) alone and a combined multiportal approach using the ETA and a transorbital precaruncular approach (TOPA) to evaluate degrees of freedom, angles of visualization, and ergonomics of aneurysm clip application to the posterior circulation depending on basilar apex position relative to the posterior clinoids. Results  ETA alone provided improved access to the posterior circulation when the basilar apex was high riding compared with the posterior clinoids. ETA + TOPA provided a significantly improved functional working area for instruments and visualization of the posterior circulation for a midlevel basilar apex. A single-shaft clip applier provided improved visualization and space for instruments. Proximal and distal vascular control and feasibility of aneurysmal clipping were demonstrated. Conclusions  TOPA is a medial orbital approach to the central skull base; a transorbital neuroendoscopic surgery approach. This anatomical simulation provides surgical teams an alternative to the ETA approach alone to address posterior circulation aneurysms, and a means to preoperatively prepare for intraoperative anatomical and surgical instrumentation challenges.

The role of three-dimensional printed models of skull in anatomy education: a randomized controlled trail

Three-dimensional (3D) printed models represent educational tools of high quality compared with traditional teaching aids. Colored skull models were produced by 3D printing technology. A randomized controlled trial (RCT) was conducted to compare the learning efficiency of 3D printed skulls with that of cadaveric skulls and atlas. Seventy-nine medical students, who never studied anatomy, were randomized into three groups by drawing lots, using 3D printed skulls, cadaveric skulls, and atlas, respectively, to study the anatomical structures in skull through an introductory lecture and small group discussions. All students completed identical tests, which composed of a theory test and a lab test, before and after a lecture. Pre-test scores showed no differences between the three groups. In post-test, the 3D group was better than the other two groups in total score (cadaver: 29.5 [IQR: 25–33], 3D: 31.5 [IQR: 29–36], atlas: 27.75 [IQR: 24.125–32]; p = 0.044) and scores of lab test (cadaver: 14 [IQR: 10.5–18], 3D: 16.5 [IQR: 14.375–21.625], atlas: 14.5 [IQR: 10–18.125]; p = 0.049). Scores involving theory test, however, showed no difference between the three groups. In this RCT, an inexpensive, precise and rapidly-produced skull model had advantages in assisting anatomy study, especially in structure recognition, compared with traditional education materials.

Three-dimensional printing of a sinus pericranii model: technical note

BACKGROUND

Sinus pericranii (SP) is a rare venous malformation consisting of a single or multiple abnormal emissary veins communicating between intracranial sinuses and dilated epicranial veins. There is no consensus concerning diagnosis, management, and treatment of SP.

TECHNICAL NOTE

We report the case of a 4-month-old infant with a SP for whom we used a three-dimensional printed model in order to define the angioarchitecture, improve management, and help parents' understanding of this uncommon condition.

Endoscopic Management of Cavernous Carotid Surgical Complications: Evaluation of a Simulated Perfusion Model

OBJECTIVE

Endoscopic surgical treatment of pituitary tumors, lateral invading tumors, or aneurysms requires surgeons to operate adjacent to the cavernous sinus. During these endoscopic endonasal procedures, the carotid artery is vulnerable to surgical injury at its genu. The objective of this simulation model was to evaluate trainees regarding management of a potentially life-threatening vascular injury.

METHODS

Cadaveric heads were prepared in accordance with the Oregon Health & Science University body donation program. An endoscopic endonasal approach was used, and a perfusion pump with a catheter was placed in the ipsilateral common carotid artery at its origin in the neck. Learners used a muscle graft to establish vascular control and were evaluated over 3 training sessions. Simulation assessment, blood loss during sessions, and performance metric data were collected for learners.

RESULTS

Vascular control was obtained at a mean arterial pressure of 65 mm Hg using a muscle graft correctly positioned at the arteriotomy site. Learners improved over the course of training, with senior residents (n = 4) performing better across all simulation categories (situation awareness, decision making, communications and teamwork, and leadership); the largest mean difference was in communication and teamwork. Additionally, learner performance concerning blood loss improved between sessions (t = 3.667, P < 0.01).

CONCLUSIONS

In this pilot endoscopic endonasal simulation study, we successfully demonstrate a vascular complication perfusion model. Learners were able to gain direct applicable expertise in endoscopic endonasal techniques, instrumentation use, and teamwork required to optimize the technique. Learners gained skills of vascular complication management that transcend this model.

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.

Interactive navigation-guided ophthalmic plastic surgery: assessment of optical versus electromagnetic modes and role of dynamic reference frame location using navigation-enabled human skulls

AIM

The aim of this study was to assess the anatomical accuracy of navigation technology in localizing defined anatomic landmarks within the orbit with respect to type of technology (optical versus electromagnetic systems) and position of the dynamic reference marker on the skull (vertex, temporal, parietal, and mastoid) using in vitro navigation-enabled human skulls. The role of this model as a possible learning tool for anatomicoradiological correlations was also assessed.

METHODS

Computed tomography (CT) scans were performed on three cadaveric human skulls using the standard image-guidance acquisition protocols. Thirty-five anatomical landmarks were identified for stereotactic navigation using the image-guided StealthStation S7™ in both electromagnetic and optical modes. Three outcome measures studied were accuracy of anatomical localization and its repeatability, comparisons between the electromagnetic and optical modes in assessing radiological accuracy, and the efficacy of dynamic reference frame (DRF) at different locations on the skull.

RESULTS

The geometric localization of all the identified anatomical landmarks could be achieved accurately. The Cohen's kappa agreements between the surgeons were found to be perfect (kappa =0.941) at all predetermined points. There was no difference in anatomical localization between the optical and electromagnetic modes (P≤0.001). Precision for radiological identification did not differ with various positions of the DRF. Skulls with intact anatomical details and careful CT image acquisitions were found to be stereotactically useful.

CONCLUSION

Accuracy of anatomic localization within the orbit with navigation technology is equal with optical and electromagnetic system. The location of DRF does not affect the accuracy. Navigation-enabled skull models can be potentially useful as teaching tools for achieving the accurate radiological orientation of orbital and periorbital structures.

Three-Dimensional Printing and Its Applications in Otorhinolaryngology-Head and Neck Surgery

Objective Three-dimensional (3D)-printing technology is being employed in a variety of medical and surgical specialties to improve patient care and advance resident physician training. As the costs of implementing 3D printing have declined, the use of this technology has expanded, especially within surgical specialties. This article explores the types of 3D printing available, highlights the benefits and drawbacks of each methodology, provides examples of how 3D printing has been applied within the field of otolaryngology-head and neck surgery, discusses future innovations, and explores the financial impact of these advances. Data Sources Articles were identified from PubMed and Ovid MEDLINE. Review Methods PubMed and Ovid Medline were queried for English articles published between 2011 and 2016, including a few articles prior to this time as relevant examples. Search terms included 3-dimensional printing, 3 D printing, otolaryngology, additive manufacturing, craniofacial, reconstruction, temporal bone, airway, sinus, cost, and anatomic models. Conclusions Three-dimensional printing has been used in recent years in otolaryngology for preoperative planning, education, prostheses, grafting, and reconstruction. Emerging technologies include the printing of tissue scaffolds for the auricle and nose, more realistic training models, and personalized implantable medical devices. Implications for Practice After the up-front costs of 3D printing are accounted for, its utilization in surgical models, patient-specific implants, and custom instruments can reduce operating room time and thus decrease costs. Educational and training models provide an opportunity to better visualize anomalies, practice surgical technique, predict problems that might arise, and improve quality by reducing mistakes.

The utility of a multimaterial 3D printed model for surgical planning of complex deformity of the skull base and craniovertebral junction

Utilizing advanced 3D printing techniques, a multimaterial model was created for the surgical planning of a complex deformity of the skull base and craniovertebral junction. The model contained bone anatomy as well as vasculature and the previously placed occipital cervical instrumentation. Careful evaluation allowed for a unique preoperative perspective of the craniovertebral deformity and instrumentation options. This patient-specific model was invaluable in choosing the most effective approach and correction strategy, which was not readily apparent from standard 2D imaging. Advanced 3D multimaterial printing provides a cost-effective method of presurgical planning, which can also be used for both patient and resident education.