Biomechanical comparison of bone staple fixation methods with suture material for median sternotomy closure using 3D-printed bone models

AIM

To compare the biomechanical properties of three different sternal closure techniques in a 3D-printed bone model of a sternum from a 30-kg dog.

METHODS

Median sternotomy was performed on a total of 90 three-dimensional (3D) copies of a polycarbonate (PC) model of a sternum, generated from the CT images of the sternum of a 30-kg German Shepherd dog. Three different methods were used to repair the sternotomies: polydioxanone suture (group PDS, n = 30), stainless steel bone staples (group SS, n = 30), and nitinol bone staples (group NS, n = 30). Each repair method was tested by applying tensile force in one of three ways (longitudinally, laterally, or torsionally) resulting in a sample size of n = 10 for each repair method-loading combination. In all experiments, the loads at 1-mm and 2-mm gap formation, failure, and the displacement at the failure point were measured.

RESULTS

In lateral distraction and longitudinal shear tests, NS and SS staple repairs required application of significantly greater force than PDS across all displacement criteria (1 and 2 mm). NS exhibited significantly greater failure load than PDS. In torsion tests, NS required significantly greater application of force compared to SS or PDS at all displacement criteria (1 and 2 mm) and exhibited a greater failure load than PDS. In terms of displacement at failure point, PDS suture showed more displacement than SS or NS across all experiments (laterally, longitudinally, torsionally).

CONCLUSIONS

In this study, bone staples were mechanically superior to PDS suture in median sternotomy closure using 3D-printed bone model in terms of 1-mm, 2-mm displacement loads, and displacement at failure. NS had a higher failure load than PDS under lateral, longitudinal, and torsional distraction.

CLINICAL RELEVANCE

These study results imply that bone staples can be considered as an alternative surgical method for median sternotomy closure in dogs.

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.

Educational simulator for mastoidectomy considering mechanical properties using 3D printing and its usability evaluation

Complex temporal bone anatomy complicates operations; thus, surgeons must engage in practice to mitigate risks, improving patient safety and outcomes. However, existing training methods often involve prohibitive costs and ethical problems. Therefore, we developed an educational mastoidectomy simulator, considering mechanical properties using 3D printing. The mastoidectomy simulator was modeled on computed tomography images of a patient undergoing a mastoidectomy. Infill was modeled for each anatomical part to provide a realistic drilling sensation. Bone and other anatomies appear in assorted colors to enhance the simulator's educational utility. The mechanical properties of the simulator were evaluated by measuring the screw insertion torque for infill specimens and cadaveric temporal bones and investigating its usability with a five-point Likert-scale questionnaire completed by five otolaryngologists. The maximum insertion torque values of the sigmoid sinus, tegmen, and semicircular canal were 1.08 ± 0.62, 0.44 ± 0.42, and 1.54 ± 0.43 N mm, displaying similar-strength infill specimens of 40%, 30%, and 50%. Otolaryngologists evaluated the quality and usability at 4.25 ± 0.81 and 4.53 ± 0.62. The mastoidectomy simulator could provide realistic bone drilling feedback for educational mastoidectomy training while reinforcing skills and comprehension of anatomical structures.

Quality and haptic feedback of three-dimensionally printed models for simulating dental implant surgery

STATEMENT OF PROBLEM

A model offering anatomic replication and haptic feedback similar to that of real bone is essential for hands-on surgical dental implant training. Patient-specific skeletal models can be produced with 3-dimensional (3D) printing, but whether these models can offer optimal haptic feedback for simulating implant surgery is unknown.

PURPOSE

The purpose of this trial was to compare the haptic feedback of different 3D printed models for simulating dental implant surgery.

MATERIAL AND METHODS

A cone beam computed tomography image of a 60-year-old man with a partially edentulous mandible was manipulated to segment the mandible and isolated from the rest of the scan. Three-dimensional models were printed with 6 different printers and materials: material jetting-based printer (MJ, acrylic-based resin); digital light processing-based printer (DLP, acrylic-based resin); fused filament fabrication-based printer (FFF1, polycarbonate filament; FFF2, polylactic acid filament); stereolithography-based printer (SLA, acrylic-based resin); and selective laser sintering-based printer (SLS, polyamide filament). Five experienced maxillofacial surgeons performed a simulated implant surgery on the models. A 5-point Likert scale questionnaire was established to assess the haptic feedback. The Friedman test and cumulative logit models were applied to evaluate differences among the models (α=.05).

RESULTS

The median score for drilling perception and implant insertion was highest for the MJ-based model and lowest for the SLS-based model. In relation to the drill chips, a median score of ≥3 was observed for all models. The score for corticotrabecular transition was highest for the MJ-based model and lowest for the FFF2-based model. Overall, the MJ-based model offered the highest score compared with the other models.

CONCLUSIONS

The 3D printed model with MJ technology and acrylic-based resin provided the best haptic feedback for performing implant surgery. However, none of the models were able to completely replicate the haptic perception of real bone.

Unveiling the Intricacies of the Inner Ear Anatomy: Novel 3D-Printed Model for Detailed Visualization and Functional Demonstrations

OBJECTIVES

This research aimed to print realistically detailed and magnified three-dimensional models of the inner ear, specifically focusing on visualising its complex labyrinth structure and functioning simulation.

METHODS

Temporal bone computed-tomography data were imported into Mimics software to construct an initial three-dimensional inner-ear model. Subsequently, the model was amplified and printed with precision using a three-dimensional printer. Five senior attending physicians evaluated the printed model using a Likert scale to gauge its morphological accuracy, clinical applicability and anatomical teaching value.

RESULTS

The printed inner-ear model effectively demonstrated the intricate internal structure. All five physicians agreed that the model closely resembled the real inner ear in shape and structure, and simulated certain inner-ear functions. The model was considered highly valuable for understanding anatomical structure and disorders.

CONCLUSION

The three-dimensionally printed inner-ear model is highly simulated and provides a valuable visual tool for studying inner-ear anatomy and clinical teaching, benefiting otologists.

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.

Comparing Feedback Techniques in Bilobe Flap Simulation Using 3D-Printed Facial Models

Objective

To compare live versus delayed feedback on trainee performance of bilobe flaps using 3-dimensional (3D)-printed facial simulators and determine whether these effects are sustained on repeat performance.

Study Design

Cohort study.

Setting

University of Arkansas for Medical Sciences.

Methods

3D-printed facial models with a nasal ala defect were provided to 18 subjects. Subjects were stratified and randomized based on their training level into 1 of 3 groups corresponding to live feedback (Group 1), delayed feedback (Group 2), and no feedback (Group 3). Subjects performed a bilobe flap following a structured lecture. Four weeks later, subjects independently repeated the exercise on the contralateral ala. Likert surveys were used to assess subjective parameters. Objective grading was performed by a plastic surgeon, which included a point system and score for the overall appearance.

Results

Following exercise 1, Group 1 reported a significant improvement in knowledge (P < .001), which was sustained after exercise 2 (P < .001); Group 2 reported a significant improvement after exercise 1 (P = .03) but was not sustained (P = .435). After the second exercise, Group 1 and Group 2 improved their confidence in bilobed repair (P = .001 and P = .003, respectively), but this was greater for Group 1. Group 1 showed a significant improvement in their design time following exercise 2 (P = .007). There were no significant differences between groups on total time for repair, total score, and appearance.

Conclusion

3D-printed models are valuable in teaching the bilobe flap for nasal defects, with live feedback providing the greatest level of improvement in self-reported knowledge and confidence.

3D Bioprinting in Otolaryngology: A Review

The evolution of tissue engineering and 3D bioprinting has allowed for increased opportunities to generate musculoskeletal tissue grafts that can enhance functional and aesthetic outcomes in otolaryngology-head and neck surgery. Despite literature reporting successes in the fabrication of cartilage and bone scaffolds for applications in the head and neck, the full potential of this technology has yet to be realized. Otolaryngology as a field has always been at the forefront of new advancements and technology and is well poised to spearhead clinical application of these engineered tissues. In this review, current 3D bioprinting methods are described and an overview of potential cell types, bioinks, and bioactive factors available for musculoskeletal engineering using this technology is presented. The otologic, nasal, tracheal, and craniofacial bone applications of 3D bioprinting with a focus on engineered graft implantation in animal models to highlight the status of functional outcomes in vivo; a necessary step to future clinical translation are reviewed. Continued multidisciplinary efforts between material chemistry, biological sciences, and otolaryngologists will play a key role in the translation of engineered, 3D bioprinted constructs for head and neck surgery.

3D-printing a cost-effective model for mastoidectomy training

BACKGROUND

3D-printed temporal bone models can potentially provide a cost-effective alternative to cadaver surgery that can be manufactured locally at the training department. The objective of this study was to create a cost-effective 3D-printed model suitable for mastoidectomy training using entry level and commercially available print technologies, enabling individuals, without prior experience on 3D-printing, to manufacture their own models for basic temporal bone training.

METHODS

Expert technical professionals and an experienced otosurgeon identified the best material for replicating the temporal bone and created a cost-effective printing routine for the model using entry-level print technologies. Eleven participants at a temporal bone dissection course evaluated the model using a questionnaire.

RESULTS

The 3D-printed temporal bone model was printed using a material extrusion 3D-printer with a heat resistant filament, reducing melting during drilling. After printing, a few simple post-processing steps were designed to replicate the dura, sigmoid sinus and facial nerve. Modifying the 3D-printer by installing a direct-drive and ruby nozzle resulted in more successful prints and less need for maintenance. Upon evaluation by otorhinolaryngology trainees, unanimous feedback was that the model provided a good introduction to the mastoidectomy procedure, and supplementing practice to cadaveric temporal bones.

CONCLUSION

In-house production of a cost-effective 3D-printed model for temporal bone training is feasible and enables training institutions to manufacture their own models. Further, this work demonstrates the feasibility of creating new temporal bone models with anatomical variation to provide ample training opportunity.

Craniotomy Simulator with Force Myography and Machine Learning-Based Skills Assessment

Craniotomy is a fundamental component of neurosurgery that involves the removal of the skull bone flap. Simulation-based training of craniotomy is an efficient method to develop competent skills outside the operating room. Traditionally, an expert surgeon evaluates the surgical skills using rating scales, but this method is subjective, time-consuming, and tedious. Accordingly, the objective of the present study was to develop an anatomically accurate craniotomy simulator with realistic haptic feedback and objective evaluation of surgical skills. A CT scan segmentation-based craniotomy simulator with two bone flaps for drilling task was developed using 3D printed bone matrix material. Force myography (FMG) and machine learning were used to automatically evaluate the surgical skills. Twenty-two neurosurgeons participated in this study, including novices (n = 8), intermediates (n = 8), and experts (n = 6), and they performed the defined drilling experiments. They provided feedback on the effectiveness of the simulator using a Likert scale questionnaire on a scale ranging from 1 to 10. The data acquired from the FMG band was used to classify the surgical expertise into novice, intermediate and expert categories. The study employed naïve Bayes, linear discriminant (LDA), support vector machine (SVM), and decision tree (DT) classifiers with leave one out cross-validation. The neurosurgeons' feedback indicates that the developed simulator was found to be an effective tool to hone drilling skills. In addition, the bone matrix material provided good value in terms of haptic feedback (average score 7.1). For FMG-data-based skills evaluation, we achieved maximum accuracy using the naïve Bayes classifier (90.0 ± 14.8%). DT had a classification accuracy of 86.22 ± 20.8%, LDA had an accuracy of 81.9 ± 23.6%, and SVM had an accuracy of 76.7 ± 32.9%. The findings of this study indicate that materials with comparable biomechanical properties to those of real tissues are more effective for surgical simulation. In addition, force myography and machine learning provide objective and automated assessment of surgical drilling skills.

A three-dimensionally printed otological model for cholesteatoma mastoidectomy training

PURPOSE

To relate the creation and expert validation (face and content validity) of an affordable three-dimensional (3-D) printed model of temporal bones with chronic otitis media with cholesteatoma (COMC) as a simulator for mastoidectomy.

METHODS

We performed computed tomography (CT) of the temporal bones of a patient with COMC followed at the University of São Paulo (USP) Hospital with 3-D Slicer to create a 3-D model of the affected bone using light-curing resin and silicone (cholesteatoma). The final 3-D printed images were scored by 10 otologists using a customized version of the Michigan Standard Simulation Scale Experience (MiSSES). Internal consistency and inter-rater reliability were assessed using Cronbach's α and intraclass correlations.

RESULTS

Otologists consistently scored the model positively for fidelity, educational value, reactions, and the overall model quality. Nine otologists agreed that the model was a good educational device for surgical training of COMC. All experts deemed the model ready-or nearly ready-for use. The final cost of the model, including raw materials and manufacturing, was 120 USD.

CONCLUSIONS

Using 3-D printing technology, we created the first anatomically accurate, low-cost, disease-reproducing 3-D model of temporal bones for mastoidectomy training for cholesteatoma.

Biomechanical validation of additively manufactured artificial femoral bones

Replicating the mechanical behavior of human bones, especially cancellous bone tissue, is challenging. Typically, conventional bone models primarily consist of polyurethane foam surrounded by a solid shell. Although nearly isotropic foam components have mechanical properties similar to cancellous bone, they do not represent the anisotropy and inhomogeneity of bone architecture. To consider the architecture of bone, models were developed whose core was additively manufactured based on CT data. This core was subsequently coated with glass fiber composite. Specimens consisting of a gyroid-structure were fabricated using fused filament fabrication (FFF) techniques from different materials and various filler levels. Subsequent compression tests showed good accordance between the mechanical behavior of the printed specimens and human bone. The unidirectional fiberglass composite showed higher strength and stiffness than human cortical bone in 3-point bending tests, with comparable material behaviors being observed. During biomechanical investigation of the entire assembly, femoral prosthetic stems were inserted into both artificial and human bones under controlled conditions, while recording occurring forces and strains. All of the artificial prototypes, made of different materials, showed analogous behavior to human bone. In conclusion, it was shown that low-cost FFF technique can be used to generate valid bone models and selectively modify their properties by changing the infill.

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.

A simple and convenient 3D printed temporal bone model for drilling simulating surgery

BACKGROUND

It is still far away from most of us in that it requires complex 3D modeling.

AIMS/OBJECTIVES

To investigate a more precision, simple, convenient and economical three-dimensional (3D) printed temporal bone model printed by a commercial desktop 3D printer, which can be widely promoted and applied in the training of beginners in otology.

MATERIAL AND METHODS

The CT data of the temporal bone were imported into Mimics to construct a 3D digital model of the temporal bone. After loaded into a high-precision 3D printer, a high-precision temporal bone model was printed at a scale of 1:1. Then, the model was evaluated by 5 senior attending physicians, including its morphological accuracy, simulation about surgery, advantages and educational value, using the 7-point Likert scale.

RESULTS

A life-like temporal bone model was successfully printed out. Five senior attending physicians all thought that the printed model was similar to the natural temporal bone in physical properties and the haptic sensation of bone drilling, and was accurate, simple, convenient and effective. In addition, the model was considered to be of high application value in the teaching of temporal bone anatomy and surgery simulation, which had a material cost of only 3 dollars.

CONCLUSIONS

The high-precision 3D printed temporal bone model is highly similar to the natural temporal bone, and can be conveniently and effectively used in the training of simulating temporal bone surgery for beginners in otology. Its production is simple and economical, so it can be popularized on a large scale.

Effect of 3D-Printed Models on Cadaveric Dissection in Temporal Bone Training

Objective

Mastoidectomy is a cornerstone in the surgical management of middle and inner ear diseases. Unfortunately, training is challenged by insufficient access to human cadavers. Three-dimensional (3D) printing of temporal bones could alleviate this problem, but evidence on their educational effectiveness is lacking. It is largely unknown whether training on 3D-printed temporal bones improves mastoidectomy performance, including on cadavers, and how this training compares with virtual reality (VR) simulation. To address this knowledge gap, this study investigated whether training on 3D-printed temporal bones improves cadaveric dissection performance, and it compared this training with the already-established VR simulation.

Study Design

Prospective cohort study of an educational intervention.

Setting

Tertiary university hospital, cadaver dissection laboratory, and simulation center in Copenhagen, Denmark.

Methods

Eighteen otorhinolaryngology residents (intervention) attending the national temporal bone dissection course received 3 hours of mastoidectomy training on 3D-printed temporal bones. Posttraining cadaver mastoidectomy performances were rated by 3 experts using a validated assessment tool and compared with those of 66 previous course participants (control) who had received time-equivalent VR training prior to dissection.

Results

The intervention cohort outperformed the controls during cadaver dissection by 29% (P < .001); their performances were largely similar across training modalities but remained at a modest level (~50% of the maximum score).

Conclusion

Mastoidectomy skills improved from training on 3D-printed temporal bone and seemingly more so than on time-equivalent VR simulation. Importantly, these skills transferred to cadaveric dissection. Training on 3D-printed temporal bones can effectively supplement cadaver training when learning mastoidectomy.

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.

Visual and haptic perceptibility of 3D printed skeletal models in orthognathic surgery

OBJECTIVE

To assess the anatomical and tactile quality of 3D printed models derived from medical printers for application in orthognathic surgery.

METHODS

A CBCT-scan of an 18 years old female patient was acquired with NewTom VGi evo (NewTom, Verona, Italy). Thereafter, mandibular bone was segmented and isolated from the scan using Mimics inPrint 2.0 software (Materialise NV, Leuven, Belgium). Six printers with different technologies were utilized for printing skeletal models, which included stereolithography (ProX800, 3D Systems, Rock Hill, SC, USA), digital light processing (Perfactory 4 mini XL, Envisiontec, Dearborn, MI, USA), fused deposition modeling (uPrint SE, Stratasys, Eden Prairie, MI, US), colorjet (ProJet CJP 660Pro, 3D Systems, Rock Hill, SC, USA), multijet (Objet Connex 350, Stratasys, Eden Prairie, MN, USA) and selective laser sintering (EOSINT P700, EOS GmbH, Munich, Germany). A questionnaire was designed, where 22 maxillofacial residents scored whether the printed models were able to mimic bone color, texture and anatomy. Five maxillofacial surgeons performed bone cutting with screw insertion/removal to assess the tactile perceptibility.

RESULTS

In relation to texture and cortical and medullary anatomy replication, Perfactory 4 mini XL printer showed the highest mean score, whereas, Objet Connex 350 scored highest for color replication. The haptic feedback for cutting and screw insertion/removal varied for each printer, however, overall it was found to be highest for ProX800, whereas, EOSINT P700 was found to be least favorable.

CONCLUSIONS

The digital light processing based Perfactory 4 mini XL printer offered the most acceptable anatomical model, whereas, deficiencies existed for the replication of haptic feedback to that of real bone with each printer.

CLINICAL SIGNIFICANCE

The study outcomes provide pearls and pitfalls of 3D printed models utilizing various printers and technologies. There is a need for research on multi-material printing as such to improve the haptic feedback of skeletal models and render the models more human bone-like to improve surgical planning and clinical training.

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.

3D Printed Biomimetic Rabbit Airway Simulation Model for Nasotracheal Intubation Training

Rabbit inhalation anesthesia by endotracheal intubation involves a higher risk among small animals owing to several anatomical and physiological features, which is pathognomonic to this species of lagomorphs. Rabbit-specific airway devices have been designed to prevent misguided intubation attempts. However, it is believed that expert anesthetic training could be a boon in limiting the aftermaths of this procedure. Our research is aimed to develop a novel biomimetic 3D printed rabbit airway model with representative biomechanical material behavior and radiodensity. Imaging data were collected for two sacrificed rabbit heads using micro-computed tomography (μCT) and micro-magnetic resonance imaging for the first head and cone beam computed tomography (CBCT) for the second head. Imaging-based life-size musculoskeletal airway models were printed using polyjet technology with a combination of hard and soft materials in replicates of three. The models were evaluated quantitatively for dimensional accuracy and radiodensity and qualitatively using digital microscopy and endoscopy for technical, tactic, and visual realism. The results displayed that simulation models printed with polyjet technology have an overall surface representation of 93% for μCT-based images and 97% for CBCT-based images within a range of 0.0-2.5 mm, with μCT showing a more detailed reproduction of the nasotracheal anatomy. Dimensional discrepancies can be caused due to inadequate support material removal and due to the limited reconstruction of microstructures from the imaging on the 3D printed model. The model showed a significant difference in radiodensities in hard and soft tissue regions. Endoscopic evaluation provided good visual and tactile feedback, comparable to the real animal. Overall, the model, being a practical low-cost simulator, comprehensively accelerates the learning curve of veterinary nasotracheal intubation and paves the way for 3D simulation-based image-guided interventional procedures.