Creation of Three-dimensional Anatomic Models in Pediatric Surgical Patients Using Cross-sectional Imaging: A Demonstration of Low-cost Methods and Applications.

BACKGROUND: Pediatric surgery patients often present with complex congenital anomalies or other conditions requiring deep understanding of their intricate anatomy. Commercial applications and services exist for the conversion of cross-sectional imaging data into three-dimensional (3D) models for education and preoperative planning. However, the associated costs and lack of familiarity may discourage their use in centers with limited resources. The purpose of this report is to present a low-cost, reproducible method for generating 3D images to visualize patient anatomy. METHODS: De-identified DICOM files were obtained from the hospital PACS system in preparation for assorted pediatric surgical procedures. Using open-source visualization software, variations in anatomic structures were examined using volume rendering and segmentation techniques. Images were further refined using available editing tools or artificial intelligence-assisted software extensions. RESULTS: Using the described techniques we were able to obtain excellent visualization of desired structures and associated anatomic variations. Once structures were selected and modeled in 3D (segmentation), they could be exported as one of several 3D object file formats. These could then be retained for 3D printing, visualization in virtual reality, or as an anatomic reference during the perioperative period. Models may also be imported into commercial gaming engines for rendering under optimal lighting conditions and with enhanced detail. CONCLUSION: Pediatric surgeons are frequently tasked with the treatment of patients with complex and rare anomalies. Visualization and preoperative planning can be assisted by advanced imaging software at minimal to no cost, thereby facilitating enhanced understanding of these conditions in resource-limited environments. LEVEL OF EVIDENCE: V, Case Series, Description of Technique.

Accuracy assessment of implant placement with versus without a CAD/CAM surgical guide by novices versus specialists via the digital registration method: an in vitro randomized crossover study.

BACKGROUND: Many studies demonstrated that surgical guides might reduce discrepancies compared with freehand implant placement. This randomized crossover study aimed to assess the effects of approaches, practitioners' experience and learning sequences on the accuracy of single tooth implantation via digital registration method. No similar study was found. METHODS: This in vitro randomized crossover study enrolled 60 novice students (Group S) and 10 experienced instructors (Group I). Sixty students were randomly and evenly assigned to two groups (Group SA and SB). In Group SA, 30 students first performed single molar implant on a simulation model freehand (Group SAFH), and then with a CAD/CAM surgical guide (Group SASG). In Group SB, another 30 students first performed guided (Group SBSG) and then freehand (Group SBFH). Ten instructors were also divided into Group IAFH/IASG (n = 5) and IBSG/IBFH (n = 5) following the same rules. The accuracy of implant placement was assessed by the coronal and apical distance (mm) and angular (°) deviations using the digital registration method. T tests and nonparametric tests were used to compare the results among different groups of approaches, experience and sequences. RESULTS: For students, the coronal and apical distance and the angular deviations were significantly lower in surgical guide group than freehand group in total and in learning freehand first subgroup, but for learning surgical guide first subgroup the apical distance deviation showed no significant difference between two approaches. For students, the angular deviation of freehand group was significantly lower in learning surgical guide first group than learning freehand first group. For instructors, the coronal and apical distance and angular deviations showed no significant difference between two approaches and two sequences. For freehand approach, the coronal and apical distance and the angular deviations were significantly higher in student group than instructor group, while not significantly different between two groups for surgical guide approach. CONCLUSIONS: For novices, using a surgical guide for the first implant placement may reduce the potential deviations compared with freehand surgery, and may reach a comparable accuracy with that of specialists. For simple single molar implantation, the surgical guide may not be significantly helpful for experienced specialists.

Nonsinusoidalin situelectric field caused by magnetic deactivator device for EAS labels-assessment of field strength inside a detailed anatomical hand model.

In order to evaluate the localised magnetic field (MF) exposure of the cashier's hand due to a particular demagnetization device (deactivator) for single-use labels of an acoustomagnetic (AM) electronic article surveillance (EAS) system, comprehensive measurements of the MF near the surface of the deactivator, and numerical computations of the induced electric field strengthEi, were performed in high-resolution anatomical hand models of different postures and positions with respect to the deactivator. The measurement results for magnetic inductionBwere assessed with respect to the action levels (AL) for limb exposure, and the computational results forEiwere evaluated with respect to the exposure limit values (ELV) for health effects according to European Union (EU) directive 2013/35/EU. For the ELV-based assessment, a maximum of the 2 × 2 × 2 mm3averagedEi(maxEi,avg) and the respective 99.9th, 99.5th, and 99.0th percentiles were used. As the MF impulse emitted by the deactivator for demagnetization of the AM-EAS labels was highly nonsinusoidal, measurement results were assessed based on the weighted peak method in the time domain (WPM-TD). A newly developed scaling technique was proposed to also apply the WPM-TD to the assessment of the (nonsinusoidal)Eiregarding the ELV. It was used to calculate the resulting WPM-TD-based exposure index (EI) from frequency domain computations. The assessment regarding the AL for limbs yielded peak values of magnetic induction of up to 97 mT (measured with a 3 cm2MF probe on top of the deactivator surface) corresponding to an EI of 443%. However, this was considered an overestimation of the actual exposure in terms ofEias the AL were intentionally defined conservatively. A WPM-TD-based assessment ofEifinally led to the worst case EI of up to 135%, 93%, 78%, and 72% when using the maxEi,avg, 99.9th, 99.5th, and 99.0th percentiles, respectively.

Medicine and History: a Surgical Model for National Integration.

Historians and physicians have struggled to incorporate history into American medical education for over a century. Most efforts focus on local initiatives targeting a narrow audience. We describe a novel method involving the American College of Surgeons, a national organization with tens of thousands of members. Capitalizing on its infrastructure and influence over the field, we have implemented a variety of ventures that include panel sessions at meetings, poster competitions, travel grants, themed breakfasts, online communities, and other such projects. This programming has reached thousands of participants, ranging from pre-medical students to retired physicians, and it has increased both the exposure to and production of surgical history. Our article describes the process of establishing this nationally coordinated enterprise in the hopes that other medical specialties can emulate it and further the study of and appreciation for medical history.

Utility and Costs During the Initial Year of 3D Printing in an Academic Hospital.

OBJECTIVE: There is a paucity of utility and cost data regarding the launch of 3D printing in a hospital. The objective of this project is to benchmark utility and costs for radiology-based in-hospital 3D printing of anatomic models in a single, adult academic hospital. METHODS: All consecutive patients for whom 3D printed anatomic models were requested during the first year of operation were included. All 3D printing activities were documented by the 3D printing faculty and referring specialists. For patients who underwent a procedure informed by 3D printing, clinical utility was determined by the specialist who requested the model. A new metric for utility termed Anatomic Model Utility Points with range 0 (lowest utility) to 500 (highest utility) was derived from the specialist answers to Likert statements. Costs expressed in United States dollars were tallied from all 3D printing human resources and overhead. Total costs, focused costs, and outsourced costs were estimated. The specialist estimated the procedure room time saved from the 3D printed model. The time saved was converted to dollars using hospital procedure room costs. RESULTS: The 78 patients referred for 3D printed anatomic models included 11 clinical indications. For the 68 patients who had a procedure, the anatomic model utility points had an overall mean (SD) of 312 (57) per patient (range, 200-450 points). The total operation cost was $213,450. The total cost, focused costs, and outsourced costs were $2,737, $2,180, and $2,467 per model, respectively. Estimated procedure time saved had a mean (SD) of 29.9 (12.1) min (range, 0-60 min). The hospital procedure room cost per minute was $97 (theoretical $2,900 per patient saved with model). DISCUSSION: Utility and cost benchmarks for anatomic models 3D printed in a hospital can inform health care budgets. Realizing pecuniary benefit from the procedure time saved requires future research.

Smartphone-Based DIY Home Microsurgical Training with 3D Printed Microvascular Clamps and Japanese Noodles.

We have recently incorporated simple modifications of the konjac flour noodle model to enable DIY home microsurgical training by (i) placing a smartphone on a mug to act as a microscope with at least ×3.5-5 magnification, and (ii) rather than cannulating with a 22G needle as described by others, we have found that cannulation with a 23G needle followed by a second pass with an 18G needle will create a lumen (approximately 0.83 mm) without an overly thick and unrealistic "vessel" wall. The current setup, however, did not allow realistic evaluation of anastomotic patency as the noodles became macerated after application of standard microvascular clamps, which also did not facilitate practice of back-wall anastomoses. In order to simulate the actual operative environment as much as possible, we introduced the use of 3D-printed microvascular clamps. These were modified from its previous iteration (suitable for use in silastic and chicken thigh vessels), and video recordings were submitted for internal validation by senior surgeons. A "wet" operative field where the konjac noodle lumen can be distended or collapsed, unlike other nonliving models, was noted by senior surgeons. With the 3D clamps, the noodle could now be flipped over for back-wall anastomosis and allowed patency testing upon completion as it did not become macerated, unlike that from clinical microvascular clamps. The perceived advantages of this model are numerous. Not only does it comply with the 3Rs of simulation-based training, but it can also reduce the associated costs of training by up to a hundred-fold or more when compared to a traditional rat course and potentially be extended to low-middle income countries without routine access to microsurgical training for capacity development. That it can be utilized remotely also bodes well with the current limitations on face-to-face training due to COVID restrictions and lockdowns.

Sports Economic Operation Index Prediction Model Based on Deep Learning and Ensemble Learning.

In order to construct a prediction model of sports economic operation indicators, this paper combines deep learning and ensemble learning algorithms to integrate and improve the algorithms and analyzes the principles of the LightGBM ensemble learning model and the hyperparameters of the model. Moreover, this paper obtains appropriate intelligent algorithms according to the data analysis requirements of sports economic operation. The break-even analysis method of sports event operation is to find the critical point of the program's profit and loss by analyzing the relationship between the operating cost and profit of the sports event. In addition, this paper uses deep learning and ensemble learning to comprehensively evaluate sports events, constructs a summary evaluation structure of sports items, and evaluates the model in this paper combined with experimental research. The test results verify the reliability of the model in this paper.

The Virtual Nose: Assessment of Static Nasal Airway Obstruction Using Computational Simulations and 3D-Printed Models.

Background: The use of virtual noses to predict the outcome of surgery is of increasing interests, particularly, as detailed and objective pre- and postoperative assessments of nasal airway obstruction (NAO) are difficult to perform. The objective of this article is to validate predictions using virtual noses against their experimentally measured counterpart in rigid 3D-printed models. Methods: Virtual nose models, with and without NAO, were reconstructed from patients' cone beam computed tomography scans, and used to evaluate airflow characteristics through computational fluid dynamics simulations. Prototypes of the reconstructed models were 3D printed and instrumented experimentally for pressure measurements. Results: Correlation between the numerical predictions and experimental measurements was shown. Analysis of the flow field indicated that the NAO in the nasal valve increases significantly the wall pressure, shear stress, and incremental nasal resistance behind the obstruction. Conclusions: Airflow predictions in static virtual noses correlate well with detailed experimental measurements on 3D-printed replicas of patient airways.

Assessment of fenestrated Anaconda stent graft design by numerical simulation: Results of a European prospective multicenter study.

OBJECTIVE: A crucial step in designing fenestrated stent grafts for treatment of complex aortic abdominal aneurysms is the accurate positioning of the fenestrations. The deployment of a fenestrated stent graft prototype in a patient-specific rigid aortic model can be used for design verification in vitro, but is time and human resources consuming. Numerical simulation (NS) of fenestrated stent graft deployment using the finite element analysis has recently been developed; the aim of this study was to compare the accuracy of fenestration positioning by NS and in vitro. METHODS: All consecutive cases of complex aortic abdominal aneurysm treated with the Fenestrated Anaconda (Terumo Aortic) in six European centers were included in a prospective, observational study. To compare fenestration positioning, the distance from the center of the fenestration to the proximal end of the stent graft (L) and the angular distance from the 0° position (C) were measured and compared between in vitro testing (L1, C1) and NS (L2, C2). The primary hypothesis was that ΔL (|L2 - L1|) and ΔC (|C2 - C1|) would be 2.5 or less mm in more than 80% of the cases. The duration of both processes was also compared. RESULTS: Between May 2018 and January 2019, 50 patients with complex aortic abdominal aneurysms received a fenestrated stent graft with a total of 176 fenestrations. The ΔL and ΔC was 2.5 mm or less for 173 (98%) and 174 (99%) fenestrations, respectively. The NS process duration was significantly shorter than the in vitro (2.1 days [range, 1.0-5.2 days] vs 20.6 days [range, 9-82 days]; P < .001). CONCLUSIONS: Positioning of fenestrations using NS is as accurate as in vitro and could significantly decrease delivery time of fenestrated stent grafts.

Clinical Applications of Meshed Multilayered Anatomical Models by Low-Cost Three-Dimensional Printer.

SUMMARY: In recent years, even low-cost fused deposition modeling-type three-dimensional printers can be used to create a three-dimensional model with few errors. The authors devised a method to create a three-dimensional multilayered anatomical model at a lower cost and more easily than with established methods, by using a meshlike structure as the surface layer. Fused deposition modeling-type three-dimensional printers were used, with opaque polylactide filament for material. Using the three-dimensional data-editing software Blender (Blender Foundation, www.blender.org) and Instant Meshes (Jakob et al., https://igl.ethz.ch/projects/instant-meshes/) together, the body surface data were converted into a meshlike structure while retaining its overall shape. The meshed data were printed together with other data (nonmeshed) or printed separately. In each case, the multilayer model in which the layer of the body surface was meshed could be output without any trouble. It was possible to grasp the positional relationship between the body surface and the deep target, and it was clinically useful. The total work time for preparation and processing of three-dimensional data ranged from 1 hour to several hours, depending on the case, but the work time required for converting into a meshlike shape was about 10 minutes in all cases. The filament cost was $2 to $8. In conclusion, the authors devised a method to create a three-dimensional multilayered anatomical model to easily visualize positional relationships within the structure by converting the surface layer into a meshlike structure. This method is easy to adopt, regardless of the available facilities and economic environment, and has broad applications.

How I Do It: Cost-effective 3D printed models for renal masses.

3D printing has been growing in many surgical fields including Urology. The primary use has been to print kidneys with tumors to better understand anatomy and to assist with surgical planning and education. Previous studies that utilized 3D printing of kidneys for partial nephrectomies have been limited by the cost and complexity of model creation, rendering them highly impractical to be used on a routine basis. Using a simpler and more cost-effective design and materials allow the 3D kidney models to be used in a wider range and number of patients. We describe our streamlined process to create 3D kidney models costing $30 on average and we believe this process can be repeated by others.

Development, manufacture and initial assessment of validity of a 3-dimensional-printed bowel anastomosis simulation training model.

BACKGROUND: It is critical that junior residents be given opportunities to practise bowel anastomosis before performing the procedure in patients. Three-dimensional (3D) printing is an affordable way to provide realistic, reusable intestinal simulators. The aim of this study was to test the face and content validity of a 3D-printed simulator for bowel anastomosis. METHODS: The bowel anastomosis simulator was designed and assembled with the use of desktop 3D printers and silicone solutions. The production cost ranges from $2.67 to $131, depending on which aspects of the model one prefers to include. We incorporated input from a general surgeon regarding design modifications to improve the realism of the model. Nine experts in general surgery (6 staff surgeons and 3 senior residents) were asked to perform an anastomosis with the model and then complete 2 surveys regarding face and content validity. Items were rated on a 5-point Likert scale ranging from 1 ("strongly disagree") to 5 ("strongly agree"). RESULTS: The overall average score for product quality was 3.58, indicating good face validity. The average score for realism (e.g., flexibility and texture of the model) was 3.77. The simulator was rated as being useful for training, with an overall average score of 3.98. In general, the participants agreed that the simulator would be a valuable addition to current simulation-based medical education (average score 4.11). They commented that the model would be improved by adding extra layers to simulate mucosa. CONCLUSION: Experts found the 3D-printed bowel anastomosis simulator to be an appropriate tool for the education of surgical residents, based on the model's texture, appearance and ability to undergo an anastomosis. This model provides an affordable way for surgical residents to learn bowel anastomosis. Future research will focus on proving educational efficacy, effectiveness and transfer that can be adapted for laparoscopic anastomosis training, hand-sewing and stapling procedures.

Scanning Electron Microscopic Assessment of Stent Coating Integrity in Jailed Wire Technique for Bifurcation Treatment.

OBJECTIVES: To assess the impact of different guidewires on stent coating integrity in jailed wire technique (JWT) for bifurcation treatment. BACKGROUND: JWT is commonly adopted to protect side branch in provisional one-stent strategy for coronary bifurcation lesions. However, this technique may cause defects in stent coatings. The degree of coating damage caused by different types of jailed wires remains unknown. METHODS: A fluid model with a bifurcation was established to mimic the condition in vivo. One-stent strategy was performed with three types of guidewire (nonpolymer-jacketed wire, intermediate polymer-jacketed wire, and full polymer-jacketed wire) tested for JWT. Scanning electron microscopy (SEM) was used to evaluate stent coating integrity and wire structure. The degrees of coating defects were recorded as no, slight, moderate, and severe defects. RESULTS: A total of 27 samples were tested. Analyses of SEM images showed a significant difference in the degree of coating damage among the three types of wire after the procedure of JWT (P < 0.001). Nonpolymer-jacketed wire could inevitably cause a severe defect in stent coatings, while full polymer-jacketed wire caused the least coating damages. Besides, there were varying degrees of coil deformation in nonpolymer-jacketed wires, while no surface damage or jacket shearing was observed in full polymer-jacketed wires. CONCLUSIONS: Although nonpolymer-jacketed wire has long been recommended for JWT, our bench-side study suggests that full polymer-jacketed wire may be a better choice. Further clinical studies are needed to confirm our findings.

A novel surgical model for the preclinical assessment of the osseointegration of dental implants: a surgical protocol and pilot study results.

BACKGROUND: Dental implants are considered the gold standard replacement for missing natural teeth. The successful clinical performance of dental implants is due to their ability to osseointegrate with the surrounding bone. Most dental implants are manufactured from Titanium and it alloys. Titanium does however have some shortcomings so alternative materials are frequently being investigated. Effective preclinical studies are essential to transfer the innovations from the benchtop to the patients. Many preclinical studies are carried out in the extra-oral bones of small animal models to assess the osseointegration of the newly developed materials. This does not simulate the oral environment where the dental implants are subjected to several factors that influence osseointegration; therefore, they can have limited clinical value. AIM: This study aimed to develop an appropriate in-vivo model for dental implant research that mimic the clinical setting. The study evaluated the applicability of the new model and investigated the impact of the surgical procedure on animal welfare. MATERIALS AND METHODS: The model was developed in male New Zealand white rabbits. The implants were inserted in the extraction sockets of the secondary incisors in the maxilla. The model allows a split-mouth comparative analysis. The implants' osseointegration was assessed clinically, radiographically using micro-computed tomography (µ-CT), and histologically. A randomised, controlled split-mouth design was conducted in 6 rabbits. A total of twelve implants were inserted. In each rabbit, two implants; one experimental implant on one side, and one control implant on the other side were applied. Screw-shaped implants were used with a length of 8 mm and a diameter of 2 mm. RESULTS: All the rabbits tolerated the surgical procedure well. The osseointegration was confirmed clinically, histologically and radiographically. Quantitative assessment of bone volume and mineral density was measured in the peri-implant bone tissues. The findings suggest that the new preclinical model is excellent, facilitating a comprehensive evaluation of osseointegration of dental implants in translational research pertaining to the human application. CONCLUSION: The presented model proved to be safe, reproducible and required basic surgical skills to perform.

Objective structured assessment of technical skill in temporal bone dissection: validation of a novel tool.

OBJECTIVE: This study developed an assessment tool that was based on the objective structured assessment for technical skills principles, to be used for evaluation of surgical skills in cortical mastoidectomy. The objective structured assessment of technical skill is a well-established tool for evaluation of surgical ability. This study also aimed to identify the best material and printing method to make a three-dimensional printed temporal bone model. METHODS: Twenty-four otolaryngologists in training were asked to perform a cortical mastoidectomy on a three-dimensional printed temporal bone (selective laser sintering resin). They were scored according to the objective structured assessment of technical skill in temporal bone dissection tool developed in this study and an already validated global rating scale. RESULTS: Two external assessors scored the candidates, and it was concluded that the objective structured assessment of technical skill in temporal bone dissection tool demonstrated some main aspects of validity and reliability that can be used in training and performance evaluation of technical skills in mastoid surgery. CONCLUSION: Apart from validating the new tool for temporal bone dissection training, the study showed that evolving three-dimensional printing technologies is of high value in simulation training with several advantages over traditional teaching methods.

Utilizing In-Hospital Fabrication to Decrease Simulation Costs.

BACKGROUND: Two restrictive factors for surgical training through simulation, are the cost of and accessibility to materials and consoles for simulation models. Commercial surgical simulation models continue to maintain high prices with a wide range of fidelity levels. We believe that by utilizing in-house fabrication, these barriers can be decreased while maintaining and even improving the functionality of surgical simulation models as well as increase their individualization and customization. METHODS: By using a combination of digital and manual fabrication techniques such as 3D printing and basic mold making methods, we were able to create models equivalent to current commercial products by utilizing the first of its kind MakerHEALTH space and collaborating with our surgical simulation staff. We then compared our research and development, start-up, materials, operational, and labor costs to buying comparable commercial models with the simulation usage rates of our institution. RESULTS: We were able to decrease the costs of a 6 model simulation sample set (appendectomy, cholecystectomy, common bile duct exploration, ventral hernia, chest tube insertion, and suture pads) at our institution from $99,646.60 to $13,817.21 for a medical student laborer, $14,500.56 for a surgical resident laborer, $15,321.08 for a simulation staff laborer, and $18,984.48 for an attending physician laborer. CONCLUSION: We describe successful approaches for the creation of cost-effective and modular simulation models with the aim of decreasing the barriers to entry and improving surgical training and skills. These techniques make it financially feasible for learners to train during larger faculty-led workshops and on an individual basis, allowing for access to simulation at any time or place.