Anatomical Models Research Articles

3D bioprinting: a review and potential applications for Mohs micrographic surgery.

Mohs Micrographic Surgery (MMS) is effective for treating common cutaneous malignancies, but complex repairs may often present challenges for reconstruction. This paper explores the potential of three-dimensional (3D) bioprinting in MMS, offering superior outcomes compared to traditional methods. 3D printing technologies show promise in advancing skin regeneration and refining surgical techniques in dermatologic surgery. A PubMed search was conducted using the following keywords: "Three-dimensional bioprinting" OR "3-D printing" AND "Mohs" OR "Mohs surgery" OR "Surgery." Peer-reviewed English articles discussing medical applications of 3D bioprinting were included, while non-peer-reviewed and non-English articles were excluded. Patients using 3D MMS models had lower anxiety scores (3.00 to 1.7, p < 0.0001) and higher knowledge assessment scores (5.59 or 93.25% correct responses), indicating better understanding of their procedure. Surgical residents using 3D models demonstrated improved proficiency in flap reconstructions (p = 0.002) and knowledge assessment (p = 0.001). Additionally, 3D printing offers personalized patient care through tailored surgical guides and anatomical models, reducing intraoperative time while enhancing surgical. Concurrently, efforts in tissue engineering and regenerative medicine are being explored as potential alternatives to address organ donor shortages, eliminating autografting needs. However, challenges like limited training and technological constraints persist. Integrating optical coherence tomography with 3D bioprinting may expedite grafting, but challenges remain in pre-printing grafts for complex cases. Regulatory and ethical considerations are paramount for patient safety, and further research is needed to understand long-term effects and cost-effectiveness. While promising, significant advancements are necessary for full utilization in MMS.

Personalized coronary and myocardial blood flow models incorporating CT perfusion imaging and synthetic vascular trees

Computational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges – incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature. It includes image-based coronary anatomies combined with synthetic vasculature for arteries below the imaging resolution, myocardial blood flow simulated using Darcy models, and systemic circulation represented as lumped-parameter networks. We propose an optimization-based method to personalize multiscale coronary flow simulations by assimilating clinical CT myocardial perfusion imaging and cardiac function measurements to yield patient-specific flow distributions and model parameters. Using this proof-of-concept study on a cohort of six patients, we reveal substantial differences in flow distributions and clinical diagnosis metrics between the proposed personalized framework and empirical methods based purely on anatomy; these errors cannot be predicted a priori. This suggests virtual treatment planning tools would benefit from increased personalization informed by emerging imaging methods.

Kinanthropometry and Anatomical Body Composition of Elite Soccer Players in Argentina: The FUTREF Project

Introduction: Anthropometric references for sports enable researchers and sports nutrition professionals to accurately assess body composition in an economical and efficient manner. The objective of this study was to provide an extensive anthropometric profile of elite soccer players divided by playing position. Seven hundred fifty-two players (age 24.0 ± 4.4 years) from 18 different Argentine teams were involved in the FUTREF project and measured according to the protocol defined by the International Society for the Advancement of Kinanthropometry (ISAK). Methods: Raw anthropometric parameters were reported and used to calculate somatotype and body mass components according to molecular (two-components) and anatomical (five-components) models. Results: Statistically significant differences (p&gt;0.01) were identified for anthropometric parameters among different playing positions and between players selected and not selected for the senior national team. The 5th, 25th, 50th, 75th, and 95th percentiles for the muscle-to-bone ratio were provided. Furthermore, the use of different equations showed different outputs in predicting body composition. Conclusion: This study provides anthropometric reference data for evaluating body composition in elite soccer players.

Variability in Intracranial Vessel Diameters and Considerations for Neurovascular Models: A Systematic Review and Meta‐Analysis

BACKGROUND In vitro experiments are critical for understanding the impact of medical devices and techniques on blood vessels and blood flow. However, their interpretation is often limited by anatomical models’ inability to capture the wide range of vessel sizes observed in real‐world practice. The current study aims to address this limitation by describing the distribution of vessel diameters in a real‐world population. METHODS This systematic literature review using the PubMed database analyzed cerebral vessel diameters in patients from 2000 to 2022. The diameter measurements of various vessels within the neurovasculature were extracted. Random‐effects meta‐analyses were performed to synthesize vessel diameters across studies. Predicted distributions were generated from the meta‐analytical results. RESULTS Seventy‐six studies were included in the analysis. The M1 segment, internal carotid artery (cervical and communicating segments), A1 segment, V2 segment, V4 segment, and basilar artery had sufficient data for generating predicted distributions of vessel diameters. Predicted mean diameters were as follows: M1 segment, 2.55 ± 0.42 mm (95th interpercentile range [IPR]: 1.71–3.38); internal carotid artery‐cervical segment, 4.74 ± 0.64 mm (95th IPR: 3.49–5.99); internal carotid artery‐communicating segment, 3.40 ± 0.64 mm (95th IPR: 2.15–4.66); A1 segment, 1.89 ± 0.34 mm (95th IPR: 1.23–2.55); V2 segment, 3.36 ± 0.67 mm (95th IPR: 2.05–4.67); V4 segment, 2.42 ± 0.74 mm (95th IPR: 0.98–3.86); and basilar artery, 2.96 ± 0.52 mm (95th IPR: 1.94–3.97). CONCLUSION Cerebral vessel diameter measurements can vary substantially due to patient‐specific factors and imaging techniques. This literature review highlights the diverse range of vessel sizes observed in different patient populations, emphasizing the need for anatomical models that accurately represent clinical observations.

A Critical Review of Human Jaw Biomechanical Modeling

The human jaw is a complex biomechanical system involving different anatomical components and an articulated muscular system devoted to its dynamical activation. The numerous actions exerted by the mandible, such as talking, eating or chewing, make its biomechanical comprehension absolutely indispensable. To date, even if research on this topic has achieved interesting outcomes using in vitro testing, thanks to the development of new apparatus and methods capable of performing more and more realistic experiments, theoretical modeling is still worthy of investigation. In light of this, nowadays, the Finite Element Method (FEM) approach constitutes certainly the most common tool adopted to investigate particular issues concerning stress–strain characterization of the human jaw. In addition, kinematics analyses, both direct and inverse, are also diffuse and reported in the literature. This manuscript aimed to propose a critical review of the most recurrent biomechanical models of the human mandible to give readers a comprehensive overview on the topic. In light of this, the numerical approaches, providing interesting outcomes, such as muscular activation profiles, condylar forces and stress–strain fields for the human oral cavity, are mainly differentiated between according to the joint degrees of freedom, the analytical descriptions of the muscular forces, the boundary conditions imposed, the kind of task and mandible anatomical structure modeling.

Surgeon Upper Extremity Kinematics During Error and Error-Free Retropubic Trocar Passage.

Surgeon kinematics play a significant role in the prevention of patient injury. We hypothesized that elbow extension and ulnar wrist deviation are associated with bladder injury during simulated midurethral sling (MUS) procedures. We used motion capture technology to measure surgeons' flexion/extension, abduction/adduction, and internal/external rotation angular time series for shoulder, elbow, and wrist joints. Starting and ending angles, minimum and maximum angles, and range of motion (ROM) were extracted from each time series. We created anatomical multibody models and applied linear mixed modeling to compare kinematics between trials with versus without bladder penetration and attending versus resident surgeons. A total of 32 trials would provide 90% power to detect a difference. Out of 85 passes, 62 were posterior to the suprapubic bone and 20 penetrated the bladder. Trials with versus without bladder penetration were associated with more initial wrist dorsiflexion (-27.32 vs -9.03°, p = 0.01), less final elbow flexion (39.49 vs 60.81, p = 0.03), and greater ROM in both the wrist (27.48 vs 14.01, p = 0.02), and elbow (20.45 vs 12.87, p = 0.04). Wrist deviation and arm pronation were not associated with bladder penetration. Compared with attendings, residents had more ROM in elbow flexion (14.61 vs 8.35°, p < 0.01), but less ROM in wrist dorsiflexion (13.31 vs 20.33, p = 0.02) and arm pronation (4.75 vs 38.46, p < 0.01). Bladder penetration during MUS is associated with wrist dorsiflexion and elbow flexion but not internal wrist deviation and arm supination. Attending surgeons exerted control with the wrist and forearm, surgical trainees with the elbow. Our findings have direct implications for MUS teaching.

Parotidectomy Surgical Simulation and Education with a Three-Dimensional Printed Face Model for Iraqi Surgeons

Purpose: Parotidectomy is usually suggested for many persons with parotid gland tumors. Facial nerve weakening is the most concerning of the potential consequences related to parotidectomy, resulting in a significantly reduced patient quality of life. With preoperative preparation and surgical training and simulation, a three-Dimensional (3D) printed human face anatomical model has just been designed and fabricated.&#x0D; Materials and Methods: Fifteen surgeons from Iraqi teaching hospitals evaluated the simulator model by using a Likert scale survey. The model is composed of a silicon based human face replica with an incorporated parotid gland replica and a closed electrical circuit of the facial nerve course to show when contact is made between the surgical instrument and the nerve to provide feedback.&#x0D; Results and Conclusion: All participants gave favorable feedback. Significant levels of satisfaction with the designed simulator have been relatively achieved. In comparison to experts, novice surgeons scored less for skin realism and handling. Such a difference suggests that the proposed simulator appears to have the potential to contribute to the advancement of surgical simulation, education, and planning.

Development of 3D printed tissue-mimicking materials: Combining fiber reinforcement and fluid content for improved surgical rehearsal

The prevalence of medical errors during surgical procedures has led to a higher emphasis on improving surgical outcomes, by improving surgical planning and training. Anatomical models have become valuable tools for pre-operative planning and current 3D printed models strive to better match real soft biological tissues. This study aimed to develop novel 3D printed material composites with controllable mechanical properties that mimic soft tissue. Concepts of microstructuring, fiber reinforcement and fluid infill in extrusion-based 3D printing are combined to design tunable materials towards target tissues of porcine muscle and liver. Material characterization was performed in triangular wave cyclic experiments under uniaxial tension with increasing displacements. Hereby, initial EI and final EII elastic moduli were evaluated. Further, the viscous response was characterized by the dissipated energy ratio UD and suture retention strength (SRS) was determined by single tensile pull-out tests Elastic moduli of printed materials were successfully tuned to 510 ± 10 kPa, closely resembling porcine muscle with 580 ± 150 kPa. The dissipated energy ratio UD of the silicone was increased from 0.09 ± 0.01 to 0.46 ± 0.17 by addition of gyroid infill and viscous fluid. Suture retention strength (SRS) for porcine liver tissue was 1.64 ± 0.42 N, while that of 3D printed silicone showed a mean SRS of 5.1 ± 0.6 N. Although the exact properties of porcine muscle and liver tissue require finer tuning, this study established techniques for refinement of 3D printed tissue-mimicking materials, ultimately enabling more accurate models for surgical rehearsal.

Assessment of volumetric dense tissue segmentation in tomosynthesis using deep virtual clinical trials

The adoption of artificial intelligence (AI) in medical imaging requires careful evaluation of machine-learning algorithms. We propose the use of a “deep virtual clinical trial” (DeepVCT) method to effectively evaluate the performance of AI algorithms. In this paper, DeepVCTs have been proposed to elucidate limitations of AI applications and predictions of clinical outcomes, avoiding biases in study designs. The DeepVCT method was used to evaluate the performance of nnU-Net models in assessing volumetric breast density (VBD) from digital breast tomosynthesis (DBT) images. In total, 2010 anatomical breast models were simulated. Projections were simulated using the acquisition geometry of a clinical DBT system. The projections were reconstructed using 0.1, 0.2, and 0.5 mm plane spacing. nnU-Net models were developed using the center-most planes of the reconstructions with the respective ground-truth. The results show that the accuracy of the nnU-Net improves significantly with DBT images reconstructed with 0.1 mm plane spacing (78.4×205.3×40.1 mm3). The segmentations resulted in Dice values up to 0.84 with area under the receiver operating characteristic curve of 0.92. The optimization of plane spacing for VBD assessment was used as an exemplar of a DeepVCT application, allowing us to interpret better the input parameters and outcomes of the nnU-Net. Thus, DeepVCTs can provide a plethora of evidence to predict the efficacy of these algorithms using large-scale simulation-based data.

ForCEPSS—A framework for cardiac electrophysiology simulations standardization

Background and Objective:Simulation of cardiac electrophysiology (CEP) is an important research tool that is increasingly being adopted in industrial and clinical applications. Typical workflows for CEP simulation consist of a sequence of processing stages starting with building an anatomical model and then calibrating its electrophysiological properties to match observable data. While the calibration stages are common and generalizable, most CEP studies re-implement these steps in complex and highly variable workflows. This lack of standardization renders the execution of computational CEP studies in an efficient, robust, and reproducible manner a significant challenge. Here, we propose ForCEPSS as an efficient and robust, yet flexible, software framework for standardizing CEP simulation studies. Methods and Results:Key processing stages of CEP simulation studies are identified and implemented in a standardized workflow that builds on openCARP11https://opencarp.org/. Plank et al. (2021) and the Python-based carputils22https://git.opencarp.org/openCARP/carputils. framework. Stages include (i) the definition and initialization of action potential phenotypes, (ii) the tissue scale calibration of conduction properties, (iii) the functional initialization to approximate a limit cycle corresponding to the dynamic reference state according to an experimental protocol, and, (iv) the execution of the CEP study where the electrophysiological response to a perturbation of the limit cycle is probed. As an exemplar application, we employ ForCEPSS to prepare a CEP study according to the Virtual Arrhythmia Risk Prediction protocol used for investigating the arrhythmogenic risk of developing infarct-related ventricular tachycardia (VT) in ischemic cardiomyopathy patients. We demonstrate that ForCEPSS enables a fully automated execution of all stages of this complex protocol. Conclusion:ForCEPSS offers a novel comprehensive, standardized, and automated CEP simulation workflow. The high degree of automation accelerates the execution of CEP simulation studies, reduces errors, improves robustness, and makes CEP studies reproducible. Verification of simulation studies within the CEP modeling community is thus possible. As such, ForCEPSS makes an important contribution towards increasing transparency, standardization, and reproducibility of in silico CEP experiments.

3D MODEL of an anatomically inert human hand: feasibility study

ObjectivesSurgery for congenital malformation of the hand is complex and protocols are not available. Simulation could help optimize results.The objective of the present study was to design, produce and assess a 3D-printed anatomical support, to improve success in rare and complex surgeries of the hand. Material and methodsWe acquired MRI imaging of the right hand of a 30 year-old subject, and analyzed and split the various skin layers for segmentation.We created the prototype of a healthy hand, using 3D multi-material and silicone printing devices, and drew up a printing protocol suitable for all patients.We printed a base, comprising bones, muscles and tendons, with a multi-material 3D printer, then used a 3D silicone printer for skin and subcutaneous fatty cell tissues in a glove-like shape.To evaluate the characteristics of the prototype, we performed a series of dissections on the synthetic hand and on a cadaveric hand in the anatomy lab, comparing realism, ease of handling and the final result of the two supports, and evaluated their respective advantages in surgical and training contexts. A grading form was given to each surgeon to establish a global score. ResultsThis evaluation highlighted the positive and negative features of the model. The model avoided intrinsic problems of cadavers, such as muscle rigidity and tissue fragility and atrophy and enables the anatomy of a specific patient to be rigorously respected. On the other hand, vascular and nervous networks, with their potential anatomical variants, are lacking.This preliminary phase highlighted the advantages and inconveniences of the prototype, to optimize the design and printing of future models. It is an indispensable prerequisite before performing studies in eligible pediatric patients with congenital hand malformation. ConclusionThe validation of 3D-printed anatomical model of a human hand opens a large field of applications in the area of preoperative surgical planning.The postoperative esthetic and functional benefit of such pre-intervention supports in complex surgery needs assessing.

Adaptable cascaded registration for personalized maxilla completion and cleft defect volume estimation.

Cone-beam computed tomography (CBCT) images provide high-resolution insights into the underlying craniofacial anomaly in patients with cleft lip and palate (CLP), requiring non-negligible annotation costs to measure the cleft defect for the guidance of the clinical secondary alveolar bone graft procedures. Considering the cumbersome volumetric image acquisition, there is a lack of paired CLP CBCTs and normal CBCTs for learning-based anatomical structure restoration models. Nowadays, the registration-based method relieves the annotation burden, though one-shot registration and the regular mask are limited to handling fine-grained shape variations and harmony between restored bony tissues and the defectedmaxilla. This study aimed to design and evaluate a novel method for deformable partial registration of the CLP CBCTs and normal CBCTs, enabling personalized maxilla completion and cleft defect volume prediction from CLPCBCTs. We proposed an adaptable deep registration framework for personalized maxilla completion and cleft defect volume prediction from CLP CBCTs. The key ingredient was a cascaded partial registration to exploit the maxillary morphology prior and attribute transfer. Cascaded registration with coarse-to-fine registration fields handled morphological variations of cleft defects and fine-grained maxillary restoration. We designed an adaptable cleft defect mask and volumetric Boolean operators for reliable voxel filling of the defected maxilla. A total of 36 clinically obtained CLP CBCTs were used to train and validate the proposed model, among which 22 CLP CBCTs were used to generate a training dataset with 440 synthetic CBCTs by B-spline deformation-based data augmentation and the remaining for testing. The proposed model was evaluated on maxilla completion and cleft defect volume prediction from clinically obtained unilateral and bilateral CLPCBCTs. Extensive experiments demonstrated the effectiveness of the adaptable cleft defect mask and the cascaded partial registration on maxilla completion and cleft defect volume prediction. The proposed method achieved state-of-the-art performances with the Dice similarity coefficient of 0.90 0.02 on the restored maxilla and 0.84 0.04 on the estimated cleft defect, respectively. The average Hausdorff distance between the estimated cleft defect and the manually annotated ground truth was 0.30 0.08 mm. The relative volume error of the cleft defect was 0.08. The proposed model allowed for the prediction of cleft defect maps that were in line with the ground truth in the challenging unilateral and bilateral CLP CBCTs. The results suggest that the proposed adaptable deep registration model enables patient-specific maxilla completion and automatic annotation of cleft defects, relieving tedious voxel-wise annotation and image acquisitionburdens.

Quality assurance of 3D-printed patient specific anatomical models: a systematic review

BackgroundThe responsible use of 3D-printing in medicine includes a context-based quality assurance. Considerable literature has been published in this field, yet the quality of assessment varies widely. The limited discriminatory power of some assessment methods challenges the comparison of results. The total error for patient specific anatomical models comprises relevant partial errors of the production process: segmentation error (SegE), digital editing error (DEE), printing error (PrE). The present review provides an overview to improve the general understanding of the process specific errors, quantitative analysis, and standardized terminology.MethodsThis review focuses on literature on quality assurance of patient-specific anatomical models in terms of geometric accuracy published before December 4th, 2022 (n = 139). In an attempt to organize the literature, the publications are assigned to comparable categories and the absolute values of the maximum mean deviation (AMMD) per publication are determined therein.ResultsThe three major examined types of original structures are teeth or jaw (n = 52), skull bones without jaw (n = 17) and heart with coronary arteries (n = 16). VPP (vat photopolymerization) is the most frequently employed basic 3D-printing technology (n = 112 experiments). The median values of AMMD (AMMD: The metric AMMD is defined as the largest linear deviation, based on an average value from at least two individual measurements.) are 0.8 mm for the SegE, 0.26 mm for the PrE and 0.825 mm for the total error. No average values are found for the DEE.ConclusionThe total error is not significantly higher than the partial errors which may compensate each other. Consequently SegE, DEE and PrE should be analyzed individually to describe the result quality as their sum according to rules of error propagation. Current methods for quality assurance of the segmentation are often either realistic and accurate or resource efficient. Future research should focus on implementing models for cost effective evaluations with high accuracy and realism. Our system of categorization may be enhancing the understanding of the overall process and a valuable contribution to the structural design and reporting of future experiments. It can be used to educate specialists for risk assessment and process validation within the additive manufacturing industry.Graphical Context of the figures in this review. Center: Fig. 5+ 7; top (blue): Fig. 8; right (green): Fig. 9; bottom (yellow): Fig. 10; left (red): Fig. 11. A version in high resolution can be found online in the supplementary material.

The Effect of the Use of Activation 3D Mapping on the Patient X-Ray Load During Radiofrequency Ablation of Typical Atrial Flutter

Supraventricular macro re-entry tachyarrhythmias occupy the leading places among all types of tachyarrhythmias. The most common in this category is typical atrial flutter (AFL). This heart rhythm disorder has a negative impact on the patients’ quality of life. Its complications can lead to disability and death due to possible thromboembolism. Therapeutic treatment is limited in effectiveness. The main method of intervention is catheter radiofrequency ablation (RFA). The standard approach of RFA of AFL is performed without the use of navigation systems under fluoroscopy guidance. However, this results in an increased radiation exposure to the patient and the medical personnel. Modern technologies in the field of invasive electrophysiology make it possible to create anatomical models of heart and reproduce the spread of electrical excitation. However, the routine use of additional navigation methods remains controversial.&#x0D; The aim. To compare the duration of RFA of typical AFL and radiation exposure with the use of anatomical and propagation mapping.&#x0D; Materials and methods. This study is based on the analysis of the treatment results obtained for 53 patients at the National Amosov Institute of Cardiovascular Surgery in the period from 2014 to 2023. Depending on imaging methods, the patients were divided into two groups. The first group included 27 patients with an anatomical mapping of the right atrium. The second group included 26 patients with propagation mapping.&#x0D; Results. In all the patients we have achieved a bidirectional conduction block through cavotricuspid isthmus. In the first group, the total duration of confirming the diagnosis and creating the anatomical model was 312 ± 26 seconds. The mean time to the moment of AFL termination and restoration of sinus rhythm was 230 ± 19 seconds. The average duration of the procedure was 41.5 ± 3.5 minutes, the average fluoroscopy time was 120 ± 10 seconds, the average dose area product (DAP) was 15 ± 1.3 Gy·cm2. In the second group, the average time for creating a 3D propagation model of right atrium and verifying the diagnosis was 748 ± 65 seconds. The average time from the first application to the termination of tachycardia was 227 ± 20 seconds. The average duration of the procedure was 55 ± 4.7 minutes, X-ray time was 93 ± 8 seconds, average DAP was 13 ± 1.1 Gy·cm2. The duration of the procedure in the second group was significantly longer (p = 0.03), however, the radiation exposure and DAP were not statistically different (p = 0.31) between the observation groups.&#x0D; Conclusions. The use of propagation mapping increases the time of the procedure by 24.5% and does not give a significant advantage in reducing the radiation exposure. The use of a navigation system during cavotricuspid isthmus RFA is recommended for concomitant radical treatment of complex supraventricular arrhythmias, such as atrial fibrillation.

Getting hot in here! Comparison of Holmium vs. thulium laser in an anatomic hydrogel kidney model.

As laser technology has advanced, high-power lasers have become increasingly common. The Holmium: yttrium-aluminum-garnet (Ho:YAG) laser has long been accepted as the standard for laser lithotripsy. The thulium fiber laser (TFL) has recently been established as a viable option. The aim of this study is to evaluate thermal dose and temperature for the Ho:YAG laser to the TFL at four different laser settings while varying energy, frequency, operator duty cycle (ODC). Utilizing high-fidelity, 3D-printed hydrogel models of a pelvicalyceal collecting system (PCS) with a synthetic BegoStone implanted in the renal pelvis, laser lithotripsy was performed with the Ho:YAG laser or TFL. At a standard power (40W) and irrigation (17.9ml/min), we evaluated four different laser settings with ODC variations with different time-on intervals. Temperature was measured at two separate locations. In general, the TFL yielded greater cumulative thermal doses than the Ho:YAG laser. Thermal dose and temperature were typically greater at the stone when compared away from the stone. Regarding the TFL, there was no general trend if fragmentation or dusting settings yielded greater thermal doses or temperatures. The TFL generated greater temperatures and thermal doses in general than the Ho:YAG laser with Moses technology. Temperatures and thermal doses were greater closer to the laser fiber tip. It is inconclusive as to whether fragmentation or dusting settings elicit greater thermal loads for the TFL. Energy, frequency, ODC, and laser-on time significantly impact thermal loads during ureteroscopic laser lithotripsy, independent of power.

Assessment of a New Medical Device (PirifixTM) for Positioning and Maintaining the Upper Dental Arch during Le Fort I Osteotomy.

Several medical devices (MDs) are used to assist surgeons in positioning the upper dental arch (UDA) during Le Fort I osteotomies (LFIOs). Some only allow holding, others only positioning. This study aimed to assess the accuracy of a new MD (PirifixTM) coupling these two functions during LFIO on 3D-printed models. DICOM data were selected from patients who underwent surgical planning for LFIO between 27 July 2020 and 1 December 2022. Their anatomy was reproduced after segmentation, planning, and stereolithography in two models. Each model was assigned to one of two surgical groups: the control group (positioning by occlusal splint) and the PirifixTM group. Each patient's model was planned with the objective of horizontalizing and recentering the UDA. After positioning, models were digitalized using Einscan Pro 2X and compared to the planned model with CloudCompare. The statistical analysis was performed using the Wilcoxon Mann-Whitney test. The result was considered significant if the p-value was less than 0.05. Twenty-one patients were selected. Forty-two anatomical models were 3D-printed. The mean difference compared to the planned and corrected positions was 0.69 mm for the control group and 0.84 mm for the PirifixTM group (p = 0.036). PirifixTM may be a new alternative to available MDs. Further investigations are needed to describe the relationship between the device and facial soft tissues.

Evaluation of models of sequestration flow in coronary arteries—Physiology versus anatomy?

Background:Myocardial ischaemia results from insufficient coronary blood flow. Computed virtual fractional flow reserve (vFFR) allows quantification of proportional flow loss without the need for invasive pressure-wire testing. In the current study, we describe a novel, conductivity model of side branch flow, referred to as ‘leak’. This leak model is a function of taper and local pressure, the latter of which may change radically when focal disease is present. This builds upon previous techniques, which either ignore side branch flow, or rely purely on anatomical factors. This study aimed to describe a new, conductivity model of side branch flow and compare this with established anatomical models. Methods and results:The novel technique was used to quantify vFFR, distal absolute flow (Qd) and microvascular resistance (CMVR) in 325 idealised 1D models of coronary arteries, modelled from invasive clinical data. Outputs were compared to an established anatomical model of flow. The conductivity model correlated and agreed with the reference model for vFFR (r = 0.895, p < 0.0001; ＋0.02, 95% CI 0.00 to ＋ 0.22), Qd (r = 0.959, p < 0.0001; −5.2 mL/min, 95% CI −52.2 to ＋13.0) and CMVR (r = 0.624, p < 0.0001; ＋50 Woods Units, 95% CI −325 to ＋2549). Conclusion:Agreement between the two techniques was closest for vFFR, with greater proportional differences seen for Qd and CMVR. The conductivity function assumes vessel taper was optimised for the healthy state and that CMVR was not affected by local disease. The latter may be addressed with further refinement of the technique or inferred from complementary image data. The conductivity technique may represent a refinement of current techniques for modelling coronary side-branch flow. Further work is needed to validate the technique against invasive clinical data.

Doing more with less: Realistic stereoscopic three-dimensional anatomical modeling from smartphone photogrammetry.

Traditional teaching methods struggle to convey three-dimensional concepts effectively. While 3D virtual models and virtual reality platforms offer a promising approach to teaching anatomy, their cost and specialized equipment pose limitations, especially in disadvantaged areas. A simpler alternative is to use virtual 3D models displayed on regular screens, but they lack immersion, realism, and stereoscopic vision. To address these challenges, we developed an affordable method utilizing smartphone-based 360° photogrammetry, virtual camera recording, and stereoscopic display (anaglyph or side-by-side technique). In this study, we assessed the feasibility of this method by subjecting it to various specimen types: osteological, soft organ, neuroanatomical, regional dissection, and a dedicated 3D-printed testing phantom. The results demonstrate that the 3D models obtained feature a complete mesh with a high level of detail and a realistic texture. Mesh and texture resolutions were estimated to be approximately 1 and 0.2 mm, respectively. Additionally, stereoscopic animations were both feasible and effective in enhancing depth perception. The simplicity and affordability of this method position it as a technique of choice for creating easily photorealistic anatomical models combined with stereoscopic depth visualization.

WATTS happening? Evaluation of thermal dose during holmium laser lithotripsy in a high-fidelity anatomic model.

To evaluate the thermal profiles of the holmium laser at different laser parameters at different locations in an in vitro anatomic pelvicalyceal collecting system (PCS) model. Laser lithotripsy is the cornerstone of treatment for urolithiasis. With the prevalence of high-powered lasers, stone ablation efficiency has become more pronounced. Patient safety remains paramount during surgery. It is well recognized that the heat generated from laser lithotripsy has the potential to cause thermal tissue damage. Utilizing high-fidelity, 3D printed hydrogel models of a PCS with a synthetic BegoStone implanted in the renal pelvis, laser lithotripsy was performed with the Moses 2.0 holmium laser. At a standard power (40W) and irrigation pressure (100cm H2O), we evaluated operator duty cycle (ODC) variations with different time-on intervals at four different laser settings. Temperature was measured at two separate locations-at the stone and away from the stone. Temperatures were highest closest to the laser tip with a decrease away from the laser. Fluid temperatures increased with longer laser-on times and higher ODCs. Thermal doses were greater with increased ODCs and the threshold for thermal injury was reached for ODCs of 75% and 100%. Temperature generation and thermal dose delivered are greatest closer to the tip of the laser fiber and are not dependent on power alone. Significant temperature differences were noted between four laser settings at a standardized power (40W). Temperatures can be influenced by a variety of factors, such as laser-on time, operator duty cycle, and location in the PCS.

Accuracy Analysis of 3D Bone Fracture Models: Effects of Computed Tomography (CT) Imaging and Image Segmentation.

The introduction of three-dimensional (3D) printed anatomical models has garnered interest in pre-operative planning, especially in orthopedic and trauma surgery. Identifying potential error sources and quantifying their effect on the model dimensional accuracy are crucial for the applicability and reliability of such models. In this study, twenty radii were extracted from anatomic forearm specimens and subjected to osteotomy to simulate a defined fracture of the distal radius (Colles' fracture). Various factors, including two different computed tomography (CT) technologies (energy-integrating detector (EID) and photon-counting detector (PCD)), four different CT scanners, two scan protocols (i.e., routine and high dosage), two different scan orientations, as well as two segmentation algorithms were considered to determine their effect on 3D model accuracy. Ground truth was established using 3D reconstructions of surface scans of the physical specimens. Results indicated that all investigated variables significantly impacted the3D model accuracy(p < 0.001). However, the mean absolute deviation fell within the range of 0.03 ± 0.20 to 0.32 ± 0.23mm, well below the 0.5mm threshold necessary for pre-operative planning. Intra- and inter-operator variability demonstrated fair to excellent agreement for 3D model accuracy, with an intra-class correlation (ICC)of 0.43 to 0.92. This systematic investigation displayed dimensional deviations in the magnitude of sub-voxel imaging resolution for all variables. Major pitfalls included missed or overestimated bone regions during the segmentation process, necessitating additional manual editing of 3D models. In conclusion, this study demonstrates that 3D bone fracture models can be obtained with clinical routine scanners and scan protocols, utilizing a simple global segmentation threshold, thereby providing an accurate and reliable tool for pre-operative planning.