Use Of 3D Models Research Articles

Surgical planning with patient-specific three-dimensional printed pancreaticobiliary disease models - Cross-sectional study.

Three-dimensional (3D) printing has been increasingly used in medical applications with the creation of accurate patient-specific 3D printed models in medical imaging data. This study has been planned based on the fact that research on 3D printing in pancreaticobiliary disease is limited due to lack of studies on validation of model accuracy. This is an innovative study where general surgery residents are presented 5 distinct hepatopancreatobiliary disease scenarios to generate a perception and required to compare their perception level of these cases with magnetic resonance cholangiopancreatography (MRCP), 3D images and 1:1 solid models that the pathology, diverse diagnosis and presurgery diagnosis stages can be observed. This study is single-centered. The dilated pancreaticobiliary intervention based on scenarios for general surgery residency was more original since there was no prior study that includes both model building and the evaluation of the perception created by the model. Five scenarios provided qualitative assessment with results showing the usefulness of 3D models when used as clinical tools in preoperative planning, simulation of interventional procedures, surgical education, and training. The perception level in the 3D model, MRCP (Z: 3.854, p: 0.000) and the 3D image (Z: 2.865, p: 0.004) was higher; likewise, the 3D-STL image was higher compared to the MRCP image (Z: 3.779, p: 0.000). All subspecialists agree that 3D models provided better understanding of dilated pancreaticobiliary pathoanatomy and improved surgical planning. A thoroughly outlined genuine patient situation layout aimed for general surgery training can be installed and monitored with the support of 3D printing technology of this study. This can be utilized to develop the comprehension of pathoanatomical variations of complex pancreaticobiliary illness and to adopt a surgical approach.

Do three-dimensional modeling and printing technologies have an impact on the surgical success of percutaneous transsacral screw fixation?

Objectives This study aims to determine the role of computed tomography (CT)-derived templates, produced by three- dimensional (3D) modeling, image processing and printing technology, in percutaneous transsacral screw fixation and evaluate the effects of their use on surgical success.Materials and methods This prospective study conducted between June 2018 and December 2019 utilized 15 composite pelvis models for transsacral-transiliac screw fixation. For the procedure, modeled templates were utilized for wiring on the left side of the pelvis models, while the conventional method was performed on the right side of the pelvis models. In the computed tomography images acquired after wiring, appropriate wire position was evaluated.Results The placed wires held the S1 body appropriately in all of the procedures with or without template use. With the template use, the wires were placed appropriately in the surgical bone corridor suitable for the transsacral-transiliac screw fixation in all of the models. However, with the conventional methods, the wires were not placed in the safe surgical bone corridor in four models. The wire deviation angle in the axial plane was significantly lower in the template group (p=0.001), whereas it was not different between the template group and the conventional method group in the coronal plane (p=0.054). The amount of deviation from the ideal wire entry site was significantly reduced in the template group compared to the conventional method group (p=0.001).ConclusionWith the use of 3D modeling and printing technology, CT-derived templates can be produced and utilized for transsacral screw fixation procedures and their use increases surgical success by reducing the surgical margin of error.

Effect of Curing Methods on Shrinkage Development in 3D-Printed Concrete.

Technological developments in construction have led to an increase in the use of 3D modelling using CAD environments. The popularity of this approach has increased in tandem with developments in industry branches which use 3D printers to print concrete based printing materials in construction, as these allow freedom in shaping the dimensions of supporting elements. One of the biggest challenges for researchers working on this highly innovative technology is that of cement material shrinkage. This article presents the findings of research on an original method of measuring deformations caused by shrinkage in 3D-printed concrete elements. It also discusses the results of tests on base mixes, as well as comparisons between the influence of internal and external curing methods on the development of deformations and their final outcomes. Furthermore, the article discusses differences between deformations formed after seven days of hardening without curing, with those which occur when two common, traditional concrete curing methods are used: foil insulation and shrinkage reducing admixtures. In addition, the article examines the effects of internal curing on the 1, 7, 14, 21 and 28 day mechanical properties of concrete, in accordance with EN 196-1 and EN 12390-2. Studies have shown that the optimal amount of shrinkage reducing admixtures is 4% (in relation to the mass of cement), resulting in a reduction in total shrinkage of 23%. The use of a shrinkage reducing admixture in 3D-printed concrete does not affect their strength after 28 days, but slows the strength development during the first 7 days.

3D printing in adult cardiovascular surgery and interventions: a systematic review.

3D printing in adult cardiac and vascular surgery has been evaluated over the last 10 years, and all of the available literature reports benefits from the use of 3D models. In the present study, we analyzed the current applications of 3D printing for adult cardiovascular disease treated with surgical or catheter-based interventions, including the clinical medical simulation of physiological or pathology conducted with 3D printing in this field. A search of PubMed and MEDLINE databases were supplemented by searching through bibliographies of key articles. Thereafter, data on demographic, clinical scenarios and application, imaging modality, purposes of using with 3D printing, outcomes and follow-up were extracted. A total of 43 articles were deemed eligible and included. 296 patients (mean age: 65.4±14.2 years; male, 58.2%) received 3D printing for cardiac and vascular surgery or conditions [percutaneous left atrial appendage occlusion (LAAO), TAVR, mitral valve disease, aortic valve replacement, coronary artery abnormality, HOCM, aortic aneurysm and aortic dissection, Kommerell’s diverticulum, primary cardiac tumor and ventricular aneurysm]. Eight papers reported the utility of 3D printing in the medical simulator and training fields. Most studies were conducted starting in 2014. Twenty-six was case report. The major scenario used with 3D printing technology was LAAO (50.3%) and followed by TAVR (17.6%). CT and echocardiography were two main imaging techniques that were used to generate 3D-printed heart models. All studies showed that 3D-printed models were helpful for preoperative planning, orientation, and medical teaching. The important finding is that 3D printing provides a unique patient-specific method to assess complex anatomy and is helpful for intraoperative orientation, decision-making, creating functional models, and teaching adult cardiac and vascular surgery, including catheter-based heart surgery.

Evaluating the morphological and metric sex of human crania using 3-dimensional (3D) technology.

Identifying the skeletal remains of an unidentified individual is a priority for the medico-legal system because identification increases the chances of finding the person responsible and provides closure to the family. The purpose of this research was to develop a combined morphological and metric cranial sex assessment method using 3D technology that accommodates the medico-legal system, and their use of 3D models facilitates the technological transition to digitally archived skeletal collections. A total of 91 individuals of European biogeographical ancestry from the William M. Bass Donated Skeletal Collection (University of Tennessee Knoxville) were imaged using photogrammetry, turned into 3D models using Agisoft PhotoScan, and digitally evaluated using 3D Studio Max. This novel method digitally evaluated five cranial traits, including the nasal aperture height, nasal aperturewidth, mastoid length, the general size and architecture, and the supraorbital ridges, combining techniques that can only be done digitally with those that can be completed on the actual bone. Preliminary statistical tests demonstrate an overall accuracy rate of 90% when tested against the training sample (20 males, 20 females) and 75% when tested against the test sample (51 individuals). Although no intra- or inter-observer errorrate tests were done, and further testing on other skeletal collections is necessary, this method allows forensic anthropologists to perform relatively easy point-to-point measurements, the quantification of traditionally non-quantified traits, the possibility of reproducible results, and the ability for future analyses or research.

3D Virtual Models to Visualize Pelvic Floor & Perineum in Medical Gross Anatomy

IntroductionThe pelvic floor and perineum are difficult regions to visualize with most educational tools. Cadaveric dissection of this region is cumbersome due to limited accessibility and ambiguity of structures, and presents challenges with teaching spatial orientation. Supplemental learning material such as two‐dimensional anatomical illustrations often lack the ability to demonstrate spatial depth and complex relationships of the pelvis and perineum. We developed 3D virtual models to teach this spatially complex region in a didactic session on pelvic and perineal anatomy.AimThis study explored the efficacy of 3D virtual models as a supplementary teaching tool for pelvic floor and perineum.MethodsTwo review sessions were provided to a total of 37 first year medical students. The content of the lesson was initially presented in a traditional lecture format alongside 2D illustrations and schematics. Immediately following the lecture portion, 3D models of each region of interest were presented to students using 3D4Medical Complete Anatomy application.Prior to the session, students (n=31) completed a modified Likert scale (1–5) survey on their familiarity with pelvic musculature, perineal fasciae and spaces, and the course of the pudendal nerve. After the session, students (n=37) completed a similar survey reviewing their confidence in pelvic musculature, perineal fasciae and spaces, and the course of the pudendal nerve. Relative frequencies for each question have been reported as a percentage, with a score of 3 considered neutral.ResultsOf the students who responded to the pre‐session survey (n=31), 6.5% reported being familiar (a score of 4 or 5) with the muscles of the pelvic floor, 9.7% reported being familiar with the perineal fasciae and spaces, and 12.9% reported being familiar with the course of the pudendal nerve.Responses to the post‐session survey (n=37), revealed that 91.9% of students reported improved confidence (a score of 4 or 5) in their understanding of pelvic floor musculature and perineal fasciae and spaces. While, 83.8% reported improved confidence in their understanding of the pudendal nerve course.ConclusionThe use of 3D models, as a supplement to existing course content, is an effective method for improving student confidence in pelvic floor and perineum anatomy. Our results suggest that the combination of 3D virtual models and didactic knowledge transmission, facilitates the learning of pelvic floor and perineal regions.

Analysis of the 3D prototyping in the surgical correction of congenital kyphoscoliosis

Objective . To analyze the advantages of additive technologies and 3D modeling in surgery for severe congenital spinal deformities caused by mixed and non-classified developmental anomalies, including assessing the quality of transpedicular screws. Material and Methods . A total of 20 patients with complex spinal anatomy caused by congenital vertebral anomalies were treated. Nine patients had complex unclassifiable anomalies of the spine, 11 had mixed anomalies, 3 of them had aplasia of the structures of the spinal column. In order to assess the results, patients were divided into two groups of 10 people. In Group I, standard preoperative preparation was performed according to X-ray, CT and MRI data. In Group II, preoperative preparation was accompanied by the use of a prefabricated 3D model of the patient’s spine. CT data were used to create STL-models which were printed using 3D printer. To analyze the effectiveness of 3D prototyping in preoperative planning, a survey among surgeons specializing in pathology of the spine was conducted. Results . Survey results demonstrated that there were cases of changes in surgical treatment tactics after the 2nd stage of the survey, based on the results of applying standard methods of radiation diagnostics and 3D model of the entire spine with prototyping of the thoracic, lumbar, and sacral spine. In 25.3 % of cases, tactics were changed. Significant improvement in surgical treatment results were observed in Group II with preoperative 3D modeling (94.9 % without screw malposition), compared to Group I in which surgical correction was performed using standard methods of imaging (78.1 % without screw malposition). Conclusion . 3D modeling allows increasing the accuracy of the placement of transpedicular screws and reducing the risk of malposition, which favorably affects the biomechanical properties of the instrumentation and reduces the risk of damage to neural structures. The use of 3D modeling can statistically significantly reduce the time taken to install one screw, and the number of x-rays required. Reducing the number of images allows you to reduce radiation exposure not only to the patient, but also to the staff of the department.

Utility of a three-dimensional printed pelvic model for lateral pelvic lymph node dissection.

In patients with advanced lower rectal cancer, the complex pelvic anatomy renders lateral pelvic lymph node dissection to be challenging. Therefore, we evaluated the utility of printing a three-dimensional (3D) pelvic model for lateral pelvic lymph node dissection. We included 22 patients who underwent lateral pelvic lymph node dissection for rectal cancer between June 2017 and February 2019. Using CT scans, 3D pelvic images and models were constructed and printed, respectively. Thirty colorectal surgeons subjectively evaluated the utility of 3D pelvic models based on a 5-point Likert scale questionnaire (1 = strongly disagree, 5 = strongly agree). The average Likert score for the question "Would a 3D model be useful for understanding pelvic anatomy?" was 4.68. Cases with clinically diagnosed metastatic lymph nodes (4.79 ± 0.44) scored higher than those without them (4.38 ± 0.77, p = 0.02). For spatial comprehension of pelvic anatomy, 3D models scored higher (4.83) than 3D images (4.36, p < 0.001). The ease of use of 3D models and images was scored 4.60 and 4.20, respectively (p = 0.015). With experience, the 3D image reconstruction time decreased from 900 to 150min. The 3D pelvic models may be helpful for experienced surgeons to understand the pelvic anatomy in lateral pelvic lymph node dissection.

3D-MODELS OF NATURAL OBJECTS AS A COMPONENT OF DIGITAL EDUCATIONAL RESOURCES IN TRAINING “ECOLOGY AND ENVIRONMENTAL MANAGEMENT“

The article discusses some aspects of the use of 3D-models as educational resources for bachelors trained in "Ecology and Environmental Management". The importance of such resources is noted, since a number of disciplines include the study of natural objects, and their visualization in the form of volumetric models contributes to increased visibility, enriches the thinking process, and helps to understand the connections and relations between the studied objects.

A 3D approach to reproduction

For over a century, 2D cell culture has been extensively used for all the different research fields. However, this in vitro system does not allow to reproduce the natural structures of the original tissue, causing several changes and, in most cases, the loss of cell-to-cell communications and cell-to-extracellular matrix interactions. Based on this, during the last years, novel 3D platforms, able to mimic the in vivo milieu, are being developed. The advantages of the use of 3D models are: the reduction of the gap between cell culture and physiological environment; imitation of the specific architecture; partially maintenance of the mechanical and biochemical cues of the original tissue. Currently, 3D systems are used in a broad range of studies, including the field of reproduction, where they have been applied to promote maturation of follicles and oocytes and embryo culture.Here, we review 2D and 3D cell culture methods, discussing advantages and limitations of these techniques. We report the fundamental mechanisms involved in cell ability to perceive and respond to mechanical cues and their role in transmitting signals to and between cells and in regulating intracellular signaling pathways. In particular, we focus on the main effectors of the Hippo pathway, Yes-associated protein (YAP) and WW domain-containing transcription regulator protein 1 (TAZ), describing their behavior and function in oocytes and embryos. Lastly, we provide an overall perspective of the most recent 3D technologies developed in the field of reproduction, describing how their use may revolutionize the understanding of cellular behavior and provide novel tools, useful in reproductive technologies and livestock production.

The use of three-dimensional models in tibial plateau fractures

Background: To compare three-dimensional (3D) printed models with 3D computed tomography (CT) images in terms of the reliability of the classification of tibial plateau fractures using the Hohl and Moore and the Schatzker classification systems, and whether there was any influence on surgical management. Method: The sample comprised the 20 CT scans of patients with tibial plateau fractures available in the radiology archive of Dr George Mukhari Academic Hospital (Ga-Rankuwa). Standardised illustrated guides to the Schatzker and the Hohl and Moore classification systems were used by six observers of varying orthopaedic experience. They completed questionnaires individually in three different sessions. In session one the observers had access to the 3D CT images only. On average two to five days later, in session two the observers assessed only the 3D models. In the third session, another two-to-five days later, the observers assessed the 3D CT images while handling and inspecting the corresponding 3D model. Results: The inter-observer reliability of the Schatzker system (moderate reliability) was superior to the Hohl and Moore system (fair reliability) when comparing the assessment using the images and models separately. When all observations were combined, there was no difference between the systems. For the six possible surgical management options given to the observers, there was an overall difference in agreement based on assessing only the CT images compared with assessing only the models, of 19% (23 of the possible 120 procedures). Of these 23 differing procedures, 15 were more invasive. The 3D models were considered superior to 3D CT imaging in terms of spatial awareness and the observers’ ability to assess intra-articular fracture patterns. The models were assessed as being superior to the imaging when considering the ability to estimate the quantity of bone graft required. Conclusion: Although the inter-rater reliability of classification was not significantly improved, there were several advantages to using the 3D-printed models both separately from the CT images and together with the images. The effect of 3D models on patient outcome remains untested. The clinical impact of the use of 3D models (including cost, manufacturing time and radiation exposure) should be weighed against the potential benefits. Level of evidence: Level 4

Multi-resolution 3D reconstruction of cultural landscape heritage based on cloud computing and hd image data

Cultural landscapes are cultural property and they are an illustration of the evolution of human society and the living environment over time. As cultural landscape is being valued more and more, the use of 3D modeling is becoming more and more important. As for the 3D reconstruction technology, most of the current methods are complicated in terms of network construction, use, and storage, and then affect the reconstruction efficiency of subsequent cultural landscape heritage. To obtain the 3D reconstruction technology with high reconstruction efficiency, this paper combines the circumferential binary feature extraction algorithm and cloud computing technology, and proposes a circumferential binary feature extraction and matching search method. The interior-point rate of the CBD algorithm in this paper is greater than 72%, which is higher than the interior point rate of other different algorithms, which indicates that the CBD algorithm in this paper is suitable for matching HD rotated images. The experimental results show that the circular binary features extracted by the article have strong adaptability and fast contrast rate. To better the 3D reconstruction of cultural landscape heritage in the later period, this paper also improves the 4PSC point cloud rough registration algorithm. The experimental results show that compared with other coarse registration algorithms, the improved point cloud coarse registration algorithm improves the registration accuracy and the registration effect is good, which proves the effectiveness of the algorithm.

Оценка эффективности установки дентальных имплантатов с использованием программного обеспечения 3D-планирования

Background. The use of modern digital technologies significantly changes the classical approaches to planning and conducting dental implantation. The whole process can be accomplished performed thus, so that the ideal placement of the implant can be achieved without the injured anatomical structure. Purpose. To evaluate the effectiveness of dental implant placement with the use of 3D-modeling and surgical guided. Materials and methods. A total of 148 patients with ridge defects in age group were selected for the study. All patients had a partially or totally edentulous. Computer scans, three-dimensional computer modeling were used to plan operations. 2 Patient groups were formed to evaluate the effectiveness of treatment using 3D modeling and surgical guided. Patients were included in group I, at the planning stage only a CT scan was used, Group II included patients who underwent a CT scan, 3D computer modeling (3 Shape Implant Studio) during the planning phase, and surgical guided (were fabricated with a desktop 3D printer Stratasys), were used in the surgical phase, the dental defect was restored with the with implant insertion. Results. In Group I, intraoperative or immediate post-operative complications were noted (errors in the position, inclination), anatomical risk structures were invaded, after 3 years producing a survival rate of 96.2 %. In Group II, no intra-operative or immediate post-operative complications were noted (no errors in the position, inclination,), no anatomical risk structures, after 3 years producing a survival rate of 97.6 %. Conclusion. The 3D modeling method and the use of surgical guided for dental implantation significantly risk the complications. Implant placement through the precision surgical guide is more accurate than freehand placement into the osteotomy, the guides allow installation of dental implants in the most optimal position for future prosthetic work, depth, and inclination.

The Use of 3D-Modeling for Reconstructing the Appearance and Function of Non-Utilitarian Items (the Case of Anthropomorphic Figurines from Tourist-2)

This article presents the results of study of an Early Bronze ivory figurine from Tourist-2, using 3D-scanning with various technical parameters. The aim of the study was to test the new non-invasive methods of structured light 3D-scanning, with an accurate assessment of morphometric characteristics. In addition, use-wear analysis was employed to evaluate the previously unknown features relating to function. As a result, the original appearance of the figurine, the manufacturing technique, and iconographic characteristics were reconstructed. A series of transverse sections and the evaluation of the center of mass, combined with previously known features, suggest that the figurine was a personal ornament sewn onto clothing. For comparison, two flat anthropomorphic sculptures (a buckle made of burl, and a shale figurine) from the same burial complex were analyzed. Longitudinal sections suggest that, despite morphological and technological differences and the fact that various raw materials had been used, the iconographic style of all items is one and the same.

Usability evaluation of 3D user interface for virtual planning of bone fixation plate placement

Abstract Universal pre-contoured plates are commonly used for internal fixation of bone fracture. Optimal plate placement can be determined through visual inspection of the relative position between the plate and the fractured bone as displayed on x-rays. While computer-assisted approaches have been developed to enable the manipulation of 3D models of the bone and the plate in virtual environments, as the 3D models are usually maneuvered using a 2D mouse with the virtual trackball paradigm, the process is counter-intuitive and could hamper system usability. An intuitive 3D haptic device was therefore employed to develop a virtual training system for fixation plate placement. A four-session study over two weeks were conducted with 15 subjects to evaluate the usability of the system, with 2D mouse and 3D haptic device employed as user interface. The effect of force feedback was also studied. A questionnaire was administered at the end of the study to assess user satisfaction towards the usability of the two input devices. User performance of virtual plate placement using a 3D haptic device was found to be superior to that using a 2D mouse, in terms of completion time and accuracy. The performance with and without force feedback was not significantly different. Preference toward 3D haptic device was reflected from the responses to the usability questionnaire. In conclusion, employing a 3D input device as user interface can potentially facilitate virtual planning of bone fixation plate placement.

A New Diagnostic Approach for Periprosthetic Acetabular Fractures Based on 3D Modeling: A Study Protocol.

Periprosthetic acetabular fractures after total hip arthroplasty (THA) are mostly related to low energy trauma reduced bone quality. CT-scan is widely used to evaluate acetabular fractures, however, metal artifacts produced prosthetic implants limit the visualization of the articular surface and bone loss assessment. 3D modeling software allows us to creating tridimensional images of the bony surface, removing the metallic implants trough image segmentation. We highlight the use of 3D modeling and rapid prototyping (3D printing) for the diagnostic process of periprosthetic acetabular fracture around THA. 3D modeling software was used to improve the assessment of fracture morphology and bone quality. Moreover, the 3D images were printed in a real-life size model and used for preoperative implant templating, sizing and surgical simulation.

A robust 3D point cloud watermarking method based on the graph Fourier transform

Many modern applications make use of 3D modeling and / or reconstruction of complex objects, such as historical monuments and entire urban centers. One of the most common representations of these 3D models is by point clouds, which are a dense set of points irregularly organized in a 3D coordinate system. Usually, the acquisition methods are highly expensive due to the necessary equipment and size of these models. This factor motivates the proposal of watermarking techniques to guarantee the copyright protection as well as to detect illegal copies. This paper presents a non-blind watermarking method for 3D point clouds. The method is based on the graph Fourier transform, a recently introduced signal processing tool which has been applied to signals lying over arbitrarily irregular domains. Unlike other published works regarding point cloud watermarking, instead of inserting the bit sequence in the models’ spatial coordinates, in this work the bits are embedded in the color information attributed in each point of a cloud. Simulation results show high imperceptibility and robustness against several attacks, such as affine transformations, reordering, noise addition and cropping.

Three-dimensional printing in orthopaedic preoperative planning improves intraoperative metrics: a systematic review.

Three-dimensional (3D) printing has seen increasing interest in surgery, where it improves the visualization of difficult anatomy in complex cases. This literature review investigates the benefits and limitations of 3D printed models in preoperative planning in the field of orthopaedic surgery. A literature search was performed using the Ovid platform on the Embase and MEDLINE databases using the terms '3D printing', 'Orthopaedics' and 'Surgical Planning'. Studies using 3D printed models as a part of preoperative planning were included. All others were excluded. Data regarding the metrics used to assess the benefit of the use of 3D models, surgical outcome, and surgeon or patient opinion on the technology were extracted. A total of 41 studies resulted. Eight (19.5%) were case-control studies, the remainder were case reports or case series. Assessment of benefit was mostly subjective, although the case-control studies included objective metrics such as operation time, intraoperative blood loss and intraoperative fluoroscopy time. The use of 3D printing technology showed subjective benefit for both patient and surgeon as well as indicating clinically significant improvements in intraoperative metrics. Despite the current absence of large scale trials, 3D printing has clear benefits in preoperative planning, particularly when utilized in complex cases. A streamlined workflow for case selection, in-house model creation and preoperative rehearsals is still required to be developed before the process is ready for routine use. Evidence supports an improvement in intraoperative metrics and patient engagement but data to support improved clinical outcome is lacking.

3D model processing for high throughput phenotype extraction – the case of corn

High resolution RGB imagery collected using a UAV and a handheld camera was used with structure from motion to reconstruct 3D canopies of small groups of corn plants. A methodology for the automated extraction of phenotypic characteristics of individual plants is presented based on these 3D reconstructed canopies. Such information can enhance the evaluation of crop traits and provide accurate and frequent statistics for in-season assessment of their changes with growth stage. Industries that target yield optimization and crop hybrid production can benefit greatly from this approach. The use of 3D models provides elevated information content, when compared to alternative planar methods, mainly due to the alleviation of leaf occlusions. High resolution images of corn stalks are collected and used to obtain 3D models for individual plants. Based on those extracted 3D point clouds, the calculation of phenotypic characteristics are obtained, such as the number of plants in an area, the Leaf Area Index (LAI), the individual and average plant height, the individual leaf length, the location and the angles of leaves with respect to the stem. An experimental validation using both artificial corn plants emulating real world scenarios and real corn plants in different growth stages, supports the accuracy of the proposed methodology.Our experiments conclude that phenotypic characteristics of individual plants can be extracted automatically with high accuracy based on a 3D model. The results include the individual plant segmentation and counting from a given 3D reconstructed field scene with 88.1% accuracy, the Leaf Area Index (LAI) estimation with 92.5% accuracy, the individual plant height computation with 89.2% accuracy, the leaf length extraction with 74.8% accuracy, the measurement of angles between leaves and stems, and the distance between the leaves of the same plant. We interpret the last two variables qualitatively to show that the method can show the trend of the angles to change with respect to the leaf position on the stem as the crops grow.

Three-Dimensional-Printed Model-Assisted Management of Craniovertebral Junction Abnormalities: An Institutional Experience with Literature Review.

Study DesignProspective study.PurposeTo evaluate the utility and limitations of using three-dimensional (3D)-printed models for the management of craniovertebral (CV) junction abnormalities.Overview of LiteratureIn comparison to other bony and vascular anomalies, CV junction abnormalities are difficult to treat. For cases of irreducible atlantoaxial dislocation (AAD), posterior reduction and stabilization have replaced anterior decompression as the standard management protocol. The use of 3D models, such as those described herein, can provide surgeons with in-depth knowledge of the vertebral artery course and bony anomalies associated with CV junction abnormalities.MethodsClinical and radiological features of 18 patients with CV junction abnormalities were analyzed between March 2017 and February 2019 at Sawai Man Singh Medical College, Jaipur, India. Dynamic computed tomography (CT) of the CV junction and CT angiographies of the neck with respect to the vertebral artery course at the C1–C2 joints were obtained and studied. Customized 3D models of the CV junction were then made based on the CT data, and rehearsal of the surgical procedure was performed using the 3D model one day prior to performing the actual procedure.ResultsSeventeen patients had congenital-type AAD, whereas one patient had posttraumatic AAD. Improvements in neck pain and myelopathy were seen in all patients at the follow-up, as analyzed using the Visual Analog Scale and the Japanese Orthopedic Association Scale score, respectively. There were no cases of malpositioning of screws or any direct vertebral artery injury, although in one patient, the distal flow in the dominant vertebral artery was cut off as it got compressed between the bony arch and the screw head.ConclusionsCompared to computer-generated images, 3D-printed models are a more practical approach for dealing with complex CV junction abnormalities. They provide surgeons with deep insights into the complex bony anomalies as well as variations in the vertebral artery courses, thereby improving surgical outcomes.