Reverzni inženjering dugih kostiju čoveka zasnovan na morfometrijskim parametrima

Development of new and improvement of existent methods of creating geometrical models of human bones is a continual process in modern medicine. Basically, most methods use medical images obtained from various devices (medical scanners) as input data. These devices can be classified into those which enable forming of 2D images of scanned object, such as X-ray or 2D ultrasound, and those which enable creation of 3D images (volumetric models), such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). Different types of processing can be performed on obtained data, resulting in adequate geometrical human bone models which can be used for various purposes, including: preparation and simulation of orthopedic interventions, students’ and doctor's training to perform orthopedic interventions, production of osteo-fixational material, analysis of stress and strain of assembly of bones and implants. Problem description: While creating bone models based on data acquired from medical scanners, two distinct cases which prevent their proper forming can be isolated. Both cases are related to incomplete data of morphology and geometry of human bone, but with different reasons for data deficiency. In the first case, volumetric scanners are not available, or cannot be used for specific reasons, e.g.: patient must not be treated with high level radiation, faulty device, institution doesn’t possess adequate scanner, patients with metal implants, and such. In these cases, devices such as X-ray or, less often, ultrasound are used. The outcome of this process is one or eventually two 2D images (if the device is digital), or film (if analog X-ray apparatus is used). Complete 3D bone visualization can be difficultly accomplished on the basis of 2D data, so methods which enable creation of 3D geometrical bone models based on one or more 2D images are developed today. The second case refers to inability to create an image of complete bone. This case isn’t connected to acquisition of bone data from medical images (although it can be), but it is mostly conditioned by health state of the patient. Example of these cases include: multiple bone fractures, osteoporosis, other diverse acute and chronic diseases and such. Surgeons aren’t able to properly plan surgical procedures based on a partial image; consequently, certain surgical decisions have to be made during the very surgery. Goal of research: The main goal of the dissertation has been to form a method which would enable creation of complete geometrical bone model based on both complete and incomplete entrance data of patients’ bones (regardless the cause of data deficiency), and which would also 10 greatly contribute to the process of preparation, planning and performance of orthopedic surgeries. Research Subject: Research subject of the dissertation are methods of reverse engineering which can be applied to obtain 3D geometrical models of the human long bones directly from radiology images, whether the data is complete or incomplete. Research result: Method of Anatomical Feature – MAF is formed as the result of applied research whose application enables realization of the goal of research. MAF introduce a new approach to describe geometrical entities of human bones, based on anatomical landmarks/ guide lines. MAF enables creation of 3D geometrical models and parametric point bone models. The main goal of application of MAF is to create 3D geometrical models (of whole bones, as well as of the missing bone parts) of high geometrical accuracy and anatomical correctness, even in cases when the bone data is incomplete. Based on afore mentioned, we can conclude that MAF is a universal method to create different geometrical models of bones or bones’ parts, which means that an adequate model can be created depending on the current situation (need, case). Verification and application of research results: Various types of geometrical models (polygonal, surface, volumetric, parametric) of certain bones of human body have been created to verify MAF. All created geometrical models have satisfied necessary accuracy in geometrical and anatomical terms, which is defined in scientific literature. This paper provides examples of created geometrical models of femur and tibia bones; however, more geometrical models of other bones (fibula, humerus, mandible, etc.) have been created during this research. Nevertheless, MAF has been, both directly and indirectly (geometrical models of bones created with MAF have been used) applied for other purposes. These are characteristic cases which can appear in clinical practice, some of which are: case of creation of customized sternum implant, use of MAF to create parametric model of internal fixator by Mitkovic, application of Finite Element Method (FEM) to analyze stress and strain of femur bone and internal fixator by Mitkovic, use in application prototype for the simulation of orthopedic surgeries, etc. Conclusion: Based on everything stated above, conclusion follows that research results presented in this paper display a significant scientific contribution which greatly contributes to improvement of methods used in reverse engineering and geometrical modeling of long bones of skeletal-joint system in humans

DETECTION AND HANDLING EXCEPTIONS IN BUSINESS PROCESS MANAGEMENT SYSTEMS USING ACTIVE SEMANTIC MODEL

Although business process management systems (BPM) have been used over the years, their performance in unpredicted situations has not been adequately solved. In these cases, it is common to request user assistance or invoke predefined procedures. In this paper, we propose using the Active Semantic Model (ASM) to detect and handle exceptions. This is a specifically developed semantic network model for modeling of semantic features of the business processes. ASM is capable of classifying new situations based on their similarities with existing ones. Within BPM systems this is then used to classify new situations as exceptions and to handle the exceptions by changing the process based on ASM’s previous experience. This enables automatic detection and handling of exceptions which significantly improves the performance of bpm systems

REVIEW OF BONE SCAFFOLD DESIGN CONCEPTS AND DESIGN METHODS

The paper brings out a review of existing, state-of-the-art approaches to designing the geometry of the scaffolds that are used for tissue engineering with a special emphasis on the macro scaffolds aimed for bone tissue recovery. Similar concepts of different authors are organized into groups. The focus of the paper is on determining the existing concepts as well as their advantages and disadvantages. Besides the review of scaffolds' geometry solutions, the analysis of the existing designs points to some serious misconceptions regarding the scaffold role within the (bone) tissue recovery. In the last section of the paper, the main requirements regarding geometry, that is, architecture and corresponding mechanical properties and permeability are reconsidered

Različiti pristupi za kreiranje geometrijskih modela anatomske osi femura i tijela femura

In today\u27s medicine, especially in the field of orthopedic surgery, it is very important to use geometrically accurate and anatomically correct geometrical models of human bones for the pre-operative planning and implants creation. In order to create such models, two new methods for geometrical modeling were developed and presented in this paper. These methods enable creation of femur anatomical axis and femur shaft geometrical models, and they are: GCM (Gravity Center Method), and CPM (Curve Projection Method). Both methods enable creation of geometrical models which are based on data acquired from the medical imaging devices (CT, MRI, X-Ray). The basic difference between these two methods and all the others is in the manner of generating the points through which anatomical axis model (3D curve) passes or goes near. The applied methods are developed considering the natural shape and anatomical landmarks of the femur bone, as well as standard CAD techniques for geometrical modeling which are common in engineering.U današnjoj medicini, osobito u području ortopedske kirurgije vrlo je važno koristiti geometrijski točne i anatomski ispravne geometrijske modele ljudskih kostiju za pred-operativno planiranje i kreiranje implantata. Radi kreiranja takvih modela dvije nove metode geometrijskog modeliranja su razvijene i prezentirane u ovom radu. Ove metode omogućuju kreiranje geometrijskih modela anatomske osi femura i tijela femura i one su: GCM (eng. Gravity Center Method), i CPM (eng. Curve Projection Method). Obje metode omogućavaju kreiranje geometrijskih modela koji se temelje na podacima dobivenih od medicinskih uređaja (CT, MRI, X-Ray). Osnovna razlika između ove dvije metode u odnosu na sve ostale je u načinu generiranja točaka kroz koje anatomska os modela (3D krivulja) prolazi ili je u blizini. Primijenjene su tehnike koje su razvijene uzimajući u obzir prirodni oblik i anatomske značajke femura. kao i standardne CAD tehnike za geometrijsko modeliranje koje su uobičajene u inženjerstvu

Usporedba odziva modela pneumatika s detaljnim gaznim slojem i pojednostavljenog modela za analizu kotrljanja pneumatika u stacionarnom stanju

This paper deals with the level of detail that is necessary for representation of tread pattern in finite element tire models. Different methods for creation of tire tread mesh are systematized by two different criteria: the most common approaches and the finite element analysis type. Some of the representative approaches found in literature are given in more detail and their advantages and disadvantages discussed. An example from author’s experience, which describes the creation of finite element tire model with detailed tread for steady-state rolling analysis, is presented. The paper also brings a head-to-head comparison of the response of simplified and detailed tread tire models, subjected to a range of finite element analyses, from footprint analysis at static loading conditions to steady-state rolling cornering analysis.Ovaj rad se bavi razinom detalja koja je potrebna za prikaz šare gaznoga sloja u modela pneumatika namjenjenih analizi primjenom metode konačnih elemenata. Različite metode za izradu mreže konačnih elemenata su sistematizirane po dva različita kriterija: najčešćih pristupa i tipa analize primjenom metode konačnih elemenata. Neki od tipičnih pristupa koji se mogu naći u literaturi opisani su u više detalja i navedene su njihove prednosti i nedostaci. U članku je dat primjer iz iskustva autora, koji opisuje stvaranje modela pneumatika s detaljnim gaznim slojem za analizu kotrljanja u stacionarnom stanju. U radu je također prikazana izravna usporedba odziva pojednostavljenog modela pneumatika i modela s detaljnim gaznim slojem, podvrgnutih nizu analiza, od analize kontakta između tla i pneumatika pod statičkim uvjetima opterećenja do skretanja pri kotrljanju u stacionarnom stanju

TOWARD AN INTEGRATED INFORMATION SYSTEM FOR THE DESIGN, MANUFACTURING AND APPLICATION OF CUSTOMIZED IMPLANTS

The adjustment of products to the needs of customers has been present in various industries for many years. Personalized medicine is a field that has been rapidly developing recently. This kind of medical help mainly implies the use of medications which are adjusted to each patient individually. In this paper, we describe an information system which manages the process of designing and manufacturing personalized products in the area of orthopaedics. The system output comprises patient-adjusted orthopaedic implants. In addition to the process management, the information system ought to enable the process to be adjusted to unexpected situations which may occur in different stages of designing and manufacturing. The information system should also assist doctors and engineers in the decision making process. This aid is realized in the form of the expert system which provides doctors and engineers with advice about defining an appropriate treatment for the patient

REVERSE ENGINEERING OF THE HUMAN FIBULA BY USING METHOD OF ANATOMICAL FEATURES

This paper describes reverse engineering (RE) of human fibula, on right male bone, using the method of anatomical features (MAF) with the aim to obtain 3D surface model. The first step in the process of reverse engineering was CT scanning and digitalization of data. CT data were obtained with Toshiba MSCT scanner Aquillion 64 and saved in DICOM format. This data were subjected to further processing and imported in Computer Aided Design (CAD) program as STL file. The process continues in CAD program with identification and determination of Referential Geometrical Entities (RGEs) which are crucial for RE process. These RGEs are the basis for definition of axis and planes of intersection. Intersecting polygonal model of fibula bone on upper and lower extremities and the body with these planes gives as result set of curves, which were used for points determination on them. Through these points splines were pulled, and with loft function surface models of extremities and the body of fibula bone is built. Joining and merging of these models leaded to 3D shape model of fibula bone. Accuracy of the model is confirmed by conducting distance and deviation analysis. Model is suitable for rapid prototyping, reconstruction missing parts of fibula bone, orthopedic training and simulation

Procedure for Creating Personalized Geometrical Models of the Human Mandible and Corresponding Implants

The greatest challenge in engineering of human mandible implants lies in its customization for each patient individually, by adapting them to the patient's anatomical, morphological and physiological characteristics. This customization maximizes the efficiency of the patient's health recovery process. The application of anatomically shaped and personalized bone endoprosthesis, fixation plate and scaffold models bring great improvement to the clinical practice in maxillofacial surgery. It ensures that implant meets the biomechanical and dentofacial aesthetic requirements and, ultimately, reduces complications during recovery. In order to create such implants, novel procedure based on personalized models of mandible and its parts, and also plates and scaffold implants is presented in this paper. Design procedures for the creation of the personalized models are based on the application of Method of Anatomical Features, which has been already applied for the creation of geometrical models of human bones. This procedure improves pre-surgical planning, enables better execution of surgical intervention, and as a consequence improves patient recovery processes

REVERSE ENGINEERING OF THE MITKOVIC TYPE INTERNAL FIXATOR FOR LATERAL TIBIAL PLATEAU

In orthopaedic surgery it is very important to use proper fixation techniques in the treatment of various medical conditions, i.e. bone fractures or other traumas. If an internal fixation method, such as plating, is required, it is possible to use Dynamic Compression Plates (DCP) or Locking Compression Plates (LCP) and their variants. For DCP implants it is important to match the patient's bone shape with the most possible accuracy, so that the most frequent implant bending is applied in the surgery. For LCP implants it is not so important to match the patient’s bone shape, but additional locking screw holes are required. To improve the geometrical accuracy and anatomical correctness of the shape of DCP and to improve the LCP geometric definition, new geometrical modelling methods for the Mitkovic type internal fixator for Lateral Tibia Plateau are developed and presented in this research. The presented results are quite promising; it can be concluded that these methods can be applied to the creation of geometrical models of internal fixator customized for the given patient or optimized for a group of patients with required geometrical accuracy and morphological correctness

TOWARDS PATIENT SPECIFIC PLATE IMPLANTS FOR THE HUMAN LONG BONES: A DISTAL HUMERUS EXAMPLE

Plate implants are the most used internal fixators for the surgical treatments of the bone fractures. In clinical cases where there is a requirement to use reconstruction plates, and/or to stabilize the fracture, adaptation of plate shape (e.g. bending) to the patient anatomy is required, and it is usually done during the surgery. In order to eliminate the need for intra-operative bending of plates, precontoured plates can be used. These are patient specific implants whose shape and geometry is adapted to the anatomy and morphology of the specific patient. In order to create a patient specific 3D model of the plate implant, the bone model acquired through medical imaging (e.g. Computed Tomography - CT) is commonly used. By the application of various CAD techniques, the volume model of specific plate implant can be created, and used for the production of the plate, by conventional or additive manufacturing technologies. In this paper the authors present a new approach to the creation of a 3D parametric model of the patient specific plate implant for distal humerus. By using such model the surgeon can perform preoperative planning and adapt shape of plate to the specific patient before the surgery, and in this way he can improve pre, intra and post-operative processes