W. Wolański

Modeling and biomechanical analysis of craniosynostosis correction with the use of finite element method

Craniosynostosis is a skull malformation because of premature fusing of one or more cranial sutures. The most common types of craniosynostosis are scaphocephaly (with the sagittal suture fused) and trigonocephaly (with the metopic suture fused). In this paper we describe and discuss how finite element analysis and three-dimensional modeling can be used for preoperative planning of the correction of craniosynostosis and for the postoperative evaluation of the treatment results. We used the engineering software MIMICS MATERIALISE to obtain three-dimensional geometry from computed tomography scans, and applied finite element method for the sake of biomechanical analysis. These simulations help to improve the surgical treatment, making it more accurate, safer, and faster.

Engineering-aided treatment of chest deformities to improve the process of breathing.

In this paper, the application of new visualization technologies in correction of funnel chest is presented. Often, such defects cause problems with breathing, and therefore, to improve the cardiorespiratory efficiency, a correction is required. The virtual model of chest was formulated to determine the strains and stresses after correction of deformation with using the stabilizing plate. From biomechanical point of view, the knowledge of the load-affecting stabilizer is necessary to select optimal parameters of the plate. The force-affecting plate that was used in the correction of chest deformation by Nuss method was determined on the basis of finite element model of funnel chest. The main aim of this work was to select the optimal thickness of plate. Calculations were conducted for three alternative constraints.

Comparison of numerical and experimental analysis of plates used in treatment of anterior surface deformity of chest

The work discusses the results of numerical and experimental research of the plates for treatment of deformations of the frontal wall of chest. The conducted analyses included determination of: within numerical research, the state of displacement, strain and reduced stresses as well as reactions and moments of forces in supports, while within experimental research, the values of displacements at characteristic points of the system.

Statistical Analysis of Cranial Measurements - Determination of Indices for Assessing Skull Shape in Patients with Isolated Craniosynostosis

This paper presents a morphological analysis of the skull shape in infants under one year of age. Three-dimensional measurements were performed on models generated from images in Mimics software. Subsequently, a multivariate statistical analysis of the measured dimensions was performed to determine key indicators of the skull shape. Eventually it was developed the norms of skull indices for children up to one year of age. Regular values of these indices were compared with abnormal values measured in patients with isolated craniosynostosis. With the use of these indices it is possible to perform a quantitative evaluation of head deformity.

Biomechanical analysis of injuries of rally driver with head supporting device

PURPOSE The aim of the study was to develop and verify a model of rally driver with a safety system HANS (head supporting device), which will enable biomechanical analysis of injuries in rally accident. METHODS Simulations were carried out in Madymo® software, the results of which were verified based on sled test performed in the Automotive Industry Institute (PIMOT) in Warsaw. The model being verified allowed us to perform a multivariate simulation of rally accident in terms of assessing effectiveness of protection and usefulness of HANS system. RESULTS Acceleration waveforms of the head and chest were obtained from numerical experiment and also forces and moments occurring in the upper cervical spine. The results obtained allowed driver injuries to be analyzed based on injury criteria of the head and neck: HIC15, NTE, NTF, NCE and NCF. CONCLUSIONS The analysis enabled assessment of the driver safety while using 4 and 5 point harness with HANS system. In further studies the model developed was used to identify factors affecting the safety of a rally driver.

Application of 3D modeling and modern visualization technique to neurosurgical trigonocephaly correction in children

The attempt to a new methodology creation, supported neurosurgical correction of trigonocephaly by engineers is presented in this paper. Trigonocephaly is an example of skull deformity, that wrong influence on child physical and psychological development. Conventional procedures in such cases are connected with invasive operation. Up to now neurosurgeons during pre-operation planning of bones correction, based on their own knowledge and experience. Modeling in biomechanics connected with modern visualization methods give new possibilities of engineer support for medical procedures. Three-dimensional model of deformed skull was created on the basis of CT scans with use of Mimics software. The model was transformed to FEM and used for suitable shape of forehead bone determination. Material properties of modeled bones were assumed on the basis of experimental researches. The geometrical model was presented in 3-dimensional virtual reality. It helps to better imagine about the real shape of skull hidden under head skin and take the best decision how to operate the example of trigonocephaly.

Numerical Analysis of Blood Flow Through Artery with Elastic Wall of a Vessel

The main objective of the work was to prepare the analysis of blood flow through the arteries taking into account the mechanical properties of the vessel wall. The mechanical properties of the specimens were determined using a testing machine MTS Insight 2, and digital image correlation (DIC). The developed numerical model allowed the assessment of the state of stress and deformation of the walls while the blood flow through the physiologically correct aorta.

Development of New Testing Method of Mechanical Properties of Porcine Coronary Arteries

This study aims to develop a testing methodology enabling the determination of mechanical properties of coronary arteries based on the example of porcine arteries using the MTS Insight 2 strength testing machine and digital image correlation (DIC). The conducted ballooning strength tests and static tensile tests revealed linear dependence between longitudinal and transverse strain of the arteries. The test results presented enable the evaluation and identification of the mechanical properties of porcine coronary arteries as well as prediction of the risk of the coronary artery rupture in the planned angioplasty and stent implantation procedures.

Risk Factors Influencing Lower Limbs Injuries During IED Blast

Improvised explosive device IED attack becomes main reason of casualties among coalition soldiers during military missions in Afghanistan and Iraq. In under-belly explosion scenario the most exposed on blast effects body part is leg. The aim of studies presented in this paper has been indication of factors enhancing lower leg injury risk during IDE attack. Model of soldier in KTO Rosomak (Polish army wheeled armoured vehicle) crew compartment created in Madymo software has been used for research. Results of simulations has been analysed and injury criteria has been determined.

Preoperative Planning of Surgical Treatment with the Use of 3D Visualization and Finite Element Method

This chapter describes a method of engineering support of preoperative planning of surgical procedures with the use of engineering tools, such as state-of-the-art software for medical image processing, or a finite element method. The procedure of pre-operative planning consists in matching individual cases of incision sites and directions, visualization and selection of areas for resection as well as planning the technique of implant positioning and fixation. Also, the final visualization of the result of the planned medical procedure can be performed. This paper presents procedural propositions in surgery planning in the cases of corrections of the head shape in patients with craniosynostosis, corrections of the chest deformity such as pigeon chest and stabilization of the lumbar spine. 3D models created on the basis of computer tomography (CT) or magnetic resonance imaging (MRI) enabled it to conduct a biomechanical analysis as well as an objective quantitative and qualitative virtual evaluation of the surgical procedure. Preoperative planning support gives the physician an opportunity to prepare for the operation in a better way, which results in the selection of the best possible variant of an operative technique, reduction of time of the surgical procedure and minimization of the risk of intraoperative complications.