BACKGROUND: Brain strokes comprise the third leading cause of death worldwide. Microsurgical clipping is recognized as being one of the most effective approaches to the treatment of brain aneurysms. The incomplete closure of the distal-side aneurysm neck is the most common cause of the persistent filling of the dome. Since the diameter of the neck increases when the neck of the aneurysm is squeezed closed by the blades of the clip, the blades should be correspondingly longer. This study provided an assessment of whether the presurgical selection of clips using a 3D planning system is feasible in terms of selecting the most suitable clip for aneurysm occlusion. METHODS: The computational model was created based on computer tomography data obtained from nine brain aneurysms. The closing of the aneurysm was provided in two steps. The first the length of the blades used for closing corresponded to the length of the aneurysm neck as confirmed by the radiological measurements. The second the length of the blades was adjusted according to stage one, so as to determine the minimum required for the closure of all the gaps in the interior space of the aneurysm neck. RESULTS: No differences were detected between the radiological measurement of the aneurysm neck size and the measurements obtained from the reconstructed stereolithographic 3D models. It was observed that the size of the aneurysm neck increased following clipping by 40% to 60% of its original size. The larger the aneurysm neck, the greater the deformation of the aneurysm. CONCLUSION: Firstly, the 3D reconstruction of CT/MRI data did not result in any loss of accuracy and the measurement of the neck of the aneurysm was the same for both of the methods employed. The second, and more important, outcome was that the deformation of the neck of the cerebral aneurysm is at least 1.4x greater than its original size. This information is essential in terms of the pre-selection of the size of the clip.
Cíl: Cílem této práce bylo zhodnocení našich zkušeností s metodou 3D tisku v neurochirurgii. Vedle známé tvorby kraniálních implantátů je možné mnohem širší využití této moderní, rychle se rozvíjející technologie. Metodika: Představujeme a hodnotíme soubor našich deseti pacientů, kteří byli operováni s využitím metody 3D tisku. V oblasti cévní neurochirurgie se jednalo ve čtyřech případech o model mozkového aneuryzmatu a o jeden model arteriovenózních malformací. U dvou pacientů metoda přispěla k uzavření defektu lební baze „na míru“ tvarovanou mřížkou a v neuroonkologii u dvou pacientů zlepšila naši představu o pozici nádorů lební baze. U jednoho pacienta 3D model obratle C2 umožnil volbu optimální trajektorie fixačního materiálu. Výsledky: Ve zmíněných případech bylo dosaženo požadovaného výsledku a u všech pacientů metoda 3D tisku přispěla ke správnému ošetření. Závěr: Na základě našich zkušeností si dovolujeme konstatovat, že kromě již běžně využívané 3D implantologie metoda 3D tisku představuje zajímavou a inovativní modalitu v oblastech neurochirurgického plánování, simulace a tréninku. Předpokládáme, že se bude stále více uplatňovat v mnoha oblastech neurochirurgie.
Aim: The aim of this work was to evaluate our experience with the 3D printing method in neurosurgery. In addition to the well-known utilization of cranial implants, a significant use of this modern, rapidly developing technology is possible. Methods: We present and evaluate the series of our ten patients, which we operated on using 3D printing methods. In the field of vascular neurosurgery, four cases involved a brain aneurysm model and one arteriovenous malformation model. In two patients, this method contributed to the closure of the skull base defect with a custom-shaped cranial grid and in neuro-oncology, it improved the visualization of skull base tumors in two patients. In one patient, the 3D model of the C2 vertebra allowed the choice of the optimal trajectory of the fixation material. Results: In the mentioned cases, the desired result was achieved and the 3D printing method was adapted to the correct treatment in all patients. Conclusion: Based on our experiences, we can claim that the 3D printing method, in addition to the already commonly used 3D implantology, also presents a new and interesting modality in the field of neurosurgical planning, simulation and training. We assume that it will be increasingly used in many areas of neurosurgery.
- MeSH
- 3D tisk * přístrojové vybavení MeSH
- dospělí MeSH
- intrakraniální aneurysma chirurgie diagnostické zobrazování MeSH
- lidé středního věku MeSH
- lidé MeSH
- nemoci centrálního nervového systému chirurgie diagnostické zobrazování MeSH
- neurochirurgie * metody trendy MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- klinická studie MeSH
- práce podpořená grantem MeSH
BACKGROUND: This study is focused on the opening technique of the cervical vertebrae during laminoplasty which serves to substantially reduce the most severe adverse effects of the simple resection of posterior vertebral elements. This computational study aims to clarify by an optimisation approach what shape and position upon the lamina the groove should have. METHODS: The computational model was developed in the computational software COMSOL Multiphysics 5.6a based on a computer tomography data obtained from the C4 vertebra. For finding the optimal minimum or maximum of a function (surface), optimisation algorithms are developed following the Nelder-Mead algorithm. RESULTS: The reaction-opening force increases with a decreasing groove radius and an increasing position from the vertebra body. The created area increases with a decreasing groove radius and a decreasing position. As the opening happens mostly only above the groove, the opening area increases only in this location. Moreover, the von Mises stress peak value is almost twice as large as in the case of maximization of the opening area, which might result in breaking of the lamina as the thickness of the lamina would be reduced to its minimum. CONCLUSION: The groove radius and position can affect the opening force and the opening area in case of double door laminoplasty. The opening force is highly influenced by the groove position and radius. The best position for placing the groove is in the middle of the lamina and the radius of the groove should be as large as possible.
- MeSH
- algoritmy MeSH
- biomechanika MeSH
- krční obratle diagnostické zobrazování chirurgie MeSH
- laminoplastika * škodlivé účinky MeSH
- lidé MeSH
- počítačová rentgenová tomografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Tkáňové expandéry jsou od osmdesátých let 20. století akceptovanou chirurgickou technikou v řešení traumatických, pooperačních a jiných defektů nebo nedostatku tkání. Ve vlasaté části hlavy se zavádí buď podkožně, nebo subgaleárně nad periost, a umožňují tak získat kožní lalok včetně vlasových folikulů. Jednou z největších komplikací je špatný výběr místa pro tkáňový expandér. Na kazuistice ukazujeme, že k plánování jeho vhodného umístění může pomoci 3D rekonstrukce z CT a následně 3D tisk.
Tissue expanders have been an accepted surgical technique in the treatment of traumatic, post-operative and other defects and loss of tissue since the 1980s. The expander is inserted in the hairy part of the scalp either subcutaneously or subgaleally above the periosteum, thus enabling the skin lobe, including hair follicles, to develop normally. One of the major complications is the poor choice of location for the tissue expander. In the case report, we will present that 3D modeling from CT and subsequent 3D printing can help to plan its most suitable location.
- MeSH
- 3D tisk MeSH
- bazocelulární karcinom chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- skalp chirurgie MeSH
- tkáňové expandéry * MeSH
- zobrazování trojrozměrné MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Cíl studie: Popis případu úmrtí novorozence po porodu akutním císařským řezem ve 31. týdnu gravidity jako následek syfilitické infekce matky. Výsledky: Patnáctiletá primigravida v grav. hebd. 31+3 byla přeložena do intermediárního centra pro hrozící předčasný porod. Na základě patologického kardiotokografického záznamu bylo těhotenství ukončeno akutním císařským řezem s následným úmrtím novorozence po 35 min resuscitace. Z pupečníkové krve a nezávisle z testů provedených registrujícím gynekologem ve 30. týdnu těhotenství byla hlášena pozitivita na syfilis. Ve spolupráci s dermatovenerologem byla zajištěna léčba, depistáž a hlášení Národní referenční laboratoři. Pitvou zemřelého novorozence patolog konstatoval masivní projevy adnátní pneumonie ve všech plicních lalocích s vaskulitidou a perivaskulárním krvácením, nekrotizující lymfadenitidu uzlin a pyokélu. Závěr: Diagnóza kongenitální syfilis byla stanovena až po úmrtí předčasně narozeného novorozence. Resuscitace již neměla šanci na úspěch vzhledem k rozsahu postižení plic vinou syfilis.
Objective: Description of a case of newborn death after acute caesarean section in 31st week of pregnancy because of mother's syphilitic infection. Results: Fifteen-years-old primigravid woman in 31st week of pregnancy was admitted to a secondary level hospital due to a high risk of preterm labor. The pregnancy was terminated with an acute caesarean section because of pathological cardiotocograph record. The newborn died after 35 min of resuscitation. Blood samples from the umbilical cord and mother's blood taken by her gynecologist were positive for syphilis. In cooperation with a dermatologist, the treatment has been provided and reported to the National Referential Laboratory. The autopsy of the newborn had found severe pneumonia, necrotic lymphadenitis and pyocele. Conclusion: The diagnosis of congenital syphilis had been determined after the death of a preterm delivered newborn. Resuscitation had no chance to success because of syphilitic damage of the lungs.
- MeSH
- císařský řez MeSH
- infekční komplikace v těhotenství * diagnóza MeSH
- lidé MeSH
- mladiství MeSH
- novorozenec MeSH
- příčina smrti MeSH
- syfilis diagnóza MeSH
- těhotenství MeSH
- vrozená syfilis * diagnóza MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- mladiství MeSH
- novorozenec MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
BACKGROUND: The expansion of the cervical vertebrae lamina appears to be crucial to related surgical procedures. The dimensions of the groove influence the strain concentration within the lamina of the vertebra and, thus, the potential success or failure of respective surgical procedure. The aim of this computational study is to clarify both the role of the size of the groove with concern to both the open door and the double door laminoplasty techniques. METHODS: Finite element models were created via computer tomography with varying lamina groove dimensions. Displacements were applied to the models at the open side of the vertebral arch and the vertebral body was constrained prior to movement along all the axes. The maximal opening size measured on the inner side of the lamina and the percentage increase in the initial spinal areas were subsequently analyzed. FINDINGS: The elastic strain concentration value was observed for the groove in all cases, while the maximal principal elastic strain concentration value was observed at the opposite side to the groove cut into the lamina, also in all cases. The maximal area increase related to the 4 mm groove accompanied by the preservation of the ventral cortex of the bone. INTERPRETATION: The study suggested three conclusions a) the wider the groove, the greater is the opening potential, b) the maximal opening size following laminoplasty is not dependent on the depth of the bone cut for this type of groove, c) no benefit accrues in terms of the opening size following the cutting of a supplementary groove at the beginning of the lamina.
This article focuses on the problem of maximal compliance design of a hyper-elastic solid with the optimal design of human skin grafts as the application in mind. The solution method is a phasefield-based topology optimization method that supposes multiple local phasefields and a minimum distance constraint in order to prevent the phasefields from merging. Consequently, structurally disintegrating solutions such as by the coalescence of voids can be prevented. The method is used to find an optimal graft meshing pattern for a sample that is subjected to a biaxial extension of up to 150%, which corresponds to an expansion ratio of 1 : 2.25. Three prospective unitcell solutions that exhibit meta-material behavior are proposed for a periodic graft pattern. The results are a step toward improving the skin graft meshing efficiency. This work does not cover experimental validation.
- MeSH
- kůže * MeSH
- lidé MeSH
- prospektivní studie MeSH
- transplantace kůže * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
PURPOSE: The cement augmentation of a conventional anterior screw fixation in type II odontoid process fractures for elderly patients significantly increased stiffness and load to failure under anterior-posterior load in comparison with non-augmented fixation. The amount and quality of bone cement are usually taken ad hoc in clinical practise. In this study, we wanted to clarify the role of bone cement amount and its quality to the stiffness of odontoid and vertebrae body junction. METHODS: Finite-element method was used to achieve different scenarios of cement augmentation. For all models, an initial stiffness was calculated. Model (1) the intact vertebrae were virtually potted into a polymethylmethacrylate base via the posterior vertebral arches. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. (2) The odontoid fracture type IIa (Anderson-D'Alonzo classification) was achieved by virtual transverse osteotomy. Anterior screw fixation was virtually performed by putting self-drilling titanium alloy 3.5 mm diameter anterior cannulated lag screw with a 12 mm thread into the inspected vertebrae. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. The vertebrae body was assumed to be non-cemented and cemented with different volume. RESULTS: The mean cement volume was lowest for body base filling with 0.47 ± 0.03 ml. The standard body filling corresponds to 0.95 ± 0.15 ml. The largest volume corresponds to 1.62 ± 0.12 ml in the presence of cement leakage. The initial stiffness of the intact C2 vertebrae was taken as the reference value. The mean initial stiffness for non-porous cement (E = 3000 MPa) increased linearly (R2 = 0.98). The lowest stiffness (123.3 ± 5.8 N/mm) was measured in the intact C2 vertebrae. However, the highest stiffness (165.2 ± 5.2 N/mm) was measured when cement leakage out of the odontoid peg occurred. The mean initial stiffness of the base-only cemented group was 147.2 ± 8.4 N/mm compared with 157.9 ± 6.6 N/mm for the base and body cemented group. This difference was statistically significant (p < 0.0061). The mean initial stiffness for porous cement (E = 500 MPa) remains constant. Therefore, there is no difference between cemented and non-cemented junction. This difference was not statistically significant (p < 0.18). CONCLUSION: The present study showed that the low porous cement was able to significantly influence the stiffness of the augmented odontoid screw fixation in vitro, although further in vivo clinical studies should be undertaken. Our results suggest that only a small amount of non-porous cement is needed to restore stiffness at least to its pre-fracture level and this can be achieved with the injection of 0.7-1.2 ml of cement. These slides can be retrieved under Electronic Supplementary Material.
- MeSH
- dens axis * diagnostické zobrazování zranění chirurgie MeSH
- fraktury páteře * diagnostické zobrazování chirurgie MeSH
- kostní cementy terapeutické užití MeSH
- kostní šrouby MeSH
- lidé MeSH
- senioři MeSH
- vnitřní fixace fraktury MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The purpose of the present study was to describe the structural density and geometry of the bone, as well as its sensitivity to the resolution of finite element discretisation. The study introduces a novel way to validate biomechanical model of the bone by experimental modal analysis. The structural density and geometry of the model was obtained from a composite bone. A detailed investigation of the weight dependence of the bone on the mesh resolution was performed to obtain the best match with the real weight of the tested bone. The computational model was compared with the experimental results obtained from the modal analysis. The overall changes of the modal properties and bone weight in the model caused by different mesh resolutions and order of approximation were below 10%, despite the bone was modelled with simple isotropic material properties. The experimental modal analysis shows a great potential to be a robust verification tool of computational biomechanical models because it provides boundary conditions-free results. The sensitivity analysis revealed that the linear approximation of the density field is not suitable for the modelling of the modal response of composite bone.
- MeSH
- analýza metodou konečných prvků MeSH
- biomechanika MeSH
- lidé MeSH
- lineární modely MeSH
- mechanický stres MeSH
- pánevní kosti anatomie a histologie diagnostické zobrazování MeSH
- počítačová rentgenová tomografie MeSH
- počítačová simulace * MeSH
- reprodukovatelnost výsledků MeSH
- velikost orgánu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
1. vydání 206 stran : ilustrace ; 24 cm
- Klíčová slova
- výpočtová biomechanika,
- MeSH
- anatomie MeSH
- biomechanika MeSH
- tkáně MeSH
- Konspekt
- Patologie. Klinická medicína
- Učební osnovy. Vyučovací předměty. Učebnice
- NLK Obory
- fyzika, biofyzika
- NLK Publikační typ
- kolektivní monografie
