Academic literature on the topic 'Pre-surgical Planning'

Summary Epilepsy is one of the most frequent chronic neurological pathologies, with high incidence and prevalence worldwide. A third of these patients are resistant to treatment, which is known as refractory epilepsy. Most of these patients suffer epilepsy secondary to epileptogenic lesions, where the surgery is the only treatment that could cure epilepsy. The goal of epilepsy surgery is to remove the epileptogenic area with preservation of eloquent areas, and here the surgical experience, the neuroimaging technology and the availability of image-guided surgery systems known as a neuronavigator plays a key role. Objectives: To demonstrate the usefulness of neuronavigation in pre-surgical planning and in the surgery of refractory epilepsy. Method: A cross-sectional and analytical descriptive study was conducted based on 47 surgeries performed (12 resective, 32 palliative and 3 diagnostic) in patients with refractory epilepsy and mean age of 9.93 years (SD 4.1). In 27 patients (57.44%) the neuronavigator was used. In the group of patients operated with neuronavigation, the surgical time decreased by 47.17 minutes (p = 0.022), the amount of bleeding by 111.41 milliliters (p = 0.011) and the days of hospitalization by 6.68 days (p = 0.005), compared with the group operated without neuronavigation. Complications in the neuronavigation group were 29.63% compared to 65% in the group operated without neuronavigation (p = 0.034). Conclusions: In our series, the use of the neuronavigator in the planning and development of the surgery had a significant impact by reducing the amount of bleeding lost, the surgical time, the days of hospitalization, and the post-surgical complications.

Computer technology has many applications in different fields of industry, health care and medicine. This encompasses paper-based information processing as well as data processing machines (Hospital information system or Clinical information system) and image digitalization of a large variety of medical diagnostic equipment (e.g. computer images of X-ray, MR, CT). The aim of the computer technology in medicine is to achieve the best possible support of patient care, preoperative surgery planning and administration by electronic data processing. At the present time in many countries of the worlds preoperative planning of interventions for lumbar joint is realized with caliper, protractor, plastic templates and x-ray images. Orthopaedic surgeons use transparent template radiographs as part of pre-operative planning in order to gauge the suitability and correct size of an implant. The newly developed CoXaM software offers a simple solution of the problems by using the digital x-ray images and handmade transparent plastic templates. The CoXaM software was developed in Visual Studio 2005 in the Visual C++ programming language at the Department of Biomedical Engineering and Measurement at the Faculty of Mechanical Engineering, Technical University of Kosice. The software was designed for pre-operative planning and helps to determine on the X-ray image a length dimensions, a center of rotation, an angle values. It enables the digitalization of plastic templates from several producers, which will assess the suitability of the type of implant.

Objective: To perform the correlation between the preoperative tomographic evaluation of patients with calcaneal fracture diagnosis and the access routes of choice, as well as the synthesis materials used.Methods: We reviewed 19 medical records of patients between 23 and 56 years old who underwent calcaneal fracture surgery from 01/01/2014 to 12/31/2015. We evaluated the mechanism of trauma, side, Essex-Lopresti classification, Böhler and Gissane angle in the pre- and postoperative period, Sanders tomographic classification and type of osteosynthesis performed. Angular measurements served as a reference for radiological analysis of the quality of the reduction. Results: 90% of the cases were of joint depression, the other 10% considered extra-articular. The preoperative Böhler angle varied between 5 and 40°, and between 10 and 38° in the postoperative period, and 55% of the fractures had an angular reconstruction considered good (between 20° and 40°). Gissane’s angle, on the other hand, varied between 110 and 170° in the preoperative period, and 102 and 132° in the postoperative period. In the tomographic analysis, Sanders IV classification was predominant (65%), followed by type IIIBC fractures (20%), and fractures type I, IIA and IIIAB (5% each). Osteosynthesis with plate and screw was the most used method (89.47%). Conclusion: Correct use of existing diagnostic imaging resources through radiographic and tomographic results provides the possibility of better preoperative planning in the intra-articular fractures of the calcaneus. However, in this study, there was no difference in the access route and synthesis according to the tomographic classification. Level of Evidence III; Diagnostic Studies; Study of Non-Consecutive Patients.

Background. Since its inception almost 20 years ago, functional magnetic resonance imaging (fMRI) has greatly advanced our knowledge of human brain function. Although the clinical applications of fMRI are still limited, there have recently been encouraging advances for its use in pre-operative functional cortical mapping to identify potentially eloquent areas prior to neurosurgery. Objectives. We explore the potential use of this emerging technique by presenting a neurosurgical case study, as performed at the Cape Universities Brain Imaging Centre (CUBIC), Tygerberg, Cape Town. We conclude with a brief summary of the potential pitfalls of this technique, as well as cautionary guidelines based on our experience. Methods and results. A 22-year-old male patient from Tygerberg Hospital underwent the successful resection of an anaplastic astrocytoma after fMRI presurgical planning at our facility. The subject was able to leave the ward unassisted. Conclusion. If consideration is given to the many limitations of this emerging technique, fMRI can be useful in aiding the neurosurgeon in pre-operative planning of his surgical approach.

The simultaneous acquisitions of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have been applied to improve the surgery planning of patients with drug resistant epilepsy. However, the classical approach of analyzing the EEG-fMRI data is inefficient in patients whom only few or non interictal epileptiforms discharges (IEDs) are detected during the simultaneous acquisition. Another issue of EEG-fMRI acquisition is related to its high sensitivity to motion, which decreases the quality of both data, even worse in non-cooperative patients. In this work we propose and discuss the application of two methods of analyzing fMRI data of patients with focal epilepsy: Independent component analysis (ICA) and two-dimensional temporal clustering (2dTCA). Each method was applied in a distinct group of patients and the results were compared to those obtained by the classic EEG-fMRI analysis. We have also proposed a method to improve the quality of EEG data using the head position measurements obtained, by a prospective motion correction (PMC) system, during the EEG-fMRI acquisitions. In the ICA study, we have used the electrical source images for selecting independent components (ICs) in EEG data of 13 patients with different spiking frequency. The method detected epilepsy-related BOLD activity in all the patients. Comparatively, the classic EEG-fMRI could be applied in 11 patients and epilepsy-related BOLD activities were found in seven of them. In the 2dTCA study, we have evaluated 20 patients and found epilepsy-related maps in 14 of them. Thirteen of the twenty patients have IEDs detected during the simultaneous acquisition; the classic EEG-fMRI provided maps related to the epileptogenic region in six of them. Finally we have verified in three health subjects that the proposed method for correcting motion-induced artefacts in the EEG data is effective for high amplitude and velocities (~1cm and 55mm/s). We concluded that the ICA and 2dTCA methods increase the sensitivity of using fMRI for mapping the epileptogenic region, mainly in patients presenting few or no IEDs in the EEG data simultaneously acquired to the fMRI. The PMC use during the fMRI acquisition does not degrade the quality of the EEG data acquired simultaneously. In fact, the motion information can be used for improving its quality by correcting motion-induced artefacts.
As aquisições simultâneas de dados de eletroencefalografia (EEG) e imagens funcionais por ressonância magnética (fMRI) vêm sendo utilizadas com intuito de melhorar o planejamento cirúrgico de pacientes com epilepsia refratária. Entretanto, o processamento classicamente usado nestes dados combinados não é possível em pacientes sem descargas epileptiformes interictais (IEDs) e possui baixa sensibilidade para aqueles em que poucas IEDs são detectadas durante a aquisição simultânea. Além disto, a técnica é sensível ao movimento dos pacientes durante as aquisições, o que reduz a qualidade dos dados, principalmente em pacientes não cooperantes. Neste trabalho é proposto e discutido o uso de dois métodos de processamento, baseados nas técnicas de análise de componentes independentes (ICA) e análise temporal de clusters em duas dimensões (2dtca), para se mapear regiões epileptogênicas. Cada método foi analisado em um conjunto diferente de pacientes e os resultados foram comparados com os obtidos pelo EEG-fMRI clássico. Finalmente, propomos um método que utiliza às medidas de posicionamento da cabeça, obtidas durante a aquisição das fMRI, para aumentar a qualidade dos dados de EEG adquiridos simultaneamente. No estudo usando ICA combinado com imagens de fontes elétricas analisamos os dados de 13 pacientes com diferentes frequências de descargas e observamos que este método encontrou ao menos uma componente independente relacionada à epilepsia em cada paciente. Comparativamente usando o processamento convencional foi possível avaliar 11 dos 13 pacientes, e em apenas sete deles os mapas resultantes foram considerados concordantes com a região epileptogênica (RE). No estudo utilizando 2dTCA avaliamos 20 pacientes e encontramos mapas relacionados com a RE em 14 deles. Neste conjunto de pacientes, 13 apresentaram IEDs durante as aquisições; neles o método clássico de processamento teve resultados concordantes com a RE em seis deles. Finalmente verificamos em três sujeitos saudáveis que o método aqui proposto para corrigir os artefatos induzidos no EEG devido ao movimento é efetivo para altas amplitudes e velocidades (~1cm e 55mm/s). Concluímos que os métodos ICA e 2dTCA aumentam a sensibilidade do uso de fMRI para mapear RE, principalmente em pacientes com baixa ou nenhuma detecção de IEDs durante às aquisições. Também concluímos que o uso da correção prospectiva de movimento em aquisições de fMRI não reduz a qualidade do dado de EEG adquirido simultaneamente e que às informações de movimento mensuradas podem melhorar a qualidade deste dado em situações de repouso e movimento do sujeito durante o experimento.

Highly comminuted intra-articular fractures are complex and difficult injuries to treat. Once emergent care is rendered, the definitive treatment objective is to restore the original anatomy while minimizing surgically induced trauma. Operations that use limited or percutaneous approaches help preserve tissue vitality, but reduced visibility makes reconstruction more difficult. A pre-operative plan of how comminuted fragments would best be re-positioned to restore anatomy helps in executing a successful reduction. The objective of this work was to create new virtual fracture reconstruction technologies that would deliver that information for a clinical series of severe intra-articular fractures. As a step toward clinical application, algorithmic development benefits from the availability of more precise and controlled data. Therefore, this work first developed 3D puzzle solving methods in a surrogate platform not confounded by various in vivo complexities. Typical tibial plafond fracture fragmentation/dispersal patterns were generated with five identical replicas of human distal tibia anatomy that were machined from blocks of high-density polyetherurethane foam (bone fragmentation surrogate). Replicas were fractured using an instrumented drop tower and pre- and post-fracture geometries were obtained using laser scans and CT. A semi-automatic virtual reconstruction computer program aligned fragment native surfaces to a pre-fracture template. After effective reconstruction algorithms were created for the surrogate tibias, the next aim was to develop new algorithms that would accommodate confounding biologic factors and puzzle solve clinical fracture cases. First, a novel image analysis technique was developed to segment bone geometries from pre- and post-surgical reduction CT scans using a modified 3D watershed segmentation algorithm. Next, 3D puzzle solving algorithms were advanced to obtain fracture reconstructions in a series of highly comminuted tibial plafond fracture cases. Each tibia was methodically reconstructed by matching fragment native (periosteal and articular) surfaces to an intact template that was created from a mirror image of the healthy contralateral limb. Virtual reconstructions obtained for ten tibial plafond fracture cases had average alignment errors of 0.39±0.5 mm. These novel 3D puzzle solving methods are a significant advancement toward improving treatment by providing a powerful new tool for planning the surgical reconstruction of comminuted articular fractures.

碩士
國立臺北科技大學
自動化科技研究所
94
In orthopedics, conventional treatments often retrieve images from either X-ray or Computer Tomography (CT) for surgical planning, and then precede surgical operation with those information and experiences. Since three dimensional models can not be represented adequately by two dimensional images, also, the lack of precise mechanism for guiding during surgical operation result in imprecise motions even though the surgical planning is accurate enough. Thus the quality of operation is not confidential for doctors. This research aims to develop a software system in using STL by CT reconstruction, which to gain data of knee to build boundary of total knee replacement, in order to assist orthopedist in proceeding 3-D surgical planning and simulation of osteotomy. The software is developed in Borland C++ Builder 6.0, and OpenGL library as the tool for graphical presentation of this system. We extracted the features for describing the outline of the knee joint through x-ray images and adopted a CT image as our standard template to customize all size of knee models. And then we apply our three dimensional model for surgical planning so as to acquire and select the size of the knee implant, cutting path and borders for replacement surgery.

碩士
國立成功大學
機械工程學系碩博士班
100
Using fibular flap for mandibular reconstrcution is a common method. In order to achieve a better functional and aesthetic reconstruction result, many studies for pre-surgical planning are employed to assist surgeons in the surgery, especially for computer-aided system that is widely used in recently. Most of methods for pre-surgical planning are performed by observing the geometry features of mandible defect portion, and then the number of fibular segment required to shape the original contour can be determined. However, this relies on vision measurement and model production. In order to simplify this process, this study aims to develop an automatic surgical planning system for mandibular reconstrcution using fibular flap. The study insists of two major parts, which are parameterization and reconstruction planning. In the parameterization, a mandible Stereo Lithograph (STL) model and fibula scan data will be parameterized into feature-defined structure points according to their geometry characteristics. A New STL model can be generated using structure points. For reconstruction planning, the structure parameters are used to determine the mandible defect and the orientation of fibula to reconstruct, and then to calculate for the optimal reconstruction solution. Finally, the simulation of osteotomy and reconstruction are performed in the virtual reality.

The glenohumeral joint has the largest range of motion in the body. This is due to its anatomy of the bony structure of the glenoid fossa providing a shallow socket with minimal constraint of the humeral head and the surrounding soft tissue structures serving as restraints to limit excessive humeral head translation. The bony and soft tissue structures function together with a delicate balance that when disrupted lead to several pathologies including degenerative osteoarthritis or glenohumeral instability, which are the focus of this research. For glenohumeral osteoarthritis, the gold standard treatment is total shoulder arthroplasty. Although the surgical success rate is reported at 95%, the long-term failure rate is as high as 30% and often caused by glenoid component failure. For glenohumeral instability, surgical capsular plication can significantly reduce recurrent dislocation rates, however, up to 70% of patients experience joint stiffness and a reduced range of motion. For these treatments, there is little consensus regarding what surgical parameters optimize functional recovery - consequently, several surgical techniques exist. Since long-term follow-ups are lacking and difficult to perform, basic science studies are needed to identify what surgical parameters are most likely to influence patient recovery. The objective of this research was to develop patient-specific computer models to create accurate representations of these pathologies and to investigate the effects of different surgical parameters in total shoulder arthroplasty and glenohumeral instability repair. A total shoulder arthroplasty computer model was developed to investigate the effect of surgical parameters of the glenoid implant component. An initial study performed a cadaveric validation of the methodology to simulate the reaming process for resurfacing the glenoid surface. This validated computer model was then used to investigate how the degree of correction of glenoid retroversion affects cement mantle stress and potential cement failure. The use of physiologic patient-specific bone models revealed that maintaining the cortical bone layer should take precedence over version correction when a high degree of glenoid deformity is encountered. A glenohumeral instability computer model was developed to investigate the effect of capsular repair on shoulder stability and joint range of motion. The computer model suggests that adding a plication of the posterior band of the inferior glenohumeral ligament offloads regions of high strain from the anterior region of the glenoid attachment site which may indicate a reduced risk of anterior capsular repair failure. An anisotropic hyperelastic material behavior was then incorporated to model the glenohumeral capsule by performing an inverse finite element analysis to obtain the optimized material parameters. The computer models developed in this research utilize radiographic patient images in order to replicate and investigate actual pathology. As a result, the studies performed provide a deeper understanding of the glenohumeral joint mechanics associated with the treatments of total shoulder arthroplasty and glenohumeral capsular plication. This information provides insight for the practicing shoulder surgeon in their pre-operative surgical planning to decide the optimal technique and approach for a patient with these challenging pathologies. Moreover, the methodologies developed for simulating these surgical techniques can have a wide application to advance the foundation of pre-surgical virtual simulation and provide critical data for computer aided surgical navigation of other joints and diseases.

Tese de mestrado integrado, Engenharia Biomédica e Biofísica (Engenharia Clínica e Instrumentação Médica) Universidade de Lisboa, Faculdade de Ciências, 2020
Neurosurgery has been considered as a treatment or a therapy option for brain lesions with satisfactory outcomes regarding the maximal resection of the lesioned area and the minimal post-surgical neurological dysfunctions by avoiding eloquent areas. For the last two decades, resting-state functional magnetic resonance imaging (rs-fMRI) has emerged as an effective non-invasive neuro-imaging technique that can be used for pre-surgical functional brain mapping at rest. The analysis of these maps can focus on both the local function of specific regions (segregation) and the functional connections between them (integration) for the assessment of lesion-induced changes. The brain network can be characterized resorting to graph theory analysis for the calculation of these segregation and integration properties which is more facilitated on thresholded binarized matrices. These can be obtained by proportional thresholds revealing the top strongest connections that are present in the network. This study intends to analyse and compare the segregation and integration properties of lesioned and non lesioned hemispheric networks from a group of 7 patients with brain tumors and a cavernous malformation. Moreover, it also aims to evaluate the effect of the proportional thresholds in those properties. By using rs-fMRI and graph theory analysis, the network features of lesioned and non lesioned hemispheres were investigated, over a range between 20%-40% (at intervals of 5%) of proportional thresholds. The results reflected more integrated and segregated networks as more connections were included in the networks. The lesioned network revealed higher global integration and local processing at the highest density of 40%. However, the lesioned small-world organization was less optimal when comparing to the non lesioned network. In conclusion, our findings indicated that the lesion-induced perturbations disturbed the functional connectivity of the lesioned hemisphere. Nevertheless, compensatory mechanisms should be accounted for the pre-surgical evaluation of the affected and unaffected brain areas.
A remoção cirúrgica de uma lesão cerebral envolve a resseção da maior área lesada sem comprometer o tecido eloquente e não lesado envolvente. Desta forma, pretende-se minimizar disfunções neurológicas após a cirurgia garantindo a melhor qualidade de vida possível. Como tal, há a necessidade de incluir técnicas de imagem auxiliares à cirurgia que permitam fazer um mapeamento da lesão cerebral, não só ao nível anatómico mas principalmente funcional. Atualmente, existem diversas técnicas de neuro-imagem que atuam de forma não invasiva e que contribuem para o mapeamento funcional do cérebro, num contexto pré-cirúrgico. Destas destaca-se a imagem de ressonância magnética funcional que, tradicionalmente requer que o sujeito execute uma tarefa de modo a extrair as redes neuronais associadas `as regiões ativadas pelo desempenho da tarefa. No entanto, o facto desta técnica apenas possibilitar a extração de redes neuronais singulares somente associadas à tarefa em questão bem como sujeitos com lesões poderem ter dificuldades em realizar a tarefa requerida levou a que nas últimas duas décadas tenha emergido uma nova modalidade - a imagem de ressonância magnética funcional de repouso. Esta distingue-se da anterior no sentido do sujeito não executar qualquer tarefa nem ser submetido a qualquer estímulo. Através da aquisição da actividade cerebral espontânea é possível extrair as redes neuronais relacionadas com a atividade neuronal. Desta forma, a imagem de ressonância magnética funcional de repouso não só supera a limitação da eventual dificuldade ou incapacidade de execução de uma tarefa como também faculta a identificação de múltiplas redes neuronais, ao contrário da ressonância funcional baseada numa tarefa requerida. A extração destas redes neuronais funcionais é conseguida mediante a aplicação de métodos de análise que se focam na localização da função de determinadas regiões cerebrais (segregação) ou na conectividade funcional entre as mesmas (integração). Complementarmente, métodos que englobam tanto a análise da atividade (segregação) como da conectividade (integração) da imagem da ressonância magnética funcional de repouso têm sido combinados com a teoria dos grafos com o objetivo de investigar o cérebro enquanto uma rede neuronal complexa com conexões contínuas e dispersas entre as suas regiões. Ao mesmo tempo também permitem determinar as propriedades da organização funcional cerebral tanto a nível global como local, isto é, em grupos de regiões interligados igualmente denominados de módulos ou comunidades. Para caracterizar a integração e segregação da rede neuronal diversas medidas topológicas associadas à capacidade da rede neuronal partilhar informação entre diferentes regiões podem ser calculadas. O cálculo destas medidas implica a construção da rede neuronal funcional enquanto um conectoma definido por um dado número de regiões cerebrais, designadas de nodos, e pelas conexões funcionais estabelecidas entre as mesmas. O nível de conectividade funcional entre os nodos, também denominado de correlação funcional, é determinado pela computação da correlação entre as séries temporais de cada par de nodos. Posteriormente, estes dados podem ser organizados numa matriz de conectividade cujas entradas representam os pesos da correlação funcional. Contudo, o elevado número de conexões entre as regiões cerebrais dificulta a extração de informação relevante. Neste sentido, a binarização e aplicação de um limiar à matriz de conectividade assegura a redução dessas interações facilitando a determinação das propriedades topológicas da rede neuronal. Limiares que consideram um coeficiente de correlação funcional entre as regiões como o valor limiar para a inclusão das conexões (limiar absoluto) podem ser impostos `a matriz. Por outro lado, ao invés de um limite de correlação, também se pode selecionar uma percentagem das conexões mais fortes a serem incluídas na rede (limiar proporcional ou densidade). Estudos anteriores mostram evidências que limitar as redes neuronais por via de um limite de densidade resulta em medidas topológicas mais estáveis, razão pelo qual os limites proporcionais têm sido mais frequentemente aplicados na sua computação. Ainda assim, não existe um consenso relativamente à escolha ideal do valor do limiar que evita resultados incompletos ou falaciosos. O objetivo deste estudo engloba a análise de redes neuronais relativas aos hemisférios lesados e não lesados para um grupo de sete sujeitos com tumores cerebrais e uma malformação cavernosa. Adicionalmente, para cada hemisfério será calculado um conjunto de medidas de segregação e integração que permite caracterizar a respetiva rede neuronal, seguido de uma comparação entre as mesmas. Estas medidas serão determinadas com base na teoria de grafos aplicação de um conjunto de limiares proporcionais à matriz binarizada, com fundamento nos benefícios explorados acima. Deste modo, em cada rede neuronal, as conexões funcionais entre as suas regiões serão limitadas por um leque de densidades que varia entre 20% e 40%, com intervalos de 5%. Assim, a comparação entre as propriedades hemisféricas será realizada para cada limiar. Além do mais, uma comparação das medidas de grafos entre os diferentes limiares também será conduzida de modo a estudar o efeito dos mesmos na topologia de cada rede neuronal. Em primeiro lugar, os resultados deste estudo demonstraram que tanto o hemisfério lesado como o hemisfério não lesado estão organizados segundo uma rede de pequeno mundo, equilibrando de forma eficaz o processamento local e a integração global. Contudo, o hemisfério lesado mostrou ter uma organização topológica sub-ótima em comparação com o hemisfério não lesado. Os resultados da análise das medidas de integração revelaram que a inclusão de mais conexões nas redes lesadas e não lesadas, através do aumento do limiar proporcional, levou a uma diminuição da distância mínima entre duas regiões, sendo essa diminuição maior no hemisfério não lesado. Complementarmente, a eficiência global associada à comunicação entre as regiões também aumentou com a inclusão de mais conexões nos hemisférios. Desta forma pôde concluir-se que a consideração de mais conexões funcionais nas redes neuronais permitiu comunicações intra hemisféricas mais curtas e consequentemente mais eficientes, numa perspetiva global para as redes neuronais. Para além disso, o hemisfério não lesado revelou uma maior integração global para todas as densidades, exceto para a densidade de 40%. Para esta densidade, a reorganização funcional da rede neuronal lesada mostrou ser mais construtiva permitindo uma eficiência global mais elevada. Ao nível da segregação, os resultados evidenciaram que a escolha de densidades mais elevadas levou a que as redes neuronais fossem mais segregadas. Excluindo as densidades mais elevadas, o nível de conexões locais na rede lesada bem como a sua eficiência de propagação informação local foi menor em comparação com a rede não lesada. Para a densidade de 40%, a transferência de informação local foi mais eficiente no hemisfério lesado. Assim, o hemisfério lesado revelou não só uma maior integração global como também uma especialização local mais eficiente. Em conclusão, as medidas topológicas calculadas pareceram depender da escolha do limiar proporcional que foi aplicado nas redes neuronais. Para as densidades entre 20%-35%, os resultados mostraram que a lesão localizada no hemisfério lesado conduziu a disrupções na estrutura funcional desse mesmo hemisfério (menor integração e segregação). Porém, na densidade de 40%, a reorganização funcional pareceu indicar o estabelecimento de mecanismos e conexões compensatórios suficientes para compensar as perturbações causadas pela presença da lesão nesse hemisfério. De notar que os resultados não mostraram ser totalmente conclusivos quanto ao impacto da lesão na rede não lesada, através de interações funcionais entre os hemisférios. Assim, os resultados deste estudo sugeriram que as perturbações funcionais induzidas pela lesão afetaram a conectividade funcional entre as regiões do hemisfério onde a mesma estava localizada. Como consequência, a escolha de densidades mais elevadas pareceu clarificar conexões e mecanismos de compensação no hemisfério lesado. Deste modo, estas alterações devem ser tidas em conta para a avaliação pré-cirúrgica das áreas cerebrais afetadas e não afetadas.

Lo scopo della tesi e' quello di studiare un applicazione clinica dedicata alla chirurgia dei tumori cerebrali basata sulle immagini di diffusione MR. L'obbiettivo della chirurgia dei tumori cerebrali e' quello di massimizzare la resezione dei tessuti patologici preservando le aree eloquenti corticali e sottocorticali. La risonanza magnetica e le tecniche avanzate elaborazione di immagini permettono al neurochirurgo di definire come la lesione cambia l'anatomia del paziente. In questa tesi descriviamo i principi ed i metodi basati sulla diffusione MR e definiamo un protocollo neuro radiologico necessario per la pianificazione della strategia chirurgica che minimizza il rischio nella resezione di un tumore maligno sito in area eloquente. Nonostante gli artefatti ed i limiti delle tecnologie coinvolte, il metodo proposto offre un supporto intra-operatorio in grado di rappresentare la relazione spaziale tra la lesione e le aree eloquenti circostanti. Basato sull'integrazione della DTI e gli strumenti di localizzazione intraoperatoria (neuronavigatore e monitoraggio neurofisiologico) il metodo proposto permette di correlare e verificare i risultati ottenuti in fase di pianificazione. Da Gennaio 2011 a Dicembre 2013 144 pazienti con tumore cerebrale in area eloquente sono stati studiati con DTI trattografia e pianificatore pre-operatorio. Di questi, 94 sono stati poi trattati chirurgicamente.
The purpose of the thesis is to investigate a clinical application of Diffusion Tensor Imaging in brain surgery. Brain Surgery aims to maximize lesion resection while preserving surrounding vital cortical and subcortical area. MRI techniques enables neurosurgeons to define how lesions change the individual anatomy in relation to brain function mapping. In this thesis we describe principles and methods of diffusion model and specific neuro radiological protocols for pre surgical planning (minimal risk strategy) of malignant brain tumors in eloquent area. Despite artifacts and limits, the developed framework based on DTI integrated with intra-operative localization supports neurosurgeon to analyze surgical strategies while preserving brain functions. We compare methods, procedures and different implementation of algorithms affecting the complex multi-modal processing of imaging protocol. Clinical information (deficit quantification), and intra-operative neurophysiological stimulations with morphological characteristics of fiber bundles corrupted by tumor is widely examined. From January 2011 to December 2013, 144 patients with lesions in eloquent areas were submitted to pre-operative DTI tractography and 94 of 144 were treated surgically.

In most cases, women with headache disorders have normal pregnancy and delivery outcomes and should not be discouraged from becoming pregnant. Pre-pregnancy planning includes weaning of contraindicated medications. Most women with migraine without aura improve during pregnancy. Although there are limitations, various acute and preventive treatments may be employed, including non-pharmacologic options. Anti-epileptic medications should be avoided. For pseudotumor cerebri, the mainstay of treatment includes diuretics and therapeutic lumbar punctures, avoiding topiramate. Surgical treatment may be necessary if vision is threatened. Close monitoring and collaboration between an ophthalmologist, neurologist and obstetrician are critical. New-onset pseudotumor cerebri requires an investigation for secondary causes such as cerebral venous thrombosis. In the absence of a pre-existing primary headache disorder, new headaches in the postnatal period warrant evaluation for secondary headache disorders, including post-dural puncture headache, stroke, cerebral venous thrombosis, pre-eclampsia, eclampsia, reversible cerebral vasoconstriction syndrome (RCVS), and pituitary apoplexy.

This chapter covers airway assessment and management with the conduct of anaesthesia for ENT and maxillofacial procedures, both elective and emergency. Airway assessment allows some prediction of the difficult airway. Management of the anticipated difficult airway is discussed with techniques including awake fibreoptic intubation. Management of the unanticipated difficult airway and the obstructed airway is discussed following Difficult Airway Society algorithms. Emergency airway management includes cricothyroidotomy and jet ventilation. Indications for tracheostomy, descriptions of surgical and percutaneous procedures and guidelines for the emergency management of tracheostomy/laryngectomy airway emergencies are included. Anaesthesia for ENT covers the common anaesthetic considerations in the pre-assessment and perioperative period during management of patients for common ENT procedures. The special considerations for laser airway surgery and emergency surgery (such as bleeding tonsils and epiglottitis) are described. Most maxillofacial trauma is performed on a semi-elective basis and the airway management planning for lower, mid and upper-face fractures is included.

AbstractIn unilateral cleft lip and palate, the orbicularis muscle, the alveolar bone, the floor of the nose, and the hard and soft palate are interrupted, creating an open communication between nasopharynx and oropharynx. Patients with a cleft lip and palate are treated in specialized cleft centers by a multidisciplinary team. Having cleft lip and/or palate has a noteworthy impact on quality of life and psychosocial functioning. Surgical scars are in the center of the face and can be quite noteworthy. Postoperative scarring is a common cause of patient dissatisfaction.Here, we describe a patient with an unpleasing esthetic result after surgical correction of unilateral cleft lip and palate in China. After careful surgical planning, scar excision and a single Z-plasty were performed to achieve scar lengthening. Pre- and postoperative images are shown.

Orthodontists play a key role in orthognathic surgery (OS) cases. They need to be involved in the assessment, surgical planning, orthodontic treatment, pre- and post-surgical management, and in finishing and retention of the cases. The complicated nature of these cases requires that the orthodontist be equipped with additional skills to manage them properly not only from a dental perspective, but also from a psychological one. In this chapter, we will be looking at the different roles the orthodontist plays in OS cases and how to best perform them.

Aortic valve disease remains the second most common valvular heart disease worldwide. Surgical aortic valve replacement (SAVR) with mechanical or bioprosthetic valves and transcatheter aortic valve replacement (TAVR) with bioprosthetic valves are both approved therapies for patients with severe aortic stenosis (AS) across all surgical risk categories. On the other hand, SAVR remains the mainstay of treatment for severe aortic regurgitation (AR) with TAVR reserved for selected patients at prohibitive surgical risk. Both surgical and transcatheter bioprosthetic valves are prone to bioprosthetic valve failure (BVF) due to various etiologies, and can lead to restenosis, regurgitation, or a combination of both. BVF can now be addressed by repeat valve replacement whether surgical or valve-in-valve TAVR (ViV). ViV is a desirable option for elderly patients at high surgical risk and requires meticulous planning with pre-operative CT imaging to optimize outcomes and minimize complications.

This chapter covers the diagnosis, assessment, and treatment planning for orthognathic surgery. Pre- and postsurgical orthodontics are described, and surgical management is outlined. Maxillary, mandibular, and chin osteotomies along with various modifications including segmental surgery are explained and illustrated. Subsequently, complications arising from the procedures and their management are explained. The chapter ends with sections on soft tissue changes, stability of postoperative results, distraction osteogenesis, and lastly, obstructive sleep apnoea.

Obstructive sleep apnea (OSA) is a highly prevalent disease, with physiologic disturbances encompassing the pre-, intra-, and postoperative periods. Unlike many comorbid conditions that surgical patients present with, increased risk remains despite the anesthetic approach. Beginning with the preoperative period, patients with known OSA must have thorough assessments of their pulmonary, cardiac, and endocrine systems. Initial planning should also assess the suitability of the patient for the operative facility. With regards to intraoperative concerns, difficult airway and intravenous access supplies should be available, generally along with bariatric equipment. Intraoperative planning should also involve early intervention for postoperative pain management. The transition to the postoperative period should continue to focus on appropriate analgesia and respiratory support. Throughout this process, communication with the surgical team is of utmost concern given the complexity of this patient population and the many potential pitfalls.

Defining the extent of the epileptogenic zone is particularly problematic in posterior cortex epilepsies (PCEs). Non-invasive information is frequently insufficient for surgical planning, and individually tailored surgery is likely to be curative only when guided by invasive investigation. Stereotactic placement of intracerebral multicontact electrodes is performed according to an individually tailored pre-implantation hypothesis of the presumed epileptogenic zone and, in the posterior cortex, usually follows three main exploration patterns, in relation to the origin and preferential spreading pattern of ictal discharges. This chapter presents the methodology for stereo-EEG (SEEG) exploration of PCEs by means of illustrative cases. It also presents the characteristics and the surgical outcome and its determinants of a cohort of patients operated on for drug-resistant PCE, about half of whom underwent invasive investigation by SEEG. Duration of epilepsy represented the most consistent predictor of surgical outcome, with early surgery being correlated with higher chances of surgical success.

This chapter discusses how the results of a cardiopulmonary exercise test (CPET) can be used for preoperative surgical planning. A low preoperative maximum oxygen uptake (VO₂max) is associated with a poor outcome. The lower the VO₂max, the worse the prognosis. Use of the anaerobic threshold is less reliable. The CPET may identify clinical problems which can be optimized prior to surgery. Pre-habilitation can improve the chances of a good outcome from surgery.

Visualization of spinal pathologies such as scoliosis is imperative to proper surgical treatment. Current visualization techniques use 2D representations of the anatomy in the form of radiographs, CT, or MRI. The ability to view patient anatomy in three dimensions prior to surgical intervention allows for a more thorough evaluation and planning of the surgical requirements. Manufacturing methods such as three dimensional printing can be employed to rapidly generate a physical 3D representation of patient anatomy which can be used for visualization and/or surgical planning.

Computer-based surgical planning of cardiothoracic surgery is a new paradigm that uses engineering tools to model and evaluate patient-specific surgical options and thus provide insights on the hemodynamic implications of a given design. In this study, the total cavopulmonary palliation of single ventricle defects serves as a test-bed for such techniques by comparing the output of pre-operative modeling to hemodynamic outcomes derived from post-operative imaging. The resulting accuracy of the models demonstrates that, despite the inherent challenges, surgical planning is a viable reality in single ventricle cardiothoracic surgery that can potentially deliver significant clinical impact.

Unbalanced distribution of hepatic blood flow to the lungs in single ventricle patients can result in the formation of harmful arterial-venous shunts. Careful planning of the hepatic baffle placement to optimize its distribution can help to minimize this risk. The combination of in vivo imaging, a computational fluids solver, and a state-of-the-art virtual surgery interface have successfully been demonstrated to assist in this planning step. In the present study, we analyze the effect of the patient-derived flow boundary conditions on the optimal solutions obtained from the simulations for a particular set of complex cases with interrupted inferior vena cava. By considering two patients with similar anatomical configurations but drastically different hemodynamics, we see that differences in the percentage of cardiac output carried by each of the inflow vessels can drastically alter the optimal surgical approach.

Abstract Computational models and three-dimensional prints were developed to aid in the pre-procedural planning of a LVAD exchange surgery. Clinical imaging was used to model and segment the anatomy and implanted device for computational implantation and 3D printing. The physicians visualized the pre-procedural anatomy in a 3D space to better understand the device-tissue-interface of the current implant and assess the optimal location for surgical entry. The models also contributed to the education of the surgical team by providing hands-on tools to understand the planned steps involved in the procedure.

Several types of implants, plates, and screws have been developed for corresponding bone fractures at different sites. To understand the mechanical behavior of a bone plate and to provide surgeons with suggestions for selecting screw positions, this study aimed to create an APP to provide pre-surgical planning using a computed tomography (CT)-based finite element model. This model was validated using a compression test of synthetic sawbones. Furthermore, the specific APP was established using the COMSOL application builder to calculate the stress and strain of the implant under different screw positions. This APP reveals how the number and location of screws affect the stress distribution of the implant. It can provide clinicians with preliminary reference information before surgery.