Records of all neurosurgical inpatients admitted to Royal North Shore Hospital since 1976 have been prospectively kept in a relational database. Demographic details, diagnoses, operations and complications have been entered continuously since 1982 by the author of this study. Complications are monitored at monthly review meetings attended by medical staff. The recurrence of deep vein thrombosis (DVT) and pulmonary embolism (PE) at these meetings, despite continual improvements in patient care, prompted this study. It aims to use the database to study changes in the incidence of DVT and PE over the previous twenty years; to find what database variables predict these complications; and whether use of mechanical and pharmacological agents has had an impact on DVT and PE rate. Univariate analysis of the incidence of DVT and PE by age, sex, length of stay (LOS), admission month, diagnosis, operation and surgeon over time was run. Any significant variables were then analysed by multivariate logistic regression. The DVT rate was low by world standards, but rose from 0.6% in 1979-83 to 1.2% in 1984-88, then rose exponentially to 3.60% in 1994-98 with a significantly increasing trend over the twenty years (c2 MH =114.20, with IDF, P<0.001). PE rate doubled significantly over the twenty years from 0.6% to 1.2% (c2 MH =17.94 with 1DF, P<0.001). Age, LOS, diagnosis, operation and surgeon were significant predictors of DVT and PE. After adjustment for LOS, time period and age, vascular surgery was found to be the strongest predictor of DVT (OR=2.82, 95% CI: 2.08-3.82, c2 =43.91, P<0.01). Vascular diagnosis was the strongest diagnosis predictor. No effect of sex or month of admission was shown. After adjustment for LOS, time period and age, spinal fusion was the strongest predictor of PE (OR=4.04, 95% CI: 1.81-9.03). Anterior communicating artery aneurysm was the diagnosis most highly associated with PE. The rise in DVT rate may be due to increased complexity of surgical and nursing management, and some screening of patients with the introduction of duplex scanning. The doubling of PE rate is unexplained. The risk of brain or spinal cord haemorrhage makes prophylactic anticoagulation a difficult choice. This study reveals groupings which can be used to determine appropriate prophylaxis. Use of mechanical and pharmaceutical agents is not recorded consistently in the database, but it is known approximately when they were introduced. No impact on the rate of DVT and PE can be demonstrated by these agents. More vigilant and widespread use of mechanical prophylaxis might be just as effective in controlling DVT and PE.

Proefschrift--Groningen. / Summary in Dutch and French.

Proefschrift--Groningen. / Summary in Dutch and French.

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Abstract Interactive image-guided neurosurgery for the resection of brain tumors was developed within the last 10 years at different neurosurgical centers around the world to improve the safety of the surgery and the functional outcome of the patients. Since 1987, the Oulu Neuronavigator System, consisting mainly of a mechanical arm, visualization software, an ultrasound transducer and a computer, was developed at the Neurosurgical Research Unit, University of Oulu, Finland. It was the first system to incorporate the principle of the common surgical axis for visualization, including intraoperative ultrasonography. A precommercial version of the device was jointly developed with Elekta Ab, Stockholm, Sweden, as a public project under EUREKA and introduced into a clinical beta-phase trial in 1994 as the Leksell Index System™. A total of 19 operations were performed at the Oulu University Hospital between September 1994 and September 1996 for patients harboring different kinds of intracranial tumors, especially cerebral gliomas. This thesis gives a comprehensive review of the literature from the roots of stereotaxy to the latest developments in interactive image-guided neurosurgery and discusses the advantages and disadvantages of the Leksell Index System™ with special reference to the clinical series that was performed at our institution. Future therapy strategies for the treatment of patients with cerebral gliomas, especially glioblastoma multiforme are envisioned, focusing on the further improvement of surgical interventions. The clinical trial proved that the employed neuronavigator system is versatile and safe and that there are no adverse effects, complications or surgical mortality due to the device. It enabled the surgeon to plan smaller sized and better centered skin incisions and craniotomies and to approach the target lesion with less dissection of intact brain tissue. Despite more radical removal of lesions the overall invasiveness of the operation was decreased in 63.2% of the cases, the duration of the procedure was decreased in 78.9%, and the surgeon's feeling of safety could be improved in 89.5% of the operations. Due to the use of intraoperative imaging (with ultrasound) the experience provides a unique basis for next generation neuronavigators and also for interventional MRI.

<p>Radio-frequency (RF) lesioning is a method utilising high frequency currents for thermal coagulation of pathological tissue or signal pathways. The current is delivered from an electrode with a temperature sensor, permitting control of the current at a desired target temperature. In the brain RF-lesioning can e.g. be used for severe chronic pain and movement disorders such as Parkinson’s disease. This thesis focuses on modelling and simulation with the aim of gaining better understanding and predictability of the lesioning process in deep brain structures. The finite element method (FEM) together with experimental comparisons was used to study the effects of electrode dimensions, electrode target temperature, electric and thermal conductivity of the brain tissue, blood perfusion and cerebrospinal fluid (CSF) filled cysts. Equations for steady current, thermal transport and incompressible flow were used together with statistical factorial design and regression analysis for this purpose.</p><p>Increased target temperature, electrode tip length and electrode diameter increased the simulated lesion size, which is in accordance with experimental results. The influence of blood perfusion, modelled as an increase in thermal conductivity in non-coagulated tissue, gave smaller simulated lesions with increasing blood perfusion as heat was more efficiently conducted from the rim of the lesion. If no consideration was taken to the coagulation the lesion became larger with increased thermal conductivity instead, as the increase in conducted heat was compensated for through an increased power output in order to maintain the target temperature. Simulated lesions corresponded well to experimental in-vivo lesions.</p><p>The electric conductivity in a homogeneous surrounding had little impact on lesion development. However this was not valid for a heterogeneous surrounding. CSF-filled cysts have a much higher electric conductivity than brain tissue focussing the current to them if the electrode tip is in contact with both. Heating of CSF can also cause considerable convective flow and as a result a very efficient heat transfer. This affected simulated as well as experimental lesion sizes and shapes resulting in both very large lesions if sufficient power compared to the cysts size was supplied and very small lesions if the power was low, mitigating the heat over a large volume.</p><p>In conclusion especially blood perfusion and CSF can greatly affect the lesioning process and appear to be important to consider when planning surgical procedures. Hopefully this thesis will help improve knowledge about and predictability of clinical lesioning.</p>

O interesse crescente pelo tema qualidade de vida no campo da neurocirurgia é notório, tanto para avaliar o impacto da doença e a eficácia dos tratamentos, quanto para avaliar o impacto físico e psicossocial nas pessoas acometidas. Encontramos na literatura poucos estudos que discutem o tema sistematicamente, utilizando instrumentos que possibilitem abarcar as dimensões que compõe o que denominamos qualidade de vida. O objetivo principal deste estudo foi avaliar a qualidade de vida antes e a evolução após três, seis e doze meses da ressecção de meningeomas. Foi realizado estudo prospectivo de 29 pacientes portadores de meningeomas benignos (17 mulheres e 12 homens), com idade variando entre 28 e 76 anos. Para avaliação da qualidade de vida foram utilizados dois instrumentos, o Perfil de Saúde de Nottingham (PSN) e o Questionário de Dimensões de Saúde de Innsbruck para Pacientes Neurocirúrgicos (DSI-NC). Foram encontradas diferenças significativas nos escores totais das escalas PSN e DSI-NC, quando comparadas às avaliações nos quatro momentos (pré, após três, seis e doze meses). Observou-se melhora significativa nos domínios Dor, Reações Emocionais, Habilidades Físicas, Sono, Comunicação, Condição Física, Independência e Condição Psicológica. Nas dimensões restantes (Função do Sistema Nervoso Autônomo, Nível de Energia, Isolamento e Interação Social) observou-se somente tendência à redução dos sintomas. Neste estudo, pode-se constatar que os pacientes submetidos à intervenção cirúrgica para ressecção de meningeomas, apresentaram melhora significativa da qualidade de vida, com maior intensidade até os primeiros três meses. Cabe ressaltar que dos três aos seis meses ocorreu certa estabilização no quadro (pelo impacto da elevação dos sintomas nos domínio Reações Emocionais) e nova redução dos sintomas aconteceu até os doze meses da intervenção. Considerando os resultados obtidos, parece relevante iniciar um trabalho terapêutico preventivo após três meses da intervenção cirúrgica, para que sejam abordadas questões de ordem afetivo-emocional. O tamanho da amostra impossibilitou análises mais específicas com relação à fatores como idade, escolaridade, grau de ressecção e localização do meningeoma, fatores estes que devem ser melhor explorados em estudos posteriores / The growing interest in studying quality of life within the neurosurgical field is noticeable, in as much to evaluate the disease impact and the treatment efficiency as to evaluate the physical and psychosocial impacts on those taken by the illness. Few are the studies found in the literature discussing this matter methodically, using instruments which enable us to embrace the composing dimensions of what we call quality of life. This study aimed mainly to evaluate the quality of life before and the development after three, six and twelve months from the meningeoma resection. A prospective study was carried out with 29 patients carrying benign meningeoma (17 women and 12 men) whose ages ranged from 28 and 76 years old. In order to evaluate the quality of life two instruments were used: the Nottingham Health Profile (NHP) and the Innsbruck Health Dimensions Questionnaire for Neurosurgical Patients (IHD-NS). Meaningful differences in the total score were found between NHP and IHD-NS scales when compared to the evaluation over the four moments. A relevant improvement was noticed in the following domains: Pain, Emotional Reactions, Physical Abilities, Sleepiness, Communication, Physical Condition, Independence and Psychological Condition. In the remaining dimensions domains (Autonomic Nervous System, Energy Level, Isolation and Social Interaction) we only observed that the symptoms were tending towards a reduction. In this study we could observe that the patients, who were submitted to the surgical intervention for the meningeoma resection, presented a relevant improvement in their quality of life, with greater intensity up to the first three months. It is worth noticing that between three and six months the patients situation revealed certain stabilization (for the impact caused by the increasing symptoms in the Emotional Reactions domain) and a new reduction of the symptoms took place up to twelve months from intervention. Considering the achieved results, it seems relevant to begin a preventive therapeutic procedure after three months from surgical intervention, in order to approach affective-emotional matters. The sample amplitude disabled us from making more specific analysis concerning age, school educational level, resection level and meningeoma location, such matters must be better exploited in further studies

Since the first robotic surgical intervention was performed in 1985 using a PUMA industrial manipulator, development in the field of surgical robotics has been relatively fast paced, despite the tremendous costs involved in developing new robotic interventional devices. This is due to the clear advantages to augmented a clinicians skill and dexterity with the precision and reliability of computer controlled motion. A natural extension of robotic surgical intervention is the integration of image guided interventions, which give the promise of reduced trauma, procedure time and inaccuracies. Despite magnetic resonance imaging (MRI) being one of the most effective imaging modalities for visualizing soft tissue structures within the body, MRI guided surgical robotics has been frustrated by the high magnetic field in the MRI image space and the extreme sensitivity to electromagnetic interference. The primary contributions of this dissertation relate to enabling the use of direct, live MR imaging to guide and assist interventional procedures. These are the two focus areas: creation both of an integrated MRI-guided development platform and of a stereotactic neural intervention system. The integrated series of modules of the development platform represent a significant advancement in the practice of creating MRI guided mechatronic devices, as well as an understanding of design requirements for creating actuated devices to operate within a diagnostic MRI. This knowledge was gained through a systematic approach to understanding, isolating, characterizing, and circumventing difficulties associated with developing MRI-guided interventional systems. These contributions have been validated on the levels of the individual modules, the total development system, and several deployed interventional devices. An overview of this work is presented with a summary of contributions and lessons learned along the way.