Background: Mechanical thrombectomy is the gold standard for treating patients with certain acute ischemic stroke (AIS) due to large vessel occlusion (LVO). However, even with major advancements and increasing procedural volumes, acute endovascular therapy remains a high-risk procedure with a considerable 90-day mortality rate, affected by a variety of factors. Purpose: To investigate various clinical and procedural factors associated with 90-day mortality in patients undergoing mechanical thrombectomy for emergent treatment of AIS and determine which of these factors made unique contributions to post-thrombectomy prognosis. Methods: We examined a prospective registry of 323 patients treated with endovascular thrombectomy for AIS between 2016 and 2019 at a high-volume comprehensive stroke center in central Massachusetts. We developed two multivariable logistic regression models adjusting for the contributions of baseline characteristics and recanalization parameters, to identify potential predictors of mortality at 90 days. Results: Among 323 AIS patients treated with mechanical thrombectomy, the overall rate of successful recanalization was 86% and the overall post-procedure mortality rate was 29% by 90 days. After univariate analysis, a baseline multivariable model comprised of: history of stroke (OR 0.28, 95% CI 0.09 – 0.68), pre-stroke modified Rankin Scale (mRS 2: OR 3.75, 95% CI), severe admission National Institutes of Health Stroke Scale (NIHSS 21–42: OR 12.36, 95% CI 1.48 – 103.27), internal carotid artery (ICA) occlusion (OR 2.77, 95% CI 1.18 – 6.55), and posterior circulation occlusion (OR 2.69, 95% CI 1.06 – 6.83) was prognostic of 90-day mortality. A second multivariable model also found the procedural factors of: clot obtained after each pass (OR 0.49, 95% CI 0.24 – 1.00), successful recanalization (OR 0.21, 95% CI 0.06 – 0.8) and symptomatic intracranial hemorrhage (sICH; OR 17.89, 95% CI 5.22 – 61.29) to be identifiable predictors of post-thrombectomy mortality. Conclusion: Death within 90 days after thrombectomy was increased among patients with higher pre-stroke disability, higher stroke severity on admission, ICA or posterior occlusion, and those with sICH complication. A history of stroke, clot extraction after each device pass, and successful recanalization are associated with decreased 90-day mortality. These identifiable contributors may inform patient selection, prognosis evolution, and shared decision-making regarding emergent thrombectomy for treatment of AIS.

Glioblastoma multiforme (Glioma) is an extremely aggressive tumor that arises from intrinsic glial cells in the central nervous system (CNS)5. It is the most common primary brain tumor in humans and has a typical survival time of 15-16 months5. Current treatments for gliomas include surgery, radiation, and treatment with temozolomide (TMZ). While these treatments tend to add 2-3 months to a patient’s survival, none have been capable of altering the course of the disease1. One of the shortcomings of novel therapeutics for glioma, is the inability to evaluate in real time how therapeutics are affecting the patient. There is also the problem of the blood brain barrier (BBB), which can be overcome by administering drugs through an intracranial catheter (delivered via CED). The primary obstacle that’s been observed in intracranial drug delivery is the inadequacy of the delivery. This inadequacy is an inability of the drug to diffuse homogenously throughout the tumor. CED also creates a possibility for toxicity due to highly concentrated volumes of drugs delivered; we believe the novel delivery method we are trying to develop, will make this possibility null. The purpose of this study was initially to demonstrate the problem of delivering drugs via diffusion while simultaneously collecting biomarkers to interpret efficacy of the drugs, due to differing molecular weights. The other objective of this study was to demonstrate that it is possible to manipulate both the direction of bulk flow and the rate of diffusion of drugs delivered through a catheter using a gel phantom as a representative of brain tissue. What we found is that by utilizing a two-catheter method with convection and retro-convection enhanced delivery, we could in fact manipulate these parameters and achieve a more even distribution of drug (represented by fluorophores in our experiments). Using these two catheter methods, we will also be able to collect fluids from the tumor to monitor the effect of any treatment in real time.

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. 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. 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. 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.

Detta examensarbete är ett produktutvecklingsprojekt som behandlar utvecklingen av ett koncept av en ny stereotaktisk huvudram för användning inom neurokirurgin. Arbetet har utförts i samarbete med Elekta Instrument AB som är ett av världens ledande företag för utveckling av utrustning som behandlar cancer och andra sjukdomar i hjärnan. Elekta har idag en produkt som heter Leksell Stereotactic System (LSS) och består av en ram och en båge, tillverkade i aluminium, som används vid stereotaktisk kirurgi. I och med att diagnosmetoderna förändras och att främst MRI använder kraftfullare magnetfält finns ett behov av att använda icke elektriskt ledande eller magnetiska material i ramen. Målet med arbetet var att ta fram en ny huvudfixeringsram som fram-för allt var förbättrad inom följande; material, kompatibilitet, design och patientkomfort. Arbetet inleddes med en förstudie och en studie av användarnas antropometriska mått. En QFD genomfördes för att ta fram kundönskemål och krav på produkten. Ett funktions-medel-träd skapades för att studera produktens funktioner. De medel som skapats i funktions-medel-trädet användes sedan för att generera konceptlösningar som sedan utvärderades och en slutlig lösning valdes. Ett materialseminarium hölls där bästa materialet ansågs vara glasfiber förstärkt epoxy tillverkad i RTM med en lackad yta. En del brister fanns med det valda konceptet och som ett resultat skapades ett nytt koncept som i slutändan ansågs bättre och valdes för fortsatt utveckling. Konceptet Doublebend’s, se figur 1, fördelar var dess form, som tillät ingrepp till alla delar av hjärnan, vinklingsbara skruvinsatser och bra möjligheter till tillverkning. Ramens deformation analyserades och resultatet användes vid placering av låsningspunkter på ramen till angränsande adaptrar. En MRI-adapter togs fram och en prototyp tillverkades i SLS. Prototypen användes för validering vid ett möte med en neurokirurg. Slutsatserna från arbetet är att det framtagna konceptet har potential att utvecklas till en bra produkt, men att mycket arbete kvarstår. Djupare analyser, materialprov och detaljkonstruktion återstår som framtida arbete. / This report presents the development of a concept for a new stereotactic head frame for use in neurosurgery. The work has been performed at Elekta Instrument AB, which is one of the world's leading companies for the development of equipment that is used to treat cancer and other diseases of the brain.  Doublebend  The conclusions of the work are that the developed concept has the potential to progress into a quality product, however much work remains. Further analysis, material testing and detailed design remain as future work.

Neurokirurgisk vård i Sverige är begränsad till sex olika kliniker. Klinikerna utför planerade och akuta operationer. Beroende på tillgängliga resurser kan ibland akuta operationer dröja. Fördröjning av operationer ställer krav på sjuksköterskans kunskaper om att bemöta, informera och kommunicera med den väntande patienten. Syftet med studien var att beskriva patienters upplevelser av att vänta på en akut neurokirurgisk operation. En kvalitativ metod med induktiv ansats valdes och som datainsamlingsmetod genomfördes semistrukturerade intervjuer. Sex patienter deltog i individuella intervjuer som ägde rum mellan februari och maj år 2016 på en neurokirurgisk klinik i Sverige. Materialet analyserades med hjälp av en manifest innehållsanalys. Resultatet visade att den information patienterna fick från personalen under sin väntetid var i vissa delar otillräcklig och detta skapade en ovisshet som ledde till känslor av oro. Några patienter kände sig utsatta i sin situation vilket skapade starka känslor av ensamhet, besvikenhet och ilska. Patienterna fick fasta en längre tid vilket skapade ytterligare negativa känslor under väntan. Trots oro och ilska uttryckte patienterna en acceptans av sin situation, eftersom de hade en förståelse för varför de fick vänta. Patienterna upplevde även att personalen var hjälpsam, kunnig och positiv vilket skapade en trygghet för patienterna. Slutsatsen visar på vikten av information och tydlig kommunikation mellan patient och personal för att öka patientens trygghet och välbefinnande i en utsatt situation. / In Sweden, neurosurgical patients are treated at six different clinics around the country. The neurosurgical clinics perform both scheduled and acute surgical procedures. At times, acute surgical procedures can be delayed and patients are forced to wait. This requires knowledge for the nurse who cares for these patients on how to treat, inform and communicate with the waiting patient. The aim of the study was to describe patients’ experiences of waiting for an acute neurosurgical procedure. A qualitative method with an inductive reasoning was selected. Semi-structured interviews were chosen as an approach for data collection. Six patients participated in individual interviews performed during the months of February through May 2016 at a neurosurgical clinic in Sweden. The collected data was analyzed with a manifest content analysis. The result of the study shows that the patients lacked information about their situation during the time they waited for surgery, which lead to in feelings of uncertainty and anxiety. Some patients felt exposed, leading to strong emotions such as loneliness, disappointment and anger. The long preoperative fast enhanced the negative feelings. Although the patients expressed feelings of anxiety and anger, they seemed to accept their situation as they understood the reasons for the long wait. They experienced the health professionals as helpful, proficient and with a positive attitude, which gained the patients trust. The conclusion of the study is the importance of patient information and communication between patient and health professionals to create a trusting relationship and well-being for patients in an exposed situation.

Virtual reality (VR) for surgical training shows promise in preparing surgeons for complex procedures. However, achieving a high level of realism in VR is essential for the skills acquired to translate effectively into real-world applications. One challenge is the underestimation of perceived depth in VR compared to the real world, which can significantly impact applications requiring precise depth perception. This study aims to investigate how object shape influences depth perception in VR, as it may contribute to the observed underestimation of distances. Specifically, the research focuses on minimally invasive neurosurgery (MIS), where surgeons operate through small incisions on the skull without direct visualization of the inside of the skull. Training in a highly accurate VR simulation could offer a safe practice environment for surgeons. Previous studies have explored the use of VR for training in various fields, including medicine, transport, and military applications. However, concerns exist regarding whether VR accurately represents real-life scenarios, particularly with regard to depth perception. Research indicates that participants often underestimate egocentric distances in VR, which can pose challenges in MIS procedures where precise targeting is crucial. This study builds upon previous research conducted by KTH master’s students in 2022, which examined spatio-temporal distance perception in VR. This study expands on this work by investigating the influence of object shape on depth perception. Previous research has shown that different object shapes, luminance, and colors can impact depth perception in VR. Understanding how object shape affects depth perception can contribute to improving the realism of VR simulations for surgical training, particularly for MIS procedures. / Virtual Reality (VR) i utbildningssyfte inom kirurgi visar lovande resultat för att utbilda kirurger inför komplexa ingrepp. Dock är det viktigt att uppnå en hög grad av realism i VR för att de förvärvade färdigheterna ska kunna överföras till verkliga tillämpningar. En utmaning är att tidigare studier visat på att VR har en negativ inverkan på djupseendet, vilket kan ha en betydande påverkan på tillämpningar som kräver exakt djupseende. Denna studie syftar till att undersöka hur ett objekts form påverkar djupseendet i VR. Specifikt fokuserar vår studie på minimalinvasiv hjärnkirurgi (MIS), där kirurger utför ingrepp genom små snitt som görs i skallen med begränsad insyn. Träning i en VR-simulering kan erbjuda en säker övningsmiljö för kirurger. Tidigare studier har utforskat användningen av VR för träning inom olika områden, inklusive medicin, transport och militära tillämpningar. Dock finns det en oro för huruvida VR korrekt återger verkliga scenarion, särskilt med avseende på djupseendet. Forskning indikerar att deltagare ofta underskattar egocentriska avstånd i VR, vilket kan utgöra en utmaning för MIS-ingrepp där små avstånd är avgörande. Denna studie bygger på tidigare forskning utförd av masterstudenter vid KTH 2022, vilken undersökte uppfattningen av rumtid i VR. Denna studie bygger vidare på denna forskning genom att undersöka hur objektets form påverkar djupseendet. Tidigare forskning har visat att olika objektformer, ljusstyrkor och färger kan påverka djupseendet i VR. Att förstå hur objektets form påverkar djupseendet kan bidra till att förbättra realismen i VR-simuleringar för kirurgisk träning, särskilt för MIS-ingrepp.

Serum levels of apolipoprotein ApoC1 have been described in a number of systemic tumor entities as potential biomarkers, but little is known about ApoC1 in neurosurgical patients. A total of 230 serum samples from 96 patients were analyzed using an ELISA technique. Patient diagnoses comprised 70 glioblastomas WHO IV◦ , 10 anaplastic astrocytomas III◦ , one anaplastic oligodendroglioma III◦ , one oligodendroglioma II◦ , one diffuse astrocytoma II◦ , one pilocytic astrocytoma I◦ , and a single case of a spindle cell tumor without WHO grading, as well as 11 spinal interventions. The mean ApoC1 level of the 230 samples was 132.03 µg/mL (median 86.83, SD 292.91). In the 176 glioblastoma samples, the mean ApoC1 level was 130.0 µg/mL (median 86.23, SD 314.9), which was neither different from the whole group nor from patients with spinal interventions (215.1 µg/mL, median 63.6, SD 404.9). In the postoperative samples, the mean ApoC1 level was significantly lower (85.81 µg/mL) than in the preoperative samples (129.64 µg/mL) and in samples obtained during adjuvant chemotherapy (168.44 µg/mL). While absolute ApoC1 serum levels in a patient do not allow for the distinction between neurosurgical histological entities, future analyses will examine whether the time course of ApoC1 in an individual patient can be related to certain treatment stages.

Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p < 0.0001). Postoperatively, the FA values were more condensed around their mean (p < 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs.

Background Brain biopsy of intracranial lesions is often necessary to determine specific therapy. The cost of the currently used stereotactic rigid frame and optical tracking systems for brain biopsy in dogs is often prohibitive or accuracy is not sufficient for all types of lesion. Objectives To evaluate the application accuracy of an inexpensive magnetic resonance imaging-based personalized, 3D printed brain biopsy device. Animals Twenty-two dog heads from cadavers were separated into 2 groups according to body weight (<15 kg, >20 kg). Methods Experimental study. Two target points in each cadaver head were used (target point 1: caudate nucleus, target point 2: piriform lobe). Comparison between groups was performed using the independent Student's t test or the nonparametric Mann-Whitney U Test. Results The total median target point deviation was 0.83 mm (range 0.09-2.76 mm). The separate median target point deviations for target points 1 and 2 in all dogs were 0.57 mm (range: 0.09-1.25 mm) and 0.85 mm (range: 0.14-2.76 mm), respectively. Conclusion and Clinical Importance This magnetic resonance imaging-based 3D printed stereotactic brain biopsy device achieved an application accuracy that was better than the accuracy of most brain biopsy systems that are currently used in veterinary medicine. The device can be applied to every size and shape of skull and allows precise positioning of brain biopsy needles in dogs.

This thesis examines in detail the nature of postoperative infectious complications in patients who underwent brain tumor surgery. It deals with the incidence of these complications and their severity, depending on various factors and suggests the most appropriate nursing procedures used in the care of a patient in whom these complications occurred. For the structure of the work is divided into two parts - theoretical and empirical. The theoretical part deals with the issues examined in terms of the medical field Neurosurgery (closer diagnoses, conditions, operations and other procedures, and complications to occur after these operations or expected performance), analyzes a nursing practice and patient care on neurosurgical ICU, and finally closely examines infections and nosocomial diseases, including a description of the most common types, their agents, diagnosis and treatment. The second, empirical part focuses on the problems from a practical point of view. With the help of set of case studies it closer which specific complications are most commonly found on the neurosurgical ICU in patients after surgery of brain tumors, what are the most common methods of treatment and nursing procedures which are most used in the care of patients with these complications. In conclusion summarizes the...