Minimally invasive CT-guiding excision of benign bone tumours

Background: The management of osteoid osteoma (OO) and other small primary benign lesions of bone has evolved over the past 50 years from open surgery with wide resection margins to less invasive surgical techniques such as image guided intralesional excision and percutaneous radiofrequency ablation. We aim to evaluate the outcomes of patients treated with computerised tomography (CT guided) intralesional excision and bone grafting of small benign lesions of bone. Method: A retrospective folder review of patients treated in a large academic hospital in Cape Town, South Africa, between March 2012 and May 2016 was performed. Patient demographics, details of presentation, clinical information and outcome following treatment were analysed descriptively. Pre-operative diagnosis based on radiological examination was compared with histological diagnosis. Result: Eleven patients (5 male) with a median age of 16 years (range 5-33) were included. Pain was the most common presenting feature. A histological diagnosis of OO was confirmed in 5 of 9 patients with a suspected diagnosis of OO preoperatively. Of the 4 patients whose diagnosis changed after the procedure the diagnoses included a benign spindle cell lesion, a benign fibrous histiocytoma, subacute osteitis and an osteochondral defect with geode cyst formation. Of the 2 patients where OO was not suspected preoperatively, chondroblastoma was confirmed in one while a benign spindle cell lesion was reported in the other. Overall histological yield was thus 100%. There were no complications or repeat procedures at a median follow up of 42 months (range 30-52 months). Conclusion: CT guided intralesional curettage is a safe and minimally invasive technique. This is especially useful in less accessible regions of the skeleton as it provides a means of accurately locating the lesion with minimal risk of complications and morbidity to the patient. We consider this to be the optimal method of treatment in our setting as it provides high success rates, few complications and a histological diagnosis without the need for any additional and expensive equipment

Development of an image guidance system for laparoscopic liver surgery and evaluation of optical and computer vision techniques for the assessment of liver tissue

Introduction: Liver resection is increasingly being carried out via the laparoscopic approach (keyhole surgery) because there is mounting evidence that it benefits patients by reducing pain and length of hospitalisation. There are however ongoing concerns about oncological radicality (i.e. ability to completely remove cancer) and an inability to control massive haemorrhage. These issues can partially be attributed to a loss of sensation such as depth perception, tactile feedback and a reduced field of view. Utilisation of optical imaging and computer vision may be able to compensate for some of the lost sensory input because these modalities can facilitate visualisation of liver tissue and structural anatomy. Their use in laparoscopy is attractive because it is easy to adapt or integrate with existing technology. The aim of this thesis is to explore to what extent this technology can aid in the detection of normal and abnormal liver tissue and structures. / Methods: The current state of the art for optical imaging and computer vision in laparoscopic liver surgery is assessed in a systematic review. Evaluation of confocal laser endomicroscopy is carried out on a murine and porcine model of liver disease. Multispectral near infrared imaging is evaluated on ex-vivo liver specimen. Video magnification is assessed on a mechanical flow phantom and a porcine model of liver disease. The latter model was also employed to develop a computer vision based image guidance system for laparoscopic liver surgery. This image guidance system is further evaluated in a clinical feasibility study. Where appropriate, experimental findings are substantiated with statistical analysis. / Results: Use of confocal laser endomicroscopy enabled discrimination between cancer and normal liver tissue with a sub-millimetre precision. This technology also made it possible to verify the adequacy of thermal liver ablation. Multispectral imaging, at specific wavelengths was shown to have the potential to highlight the presence of colorectal and hepatocellular cancer. An image reprocessing algorithm is proposed to simplify visual interpretation of the resulting images. It is shown that video magnification can determine the presence of pulsatile motion but that it cannot reliably determine the extent of motion. Development and performance metrics of an image guidance system for laparoscopic liver surgery are outlined. The system was found to improve intraoperative orientation more development work is however required to enable reliable prediction of oncological margins. / Discussion: The results in this thesis indicate that confocal laser endomicroscopy and image guidance systems have reached a development stage where their intraoperative use may benefit surgeons by visualising features of liver anatomy and tissue characteristics. Video magnification and multispectral imaging require more development and suggestions are made to direct this work. It is also highlighted that it is crucial to standardise assessment methods for these technologies which will allow a more direct comparison between the outcomes of different groups. Limited imaging depth is a major restriction of these technologies but this may be overcome by combining them with preoperatively obtained imaging data. Just like laparoscopy, optical imaging and computer vision use functions of light, a shared characteristic that makes their combined use complementary

Recent Advances in Locoregional Therapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is responsible for 90% of primary hepatic cancer cases, and its incidence with associated morbidity and mortality is growing worldwide. In recent decades, there has been a revolution in HCC treatment. There are three main types of locoregional therapy: radiofrequency ablation, transarterial chemoembolisation, and transarterial radioembolisation. This article summarises recent advances in locoregional methods

Cryoablation for Small Renal Masses

Advances in imaging techniques (CT and MRI) and widespread use of imaging especially ultrasound scanning have resulted in a dramatic increase in the detection of small renal masses. While open partial nephrectomy is still the reference standard for the management of these small renal masses, its associated morbidity has encouraged clinicians to exploit the advancements in minimally invasive ablative techniques. The last decade has seen the rapid development of laparoscopic partial nephrectomy and novel ablative techniques such as, radiofrequency ablation (RFA), high-intensity focused ultrasound (HIFU), and cryoablation (CA). In particular, CA for small renal masses has gained popularity as it combines nephron-sparing surgery with a minimally invasive approach. Studies with up to 5-year followup have shown an overall and cancer-specific 5-year survival of 82% and 100%, respectively. This manuscript will focus on the principles and clinical applications of cryoablation of small renal masses, with detailed review of relevant literature

An Augmented Reality Platform for Preoperative Surgical Planning

Researching in new technologies for diagnosis, planning and medical treatment have allowed the development of computer tools that provide new ways of representing data obtained from patient's medical images such as computed tomography (CT) and magnetic resonance imaging (MRI). In this sense, augmented reality (AR) technologies provide a new form of data representation by combining the common analysis using images and the ability to superimpose virtual 3D representations of the organs of the human body in the real environment. In this paper the development of a generic computer platform based on augmented reality technology for surgical preoperative planning is presented. In particular, the surgeon can navigate in the 3D models of the patient's organs in order to have the possibility to perfectly understand the anatomy and plan in the best way the surgical procedure. In addition, a touchless interaction with the virtual organs is available thanks to the use of an armband provided of electromiographic muscle sensors. To validate the system, we focused in a navigation through aorta artery for mitral valve repair surgery

Modelling and Analysis of a new Integrated Radiofrequency Ablation and Division Device

Master'sMASTER OF ENGINEERIN

Trans-arterial hepatic radioembolisation of yttrium-90 microspheres

The liver represents a frequent site for metastatic disease, in addition to being a site for primary cancer. Hepatic metastases from certain neoplasms, such as colon, neuroendocrine, melanoma and gastrointestinal stromal tumour have a distinct predilection to metastasize the liver, which in many cases may represent the only or the dominant site of disease. In these circumstances, cytoreduction via surgery or in situ ablative techniques aims to influence the natural history of the disease progression and improve clinical outcomes

The endoscopist and malignant and non-malignant biliary obstruction

Patients with biliary strictures often represent a diagnostic and therapeutic challenge, due to the site and complexity of biliary obstruction and wide differential diagnosis. Multidisciplinary decision making is required to reach an accurate and timely diagnosis and to plan optimal care. Developments in endoscopic ultrasound and peroral cholangioscopy have advanced the diagnostic yield of biliary endoscopy, and novel optical imaging techniques are emerging. Endoscopic approaches to biliary drainage are preferred in most scenarios, and recent advances in therapeutic endoscopic ultrasound allow drainage where the previous alternatives were only percutaneous or surgical. Here we review recent advances in endoscopic practice for the diagnosis and management of biliary strictures. This article is part of a Special Issue entitled: Cholangiocytes in Health and Diseaseedited by Jesus Banales, Marco Marzioni and Peter Jansen

Computer modelling and simulation of radiofrequency ablation of bone tumors

Radiofrequency ablation (RFA) is a minimally invasive technique used for the treatment of many types of tumors, with a growing interest in the treatment of bone tumors. It uses radio waves to heat up the tissues surrounding a needle-like applicator to destroy the target tumor by exposing the surrounding tissues to high temperatures for a long enough time. However, the technique has been used mostly to treat tumors in other organs, and although it is safe and effective, with little data regarding how much damage it causes in bone tumors, it makes prospective planning challenging. Tumors must be completely destroyed to avoid recurrence but damage to healthy tissues must be minimized. The generation of heat and heat transfer can be modeled mathematically. With this, it was possible to create computer models to simulate the procedure. By looking at retrospective data from patients treated for RFA of bone tumors, the extensions of damage were measured, and the length of the procedure and other parameters were also captured. With these data, it was possible to fit the models to find the optimal parameters to predict the outcomes. Finally, complex 3D computational patient-specific models were created from medical images, and it was possible to replicate the clinical outcomes. This thesis thus showed that computational models could be used to predict the extension of thermal damage, allowing interventional radiologist to plan prospectively with greater accuracy, allowing safer and more effective interventions