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No description available.

No description available.

During the last decade, an increasing number of advanced platforms for robotic assisted Minimally Invasive Surgery (MIS) have been translated from research concepts to practical systems used in routine clinical settings. Such systems have defined their own niche in the market place and are gaining increasing acceptance by the surgical community. More importantly, they improve surgeons' dexterity and intra-operative visualisation together with the benefits of improved procedural time, safety, consistency and patient outcome. Some of the new technical features integrated within current robotic systems include higher degrees of freedom for more agile manoeuvring, tremor filtering and haptic feedback. Where the next frontier lies in terms of novel means of surgical assistance is in navigation systems that would enable intra-operative surgical guidance, imposing dynamic active constraints and high fidelity augmented reality environments. At the foundation of all navigation systems lies an accurate 3D reconstruction algorithm. To overcome the current limitations of feature-based matching and reconstruction systems, this thesis investigates a method to integrate depth information from conventional stereo 3D reconstruction with photometric cues from Shape-from-Shading techniques. This is further enhanced with a gaze-contingent framework suitable for intra-operative navigation during MIS. The resulting system is suitable for applications with existing MIS platforms without the need of additional hardware, ensuring increased accuracy in areas without salient anatomical landmarks or artificially introduced fiducials. Furthermore, a multi-scale feature detector is proposed for intra-operative stereo telestration required for telementoring and remote collaboration of robotic assisted MIS. An improved formulation of the current state-of-the-art in Shape-from-Shading is integrated with intra-operative scenes for accurate metric depth recovery. The potential clinical application of the technique is demonstrated for autonomous navigation of wireless capsule endoscopes. Future research directions and preliminary results of integrating photometric stereo constraints for reliable reconstruction of featureless, non- Lambertian deforming tissue surfaces are provided and all methods proposed have been validated with either in vivo or phantom experiments to justify their potential clinical values in MIS.

The provision of enteral feeding continues to increase with approximately 20,000 people in the United Kingdom feeding at home. Health care professionals have an ethical duty to recognise and treat malnutrition, though in clinical practice they are often faced with difficult decisions to ensure that the benefits of tube feeding are greater than the burdens; that the provision of a tube feed is in the patient's best interests. The aim of this study was to evaluate how the provision of enteral nutrition via a Percutaneous Endoscopic Gastrostomy (PEG) impacts on the Quality of Life (QoL) of patients from the patients' and carers' perspectives. Initially, QoL was measured using the SF36 Health questionnaire. A longitudinal, prospective pilot study was undertaken including clinical and QoL assessments prior to PEG placement, and at one week, one month, three months and six months following PEG insertion. The results of the pilot study of 22 patients clearly demonstrated that the SF-36 was not an appropriate tool for measuring QoL in this patient group. A semi-structured interview approach was developed to determine the concerns relating to PEG feeding and how feeding impacted on QoL. Health care professionals' views were also sought using a postal questionnaire and the results compared to those of patients and carers. These data informed the development of a preliminary QoL assessment tool which involved item generation, item reduction, response scale generation and pre-testing for acceptability and feasibility. Sixteen adult patients, 27 carers of adults and 24 carers of children were interviewed. In general, patients living in their own home viewed their QoL as acceptable. However, the carers of adult patients were less positive about the patients QoL. In contrast, the carers of children frequently reported their child's QoL to be acceptable. The reported impact of feeding on daily and social lives ranged from the PEG feeding being totally disruptive to the PEG having no impact at all. Delayed and disturbed sleep, restricted ability to go out, difficulties finding a place outside the home to feed, childcare problems, the negative attitudes of others towards feeding and family divisions emerged as key issues and concerns. A wide range of feelings towards the PEG feeding including feelings of anger, gratitude, relief and fear were expressed. Healthcare professionals, carers and patients disagreed on key issues of patient and carer involvement in the decision making process, the quantity of information provided prior to PEG placement, appropriateness of patient selection for the procedure and acceptability of QoL. The delivery of patient centred care must be based on appropriate patient selection, decisionmaking, setting of treatment goals for PEG feeding and the evaluation of the impact of treatment. Current generic QoL measures are highly likely to be inappropriate to measure the impact of feeding upon QoL and a validated PEG specific QoL tool is required to measure the impact of PEG feeding upon QoL. A research proposal has been developed to fully validate the tool for use in clinical practice. The impact of PEG feeding on QoL was variable. Although it is recognised that the results are not generalisable to wider populations, the results support increased patient and carer involvement in the decision-making process, more appropriate information, timely explanations of the procedure and flexible care in the community to meet patients' needs.

Le développement récent de l’endoscopie interventionnelle digestive nous a conduit à prendre en charge deux types de pathologies préoccupantes. Il s’agit d’une part des fistules digestives souvent responsables d’une morbi-mortalité élevée et d’autre part des sténoses œsophagiennes après résection tumorale endoscopique étendue. Dans ces deux situations, des phénomènes inflammatoires chroniques conduisent soit à l’absence de fermeture de la fistule soit à une fibrose importante responsable de sténose de l’œsophage. La thérapie cellulaire a déjà été utilisée pour diminuer ces phénomènes inflammatoires et entrainer une cicatrisation. La thérapie tissulaire par cellules souches organisées en construction 3D représente un avantage important en permettant de cibler le site d’action par dépôt direct du feuillet cellularisé. Notre objectif était d’évaluer l’effet thérapeutique de ces nouveaux outils pour fermer les fistules digestives et pour prévenir la survenue des sténoses œsophagiennes. La première étape a consisté a évaluer l’efficacité du traitement par des cellules souches mésenchymateuses provenant de moelle osseuse humaine, marquées puis organisées en doubles feuillets, dans un modèle de fistule entéro-cutanée post-chirurgicale chez la souris nude. L’évaluation clinique et en imagerie (IRM et microscopie confocale) a montré une meilleure cicatrisation avec une augmentation de la microvascularisation et une accélération de la fermeture de la fistule chez les souris greffées. Les effets observés semblent liés à une augmentation précoce de la synthèse des facteurs de réparation (EGF et le VEGF) et des cytokines anti-inflammatoires (TGF-ß2 et IL-10). Après avoir développé un modèle inédit de fistule oeso-cutanée chez le porc grâce à la mise en place par voie endoscopique et chirurgicale de prothèses plastiques entre la lumière œsophagienne et la peau, nous avons évalué l’efficacité thérapeutique d’un gel contenant des vésicules extracellulaires issues de cellules souches isolées du tissu adipeux de porc. Ce gel injecté dans la fistule par voie endoscopique a permis la fermeture des fistules. Enfin, la troisième partie de notre travail a consisté à évaluer l’efficacité de la greffe allogénique de doubles feuillets de cellules souches mésenchymateuses pour prévenir la survenue des sténoses œsophagiennes dans un modèle porcin après dissection sous muqueuse étendue. Il existait une réduction significative du taux de sténose œsophagienne cicatricielle dans le groupe greffé avec une fibrose moins importante. En conclusion, l’effet paracrine antifibrosant des cellules souches mésenchymateuses organisées en feuillets est efficace à la fois pour fermer les fistules entéro-cutanées chez la souris et pour prévenir les sténoses œsophagiennes chez le porc. Un gel avec des vésicules extracellulaires issues des cellules souches a de la même façon un effet cicatrisant anti-inflammatoire permettant la fermeture des fistules œsophagiennes chez le porc. Ces résultats sont très encourageants et posent la question d’une évaluation future chez l’homme. / Recent developments in digestive interventional endoscopy lead us to manage two types of digestive disease. First, it is digestive fistulas associated in many cases with high morbi-mortality; and second is oesophageal stenosis after extended superficial endoscopic resection. In both situations, chronic inflammatory process resulted in delayed or no fistula healing for the first case or oesophageal stenosis due to fibrosis. Cellular therapy has proved to be successful in reducing the inflammatory process and to promote tissue healing. Tissue therapy with 3D construct stem cells represents a major advantage by allowing a direct adaptation on the right place. Our objective was to evaluate the therapeutic effect of new strategy to close the digestive fistula and to prevent oesophageal stenosis. First step was to evaluate the effect of labelled human bone marrow derived mesenchymal stem cells engraftment in the form of double cellsheet in a post-surgical fistula model in nude mice. Clinical and radiological (MRI and probe based confocal microscopy) evaluation showed a better fistula healing with higher microvascularization and a faster fistula closing in grafted mice. These effects appear to be related to an increase production of factors involved in tissue repair (EGF et le VEGF) and anti-inflammatory cytokines (TGF-ß2 et IL-10). We developed an unpublished eso-cutaneous fistula in a porcine model after plastic catheters placement by surgical and endoscopic way between the oesophageal lumen and the skin. We evaluated the therapeutic effect of a hydrogel with extracellular vesicles extracted from porcine adipose derived stem cells. The hydrogel with vesicles was injected into the fistula by endoscopy. Radiological and histological evaluation 15 days after injection showed a fistula tract closure in treated group.The third part of this work was to evaluate the effect of allograft of adipose derived stem cells 3D construct to prevent the stenosis after extended endoscopic submucosal dissection in a porcine model. There was a significant reduction of number and degree of stenosis with decrease fibrosis infiltration in the grafted group.In summary, thanks to their paracrine and antifibrotic effect, the mesenchymal stem cells organised as 3D construct allowed fistula closure in an entero-cutaneous model in mice and prevention of stenosis after extended oesophageal submucosal dissection in a porcine model. Moreover, endoscopic hydrogel and extracellular vesicles injection allowed oesophageal fistula healing in a porcine model. These promising results pose the challenge of future clinical studies.