Orientador: Daniela Cristina Cataneo / Banca: Karla Magnani / Banca: Suzani Tanni / Resumo: A colecistectomia por via laparoscópica é uma técnica minimamente invasiva que permite remover a vesícula biliar com redução do tempo cirúrgico e hospitalar, possibilitando o retorno precoce às atividades diárias. Porém, apesar de ser uma técnica minimamente invasiva, pode acarretar uma série de alterações pulmonares importantes. Analisar as alterações funcionais respiratórias em indivíduos submetidos à colecistectomia videolaparoscópica. Foram avaliados, pela equipe do Hospital Estadual Bauru, no período de abril de 2008 até maio de 2010, todos os pacientes com indicação cirúrgica. No período pré-operatório todos foram submetidos à anamnese, espirometria, medida do índice diafragmático, ventilometria, manovacuometria, pico de fluxo expiratório, teste de caminhada de 6 minutos e teste de escada. Todos os testes foram repetidos no primeiro, quinto e trigésimo pós-operatórios. Somente o teste de escada não foi repetido no primeiro pós-operatório. Foi avaliada em cada pós-operatório a escala analógica de dor, e a escala de Borg foi aplicada após os testes dinâmicos. Foram avaliados 50 pacientes, sendo 76% mulheres e 24% homens. A média da idade foi de 47,8±14,2 e do IMC foi de 28,8±4,8 kg/m2. A amostra foi composta por 68% de não tabagistas, 20% de tabagistas e 12% de ex-tabagistas. Não houve qualquer caso de complicação pós-operatória. O VEF1 e CVF apresentaram queda significativa no PO1, voltando aos valores pré somente no PO30, a VVM apresentou queda significativa no PO1, voltado aos valores pré no PO5 e o PFE foi significativamente menor no PO1, já estando normalizado no PO5. A PImáx e PEmáx apresentaram queda significativa no PO1 e continuou reduzido no PO5 retornando aos valores pré no PO30. O VE e o VC não apresentaram diferença estatística em qualquer momento estudado, somente a f aumentou no PO1. O ID1 e ID2 não apresentaram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Laparoscopic cholecystectomy is a minimally invasive technique that allows removal of the gallbladder with reduced surgical time and hospital stay, allowing an earlier return to daily activities, yet can cause a series of major pulmonary changes. The increasing of laparoscopic surgery for performing cholecystectomy has shown the need for evaluation of ventilatory changes resulting from the anesthesia, the pneumoperitoneum and visceral manipulation, plus the time of return to preoperative status. To evaluate changes in respiratory function in patients undergoing laparoscopic cholecystectomy. The team of Bauru State Hospital evaluated, from April 2008 until May 2010, all patients with surgical indication. In the preoperative period all underwent medical history, spirometry, peak expiratory flow, respirometry, manometry, measurement of diaphragmatic index, six minute walking test and stair-climbing test. All tests were repeated in the first, fifth and thirtieth postoperative days. The stair climbing test was not repeated in the first postoperative day. Pain analog scale was assessed at each postoperative, and the Borg scale was applied after the dynamic tests. Fifty patients were evaluated, 76% women and 24% men. The mean age was 47,8±14,2 and BMI was 28,8±4,8 kg/m2. The sample comprised 68% of nonsmokers, 20% were smokers and 12% former smokers. There was no case of postoperative complication. FEV1 and FVC showed a significant decrease in PO1, returning to PRE values in PO30, the MVV significant drop in PO1, returning to PRE values in PO5 and PEF were significantly lower in PO1, already being normal in PO5. MV and TV did not differ significantly at any time studied, only respiratory rate increased in PO1. The MIP and MEP showed a significant drop in the PO1 returning to baseline at PO5. The ID1 and ID2 did not differ at any time studied. The 6MWD was significantly lower than... (Complete abstract click electronic access below) / Mestre

Introdução: A energia elétrica e ultrasônica são utilizadas com freqüência na prostatectomia radical laparoscópica e podem lesar os nervos cavernosos adjacentes através da dissipação térmica. Em contrapartida, a energia laser tem potencial para proporcionar uma dissecção precisa, com boa hemostasia e pequena lesão dos tecidos adjacentes. Este estudo avalia o efeito do laser KTP na dissecção laparoscópica do feixe neuro-vascular cavernoso em modelo experimental canino. Material e Métodos: Um total de 36 cães foi dividido igualmente em três grupos. Realizou-se a dissecção unilateral do feixe neurovascular cavernoso utilizando (1) laser KTP (KTP), (2) bisturi ultrasônico (BU), e (3) tesoura e clipes metálicos (TC), mantendo o lado contralateral intacto. Realizou-se a análise do tempo operatório e sangramento em cada grupo, assim como a análise funcional, através do coeficiente entre a pressão intracavernosa e pressão arterial média (PIC/PAM) durante a estimulação do feixe neurovascular cavernoso. Metade dos animais de cada grupo foi mantida viva por 30 dias e submetidos à nova neuroestimulação. Foram avaliados ainda os efeitos da dissipação térmica através da análise termográfica em fragmentos de peritôneo parietal e a extensão histológica da necrose tecidual na fáscia prostática desde a superfície de corte de cada instrumento. Resultados: O tempo de dissecção do feixe neuro-vascular cavernoso foi similar entre os grupos (KTP vs. BU p=0.21, KTP vs. TC p=0.81, BU vs. TC p=0.22). A dissecção utilizando o BU resultou em um prejuízo significativo na resposta à neuroestimulação quando comparado aos grupos TC e KTP no experimento agudo (BU vs. KTP p<0.001, BU vs. TC p<0.001), e crônico (BU vs. KTP p=0.02, BU vs. TC p=0.02). A análise histológica demonstrou uma área de necrose desde a superfície de corte com a utilização do laser KTP de aproximadamente 500 um, enquanto que com o uso do BU essa área se extendeu em média por 2 mm. A avaliação termográfica mostrou uma dissipação térmica significativamente maior do BU comparado ao laser KTP (laser KTP 0.98 mm vs. BU 6.25 mm, p<0.0001). Conclusão: O uso do laser KTP na dissecção laparoscópica do feixe neuro-vascular cavernoso apresentou resultado funcional semelhante à técnica sem emprego de energia térmica utilizando tesoura e clipes, enquanto o bisturi ultrasônico foi associado a um prejuízo significativo na função dos nervos cavernosos. / Introduction: Electrical and ultrasonic energy used in nerve-sparing laparoscopic radical prostatectomy can compromise cavernous nerve function. Laser energy may potentially allow fine dissection with good hemostasis and minimal adjacent tissue injury. This study examines the electrophysiological, histological and thermal mapping features of KTP laser dissection on cavernous nerve function in the survival canine model. Materials and Methods: A total of 36 dogs were divided into 3 groups. Laparoscopic unilateral neurovascular bundle (NVB) mobilization was performed using either: (1) KTP laser (n=12), (2) ultrasonic shears (US) (n=12), or (3) athermally with cold scissors (AT) (n=12). The contralateral NVB remained undissected as an internal control. NVB function was assessed acutely in all dogs, and after 1-month survival in 50% of the dogs of each group. Peak intracavernosal pressure response to cavernous nerve stimulation was measured as a percentage of mean arterial pressure (ICP/MAP). Strips of peritoneum were sectioned ex-vivo with the KTP laser and US shears for thermographic mapping. Histological evaluation of prostatic fascia necrosis from the cutting surface was also performed. Results: Comparing KTP and AT groups, the erectile response to nerve stimulation was similar acutely and at 1 month (acute ICP/MAP: KTP 92%, AT 96% p=0.54; chronic ICP/MAP: KTP 95%, AT 98% p=0.71). In contrast, US dissection resulted in a significant decrease in the ICP response compared to the KTP and AT groups (acute ICP/MAP: US 49%, KTP 92%, AT 96%. US vs. KTP p<0.001, US vs. AT p<0.001; chronic ICP/MAP: US 58%, KTP 95%, AT 98%, US vs. KTP p=0.02, US vs. AT p=0.02). Mean NVB dissection times were similar (KTP 27.5min, US 19.9min, AT 26.6min, KTP vs. US p=0.21, KTP vs. AT p=0.81, US vs. AT p=0.22). Histopathology demonstrated an acute zone of laser-induced necrosis of approximately 500 um compared to 2 mm with US dissection. Thermographic assessment demonstrated significantly less collateral thermal spread from the KTP laser compared to US (mean thermal spread >60 oC KTP 0.98 mm vs. US 6.25 mm, p<0.0001). Conclusions: Use of KTP laser for NVB mobilization preserved cavernous nerve function comparable to standard athermal techniques using cold scissors and was superior to ultrasonic shears.

A laparoscopia é técnica cirúrgica minimamente invasiva na qual se utiliza um laparoscópio inserido por via transabdominal por onde é possível inspecionar visualmente a superfície das vísceras e do peritônio e realizar procedimentos cirúrgicos. Até o momento, a laparoscopia diagnóstica em equinos em estação através da fossa paralombar exige que sejam realizados dois procedimentos (um de cada lado do animal) para visualização significativa da cavidade peritoneal, além do uso de laparoscópio específico. Com o intuito de desenvolver a laparoscopia diagnóstica em equinos em estação por acesso único, foi desenvolvida uma cânula óptica com espiral sem trocarte de 60 cm de comprimento que tem o objetivo de promover maior segurança ao acesso laparoscópico (penetração radial sem trocarte e sob visualização) e sustentação ao endoscópio flexível para que seja possível realizar exploração significativa de ambos os hemisférios abdominais dorsais por apenas uma das fossas paralombares. Foram utilizados seis equinos adultos, sendo três machos e três fêmeas, submetidos a jejum alimentar de 24 a 30 horas. Amostras de sangue para realização de hemograma e dosagem de fibrinogênio foram obtidas no D-Pré, D4 e D7. Os equinos foram sedados com cloridrato de detomidina, seguido de bloqueio anestésico local com cloridrato de lidocaína infundida na musculatura e tecido subcutâneo do local de incisão no centro da fossa paralombar. O procedimento cirúrgico teve início com incisão cutânea de cerca de 2 cm de comprimento. As camadas musculares da região foram afastadas através da rotação da cânula em sentido horário e o afastamento dos tecidos foi acompanhado pelas imagens produzidas pelo endoscópio flexível e reproduzidas no monitor. Logo da perfuração do peritônio, foi iniciada a exploração da cavidade. Após a exploração do lado ipsilateral ao local de acesso, foi realizada a transposição do conjunto cânula/endoscópio ventralmente à porção caudal do cólon descendente seguida de exploração do lado contralateral. Terminado o exame, o conjunto foi removido através da rotação da cânula no sentido anti-horário e a incisão de pele foi suturada junto ao subcutâneo. A movimentação da cânula entre os órgãos abdominais mostrou-se segura, no entanto, em dois animais houve lesão iatrogênica ao baço, evidenciada por discreta hemorragia local. Foi possível a identificação da maioria das estruturas abdominais descritas na literatura por procedimento laparoscópico em equinos em estação pelo acesso único. Em cinco dos seis animais houve formação de enfisema subcutâneo adjacente às feridas cirúrgicas. Os parâmetros hematológicos dos animais mantiveram-se dentro dos limites estabelecidos para a espécie, com exceção dos leucócitos totais, neutrófilos segmentados e fibrinogênio que demonstraram pequenas variações. A abordagem proposta mostrou-se viável e tem o potencial de tornar o procedimento mais rápido, prático e seguro e menos invasivo e oneroso, fomentando a aplicação da laparoscopia diagnóstica na espécie equina. / Laparoscopy is a minimally invasive surgical technique by using a laparoscope inserted through the abdominal wall where it is visually possible to inspect visceral surfaces and peritoneum, and to perform surgical procedures. Up to now, diagnostic laparoscopy in standing horses through the paralumbar fossa requires two procedures to be performed (one on each side of the animal) in order to significantly see the peritoneal cavity, in addition of using specific laparoscope. With the purpose to develop a diagnostic laparoscopy in standing horses through a single access, a trocarless threaded visual cannula 60 cm length was designed with the aim to promote higher safety to laparoscopic access (radial penetration without trocar and under visualization), and support to a flexible endoscope so that a significant exploration of both dorsal abdominal hemispheres through only one of the paralumbar fossa is possible to perform. Six mature horses were used: three males and three females. Food was withheld for 24 to 30 hours before surgery. Blood samples to perform complete blood count and fibrinogen metering were obtained in D-Pre, D4, and D7. The horses were sedated with detomidine hydrochloride, followed by local anesthesia blockade with lidocaine hydrochloride infused in the muscle and subcutaneous tissue at the incision place in the center of the paralumbar fossa. The surgical procedure started with a skin incision of nearly 2 cm length. Muscle layers of the region were moved away through clockwise cannula rotation and the distancing of the tissues were followed by images produced by the flexible endoscope and played on the monitor. After the peritoneum perforation, the cavity exploration was started. After the ipsilateral side exploration to the access site, the transposing of the set cannula/endoscope was performed ventrally to the rear portion of the descending colon followed by the contralateral side exploration. When the examination was finished, the set was removed through counterclockwise cannula rotation and the skin incision was stitched to the subcutaneous. Moving the cannula among the abdominal organs was shown to be safe; however, spleen iatrogenic injury in two animals was highlighted by minor local hemorrhage. The majority of the abdominal structures described in the literature was possible to identify through the laparoscopic procedure in standing horses by single access. There was subcutaneous emphysema formation adjoining the surgical wounds in five of the six animals. The hematological parameters of the animals were kept in the limits established for the species, with exception of total leucocytes, segmented neutrophils and fibrinogen which showed small variations. The proposed approach was shown to be feasible and has the potential to make the procedure faster, more practical and safe and less invasive and expensive, fostering the diagnostic laparoscopy application in the equine species.

Introdução: A curva de aprendizado em prostatectomia radical laparoscópica (PRL) pode variar de 10 a 150 procedimentos. Nesta fase, observa-se o maior número de complicações perioperatórias e conversões, além de resultados oncológicos e funcionais precários. Neste estudo, foram comparadas duas séries iniciais de PRL, realizadas pelos acessos transperitoneal (PRLT) e extraperitoneal (PRLE). Objetivos: Comparar os resultados obtidos com a realização da PRL pelos acessos transperitoneal e extraperitoneal durante a curva de aprendizado, avaliando-se os resultados perioperatórios, oncológicos e funcionais. Pacientes e métodos: Procedeuse a uma análise comparativa retrospectiva entre os dados das primeiras 40 PRLT realizadas no Hospital Getúlio Vargas de Pernambuco (grupo 1) e os dados das primeiras 40 PRLE realizadas no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (grupo 2). Resultados: Comparando-se as variáveis trans-operatórias dos grupos 1 e 2, observamos diferenças estatísticas na preservação dos feixes vásculonervosos (77,5% vs 90%; p=0,008), tempo cirúrgico total (175,0 min vs 267,6 min;p<0,001) e da perda sanguínea estimada (177,5 ml vs 292,4 ml; p<0,001). Duas complicações (5%) foram observadas no grupo 1 (sangramento e lesão retal) e quatro (10%) ocorreram no grupo 2 (sangramento-2, lesão retal e de bexiga). Conversão para procedimento aberto foi necessária em um caso em cada grupo (2,5%). No período pósoperatório, as principais diferenças estatisticamente significantes entre os grupos 1 e 2 foram observadas nas comparações do tempo de internamento, do tempo de uso de catéter uretral, no uso de opióides, na recorrência bioquímica, na taxa de continência urinária e no tempo médio de seguimento. Nenhuma diferença estatística foi observada na incidência de complicações precoces (17,5% vs 17,5%; p= 1,000), porém três complicações maiores foram observadas no grupo 1, levando ao óbito de um paciente neste grupo. Dentre as complicações pós-operatórias tardias, observou-se uma diferença estatística quando se comparou a taxa de complicações menores entre os grupos 1 e 2 (30% vs 15%; p=0,004). Na comparação dos resultados oncológicos entre os grupos 1 e 2, observou-se diferença estatística no número total de margens cirúrgicas positivas (MCP) (10,3% vs 32,5%; p=0,016) e no estadiamento patológico (pT2: 94,8% vs 70% e pT3: 5,2% vs 30%; p=0,005). Correlacionando-se o achado de MCP e estadiamento patológico, observou-se que a maioria das MCP no grupo 1 ocorreu no estadio pT2 (75%), ao passo que 77% das MCP no grupo 2 ocorreu no estadio pT3. Conclusões: O acesso transperitoneal mostrou-se mais eficiente que o acesso extraperitoneal para a realização da prostatectomia radical laparoscópica durante a curva de aprendizado, porém enfatizando que a taxa de complicações graves foi maior quando este acesso foi utilizado. / Introduction: The learning curve in laparoscopic radical prostatectomy (LRP) can vary from 10 to 150 procedures. This procedure can be done using the transperitoneal or the extraperitoneal approach. So far, there is no consensus about the best way to perform LRP, mainly during the initial phases of the LRP programs. Objectives: To analyze and compare the perioperative, oncological and functional results obtained with both approaches while performing LRP during the learning curve. Patients and Methods: Data of the first 40 transperitoneal LRP (Group 1) performed at Getúlio Vargas Hospital of Recife were compared with the first 40 extraperitoneal LRP (Group 2) performed at Clinics Hospital of State University of São Paulo. Results: On transoperative time, statistically significant difference were observed comparing groups 1 and 2 related to the preservation of the neurovascular bundles (77,5% x 90%; p=0,008), overall surgical time (175 min x 267,6 min; p<0,001) and estimated blood loss (177,5 ml x 292,4 ml; p<0,001). Two complications (5%) were observed in group 1 (bleeding and rectal injury), whereas four (10%) were seen in group 2 (bleeding- 5%, rectal and bladder injury). Open conversion occurred in one case (2,5%) in both groups. On postoperative time, statistical difference comparing the groups 1 and 2 were seen in the in-hospital time, indwelling catheter time, narcotic use, biochemical recurrence and mean follow-up time. No statistical difference was observed related to the incidence of early complications (17,5% vs 17,5%; p= 1,000), but three major complications occurred in group 1, leading to one death in this group. On late postoperative time, a statistical difference was observed in the incidence of minor complications (30% vs 15%; p=0,004). Comparing the oncological results between groups 1 and 2, statistical difference was observed in the incidence of positive surgical margins (10,3% vs 32,5%; p=0,016) and pathological stages (pT2: 94,8% vs 70% and pT3: 5,2% vs 30%; p=0,005). The majority of positive margins in group 1 occurred in pT2 (75%), while this observation was more prevalent in pT3 (77%) in group 2. Conclusions: The transperitoneal approach was more efficient than the extraperitoneal approach for performing laparoscopic radical prostatectomy during the learning curve, but major complications were commoner when this approach was adopted.

Bibliography: leaves 197-220. / xv, 220 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Analyses some general problems of laparoscopy, particularly in relation to induced physiological disturbances; by development and evaluation of new applications in laparoscopic gastrointestinal surgery ; and by assessing the efficacy of laparoscopic procedures which have already entered rountine practice. / Thesis (M.D.)--University of Adelaide, Dept. of Surgery, 1996?

Various techniques are used to transect the liver. With increase in laparoscopic liver resections (LLR), it is of even more interest to develop surgical techniques to minimize bleeding and the risk for gas embolism during transection. Instrument like argon enhanced coagulator provides good hemostasis but increases the danger of gas embolism. The CO2 pneumoperitoneum that is routinely used in most types of laparoscopic surgery can be modified by the use of different gas pressure. It can be assumed that different pressure influences bleeding but also the risk for gas embolism. In presented porcine studies, three instrumental combinations have been studied. In study I sixteen piglets were randomized to LLR with either the cavitron ultrasonic aspirator (CUSA™) in combination with vessels sealing system (Ligasure™) or with CUSA™ and ultrascision scissors (Autosonix™), with the endpoints of intra-operative bleeding and gas embolism.  In study IV sixteen piglets were randomized to LLR either with staple device (Endo-GIA™) or the Ligasure™ - CUSA™ combination with same primary endpoints and additionally secondary endpoints of effect on gas-exchange, systemic- and pulmonary hemodynamic. Focusing on intra-abdominal pressure (IAP) in study II, sixteen piglets were randomized to LLR with an IAP of either 8 or 16 mmHg.  Primary endpoints were bleeding and gas embolism and secondary endpoints, effect on gas-exchange, systemic- and pulmonary hemodynamic. In study III effect of argon gas was tested during LLR. Sixteen piglets were randomized to either argon pneumoperitoneum or CO2 pneumoperitoneum. Primary endpoints were effect on gas-exchange, systemic- and pulmonary hemodynamic. In presented studies, we tested efficacy and safety of different techniques for LLR. CUSA™ can be used in combination with either Ligasure™ or Autosonix™. However, Ligasure™ reduces the amount of bleeding. The recent introduction of staplers seems promising with a further reduction in bleeding, gas embolism, and operating time. The IAP influences both the amount of bleeding as well as gas embolism. It seems reasonable to use a higher IAP to decrease bleeding with caution and with close monitoring for gas embolism. Argon gas embolism gives more extensive effect on gas-exchange and hemodynamic and should probably be avoided in this type of surgery.

Background and aims: Laparoscopic technique was quickly adopted in general surgery because of less pain, quicker recovery and shorter hospital stay. In the 1990´s several reports on port site metastases restrained the enthusiasm to use laparoscopic surgery in malignant diseases. The numerous reports on port site metastases initiated a debate whether laparoscopic surgery would increase the risk of tumour spread and growth. Personal experience of two patients who devloped port site metastases from an incidental gall bladder cancer (GBC) after laparoscopic cholecystectomy (LC), encouraged us to study the incidence of wound metastases from GBC after laparoscopic and open cholecystectomy (OC). Experimentally we examined whether pneumoperitoneum would increase the risk of tumour development. Several studies had demonstrated that minimally invasive procedures exert a less negative influence on the immune system and may have beneficial effects for cancer patients. We wanted to compare the long term survival after OC and LC and if the occurence of port site metastases had any impact on survival. Material and methods: A questionnaire was sent out to all major hospitals in Sweden requesting information obout the number of port site metastases encountered 1991-94. Data on all pateints with verfied GBC were obtained from the Swedish Oncological Centres. Data on all patients with GBC registered with surgical codes for cholecystectomy were collected from the National Board of Health and Welfare (EpC). The patient files were scrutinized and long term survival data was achieved (EpC). In the first experiment on Wistar Fu rats, adenocarcinoma cells were injected intraperitoneally in animals insufflated with air, CO2 and not insufflated controls. In the following studies, rats were similarly insufflated with air,CO2 and compared to not insufflated controls. Laser Doppler blood flow in the abdominal wall was concomitantly measured. To study the effect of reduced blood flow, one rectus muscle was clamped and the other not and laser Doppler Blood flow was measured in both rectus muscles. Adenocarcinoma cells were injected into the rectus muscles in all animals at the induction of pneumoperitoneum/clamping. Results: 14 of 55 patients developed wound metastases from GBC after LC and 12 of 187 after OC. Gallbladder perforation was overrepresented in patients with wound metastases. Improved survival was noted after LC in patients with T3 tumours. Experimentally, air and CO2 equally increased intraperitoneal tumour development, Insufflation with air,CO2 and clamping decreased blood flow in the abdominal wall and increased tumour growth at the same site. Conclusion: Despite a high rate of wound metastases, LC does not seem to worsen the prognosis of GBC and may even have a positive effect on survival. Perforation of the malignant gallbladder seems to be associated with an increased risk of metastatic formation. In the experimental setting, pneumoperitoneum seems to increase tumour development. Other features of laparoscopic surgery such as decreased blood flow in the abdominal wall may contribute to increased risk of tumour progress.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 234-239).

Confocal microendoscopy provides real-time high resolution cellular level images via a minimally invasive procedure. Results from an ongoing clinical study to detect ovarian cancer with a novel confocal fluorescent microendoscope are presented. As an imaging modality, confocal fluorescence microendoscopy typically requires exogenous fluorophores, has a relatively limited penetration depth (100μm), and often employs specialized aperture configurations to achieve real-time imaging in vivo. Two primary research directions designed to overcome these limitations and improve diagnostic capability are presented. Ideal confocal imaging performance is obtained with a scanning point illumination and confocal aperture, but this approach is often unsuitable for real-time, in vivo biomedical imaging. By scanning a slit aperture in one direction, image acquisition speeds are greatly increased, but at the cost of a reduction in image quality. The design, implementation, and experimental verification of a custom multi-point-scanning modification to a slit-scanning multi-spectral confocal microendoscope is presented. This new design improves the axial resolution while maintaining real-time imaging rates. In addition, the multi-point aperture geometry greatly reduces the effects of tissue scatter on imaging performance. Optical coherence tomography (OCT) has seen wide acceptance and FDA approval as a technique for ophthalmic retinal imaging, and has been adapted for endoscopic use. As a minimally invasive imaging technique, it provides morphological characteristics of tissues at a cellular level without requiring the use of exogenous fluorophores. OCT is capable of imaging deeper into biological tissue (~1-2 mm) than confocal fluorescence microscopy. A theoretical analysis of the use of a fiber-bundle in spectral-domain OCT systems is presented. The fiber-bundle enables a flexible endoscopic design and provides fast, parallelized acquisition of the optical coherence tomography data. However, the multi-mode characteristic of the fibers in the fiber-bundle affects the depth sensitivity of the imaging system. A description of light interference in a multi-mode fiber is presented along with numerical simulations and experimental studies to illustrate the theoretical analysis.

Gastric bypass achieves weight loss in the morbidly obese. Preoperative weight loss is used to reduce the enlarged fatty liver that otherwise reduces visibility during surgery. The purpose of gastric bypass is to provide patients with long-term weight loss. The aim of this thesis was to investigate the result of preoperative low calorie diet on liver volume and to evaluate the long-term result of gastric bypass. Paper I showed that four weeks of low calorie diet reduces intrahepatic fat by 40% and facilitates surgery mainly through improved visualisation. Paper II demonstrated that all of the reduction of liver volume occurs during the first two weeks of treatment with low calorie diet.  In paper I liver volume was reduced by 12% and in paper II by 18%. Paper III focused on long-term results and showed that gastric bypass achieves a mean 63% excess body mass index loss in obese patients after 11 years. However, of these 40% undergo abdominoplasty and 2% require additional bariatric surgery. Only 24% adhere to the lifelong recommendation on multivitamins and 72% to Vitamin B12 recommendations. Paper IV evaluated gastric bypass as a revisional procedure after earlier restrictive surgery had failed. Similar weight results as after primary gastric bypass are attained. No patient taking vitamin B12 supplementation was deficient at follow-up, regardless of whether the vitamin was taken as a pill or as intramuscular injections.