Background: Diet may play an important role in the management of patients with short bowel syndrome who have colon in continuity. However, macronutrient absorption has not been well characterized, and the most appropriate dietary constituents have not been well defined. Objective: To define carbohydrate absorption characteristics in patients with short bowel syndrome and determine the potential role of pectin as a dietary substrate. Methods: The authors studied the effect of a custom pectin-based supplement in 6 subjects (3 male/3 female) aged 29-67 years with jejunocolonic anastomosis, 4 of whom required long-term parental nutrition. Small intestinal absorption capacity, macronutrient and fluid balance, gastrointestinal transit time, and energy consumption were measured. Results: Data showed that 53% nitrogen, 50% fat, and 32% total energy were malabsorbed. In contrast, the majority (92%) of total carbohydrate was utilized. Fecal short-chain fatty acids (SCFAs) were increased, an indication of increased fermentation. Although only 4% of starch was recovered in stool, it is indicative of considerable starch malabsorption, thus providing the main carbohydrate substrate, for colonic bacterial fermentation. In contrast, non-starch polysaccharide was a relatively minor fermentation substrate with only 49% utilized. Eighty percent of the pectin was fermented. Supplementation was associated with increased total SCFAs, acetate, and propionate excretion. There was a trend observed toward greater fluid absorption (-5.9% ± 25.2%) following pectin supplementation. Nonsignificant increases in gastric emptying time and orocolonic transit time were observed. Conclusion : Despite malabsorption, starch is the primary carbohydrate substrate for colonic bacterial fermentation in patients with short bowel syndrome, although soluble fiber intake also enhances colonic SCFA production.

Background: Recent national trends and distribution of ileal pouch-anal anastomosis (IPAA) procedures for patients with ulcerative colitis (UC) are unknown. We examined the frequency of use of elective IPAA procedures among patients with UC and the distribution of IPAA procedures across more than 140 U.S. academic medical centers and their affiliates. Methods: Data were obtained from the University HealthSystem Consortium for patients with a primary diagnosis of UC admitted electively between 2012 and 2015. Results: The mean age of the study population (n=6,875) was 43 years and 57% were men. Among these, one-third (n=2,307) underwent an IPAA, while two-thirds (n=4,568) underwent colectomy, proctectomy, proctocolectomy or other procedures. The proportion of IPAA cases among all elective admissions was relatively stable at 33-35% during the years under study. A total of 131 hospitals, out of 279 hospitals participating in the UHC, performed IPAA. The median number of IPAA cases performed annually was 1.9 [IQR 0.8 – 4.3]. Nearly one half (48%) of these cases were performed by the top ten hospitals. Overall, only a total of 30 centers performed ³ five elective IPAA cases annually. Conclusions: Although the frequency of elective IPAA surgery in recent years has been stable, nearly one half of all IPAA cases was performed at ten hospitals. The concentration of IPAA cases at high-volume centers, and the steady number of cases performed annually, have potential implications for fellowship training, patient clinical outcomes and access to care.

Aim: Complex arterial reconstruction in kidney transplantation (KT) using kidneys from deceased donors (DD) warrants additional study since little is known about the effects on the mid- and long-term outcome and graft survival. Methods: A total of 451 patients receiving deceased donor KT in our department between 1993 and 2017 were included in our study. Patients were divided into three groups according to the number of arteries and anastomosis: (A) 1 renal artery, 1 arterial anastomosis (N = 369); (B) >1 renal artery, 1 arterial anastomosis (N = 47); and (C) >1 renal artery, >1 arterial anastomosis (N = 35). Furthermore, the influence of localization of the arterial anastomosis (common iliac artery (CIA), versus non-CIA) was analyzed. Clinicopathological characteristics, outcome, and graft and patient survival of all groups were compared retrospectively. Results: With growing vascular complexity, the time of warm ischemia increased significantly (groups A, B, and C: 40 ± 19 min, 45 ± 19 min, and 50 ± 17 min, respectively; p = 0.006). Furthermore, the duration of operation was prolonged, although this did not reach significance (groups A, B, and C: 175 ± 98 min, 180 ± 35 min, and 210 ± 43 min, respectively; p = 0.352). There were no significant differences regarding surgical complications, post-transplant kidney function (delayed graft function, initial non-function, episodes of acute rejection), or long-term graft survival. Regarding the localization of the arterial anastomosis, non-CIA was an independent prognostic factor for deep vein thrombosis in multivariate analysis (CIA versus non-CIA: OR 11.551; 95% CI, 1.218–109.554; p = 0.033). Conclusion: Multiple-donor renal arteries should not be considered a contraindication to deceased KT, as morbidity rates and long-term outcomes seem to be comparable with grafts with single arteries and less complex anastomoses.

Background: The use of stapling equipment for intestinal surgery in cats is rarely reported, and appropriate staple sizes for cat intestine are unknown. Objective: To determine staple cartridge sizes for thoracoabdominal (TA) and endoscopic gastrointestinal anastomosis (EndoGIA) that will simultaneously prevent leakage of small intestinal contents while also allowing for sufficient vascular permeability past the staple lines for intestinal healing. Methods: Two sizes of EndoGIA cartridges (2.0/2.5/3.0mm and 3.0/3.5/4.0mm) and two sizes of TA cartridges (2.5mm and 3.5mm), applied in a transverse manner across fresh cadaveric cat jejunum, were evaluated via intestinal burst pressure testing for maximum intraluminal pressure prior to leaking, and via infusion of an intravascular dye at normal arterial pressures to determine percentage of vascular patency past the staple lines. Vascular patency was compared not only from pre-and post-staple segments of the same intestinal sample, but also EndoGIA vascular patency was evaluated against TA vascular patency. Results: Two cats met study criteria. All samples had intraluminal burst pressures over twice the chosen minimum (of 30mmHg). Vascular patency post- staple line ranged from 0-90.8%, with the most consistently high numbers noted with the TA 3.5mm cartridges. No EndoGIA cartridge had a post- staple line vascular patency higher than 31.1%, and no intravascular dye was noted in any post- staple line sample in the EndoGIA 2.0/2.5/3.0mm group. Conclusions: While statistical analysis of the dataset was unable to be performed due to low numbers of samples for comparison, both intestinal intraluminal burst pressure trends and intravascular dye patterns suggested both the TA 3.5mm cartridge and (to a lesser extent) the 3.0/3.5/4.0mm EndoGIA cartridge could provide the ideal combination of intraluminal seal without restriction of vascular access for healing. The intravascular dye infusion technique, developed during this research, shows promise as a future instrument to determine vascular patterns around intestinal implants in cadaveric cat specimens. / Master of Science / Despite the regularity of feline small intestinal surgery, few reports exist of stapled anastomoses in cats, in part due to stapler size limitations. However, the recently developed endoscopic gastrointestinal anastomosis (EndoGIA) stapler shows promise as a future surgical tool for cats because it fits into cat intestine. In dogs, 3.5mm staples are often chosen for intestinal surgery; however, dog intestine is considerably thicker than cat intestine. The study goal was to evaluate not only intestinal burst pressures (the pressure at which repaired intestine leaks), but also the ability of fluids to flow through blood vessels that cross the staple lines of four stapler cartridge types from two staple lineages (EndoGIA 2.0/2.5/3.0mm, EndoGIA 3.0/3.5/4.0mm, TA 2.5mm, and TA 3.5mm). The central hypothesis was twofold. First, smaller stapler cartridge sizes (the EndoGIA 2.0/2.5/3.0mm and TA 2.5mm) would have higher intraluminal burst pressures when compared to the larger sizes (the EndoGIA 3.0/3.5/4.0mm). Second, larger stapler cartridges (the EndoGIA 3.0/3.5/4.0mm and the TA 3.5mm) would allow for increased flow of fluids in blood vessels past the stapler lines compared to the smaller cartridges (the EndoGIA 2.0/2.5/3.0mm and the TA 2.5mm). Two cats were included in the study. Trends in the data suggested that all components of the hypothesis might be proven with further data. However, due to the low number of cats acquired during the study period, the hypotheses could not be verified with statistics. The dye infusion technique to evaluate flow of fluids in blood vessels, developed during this research, shows promise as a future instrument to determine vascular patterns around intestinal implants. Future research should focus on acquiring more cats to have the ability able to perform statistical analyses (and prove the hypothesis), before proceeding with additional related studies.

L'encéphalopathie hépatique (EH) est un syndrome neuropsychiatrique dû à une dysfonction hépatique où l'ammoniaque est un facteur central. Il a déjà été rapporté que l’intoxication aiguë d'ammoniaque induise le stress oxydatif/nitrosatif. La présente étude cible à évaluer le rôle du stress oxydatif/nitrosatif dans 2 modèles de l’EH chronique : (1) l’anastomose portocave (PCA) et (2) la ligation de la voie biliaire (BDL). Ces 2 modèles sont caractérisés par une hyperammoniémie et une augmentation d’ammoniaque centrale, cependant l’œdème cérébral est trouvé seulement chez les rats BDL. Des marqueurs du stress oxydatif/nitrosatif ont été évaluées dans le plasma et cortex frontal. Un stress nitrosatif central a été observé chez les rats PCA; tandis qu’un stress oxydatif/nitrosatif systémique a été démontré seulement chez les rats BDL. Ces résultats suggèrent (1) que l’hyperammoniémie chronique n’induise pas le stress oxydatif/nitrosatif systémique et (2) qu’un synergisme existe entre l’ammoniaque et le stress oxydatif/nitrosatif, en association avec l’œdème cérébral. / Hepatic encephalopathy (HE) is a neuropsychiatric complication due to liver failure where ammonia is believed to be central in the pathogenesis. Acute ammonia intoxication has demonstrated to induce oxidative/nitrosative stress in both in vivo and in vitro models. The present study was aimed to assess the role of oxidative/nitrosative stress in 2 models of chronic liver failure/HE; 1. portacaval anastomosis (PCA) and 2. bile duct ligation (BDL). Both models are characterised with hyperammonemia and increased brain ammonia however cerebral edema is only found in BDL rats. Oxidative/nitrosative stress markers were evaluated in plasma and frontal cortex of both animal models. Central nitrosative stress was observed in PCA rats, but systemic oxidative/ntrosative stress was demonstrated only in BDL rats. The results of our study suggest i) chronic hyperammonemia does not induce oxidative stress and ii) a synergistic effect between ammonia and systemic oxidative/nitrosative stress is associated with cerebral edema.

L'encéphalopathie hépatique (EH) est un syndrome neuropsychiatrique dû à une dysfonction hépatique où l'ammoniaque est un facteur central. Il a déjà été rapporté que l’intoxication aiguë d'ammoniaque induise le stress oxydatif/nitrosatif. La présente étude cible à évaluer le rôle du stress oxydatif/nitrosatif dans 2 modèles de l’EH chronique : (1) l’anastomose portocave (PCA) et (2) la ligation de la voie biliaire (BDL). Ces 2 modèles sont caractérisés par une hyperammoniémie et une augmentation d’ammoniaque centrale, cependant l’œdème cérébral est trouvé seulement chez les rats BDL. Des marqueurs du stress oxydatif/nitrosatif ont été évaluées dans le plasma et cortex frontal. Un stress nitrosatif central a été observé chez les rats PCA; tandis qu’un stress oxydatif/nitrosatif systémique a été démontré seulement chez les rats BDL. Ces résultats suggèrent (1) que l’hyperammoniémie chronique n’induise pas le stress oxydatif/nitrosatif systémique et (2) qu’un synergisme existe entre l’ammoniaque et le stress oxydatif/nitrosatif, en association avec l’œdème cérébral. / Hepatic encephalopathy (HE) is a neuropsychiatric complication due to liver failure where ammonia is believed to be central in the pathogenesis. Acute ammonia intoxication has demonstrated to induce oxidative/nitrosative stress in both in vivo and in vitro models. The present study was aimed to assess the role of oxidative/nitrosative stress in 2 models of chronic liver failure/HE; 1. portacaval anastomosis (PCA) and 2. bile duct ligation (BDL). Both models are characterised with hyperammonemia and increased brain ammonia however cerebral edema is only found in BDL rats. Oxidative/nitrosative stress markers were evaluated in plasma and frontal cortex of both animal models. Central nitrosative stress was observed in PCA rats, but systemic oxidative/ntrosative stress was demonstrated only in BDL rats. The results of our study suggest i) chronic hyperammonemia does not induce oxidative stress and ii) a synergistic effect between ammonia and systemic oxidative/nitrosative stress is associated with cerebral edema.

<p>UVOD: Kolorektalna anastomoza koja se formira u dubini karlice radi uspostavljanja kontinuiteta gastrointestinalnog trakta nakon resekcije dijela crijeva ima svoje specifičnosti u toku formiranja, zarastanja, kao i kada se jave komplikacije. Na sam proces zarastanja kolorektalnih anastomoza utiču sistemski, lokalni i tehnički faktori. Bilo kakav kompromis po pitanju ovih principa nosi povećan rizik od komplikacija! Najteža komplikacija na anastomozi je dehiscencija. &bdquo;Samo neučinjena anastomoza neće dehiscirati&ldquo;. Ova stara hirur&scaron;ka poslovica je važeća i danas, a &scaron;to je anastomoza distalnija, mogućnost dehiscencije je veća, posebno kod niskih subperitonealnih anastomoza sa rektumom ili anusom. Učestalost dehiscencija ovih anastomoza u literaturi varira od 0,5 - 69 %, &scaron;to može ukazivati na kvalitet hirur&scaron;kog rada, kori&scaron;ćenje definicije dehiscencije, način dijagnostike, itd. Međunarodna grupa za karcinom rektuma definisala je dehiscenciju anastomoze kao defekt crijevnog zida, uključujući &scaron;avnu ili staplersku liniju neorektalnog rezervoara, &scaron;to dovodi do komunikacije između intra i ekstra luminalnog prostora. CILJEVI: Osnovni cilj ove studije je bio da se utvrde preoperativni i perioperativni faktori rizika značajni za nastanak dehiscencija kolorektalnih anastomoza, kao i značaj prokalcitonina i C-reaktivnog proteina u detekciji dehiscencija kolorektalnih anastomoza u subkliničkoj fazi bolesti. MATERIJAL I METODOLOGIJA: Istraživanjem je obuhvaćeno 100 pacijenata operisanih u elektivnom programu, kod kojih je urađena radikalna operacija karcinoma rektuma uz kreiranje dvostruke staplerske kolorektalne anastomoze. Svi pacijenti uključeni u istraživanje, odabrani metodom slučajnog izbora, bili su podijeljeni u dvije grupe. Grupa A: pacijenti kod kojih je urađena radikalna operacija karcinoma rektuma i kreirana primarna staplerska kolorektalna anastomoza. Grupa B: pacijenti kod kojih je urađena radikalna operacija karcinoma rektuma Hartmanovom procedurom u prvom aktu, a rekonstrukcija kontinuiteta gastrointestinalnog trakta uspostavljena u drugom aktu kreiranjem sekundarne staplerske kolorektalne anastomoze. Primjenom statističkih testova analizirani su preoperativni (pol, godine života, komorbiditeti, ASA skor, indeks tjelesne mase preoperativna primjena hemoradioterapije, laboratorijske analize) i perioperativni (vrijeme trajanja operacije, udaljenost anastomoze od anokutane linije, veličina tumora u cm, intraoperativna primjena krvi) faktori rizika za nastanak dehiscencije anastomoze kod obje grupe. Kod svih pacijenata drugog i četvrtog postoperativnog dana kontrolisane su vrijednosti C reaktivnog proteina i prokalcitonina u serumu, bez obzira da li su postojali ili ne klinički manifestni znaci dehiscencije anastomoze. Takođe, primjenom ROC krive analizirana je senzitivnost, specifičnost i dijagnostička tačnost C reaktivnog proteina i prokalcitonina drugog i četvrtog postoperativnog dana u detekciji dehiscencije kolorektalne anastomoze. REZULTATI: Nema statistički značajne razlike u pojavi dehiscencije anastomoze između primarnih i sekundarnih dvostrukih staplerskih anastomoza. Incidencija dehiscencija anastomoza je bila 11% u ukupnom uzorku. Osam pacijenata je reoperisano, dok su tri pacijenta tretirana konzervativno. Kod tri pacijenta, kod kojih je nastala dehiscencija i koji su reoperisani, zbog posljedice sepse i septičnog &scaron;oka nastupio je smrtni ishod. Pol, godine života, komorbiditeti, stadijum bolesti, dužina trajanja operacije, intraoperativna primjena krvi, nisu statistički značajni faktori rizika (p&gt;0,05) za nastanak dehiscencije primarnih i sekundarnih dvostrukih staplerskih kolorektalnih anastomoza. Udaljenost anastomoze od anokutane linije (&lt;7cm), veličina tumora preko 5 cm su statistički značajni faktori rizika za nastanak dehiscencije anastomoze. Postoji visoko statistički značajna razlika (p&lt;0,001) vrijednosti CRP-a i PCT-a četvrtog postoperativnog dana kod bolesnika sa i bez prisutne dehiscenecije kolorektalne anastomoze. Na osnovu ROC analize CRP&ndash;a za četvrti postoperativni dan, za graničnu vrijednost od 130 mg/l senzitivnost iznosi 82%, specifičnost 96% i dijagnostička tačnost 94%. Za graničnu vrijednost PCT-a od 0,78 ng/ml za četvrti postoperativni dan primjenom ROC krive utvrđena je sezitivnost 91%, specifičnost 92%, dok je dijagnostička tačnost bila 86%. Četvrti postoperativni dan CRP ima veću dijagnostičku tačnost i specifičnost u detekciji dehiscencije kolorektalne anastomoze u odnosu na PCT. ZAKLJUČAK: I pored velikog tehnolo&scaron;kog napretka, usavr&scaron;avanja hirur&scaron;kih tehnika, boljeg razumijevanja prirode maligne bolesti, unapređivanja intraoperativnog i postoperativnog kontinuiranog praćenja bolesnika, uvođenja novih antimikrobnih lijekova, problem u liječenju i pojava dehiscencija kolorektalnih anastomoza su i dalje značajno prisutni. Otkrivanjem dehiscencija kolorektalnih anastomoza u subkliničkoj fazi, identifikovanje preoperativnih i perioperativnih faktora rizika značajnih za nastanak dehiscencija, omogućilo bi da se dehiscencija ranije uoči i efikasnije rije&scaron;i.</p> / <p>INTRODUCTION: Colorectal anastomosis, which is formed deep in the pelvis because of establishment of continuity of gastrointestinal tract after resection of the part of intestines, has got its specifities during forming and healing process and when complications occur. Systemic, local and technical factors influence the healing process of anastomosis itself. Any kind of compromise in terms of these principles causes higher risk of complications! The most serious complication of anastomosis is dehiscence. &ldquo;Only anastomosis which is not carried out will not dehisce.&rdquo; This old surgical saying is still true, and the more distal anastomosis is, the possibility of development of dehiscence is higher, especially in lower subperitoneal anastomosis with rectum and anus. Incidence of dehiscence of these anastomosis in literature varies from 0,5 to 69 %, which may indicate the quality of surgical work, use of definition of dehiscence, kind of diagnostics etc. International group for rectal cancer defined dehiscence of anastomosis as a defect of intestinal wall, including suturing or stapler line of neorectal reservoir, which leads to communication between intra and extra luminal space. AIMS: Basic aim of this study was to determine preoperative and postoperative risk factors significant for the development of dehiscence of colorectal anastomosis, as well as significance of procalcitonin and C-reactive protein in detection of dehiscence of colorectal anastomosis at the subclinical stage of the disease. MATERIAL AND METHODOLOGY: The study included 100 patients operated on in the elective programme, on which radical operation of the rectal cancer was carried out with creation of double stapler colorectal anastomosis. All patients included in the study were randomly chosen and divided into two groups. Group A: the patients on which radical operation of the rectal cancer was carried out and primary stapler colorectal anastomosis created. Group B: the patients on which radical operation of the rectal cancer was carried out using Hartman&#39;s procedure in the first act, and reconstruction of the continuity of gastrointestinal tract was established in the second act by creation of secondary stapler colorectal anastomosis. By application of statistical tests preoperative (sex, age, comorbidities, ASA score, body mass index, preoperative application of haemoradiotherapy, laboratory analyses) and perioperative (duration of operation, distance of anastomosis from anocutaneous line, size of tumor in cm, intraoperative application of blood) risk factors for development of dehiscence of anastomosis in both groups were analysed. In all patients on the second and fourth postoperative day values of C-reactive protein and procalcitonin in the serum were analysed, regardless of the existence of clinically or non-clinically manifested signs of dehiscence of anastomosis. Also, sensitivity, specifity and diagnostically accurate C-reactive protein and procalcitonin on the second and fourth postoperative day in detection of dehiscence of colorectal anastomosis were analysed by application of ROC curve. RESULTS: There is no statistically significant difference in the development of dehiscence of anastomosis between primary and secondary double stapler anastomosis. Incidence of dehiscence of anastomosis was 11% in all samples. Eight patients were reoperated on, whereas three patients were treated conservatively. In three patients who developed dehiscence and were reoperated on, the death occurred due to sepsis and septic shock. Sex, age, comorbidities, stage of the disease, duration of operation, intraoperative application of blood were not statistically significant risk factors (p&gt;0,05) for the development of dehiscence of primary and secondary double stapler colorectal anastomosis. Distance of anastomosis from anocutaneous line (&lt;7cm), size of tumor over 5 cm were statistically significant risk factors for the development of dehiscence of anastomosis. There is highly statistically significant difference (p&lt;0,001) values of CRP and PCT on the fourth postoperative day in patients with and without dehiscence of colorectal anastomosis. On the basis of ROC analysis of CRP for the fourth postoperative day, for the bordering value of 130 mg/l sensitivity is 82%, specificity 96% and diagnostic accuracy 94%. For bordering value of PCT of 0,78 ng/ml for the fourth postoperative day, by application of ROC curve, the following values were determined: sensitivity 91%, specificity 92% and diagnostic accuracy 86%. CRP for the fourth postoperative day has got higher diagnostic accuracy and specificity in detection of dehiscence of colorectal anastomosis in relation to PCT. CONCLUSION: In spite of huge technological advance, improvement of surgical techniques, better understanding of the nature of malignant diseases, improvement of intraoperative and postoperative continuous follow up of the patient, introduction of new antimicrobial medicines, the problem in treating and development of dehiscence of colorectal anastomosis is still significantly present. Detection of dehiscence of colorectal anastomosis at the subclinical stage, identification of preoperative and perioperative risk factors significant for the development of dehiscence would help in early detection of dehiscence and contribute to more effective operations.</p>

O transplante hepático com a técnica convencional envolve a ressecção da veia cava inferior retrohepática como parte da hepatectomia do receptor e conseqüente clampeamento da mesma acima e abaixo do fígado, bem como o clampeamento da veia porta durante a fase anepática. Este procedimento pode se caracterizar por alterações hemodinâmicas importantes, disfunção renal e maior sangramento em áreas de dissecção submetidas a um regime de maior pressão. Pacientes idosos, previamente instáveis do ponto de vista hemodinâmico ou muito graves, gealmente, não toleram esta situação. Para evitar estes distúrbios, um \"bypass\" venovenoso, é habitualmente utilizado, permitindo com que o sangue da veia porta e da veia cava inferior retorne à circulação sistêmica através da veia axilar. O \"bypass\" venovenoso, foi adotado por muitos centros transplantadores como procedimento de rotina, enquanto outros empregavam este apenas quando o clampeamento da veia cava inferior determinasse grave alteração hemodinâmica, buscando assim, redução do custo, do tempo de operação e das complicações em função do uso \"bypass\", tais como: hipotermia, coagulopatia e fenômenos tromboembólicos. Outra alternativa técnica, que consiste na preservação da veia cava inferior durante a hepatectomia foi descrita com o intuito de preservar o fluxo na veia cava inferior durante a fase anepática. Além disto, uma anastomose porto-cava temporária pode ser confeccionada para evitar o clampeamento da veia porta e conseqüente congestão esplâncnica. O objetivo deste estudo foi comparar os resultados imediatos do transplante hepático com preservação da veia cava inferior e anastomose porto-cava temporária, ou com o uso do \"bypass\" venovenoso. De outubro de 1999 a outubro de 2001, 104 pacientes submetidos ao transplante hepático foram analisados retrospectivamente. O \"bypass\" venovenoso foi utilizado em 50 pacientes e a técnica de \"piggy back\" em 54. Ambos os grupos foram comparáveis em termos de idade, sexo, diagnóstico e grau de função hepática pré-operatória. Nosso estudo demonstrou não haver diferença entre as duas técnicas em relação à duração da hepatectomia, à duração da operação e à necessidade de transfusão de hemoderivados. Observou-se uma fase anepática mais breve e um menor tempo de permanência na unidade de terapia intensiva no período pós operatório dos pacientes submetidos à técnica que reserva a veia cava inferior, além disto o estudo aponta para uma tendência à redução no tempo de internação, no índice de insuficiência renal pós-operatória e para um melhor funcionamento do enxerto quando os fluxos da veia cava inferior e da veia porta são preservados. / The liver transplant with conventional technique involves the resection of the retrohepatic inferior vena cava as part of the recipient hepatectomy and consequent clamping of the same above and below the liver, as well as the clamping of the portal vein during the anhepatic phase. This procedure can be characterized by critical hemodynamic alterations, renal disfunction and greater bleeding in dissection areas submitted to higher pressure conditions. Elderly patients, previously unstable on a hemodynamic point of view or in very serious conditions, usually do not tolerate this situation. In order to avoid these disturbances, a venovenous bypass is commonly applied, allowing blood from the portal vein and inferior vena cava to return to the systemic circulation through the axilar vein. The venovenous bypass has been adopted by many transplant centers as a routine procedure, while others have applied this procedure only when clamping of the inferior vena cava determines a serious hemodynamic alteration, eeking, in this way, cost cutting, reduction of operation time and complications caused by usage of the bypass, such as: hypothermy, coagulopathy and romboembolic phenomenae. Another technical alternative, which consists of preservation of the inferior vena cava during the hepatectomy was described focusing preservation of the inferior vena cava flow during the anhepatic phase. Besides, a temporary portocaval shunt can be made to avoid clamping of the portal vein and consequently splanchnic congestion. The objective of this study was compare the immediate results of the liver transplantation with inferior vena cava preservation and temporary portocaval shunt or using the venovenous bypass. From October 1999 to October 2001, 104 patients submitted to an liver transplantat were analyzed retrospectively. The venovenous bypass was applied in 50 patients and the \"piggy back\" technique in 54. Both groups were comparable in terms of age, gender, diagnosis and preoperative hepatic conditions. Our study has demonstrated that there was no difference between the two techniques in relation to the hepatectomy and operation time and the need of hemoderivate transfusion. As a result, a shorter anhepatic phase was observed, as well as a shorter stay in intensive care unit during the postoperative period, in relation to patients submitted to the technique that preserves the inferior vena cava. Additionally, the study points out a trend towards reduction of hospital stay, postoperative renal insufficiency, and a better graft function when the inferior cava and portal veins are preserved.

O domínio da técnica de microanastomose vascular é um pré-requisito essencial para a realização de procedimentos microcirúrgicos reconstrutivos, como reimplantes e transferência livre de tecidos. Até hoje, a técnica de sutura convencional é a mais aceita na prática clínica, por sua segurança e versatilidade. Apesar disso, ela apresenta alguns problemas por ser tecnicamente difícil, consumir tempo considerável e causar traumatismo adicional à parede do vaso. O objetivo deste estudo, foi testar um método alternativo de microanastomose arterial, reduzindo o número de pontos de sutura com aplicação do adesivo de fibrina. Sessenta ratos da raça Wistar foram submetidos a microanastomose vascular nas artérias femorais ou carótidas. Os animais foram divididos em quatro subgrupos de acordo com a artéria operada e a técnica de sutura empregada: FSC (femoral - sutura convencional), FAF (femoral - sutura mínima com adesivo de fibrina), CSC (carótida - sutura convencional) e CAF (carótida - sutura mínima com adesivo de fibrina). As duas técnicas de anastomose foram comparadas através de análise estatística dos parâmetros clínicos e histopatológicos. A média de pontos de sutura por anastomose nos subgrupos FSC e CSC foi de 7,7 e 9,5, respectivamente. No subgrupo FAF, as anastomoses foram realizadas com apenas quatro pontos de sutura e no subgrupo CAF, com apenas seis. O tempo de anastomose foi, em média: 15,81 minutos no subgrupo FSC, 13,62 minutos no subgrupo FAF, 18,87 minutos no subgrupo CSC e 17,33 minutos no subgrupo CAF. A aplicação do adesivo de fibrina reduziu, significativamente, o número de pontos e o tempo necessário para realização das anastomoses, nos subgrupos FAF e CAF. A intensidade do sangramento anastomótico também foi reduzida de maneira significativa nestes subgrupos. A freqüência da permeabilidade imediata e tardia foi de 100% em todos os subgrupos, exceto no subgrupo FAF, onde a permeabilidade tardia foi de 93,33%. Não foram observadas diferenças significativas entre as duas técnicas, em relação aos parâmetros histopatológicos avaliados (processo inflamatório, fibrose da camada média e hiperplasia subintimal). O autor concluiu que a técnica de sutura mínima com aplicação do adesivo de fibrina foi mais fácil e rápida que a técnica de sutura convencional, sem aumento da trombogenicidade das anastomoses, no modelo experimental utilizado. / Mastering of the microvascular anastomosis technique is an essencial requirement to perform reconstructive microsurgical procedures, such as replantation surgery and free tissue transfers. Until now, the conventional suture technique is the most widely accepted in the clinical setting, for its safety and versatility. However, this technique presents some problems for being technically difficult, time consuming and causes additional trauma to the vessel wall. The aim of this study was to test an alternative method of microvascular arterial anastomosis, by reducing the number of sutures with application of fibrin adhesive. Sixty Wistar rats underwent to microvascular anastomosis at the femoral or carotid arteries. The animals were divided into four subgroups, according to the operated artery and the employed suture technique: FCS (femoral - conventional suture), FFA (femoral - minimal suture with fibrin adhesive), CCS (carotid - conventional suture) and CFA (carotid - minimal suture with fibrin adhesive). Both anastomosis techniques were compared by means of statistical analisys of the clinical and histopathological parameters. The mean number of sutures required to complete the anastomosis was 7,7 in subgroup FCS and 9,5 in subgroup CCS. In subgroup FFA, the anastomosis was performed with only four sutures and in subgroup CFA, with only six. The mean anastomotic time was 15,81 minutes in subgroup FCS, 13,62 minutes in subgroup FFA, 18,87 minutes in subgroup CCS and 17,33 minutes in subgroup CCS. The application of fibrin adhesive, significantly reduced the number of sutures and the time taken to perform the anastomosis, in subgroups FFA and CFA. The amount of anastomotic bleeding was also significantly reduced in these subgroups. The immediate and late patency rates were 100% in all subgroups, except in subgroup FFA where it was 93,33%. No significant differences were observed among the two techniques, concerning the evaluated histopathological parameters (inflammatory process, medial fibrosis and subintimal hyperplasia). The author concluded that, the fibrin adhesive application with minimal suture technique was faster and easier than the conventional suture technique, without increasing the trombogenicity of the anastomosis, in this experimental model.

L'objectif de ce travail est de concevoir une nouvelle interface haptique en vue de son exploitation pour la chirurgie mini-invasive. La technique d'anastomose ciblée consiste à réunir deux parties désolidarisées d'une artère par des sutures et des nœuds. Ceci est effectué par des outils chirurgicaux introduits à travers de petites incisions. Une étude expérimentale de cette tâche a été effectuée en collaboration avec des chirurgiens afin de caractériser leurs gestes. L'enregistrement de l'opération par un système de capture de mouvement a permis d'identifier la nature et les gestes canoniques de cette technique. Une structure parallèle sphérique a été ensuite adoptée comme base de l'interface haptique. Cette architecture présente un centre fixe de rotation semblable au point d'incision réel et offre les trois degrés de liberté de rotation nécessaires autours de ce point. Une étude détaillée de cette architecture suivie d'une phase d'optimisation, a permis d'adapter la structure à l'application chirurgicale. L'optimisation, basée sur un algorithme générique, a porté dans un premier lieu sur l'espace de travail de la tâche. La dextérité de la structure a été ensuite prise en compte. Une phase de conception basée sur les paramètres résultants de cette optimisation a aboutie à la réalisation d'un premier prototype. L'influence des erreurs de fabrication sur l'orientation de la plateforme a été aussi traitée dans ce travail afin de déterminer les plages des défauts admissibles. Une modélisation, utilisant les torseurs de petits déplacements, a été élaborée.La dernière partie de ce travail porte sur la commande a retour d'effort de l'interface. Un banc d'essais à 1 degré de liberté a été réalisé afin de tester les différents schémas de contrôle pour la téléopération. Les essais en simulation on permit de dresser une vue comparative de ces schémas. / The aim of this work is to develop a new haptic interface to perform a minimally invasive surgery. The targeted anastomosis technique consists of the surgical binding of a ruptured blood vessel, using sutures and knots. This task is performed by surgical tools inserted through small incisions. An experimental study of this task was conducted in collaboration with surgeons in order to characterize their gesture. The recording of the operation by a motion capture system helped identifying the nature and the canonical actions of this technique. A spherical parallel mechanism (SPM) was then adopted as a basis for the haptic interface. This architecture has a fixed center of rotation similar to the real incision point and offers the three required degrees of freedom of rotation around that point. A detailed study of the architecture followed by an optimization procedure led to a suitable mechanism for the surgical application. The optimization, which is based on a generic algorithm, used the workspace of the task as a criterion. Then the dexterity of the structure was taken into account. A design phase based on the parameters resulting from this optimization led to building the first prototype.The influence of manufacturing errors on the orientation of the platform was also addressed in this work to determine the ranges of allowable defects. The manufacturing errors are modeled by screws of small displacement in order to determine their effect on the orientation error of the end effector. The last part of this work focuses on the command of the force feedback interface. An experimental setup made out of a one degree of freedom system, was built to test different control schemes for teleoperation. Simulation trials allowed developing a comparative view of these schemes.