Daniel Palmes

Effect of pyloric drainage procedures on gastric passage and bile reflux after esophagectomy with gastric conduit reconstruction

Background and aimsControversy still exists about the need for pyloric drainage procedures (pyloroplasty or pyloromyotomy) after esophagectomy with esophagogastrostomy and vagotomy. Although pyloric drainage may prevent postoperative delayed gastric emptying, it may also promote bile reflux into the oesophagus. We analysed pyloric drainage methods for their potential effect on gastric outlet obstruction and bile reflux in patients undergoing esophagectomy.Materials and methodsOne hundred and ninety-eight patients with esophageal carcinoma were treated by transthoracal esophagectomy with gastric conduit reconstruction either with pyloromyotomy (group II, n = 118), pyloroplasty (group III, n = 34) or without pyloric drainage (group I, n = 46) between January 2000 and December 2004. The postoperative gastrointestinal passage by radiological investigation, anastomotic leakage rate, mortality and incidence of gastroesophageal reflux by endoscopy within the first postoperative year were retrospectively analysed.ResultsPatient demographics and the types of surgical procedures did not differ between the three groups. There was no difference in hospital mortality, anastomotic leakage rate, gastrointestinal passage and postoperative hospital stay between the three groups. However, more patients with pyloric drainage showed bile reflux (I = 0% vs II+III=14.9%, p = 0.069) and reflux esophagitis (I = 10.3% vs II+III = 34.5%, p < 0.05) compared to patients without pyloric drainage. On the multivariate analysis, pyloric drainage and the anastomotic height were independent and were significant risk factors associated with postoperative reflux esophagitis.ConclusionPyloric drainage after esophagectomy with gastric conduit reconstruction should be omitted because it does not improve gastric emptying and may favour biliary reflux esophagitis.

Impact of Polypropylene Amount on Functional Outcome and Quality of Life after Inguinal Hernia Repair by the TAPP Procedure Using Pure, Mixed, and Titanium-coated Meshes

BackgroundLaparoscopic inguinal hernia repair requires the use of prosthetic material. This prospective, single-center study was intended to investigate the impact of the amount of polypropylene (PP) mesh used in hernia repair on functional results and quality of life.MethodsFor this series, 672 consecutive patients with primary inguinal hernia undergoing transabdominal preperitoneal hernia repair (TAPP) using a heavyweight PP mesh (Prolene 10 × 15 cm, 1.5 g, group I, n = 232), a mixed PP- and Polyglactin mesh (Vypro II, 10 × 15 cm, 0.53 g, group II, n = 217), or a light-weight titanized PP mesh (Ti-Mesh, 10 × 15 cm, 0.24 g, group III, n = 223) were compared in terms of postoperative complications (seroma, wound healing disorders), quality of life score (pain development, physical condition, urologic disorders), and hernia recurrence.ResultsDuring a 12-month follow-up there were no significant differences in the recurrence rate (1.3%-1.7%). Patients with a pure PP mesh (group I) showed significantly more postoperative seromas (12.1% versus 4.1%/1.8%), foreign body sensations (9.1% versus 5.5%/3.5%), and sensitivity to weather changes (5.6% versus 3.2%/2.2%) compared to groups II and III. In all groups, the quality of life score was improved postoperatively. However, among those patients in our series with few preoperative complaints, the postoperative quality of life was worsened when heavy-weight PP meshes (group I+II) were used but significantly improved when light-weight titanized PP meshes were used.ConclusionsComparable functional results, fewer postoperative complications, and improved quality of life can be achieved by reducing the amount of PP in meshes used for laparoscopic hernia repair by TAPP procedure.

Impact of failed allograft nephrectomy on initial function and graft survival after kidney retransplantation

The management of an asymptomatic failed renal graft remains controversial. The aim of our study was to explore the effect of failed allograft nephrectomy on kidney retransplantation by comparing the outcome of recipients who underwent graft nephrectomy prior to retransplantation with those who did not. Retrospective comparison of patients undergoing kidney retransplantation with (group A, n = 121) and without (group B, n = 45) preliminary nephrectomy was performed, including subgroup analysis with reference to patients with multiple (≥2) retransplantations and patients of the European Senior Program (ESP). Nephrectomy leads to increased panel reactive antibody (PRA) levels prior to retransplantation and is associated with significantly increased rates of primary nonfunction (PNF; P = 0.05) and acute rejection (P = 0.04). Overall graft survival after retransplantation was significantly worse in group A compared with group B (P = 0.03). Among the subgroups especially ESP patients showed a shorter graft survival after previous allograft nephrectomy. On the multivariate analysis, pretransplant graft nephrectomy and PRA >70% were independent and significant risk factors associated with graft loss after kidney retransplantation. Nephrectomy of the failed allograft was not beneficial for retransplant outcome in our series. Patients with failed graft nephrectomy tended to have a higher risk of PNF and acute rejection after retransplantation. The possibility that the graft nephrectomy has a negative impact on graft function and survival after retransplantation is worth studying further.

Impact of rapamycin on liver regeneration

The remarkable capacity of the liver to regenerate after injury and the prospects of organ self-renewal have attracted much interest in the understanding and modulation of the underlying molecular events. We investigated the effect of mammalian target of rapamycin (mTOR) inhibitor rapamycin (RAPA) on liver by correlating intravital microscopy, immunohistochemistry, and reverse transcriptase polymerase chain reaction in a rat model of 2/3 hepatectomy. RAPA significantly retarded proliferation of hepatocytes, endothelial cells, and hepatic stellate cells (HSCs) mostly between days 2 and 4 after hepatectomy and down-regulated major cytokines and growth factors (tumor necrosis factor alpha, hepatocyte growth factor, platelet-derived growth factor, platelet-derived growth factor receptor, insulin-like growth factor-1, transforming growth factor beta 1) important for liver regeneration. These effects were almost absent at later time points. RAPA also had a transient, but broad effect on angiogenesis, and impaired sinusoidal density as well as mRNA levels of vascular endothelial growth factor, vascular endothelial growth factor receptor 1, vascular endothelial growth factor receptor 2, and angiopoietin-1. Activation of HSC was also transiently suppressed as observed by smooth muscle protein 1 alpha protein expression and intercellular adhesion molecule-1 mRNA levels. The rate of apoptosis in liver was significantly increased by RAPA between day 3 and day 7. The effect of RAPA on liver repair, angiogenesis, and HSC activation is confined to the phase of active cell proliferation. This transient effect might allow further exploration of mTOR inhibitors in clinical situations that involve liver regeneration, and seems to have implications beyond immunosuppression.

Randomized clinical trial of the influence of intraperitoneal local anaesthesia on pain after laparoscopic surgery

There is controversy about the effectiveness of intraperitoneal local anaesthesia (LA) in laparoscopic surgery. The aim of the present randomized clinical trial was to compare the analgesic effect of pre‐emptive (preoperative) versus postoperative intraperitoneal LA in two different types of laparoscopic surgery.

Surgical Techniques of Orthotopic Rat Liver Transplantation

Liver transplantation in rats is frequently used as a transplantation model. Although liver transplantation in larger laboratory animals such as dogs and pigs is technically easier, the rat has become the most important subject for experimental liver transplantation because of the availability of genetically defined animals. Numerous surgical techniques have been developed that permit the investigator to carry out studies with high clinical relevance. In this article the principal models of orthotopic rat liver transplantation and their technical modifications of vessel anastomoses, rearterialization, and bile duct reconstruction techniques are reviewed. More than 20 transplantation models are described in detail and demonstrated with clear illustrations. Finally, the advantages and uses of all the surgical procedures (e.g., suture and cuff anastomoses, bile duct anastomoses, and rearterialization techniques), specific problems, and survival criteria are discussed and the experiences of investigators who applied these techniques are analyzed. In conclusion, an overview and critical evaluation of all surgical techniques of orthotopic rat liver transplantation are given, together with instructions for learning these techniques.

Liver bridging techniques in the treatment of acute liver failure.

The introduction of orthotopic liver transplantation in the management of acute liver failure has dramatically increased the survival rates of patients at the cost of removing the patients native liver and life-long dependence on immunosuppression. However, it is well known that in many patients with acute liver failure the diseased liver has the potential to recover. Death in these patients is often due to increased intra-cranial pressure or infection. Liver bridging techniques are assigned to temporarily provide liver function and enable the native liver to recover in patients with acute liver failure. They represent an attractive alternative to conventional liver transplantation in the management of acute liver failure, since after recovery of the native liver the patient is freed from immuno-suppression with all associated side-effects and risks. Auxiliary liver transplantation, artificial liver support devices and hepatocyte transplantation represent different ways of bridging liver function in acute liver failure. The aim of this review is to present the ideas and principles of these three different liver bridging techniques. We will discuss the relative importance and the future potential of theses bridging techniques in the treatment of acute liver failure by comparing the experimental and clinical results.The introduction of orthotopic liver transplantation in the management of acute liver failure has dramatically increased the survival rates of patients at the cost of removing the patients native liver and life-long dependence on immunosuppression. However, it is well known that in many patients with acute liver failure the diseased liver has the potential to recover. Death in these patients is often due to increased intra-cranial pressure or infection. Liver bridging techniques are assigned to temporarily provide liver function and enable the native liver to recover in patients with acute liver failure. They represent an attractive alternative to conventional liver transplantation in the management of acute liver failure, since after recovery of the native liver the patient is freed from immuno-suppression with all associated side-effects and risks. Auxiliary liver transplantation, artificial liver support devices and hepatocyte transplantation represent different ways of bridging liver function in acute liver failure. The aim of this review is to present the ideas and principles of these three different liver bridging techniques. We will discuss the relative importance and the future potential of theses bridging techniques in the treatment of acute liver failure by comparing the experimental and clinical results.

Sequence of reperfusion influences ischemia/reperfusion injury and primary graft function following porcine liver transplantation

The impact of 3 different reperfusion sequences following orthotopic liver transplantation (OLT) in pigs were evaluated. The reperfusion technique commonly performed is primary portal in order to shorten warm ischemic times (WITs). Experimental and clinical data, usually comparing 2 out of 3 possible reperfusion sequences, provide controversial results. OLT was performed in 24 pigs randomized into 3 groups: primary arterial (A), simultaneous (SIM), and primary portal (P) reperfusion. Hemodynamics were continuously monitored and reperfusion injury and primary graft function were assessed by standard serum parameters, histopathological findings, immunohistochemistry for heme oxygenase 1 (HO‐1), and heat shock protein 70 (HSP 70). Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and γ‐glutamyl transpeptidase (γGT) following reperfusion were significantly increased for group A when compared to groups SIM and P. Hemodynamics showed significant differences after reperfusion compared to physiological data; differences in group comparisons were not significant. The bile production/100 g liver/hr was significantly higher for group SIM (1.15 mL) compared to group P (0.66 mL) and group A (0.62 mL). Histology and immunohistochemistry significantly correlated with functional results and outcome. Histological score was best for group SIM and worst for group A. HSP 70, being visualized mainly in the hepatocytes, showed higher expression for groups SIM and P. Inversely, HO‐1, found in perisinusoidal cells, showed highest expression after primary arterial reperfusion. In conclusion, although associated with a 10‐minute longer warm ischemic time, simultaneous reperfusion causes the least reperfusion injury with superior primary transplant function. Primary arterial reperfusion showed the worst overall outcome and highest degree of HO‐1 expression. (Liver Transpl 2005;11:1214–1222.)

Type of Steatosis Influences Microcirculation and Fibrogenesis in Different Rat Strains

ABSTRACT This study investigates the impact of rat strain on the development of nonalcoholic fatty liver disease (NAFLD) focusing on morphological features and microcirculation. Male rats of Lewis, Wistar, and Sprague Dawley (n = 6 per strain and group) were randomized into a high-fat group which was fed with a special high-fat nutrition for a 3-week period and a control group which received standard nutrition. Intravital microscopy was used for the evaluation of microcirculation and correlated to morphological changes using a fatty liver scoring system. All three strains receiving a high-fat diet developed a grade 3 steatosis (>66% liver cell steatosis). Whereas Lewis showed a solely microvesicular steatosis, Wistar developed a mixed form and Sprague Dawley showed a pure macrovesicular steatosis and the highest degree of fibrosis and hepatocyte damage. Microcirculatory results revealed that sinusoidal density was already affected by a microvesicular steatosis and decreased with increasing macrovesicular proportion (Lewis: 18%, Wistar: 31%, Sprague Dawley: 23%). The degree of steatosis correlates with reduced blood flow velocity in central veins as well as in sinusoids (Lewis: 28%, Wistar: 39%, Sprague Dawley 44%). The densities of hepatocytes and hepatic stellate cells were only impaired once macrovesicular cell steatosis (Wistar and Sprague Dawley) was present. The development of NAFLD in the rat revealed strain-specific morphological features correlating with microcirculatory changes that should be considered in further studies using these models.

A New Clamping Technique for Biomechanical Testing of Tendons in Small Animals

When biomechanical properties of tendons are studied, the technique of clamping the tendons in the testing machine presents a methodological challenge, especially when murine tendons are examined. These short tendons tend to rupture at the transition line to the fixation, leading to false interpretations. Therefore a new clamping technique for investigation of healthy murine Achilles tendons (n = 50) was developed, in which the intramuscular tendon fibers were fixed between two paper strips and the calcaneus was wedged into a conical slot in a wooden block and then mounted in the testing machine (n = 20). This technique was compared with the conventional clamping technique that fixes both ends of the tendon by clamps (n = 15) and an earlier described method that used glue or plastic cement for the fixation of the intramuscular tendon fibers and calcaneus in the testing machine (nWhen biomechanical properties of tendons are studied, the technique of clamping the tendons in the testing machine presents a methodological challenge, especially when murine tendons are examined. These short tendons tend to rupture at the transition line to the fixation, leading to false interpretations. Therefore a new clamping technique for investigation of healthy murine Achilles tendons (n = 50) was developed, in which the intramuscular tendon fibers were fixed between two paper strips and the calcaneus was wedged into a conical slot in a wooden block and then mounted in the testing machine (n = 20). This technique was compared with the conventional clamping technique that fixes both ends of the tendon by clamps (n = 15) and an earlier described method that used glue or plastic cement for the fixation of the intramuscular tendon fibers and calcaneus in the testing machine (n = 15). When tested by the new clamping technique, 17 tendons ruptured intratendinously at a mean tensile force of 8.4 +/- 1.1 N. Three Achilles tendons (17%) tore at the site of paper fixation and had to be excluded from investigation. Data from 73% of the measurements fixed by gluing had to be excluded because slippage of the proximal tendon fibers and contamination of the tendon with glue occurred. All the conventionally clamped tendons ruptured at the site of fixation at a mean tensile force of 6.1 +/- 2.3 N (p < .05). This was 30% lower than with the new clamping technique. Thus, the newly developed clamping technique enables investigators to obtain more valid biomechanical studies of the murine Achilles tendon.