Antonio Basoli

Plastic Biliary Stent Occlusion: Factors Involved and Possible Preventive Approaches

Endoscopic biliary stenting is today the most common palliative treatment for patients suffering from obstructive jaundice associated with malignant hepatobiliary tumors or benign strictures. However, recurrent jaundice, with or without cholangitis, is a major complication of a biliary endoprosthesis insertion. Thus, stent removal and replacement with a new one frequently occurs as a consequence of device blockage caused by microbial biofilm growth and biliary sludge accumulation in the lumen. Factors and mechanisms involved in plastic stent clogging arising from epidemiological, clinical and experimental data, as well as the possible strategies to prevent biliary stent failure, will be reviewed and discussed.

Roux-en-y Hepaticojejun ostomy: A Reappraisal of its Indications and Results

A critical evaluation is made of 131 patients submitted to choledocho or hepaticojejunostomy. The main indications for hepaticojejunostomy were iatrogenic strictures of CBD (60 patients), and choledocholithiasis with markedly dilated duct (41 patients). The overall mortality rate was 4% representing principally renal hepatic failure, bile peritonitis and bleeding. The complications following hepaticojejunostomy included only in one case biliary fistula which required reoperation. The long-term results of 80 patients available for a followup study were as follows: 63 patients (78.7%) were symptom-free at 2-13 years followup; 8 patients had brief episodes of cholangitis which responded to antibiotic and corticosteroid treatment; 9 patients required reoperation for stricture of anastomosis. These overall results are a strong argument for hepaticojejunostomy which, compared with choledochoduodenostomy, avoids the hazards of the so-called sump syndrome and of the reflux of enteric contents in the CBD. An increased incidence of peptic ulcer disease in the patients submitted to hepaticojejunostomy was not observed. In very high strictures and in reinterventions anastomosis between left hepatic duct and Roux-en-Y jejunal limb was carried out. The results achieved with this technique, which was performed in 26 patients, were about the same following hepaticojejunostomy.

Hypoglycemia and insular hyperplasia: review of 148 cases.

On the bases of personal experience and the series of 148 cases from an international inquiry and a review of the literature, the relation between insular hyperplasia and hypoglycemia was examined. The fundamental points in this investigation included: age, diagnostic investigations, histological findings and postoperative results. The data on the patients with insular hyperplasia indicates that 83% were of adult age. Insular hyperplasia was the only abnormal factor determined to be present. Through treatment a high percentage of cases (71%) was cured. From a practical surgical point of view, differentiation between occult insulomas and insular hyperplasia is not critical. Consequently, good results can be achieved in botlh diseases by practicing a progressive blind resection guided by examination of the operated specimen and by intra-operative blood sugar levels.

Role of multispecies microbial biofilms in the occlusion of biliary stents

Endoscopic stenting is a standard palliative approach for the treatment of a variety of diseases involving biliary obstruction. However, the major limitation of this approach is represented by stent occlusion followed by life-threatening cholangitis, often requiring stent removal and replacement with a new one. Although it is generally believed that microbial colonization of the inner surface of the stent plays an important role in initiating the clogging process, so far available data are not enough for a full understanding of this phenomenon. In fact, it is known that when a biliary stent is inserted across the sphincter of Oddi, the loss of the antimicrobial barrier represented by the sphincter itself and the low pressure in the common bile duct allow reflux of duodenal content, thus promoting an ascending microbial colonization. The sessile mode of growth and the exopolysaccharide production, which leads to the subsequent establishment of a thick biofilm, provides microorganisms with an efficient protection from both antibacterial agents and phagocytic cells. The aim of this study was to analyze the tridimensional structure of the microbial biofilm grown in the lumen of 15 clogged biliary stents and to identify the microbial species involved in the clogging process. Scanning electron microscopy investigations revealed that sludge present in the stent lumen consist of a rich and assorted microbial flora, including aerobic and anaerobic species, mixed with a large amount of amorphous material containing dietary fibres, crystals of cholesterol and other precipitates of bacteria-driven bile salts.

Biliary stent occlusion : a microbiological and scanning electron microscopy (SEM) investigation

In obstructive jaundice the decompression of occluded common bile duct with transhepatic or perduodenoscopic positioning of a biliary stent, represents a valid alternative to surgery because of a lower incidence of morbility and mortality, a shorter mean hospital stay and the rapid regression of jaundice and itching. The main limitation of this procedure is the late occlusion of the stents which requires their removal, with an increased risk for the patient and an additional health care cost.

Hemocompatibility of carotid artery stents: alterations of the electrical parameters of erythrocyte cell membrane--a word of caution.

The hemocompatibility of standard surgical treatment of carotid artery disease through the insertion of metallic stents is investigated by means of radio wave dielectric spectroscopy technique that allows the measurements of the electrical parameters of the red blood cell membrane. Our measurements suggest that both the membrane permittivity and the membrane conductivity, which characterize the overall electrical behavior of the cell membrane, undergo an appreciable alteration of their standard values as a consequence of the stent insertion. These alterations persist over long period of time, up to 4 weeks. Even if these effects could not cause any evident damage at physiological or clinical level to the patient, the presence of a host response to the stent implant suggests that a full hemocompatibility has not yet reached, and a word of caution is necessary.

Are aortic endograft prostheses fully hemo-compatible? A dielectric spectroscopy investigation of the electrical alterations induced on erythrocyte cell membranes.

In this paper we present a new approach directed to ascertain the full hemo-compatibility of aortic endograft prostheses based on the measurement of the passive electrical parameters of the erythrocyte cell membrane. The red blood cell membrane, from an electric point of view, is characterized by an electrical permittivity, (s), which takes into account the structural charged organization of the lipid double layer, and by the electrical conductivity, sigma(s), which accounts for the ionic transport processes across the membrane. These parameters can be easily measured by means of a radiowave dielectric spectroscopy technique, analyzing the dependence of the electrical impedance of an erythrocyte suspension on the frequency of the applied electric field. In this preliminary report, we investigate the alterations induced, at a membrane level, by two different devices commonly employed for endovascular abdominal aortic aneurysm exclusion, i.e., Excluder and Zenith devices, implanted in ten patients. We observe, in all the cases investigated, a statistically significant increase of both the permittivity (s) and electrical conductivity sigma(s) of the erythrocyte membrane upon the prosthesis implant, this increase being higher than about 20% of the un-treated values. Moreover, these alterations remain roughly unaffected 30 days after surgery. These findings suggest that a complete hemo-compatibility of these prostheses is lacking, even if the observed alterations may not have a clinical relevance.