Joann Pollack

Silicone-Covered Metal Stents (An In Vitro Evaluation for Biofilm Formation and Patency)

Self-expanding metal stents are being used morecommonly to prevent biliary tract obstruction.Silicone-covered self-expanding metal stents (Wallstent,Schneider, Inc.) have been developed to prevent tumor ingrowth. Biofilm formation and occlusionmaterial in siliconecovered self-expanding metal stentscompared to standard polyethylene stents were examinedin an in vitro model. Matched pairs of polyethylene and silicone-covered metal stents were perfusedwith infected bile for 8, 12, and 16 weeks at a rate of0.5 cc/min at 37°C. Two reservoirs fitted withsilicone-covered metal stents had ampicillin/sulbactam added and were perfused for 16 weeks. Thestents were then analyzed by scanning electronmicroscopy and light microscopy for biofilm formationand presence of occlusion material. The twoampicillin/sulbactam-treated stents showed no biofilm formation. Biofilm wasseen on all of the remaining stents. There was adifference in occlusion thickness between the 8- and16-week polyethylene stents, and no difference between the biofilm thickness at 8, 12, or 16 weeks inthe silicone-covered metal stents. Silicone-coveredself-expanding metal stents will likely extend patencyrates in malignant obstructive jaundice by providing a larger lumen for bile flow and allowingcyclical antibiotics to prevent bacterial biofilmformation.

Inhibition of biliary endoprostheses occlusion by ampicillin-sulbactam in an in vitro model

An important first step in stent occlusion is the formation of a bacterial biofilm. This is followed by deposition of granules similar to that found in brown pigment stones. Previous in vitro models for studying occlusion have used synthetic biles without bilirubin or pooled human bile, which is limited in supply. Our aim was to develop a new in vitro model of stent occlusion with porcine gallbladder bile and then, with the model, assess whether ampicillin-sulbactam can prevent biofilm formation and thus occlusion. Sterile porcine gallbladder bile was contaminated with Escherichia coli then divided into eight reservoirs, four of which then received ampicillin-sulbactam. The bile was then circulated through 10F polyethylene stents. Bile was changed weekly for 8 weeks. In the stents that were untreated, biofilm and sludge were seen in all four, whereas the four ampicillin-sulbactam-treated stents had no biofilm when viewed by electron microscopy. Furthermore, the levels of calcium, cholesterol, and bilirubin in the reservoirs decreased significantly in the untreated bile as compared with the treated bile (p < 0.05). In this in vitro model, the losses of calcium, cholesterol, and bilirubin are likely caused by deposition of granules into the biofilm matrix. Ampicillin-sulbactam can prevent biofilm formation if used continuously.

Use of oral GoLytely solution in relief of refractory fecal impaction.

Constipation and fecal impaction are commondisorders with multiple treatment options. We describethe use of GoLytely oral solution in 10 patientsadmitted to a community hospital and referred to asingle gastroenterologist for fecal impactionrefractory to conventional medical treatment. Sevenwomen and three men received enemas, bisacodylsuppositories, and digital fragmentation either solelyor in combination prior to the administration of GoLytely oralsolution. The patients had no clinical and radiologicalevidence of bowel obstruction. All had underlyingcardiovascular problems. Their mean age was 78.1 years (range 49-100 years). GoLytely oral solution(Braintree Laboratories, Inc.) was administered at arate of 100 ml/hr per orem to three patients, vianasogastric tube in six patients, and via gastrostomy tube in one patient. All 10 patients were ableto regularly pass feces and show radiographicalcolorectal clearing within 6.0 to 57.25 hr (mean 23.60hr). No significant complications were observed. Eight patients were discharged from the hospitalwithin 24 hr of termination of treatment while twopatients remained for unrelated medical conditions.GoLytely oral solution effectively relieved fecalimpaction in 10 patients refractory to conventionalmedical treatment.

Case Report: Use of Single Percutaneous Endoscopic Gastrostomy in Management of Gastric Volvulus in Three Patients

Gastric volvulus is a rare condition that occurs when the stomach twists either in an organoaxial or mesenteroaxial direction. In patients with recurrent episodes of volvulus, standard therapy is surgical correction. Many patients, however, are not candidates for surgical therapy because of comorbid conditions or advanced age. Our aim was to determine if the insertion of a single percutaneous gastrostomy tube placement would assist in management of gastric volvulus in patients not able to undergo surgical therapy. The alpha-loop maneuver was used to reduce gastric volvulus in three elderly patients. A percutaneous endoscopic gastrostomy tube was then inserted to prevent recurrent volvulus. Single percutaneous gastrostomy tube placement was successful in managing volvulus in these three patients. Single percutaneous endoscopic gastrostomy tube placement is a useful treatment alternative to surgery in patients requiring therapy of gastric volvulus.

Evaluation of role of bile flow patterns in process of in vitro stent occlusion.

Stent placement above the sphincter of Oddi might have advantages over stent placement across the sphincter of Oddi in prolonging stent patency in the treatment for malignant obstructive jaundice. To evaluate the role of bile flow patterns corresponding to biliary stent positioning in the process of stent occlusion in an in vitro bile perfusion model, one group of polyethylene stents was perfused continuously and another group of stents was perfused with additional flushing three times a day, simulating gallbladder emptying. After 8 weeks, the flow rates through the perfused stents were measured for evaluating the extent of stent occlusion indirectly. The results showed that bile flow rate of stents with additional flushing was significantly higher than the continuously perfused stents (P ≤ 0.01). It was demonstrated that after 18 hr of perfusion, additional flushing obviously decreased bacterial adherence to stent when compared to continuously perfused stents. In conclusion, flushing of bile may decrease the build-up of substance in vitro and thus improve stent flow rates, for which decreasing bacterial adherence to stents may be responsible.