BackgroundTo overcome duodenobiliary reflux induced by biliary stents, antireflux valve (ARV) biliary stents have been developed and showed improvement in stent patency. However, negative study results have also been reported because stent patency may be decreased by the malfunction of ARV itself. Given such mixed results, the true efficacy of ARV remains unknown and the mechanism of its dysfunction needs to be clearly elucidated. The aim of this study was to investigate the exact mechanism of ARV dysfunction using in vitro phantom models.MethodsTwo experimental models were designed to evaluate two important environmental factors suspected to cause ARV malfunction, i.e. bile flow and pH. Three types of ARV metal stents from different companies were used for the experiments: a funnel type ARV, a windsock type ARV, and a wine glass-shaped ARV. Ten stents of each type were tested (five stents in the bile flow phantom model, and another five stents in the duodenal pH environmental model). To determine ARV malfunction, ARV-induced flow resistance was measured using a custom-made testing device. All stents from the two models were removed every 2 weeks for 12 weeks after stent insertion and were evaluated on morphological and functional changes of the ARV.ResultsOnly ARV of wine glass-shaped ARV was morphologically changed due to silicone bond detachment in the bile flow model. All types of ARV were morphologically changed in the pH model. The morphological changes of ARV influenced the flow resistance. The antegrade pressure gradients were increased over time in the pH model (p < 0.05).ConclusionsMorphological change of the ARVs may induce dysfunction of ARV metal stents, which is mainly due to duodenal pH environment. In the future, development of new ARV that is not affected by duodenal environmental factors can be expected to improve stent patency.Electronic supplementary materialThe online version of this article (10.1186/s12876-018-0878-8) contains supplementary material, which is available to authorized users.

Objectives:The clinical outcomes and prevalence of adverse events associated with biliary biodegradable stents (BS) can differ according to degradation process and time. The aim of this study was to observe the degradation process and time of different BS prototypes, and to evaluate sequential changes in their mechanical properties.Methods: Using an in vitro bile flow phantom model, we compared degradation time, radial force changes, and morphologic changes among four different BS prototypes: polydioxanone (PDO) BS, polyglycolide (PGA) BS, polydioxanone/ poly-L-lactic acid (PDO/PLLA) sheath-core BS, and polydioxaone/magnesium (PDO/Mg) sheath-core BS. Using an in vivo swine bile duct dilation model, we performed a direct peroral cholangioscopy (DPOC) examination to observe the biodegradation process and related adverse events at regular intervals. Results:In the bile flow phantom model, the PGA BS and PDO/ Mg BS prototypes showed rapid radial force reduction and morphological changes and complete degradation within six weeks. PDO/PLLA BS maintained high radial force and kept their original shape for longer than the PDO BS, up to 16 weeks. A total of 24 BS were inserted into the dilated bile ducts of 12 swine. In this animal model, DPOC examination revealed that PDO BS and PDO/PLLA BS maintained their original shapes for approximately 12 weeks, but PDO BS showed a greater degree of fragmentation and induced biliary stones and bile duct obstruction. Conclusion:Our results showed that PDO/PLLA BS maintained their original shape and radial force for a relatively long time and minimized adverse events.

Purpose The current drain tubes for preventing surgically biliary anastomotic stricture are not naturally and easily removed. If a drain tube using biodegradable material is easily available and the degradation time of the tube is well controlled, surgical anastomotic stricture and fibrosis could be prevented. The aim of this animal study was to evaluate the preventive effect of novel biodegradable stents (BS) on biliary stricture and fibrosis after duct-to-duct (DD) biliary anastomosis. Methods Ten mini-pigs were allocated to the control group (n = 5) and or the stent group (n = 5). The common bile duct was exposed through surgical laparotomy and then resected transversely. In the stent group, a 4-mm or 6-mm polydioxanone/magnesium sheath-core BS was inserted according to the width of the bile duct, followed by DD biliary anastomosis. In the control group, DD biliary anastomosis was performed without BS insertion. Results In the stent group, stents were observed without deformity for up to 4 weeks in all animals. Eight weeks later, histopathologic examination revealed that the common bile duct of the anastomosis site was relatively narrower in circumference in the control group compared to the stent group. The degree of fibrosis in the control group was more marked than in the stent group (3.84 mm vs. 0.68 mm, respectively; P < 0.05). Conclusion Our study showed that novel BS maintained their original shape and radial force for an adequate time and then disappeared without adverse events. The BS could prevent postoperative complications and strictures after DD biliary anastomosis.

Background: For laparoscopic cholecystectomy, pain is most frequent complaint and the most common cause of delayed discharge. The aim of this study was to determine the effect of preoperative administration of celecoxib on the level of postoperative pain in patient undergoing laparoscopic cholecystectomy.Methods: We enrolled 60 patients ASA class I and II, scheduled for elective laparoscopic cholecystectomy. The patients were randomized to receive celecoxib 200 mg, celecoxib 400 mg or placebo two hour before the induction of anesthesia. The patients received the same anesthetics. The intensities of abdominal pain were assessed using VAS (visual analog scale) at 1, 2, 4, 12, 24 hours after surgery.Results: In celecoxib 200 mg group, VAS score of somatic pain compared to control group decreased at 1, 2, and 4 hours after surgery. In celecoxib 400 mg group, VAS score of somatic pain compared to control group decreased at 1, 2, and 4 hours after surgery. There was no difference between celecoxib 200 mg and celecoxib 400 mg in pain scores of somatic pain. Dosage of meperidine in two celecoxib groups after surgery were each 31 mg and 26 mg and that of control group was 72 mg. There was no difference between celecoxib groups and placebo group in pain scores of visceral pain.Conclusions: The preoperative administration of celecoxib reduces the level of postoperative pain after laparoscopic cholecystectomy without adverse effects.

Non-puerperal uterine inversion is a rare clinical problem with only 150 cases reported. It usually results from a tumor implanted on fundus of the uterus. Uterine inversion associated with pelvic organ prolapse (POP) is extremely rare with only 1 case reported. A 74-year-old multiparous menopausal women was admitted to our hospital with the following condition: purulent vaginal discharge, voiding diffi culty, lower abdominal discomfort, vaginal bleeding, protruding vaginal mass and POP. She was diagnosed as a POP with uterine inversion. After a posterior hysterotomy, vaginal hysterectomy, bilateral salpingoophorectomy and colpocleisis was performed and the pathological examination revealed a pyometra. We report a rare case of uterine inversion associated with POP and pyometra with a brief review of literature.