The learning curve for colorectal stent insertion for the treatment of malignant colorectal obstruction

Background/Aims

We aimed to assess the effectiveness of self-expanding metal stent (SEMS) insertion by evaluating the learning curve in relation to the experience of an endoscopist.

Methods

We retrospectively analyzed the outcomes of 120 SEMS insertion procedures performed by one endoscopist in patients with malignant colorectal obstruction. We compared the technical and clinical success rates, complication rates, and duration of the procedures by quartiles.

Results

The mean age of the patients (76 men and 44 women) was 64.6 years. The overall technical success rate was 95.0% (114/120), and the clinical success rate was 90.0% (108/120). The median procedure duration was 16.2 minutes (range, 3.4 to 96.5 minutes). From the first to the last quartile, the technical success rates were 90.0%, 96.7%, 96.7%, and 96.7% (p=0.263), and the clinical success rates were 90.0%, 90.0%, 96.7%, and 83.3% (p=0.588), respectively. Procedure-related complications were observed in 28 patients (23.3%). The complication rates for SEMS insertion when patients were divided by quartiles were 26.7%, 23.3%, 10.0%, and 33.3% (p=0.184), respectively. Moreover, the number of stents per procedure was 1.13, 1.03, 1.00, and 1.00 (p=0.029), respectively. The median duration of SEMS insertion decreased significantly, 20.9 to 14.8 minutes after the first 30 procedures (p=0.005).

Conclusions

An experienced endoscopist was able to perform the SEMS insertion procedure easily and effectively after performing 30 SEMS insertions.     

Structural and Mechanical Characterization of Zr58.5Ti8.2Cu14.2Ni11.4Al7.7 Bulk Metallic Glass

Thermal stability, structure and mechanical properties of the multi-component Zr_58.5Ti_8.2Cu_14.2Ni_11.4Al_7.7 bulk metallic glass have been studied in detail. The glassy material displays good thermal stability against crystallization and a fairly large supercooled liquid region of 52 K. During heating, the alloy transforms into a metastable icosahedral quasicrystalline phase in the first stage of crystallization. At high temperatures, the quasicrystalline phase undergoes a transformation to form tetragonal and cubic NiZr₂-type phases. Room-temperature compression tests of the as-cast sample show good mechanical properties, namely, high compressive strength of about 1,630 MPa and fracture strain of 3.3%. This is combined with a density of 6.32 g/cm³ and values of Poisson’s ratio and Young’s modulus of 0.377 and 77 GPa, respectively. The mechanical properties of the glass can be further improved by cold rolling. The compressive strength rises to 1,780 MPa and the fracture strain increases to 8.3% for the material cold-rolled to a diameter reduction of 10%.     

Endoscopic duodenal stent versus surgical gastrojejunostomy for gastric outlet obstruction in patients with advanced pancreatic cancer

Background

Malignant gastric outlet obstruction (GOO) often develops in patients with advanced pancreatic cancer (APC). It is not clear whether endoscopic duodenal stenting (DS) or surgical gastrojejunostomy (GJJ) is preferable as palliative treatment.

重症脑卒中患者体内7种元素与低蛋白血症的关系

目的：探讨重症脑卒中患者体内7种元素水平与低蛋白血症的关系。方法选取乌鲁木齐市3家三甲医院（乌鲁木齐市友谊医院,新疆医科大学附属中医医院,新疆医科大学第五附属医院）住院的重症脑卒中患者200例,分为低蛋白血症组（ALB 30～35 g/L 者76例,ALB 25～30 g/L 者48例,ALB＜25 g/L 者8例）及对照组（ALB≥35 g/L 者68例）。于入院第7天检测血清白蛋白和全血铅（Pb）、镉（Cd）、钙（Ca）、铜（Cu）、镁（Mg）、铁（Fe）、锌（Zn）7种元素水平,比较低蛋白血症组和对照组7种元素水平的差异。结果低蛋白血症组患者体内的7种元素水平与对照组的差异均无统计学意义（P ＞0．05）,并且均不是重症脑卒中患者低蛋白血症发病的危险因素（P ＞0．05）。结论在短期内重症脑卒中患者体内7种元素水平与低蛋白血症发病无关。     

Metallic stents are more efficacious than plastic stents in unresectable malignant hilar biliary strictures: a randomized controlled trial

Background

Endoscopic biliary stenting is a well-established palliative treatment for unresectable malignant biliary strictures, for which plastic tube stents (PSs) and self-expandable metallic stents (SEMSs) are most commonly used. The efficacy of these stents has been extensively described in distal biliary strictures, but not in hilar biliary strictures. The present study aimed to compare the efficacy of PSs and SEMSs for unresectable malignant hilar biliary strictures.

Methods

From June 2004 to November 2008, 60 patients were enrolled and prospectively randomized into the PS or SEMS group.

Results

The 6-month patency rate was significantly higher in the SEMS group than in the PS group (81 vs. 20%; p = 0.0012). Kaplan–Meier analysis showed significantly longer patency in the SEMS group than in the PS group (p = 0.0002); the 50% patency period was 359 days in the SEMS group and 112 days in the PS group. There was no significant difference in the overall survival period between the PS and SEMS groups (p = 0.2834). The mean number of reinterventions for stent failures was significantly lower in the SEMS group (0.63 times/patient) than in the PS group (1.80 times/patient) (p = 0.0008). The overall total cost for the treatment was significantly lower in the SEMS group than in the PS group (p = 0.0222).

Conclusions

SEMSs were associated with a longer patency than PSs in patients with unresectable hilar biliary stricture. SEMSs were also more advantageous in reducing the number of reintervention sessions and the overall treatment cost.     

COVERED WALLSTENT FOR PALLIATION OF MALIGNANT COMMON BILE DUCT STRICTURE: PROSPECTIVE MULTICENTER EVALUATION

Background: Occlusion due to tumor ingrowth is a major drawback in self‐expandable metallic stents. Covering the stent is a probable solution to prevent tumor ingrowth. A manufactured covered self‐expandable metallic stent, Covered Wallstent, has become commercially available. We evaluated the Covered Wallstent in a prospective uncontrolled multicenter setting. Methods: Between October 2001 and October 2003, 97 patients with common bile duct strictures deemed unfit for surgical resection underwent placement of a single Covered Wallstent, and were followed prospectively until April 2004. Results: Placement of the stent was successful in all the patients attempted. As a procedure‐related complication, acute pancreatitis developed in four patients, in one of whom obstruction of the pancreatic duct orifice with the stent body seemed to be a major cause. The 30‐day mortality was 9.3% (nine patients). Stent occlusion occurred in 22 patients as a late (greater than 30 days) complication, due to either tumor overgrowth (14 patients) or encrustation (eight patients). Distal migration of the stent was demonstrated in two other patients. No stent occlusions due to tumor ingrowth were observed. Patency rates of the stent for 3‐, 6‐, and 12‐month periods were, respectively, 90.7, 82.5, and 45.9%. Conclusions: The present results in a large series suggest that placement of the Covered Wallstent is feasible and effective in the palliation of patients with malignant common bile duct strictures. The Covered Wallstent seems to be reliable in eliminating tumor ingrowth. The role of stent covering in promoting stent function should be examined in a prospective comparative study between covered‐ and uncovered Wallstents.     

Expandable Metallic Stents: in the Benign Strictures of Intrahepatic Ducts in Patients with Primary Intrahepatic Stones

Abstract: In Korea there is a prevalence for primary intrahepatic stones. Patients with primary intrahepatic stones and oriental cholangiohepatitis ofen have accompanying intrahepatic strictures. Despite complete removal of the intrahepatic stones, sustained intrahepatic strictures will evoke bile stasis and impairment of liver function. So the correction of intrahepatic strictures in addition to the removal of the stones is important in the management of primary intrahepatic stones. We inserted self-expandable metallic stents in 16 patients with primary intrahepatic stones for the correction of intrahepatic strictures after complete removal of their intrahepatic stones. All of the patients had a previous history of abdominal surgery for the removal of intrahepatic stones. The criteria for insertion of expandable metallic stents was recurrent stenosis after successful balloon dilatation. The metallic stents inserted were Gianturco-Rosch stents (24F) and the stents were inserted via a T-tube or percutaneous transhepatic biliary drainage (PTBD) track. In the follow-up period of an average of 12 months (9–15 months), 14 (88%) out of 16 patients experienced relief of pruritus and improved liver function. But two patients (12%) with secondary biliary cirrhosis showed no improvement of their clinical symptoms and signs. In conclusion, these findings suggest that expandable metallic stents will be useful in the management of intrahepatic strictures, which recurred after successful balloon dilatation, in patients with primary intrahepatic stones.     

Salt-dependent conformational diversity of alternating poly (Glu-Leu)

Alternating poly(Glu-Leu) was synthesized by the condensation of the corresponding dipeptide p-nitrophenyl ester at high concentration. It exhibits a random coil structure in pure water at neutral pH. Addition of monovalent cations, such as NH⁺₄ to a final 0.1 M solution, induces a transition to a water soluble β-structure. The salt effect is quite selective since no transition was observed with Li⁺, Na⁺ or Cs⁺ ions. Addition of 0.5 equiv. of calcium, cobalt or manganese chlorides per glutamyl residue induces similar coil to β-sheet transitions. No polymer precipitation was observed at these very low salt concentrations. Addition of 0.5 equiv. of Cu²⁺ or 0.15 equiv. of Fe³⁺ induces a coil to α-helix transition. Molecular modeling has been used to understand tentatively the main factors controlling the different conformations observed with the various metal ions. © Munksgaard 1997.     

Utilization of autologous vein graft for replacement of the inferior vena cava in living-donor liver transplantation for obliterative hepatocavopathy

Obliterative hepatocavopathy (OHC) is a subtype of Budd-Chiari syndrome in which stenosis or obstruction of the retrohepatic inferior vena cava (IVC) is observed. Although IVC replacement is necessary in OHC patients, there are hardly any graft vessels available for IVC reconstruction during living-donor liver transplantation (LDLT). Here, we describe a novel technique of IVC reconstruction using only the autologous blood vessels in an OHC patient during LDLT. In this case, sufficient drainage of the hepatic outflow and reconstruction of the venous return from the lower half of the body were simultaneously required. Therefore, we substituted the retrohepatic IVC with the suprarenal IVC of the recipient, and we reconstructed the IVC continuity by using the autologous internal jugular vein and external iliac vein. The operation was safe, and the postoperative venous drainage from the hepatic tributaries was in good condition. This procedure might be an option for IVC replacement during LDLT.