Pre-operative stenting is associated with a higher prevalence of post-operative complications following pancreatoduodenectomy

AbstractObjectivesWhilst there are theoretical benefits from pre-operatively draining the biliary tree prior to pancreatoduodenectomy (PD), the current literature does not support this intervention. The aim of this study was to explore the relationship between pre-operative stenting, bactibilia and outcome in a large United Kingdom tertiary referral practice.MethodsPatients undergoing PD were identified from a prospectively maintained database. The presence or absence of a stent prior to PD, and the results of bile cultures taken at PD were related to the subsequent post-operative course and the development of complications.Results280 patients underwent PD for periampullary malignancies, all of whom presented with jaundice. 118 patients were stented prior to referral (98 ERCP, 20 PTC). Bile cultures were positive more frequently in the stent group (83% vs. 55%; p = 0.000002) and bactibilia was more common after ERCP than PTC (83% vs. 56%; p = 0.006). The overall prevalence of complications was 54% in the stented and 41% in the non-stented group (p = 0.03) with statistical significance achieved for pancreatic leak (p = 0.013) and haemorrhagic complications (p = 0.03). Comparing stent with no stent, there as no difference in the 30-day mortalities (8.5% vs. 6.8%; p = 0.6) or the 1-year mortality rates (35% vs. 28%; p = 0.21). Mortality rates in the infection versus no infection groups were comparable at 30 days (8.5% vs. 5.5%; p = 0.21), and at 1 year (30.7% vs. 26.4%; p = 0.25).ConclusionsPre-operative stent insertion prior to PD is associated with increased morbidity but not mortality and this is greatest for stents placed at ERCP

Physicochemical and structural factors in the sulfuric acid leaching of nickel- and copper-bearing synthetic birnessites

A large number of nickel- and copper-doped samples of birnessite (0.7 nm phase), a layered-structure manganese mineral, were synthesized by dehydration of respective buserites (1 nm phase). The samples were characterized in terms of chemical composition, specific surface area, phase constituents, crystallinity, strain, morphological features, and structural complexity, in order to study the influence of the physicochemical characteristics of the samples on the leachability of doped elements and manganese in sulfuric acid. In contrast to manganese, the leaching behavior of doped nickel and copper is found to be more sensitive to the structural characteristics of the host birnessite phase. The leachability of the doped elements does not show any correlation with the specific surface area of the samples. Significant parameters affecting leachability are the interlayer spacing of the parent buserite phase used in the synthesis and the microcrystalline dimension and strain in the 〈001〉 crystallographic direction of the birnessite phase. In addition, leachability is also controlled by the crystal field stabilization energy (CFSE) of the doped metal ion. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies on leach residues indicated the transformation of birnessite phase into other minerals such as nsutite (γ-MnO2). A significant fraction of the doped nickel and copper (20 to 40 pct) remains unleached, even after prolonged leaching up to 6 days, and this is attributed to the compact structure of the newly formed phases during leaching