Do salivary bypass tubes lower the incidence of pharyngocutaneous fistula following total laryngectomy? A retrospective analysis of predictive factors using multivariate analysis

Salivary bypass tubes (SBT) are increasingly used to prevent pharyngocutaneous fistula (PCF) following laryngectomy and pharyngolaryngectomy. There is minimal evidence as to their efficacy and literature is limited. The aim of the study was to determine if SBT prevent PCF. The study was a multicentre retrospective case control series (level of evidence 3b). Patients who underwent laryngectomy or pharyngolaryngectomy for cancer or following cancer treatment between 2011 and 2014 were included in the study. The primary outcome was development of a PCF. Other variables recorded were age, sex, prior radiotherapy or chemoradiotherapy, prior tracheostomy, type of procedure, concurrent neck dissection, use of flap reconstruction, use of prophylactic antibiotics, the suture material used for the anastomosis, tumour T stage, histological margins, day one post-operative haemoglobin and whether a salivary bypass tube was used. Univariate and multivariate analysis were performed. A total of 199 patients were included and 24 received salivary bypass tubes. Fistula rates were 8.3% in the SBT group (2/24) and 24.6% in the control group (43/175). This was not statistically significant on univariate (p value 0.115) or multivariate analysis (p value 0.076). In addition, no other co-variables were found to be significant. No group has proven a benefit of salivary bypass tubes on multivariate analysis. The study was limited by a small case group, variations in tube duration and subjects given a tube may have been identified as high risk of fistula. Further prospective studies are warranted prior to recommendation of salivary bypass tubes following laryngectomy

Spinal muscular atrophy: DNA fragmentation and immaturity of muscle fibers

The presence of apoptotic fibers and the embryonic proteins desmin and vimentin were investigated in muscle biopsy specimens from patients with spinal muscular atrophy (SMA). Apoptosis was studied in 24 cases of SMA by means of in situ end labeling of nuclear DNA fragmentation using TUNEL staining and immunohistochemistry. Apoptotic nuclei were observed in 54.1% of the cases, and desmin and vimentin positive fibers were found in the majority of cases. A significant negative correlation was observed between the number of apoptotic nuclei and the duration of the disease, as well as between the number of desmin and vimentin positive fibers and the age of onset. These findings indicate that apoptosis, although probably a secondary phenomenon following denervation, plays a role in the progress of spinal muscular atrophy. © 2007 Elsevier GmbH. All rights reserved

Experimental study of a three-storey concrete frame structure with smooth bars under cyclic lateral loading

Past lateral cyclic or seismic tests of concrete frames with smooth bars in columns are very few and limited as far as the test structure’s size and geometry are concerned; moreover, they have not focused on the effect of detailing and lap-splicing of such bars on local and global behaviour. To help fill this knowledge gap with new data, the paper presents the cyclic lateral load test of a 2:3-scale three-storey, one-by-two-bay, strong beam-weak column RC frame, focusing on the effects of the column’s smooth bars and of their detailing on local and global behaviour. Slippage of bars caused concentration of column deformations in flexural cracks at the top and base sections and gave to the global hysteresis loops a shape typical of bond-slip behaviour, but without cyclic strength decay. Despite chord rotation demands of up to 0.055 rads and storey drifts of almost 5%, damage was limited and had nothing to do with the use of smooth bars in the columns. Despite the important role of bar slippage for the response, bar strains show that wherever the surrounding concrete was in compression, column bars were in compression as well. Lap splices at and/or FRP wrapping of column end regions did not have systematic effects on column behaviour. Overall, no adverse effect of the use of smooth bars was identified

Mechanical response of an industrial piping system under strong cyclic loading

The paper presents a combined experimental and numerical investigation of cyclic loading response of an internally pressurized steel piping system. The piping system comprises three elbows and is subjected to quasi-static end-displacement excitation. Global deformation and local strain measurements are obtained, indicating significant strain ratcheting at the critical locations of the elbows. The piping system failed under lowcycle fatigue undergoing through-thickness cracking at the flank of the most strained elbow. Post-fatigue metallographic examination of the elbows indicated that fatigue cracking initiates from the inner surface of the pipe elbow. In all elbows, several micro-cracks develop along the inner surface of elbow flanks, whereas the outer surface remained practically intact before through-thickness cracking. Finite element simulations, with a properly calibrated cyclic-plasticity model calibrated properly in terms of small-scale material tests, provide very good predictions in terms of local strain evolution at critical locations. Copyright © 2021 by ASME