Improving the Quality of Friction Stir Welds in Aluminium Alloys

The Stationary Shoulder Friction Stir Welding (SS-FSW) technique benefits from reduced heat input, improved mechanical properties and surface finish of the weld, avoiding the need for post weld processing. Coatings on the tool probe and the shoulder for welding of aggressive Aluminium alloys have rarely been successful. Such coatings must be well adherent and inert. In this study, coated tools were used for SS-FSW of AA6082-T6 alloy. Performance of a nanoscale multilayer TiAlN/VN coating deposited by High Power Impulse Magnetron Sputtering (HIPIMS) technology was compared with amorphous Diamond Like Carbon (a-C:H) by Plasma Assisted Chemical Vapour Deposition (PACVD), AlTiN deposited by arc evaporation and TiBCN along with TiB2 produced by Chemical Vapour Deposition (CVD) methods. The TiAlN/VN coating was found to have low affinity to aluminium, acceptable coefficient of friction and provided excellent weld quality by inhibiting intermixing between the tool and workpiece materials resulting in a significant reduction in tool wear

Functional outcomes and complications after salvage total laryngectomy for residual, recurrent, and second primary squamous cell carcinoma of the larynx and hypopharynx : a multicenter retrospective cohort study

Background/Purpose: We analyzed complications and functional outcomes and aimed at identifying prognostic factors for functional outcomes and complications in patients who underwent salvage total laryngectomy (STL) for residual, recurrent, and second primary squamous cell carcinoma (SCC) of the larynx and hypopharynx after initial (chemo)radiation. Methods: Retrospective cohort study of patients who underwent STL in four major Belgian reference hospitals between 2002 and 2018. Prognostic factors for functional outcomes and complications were identified with uni- and multivariable analysis. Results: A total of 405 patients were included in the final analysis. STL was performed for residual tumor (40.2%), local recurrence (40.5%), or second primary laryngeal or hypopharyngeal SCC (19.4%). Early postoperative complications were experienced by 34.2% of patients: postoperative hemorrhage occurred in 5.4%, wound infection in 16.2%, and clinical pharyngocutaneous fistula (PCF) in 25.5% of patients. Early readmission proved necessary in 15.1% of cases, most often due to late PCF development (72.2%). Patients achieved total peroral intake in 94.2% of cases. However, subjective dysphagia was reported by 31.3% of patients during follow-up. Functional speech, defined as functional communication by speech without additional aids, was reported in 86.7% of cases and was most often achieved by tracheo-esophageal puncture (TEP) (94.1%). In a multivariable model, lower preoperative hemoglobin (<12.5 g/dl) was identified as an independent prognostic factor for higher overall complication rate. No risk factors were found significant for clinical fistula formation. Vascularized tissue augmentation did not significantly prevent clinical PCF. Patients with positive section margins, patients initially treated with surgery combined with adjuvant RT (vs. radiotherapy alone), and those developing PCF after STL were less likely to achieve total peroral intake. Postoperative dysphagia proved more likely in patients who developed a PCF postoperatively, and less likely in patients who underwent STL without partial pharyngectomy and in patients with myocutaneous pectoralis major (PM) flap reconstruction, compared to muscle onlay PM flap. Achieving postoperative functional speech proved most likely in patients with smaller tumors (lower pT classification) and free section margins. Conclusion: Substantial complication rates and favorable functional outcomes are reported after STL

Pijler 'Wetgevende macht'

status: publishe

Pijler 'Verkiezingsautoriteit'

status: publishe

ASO Author Reflections: Salvage Total Laryngectomy, the Last Resort for Patients with Residual, Recurrent or Second Primary Laryngeal and Hypopharyngeal Cancer in Times of Nonsurgical Organ Preserving Treatment Strategies

status: publishe

Bij wijze van achtergrond: toenemende aandacht voor een onafhankelijk onderzoek na(ar) rampen in België

status: publishe

Prognostic value of 18F-FDG PET/CT radiomics in patients undergoing salvage total laryngectomy for a recurrent or second primary squamous cell carcinoma of the larynx and hypopharynx

Aim/Introduction: Salvage total laryngectomy (STL) is a valid treatment option for patients with a residual, recurrent or second primary squamous cell carcinoma of the larynx and hypopharynx after primary (chemo)radiation therapy. Although oncological outcomes are satisfactory, the prognosis after STL is highly variable between patients. As most prognostic markers for recurrence after STL are based on pathological assessment after the surgical removal of the tumor, we hoped to identify pre-operative prognostic factors by using texture analysis of presurgical ¹⁸F-FDG PET/CT imaging. Materials and Methods: In this multicenter retrospective study, 55 patients undergoing STL that received a presurgical ¹⁸F-FDG PET/CT were eligible for inclusion. Robustness of the radiomics features was analyzed by the intraclass coefcient (>0.7) on three delineation methods (1) manual delineation by an experienced nuclear medicine physician; (2) 40% of the SUVmax, and (3) three standard deviations above the liver SUVmean. In addition, the impact of the features on patient overall (OS), disease-specifc (DSS) and progression-free survival (PFS) was calculated using univariate Cox regression analysis. The prognostic impact of clinicopathological factors and statistically signifcant radiomics features was visualized by Kaplan-Meier analysis. Results: A total of 55 out of 63 radiomics features proved sufciently robust for further analysis. Besides clinical or pathological prognosticators such as T-status (p=0.004), lymphovascular (p=0.015) and perineural invasion (p=0.013), we identifed eight non-SUV related textural features signifcantly infuencing PFS, but not OS nor DSS, in univariate analysis. Of these features, the Neighbouring Gray-Level Dependency Matrix (NGLDM, p<0.001) and the Gray-Level Co-occurrence matrix dissimilarity (GLCM_dissimilarity, p=0.002) provided the highest signifcance level regarding PFS. Conclusion: This exploratory study delivers an important proof-of-concept which illustrates the potential of standard-of-care imaging in identifying patients at high risk for recurrence after STL. Prospective data are warranted to validate these preliminary fndings