18 research outputs found

    On the way of integrating evacuation approaches

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    With the growing pressure on available urban space and the construction of more and more complex building infrastructures, the navigational task for building users is getting increasingly difficult. As people react more impulsive under stressful situations, emergencies can exacerbate way finding problems. Additionally, leadership and familiarity with the (topological structure of a) building can influence the ease of finding appropriate evacuation routes. In research, two separate and distinctive techniques for modelling evacuation paths have been developed: evacuation simulation modelling through complex computer simulations and 3D network modelling based on graph theory. Taking into account a global user perspective, the 3D network modelling approach has the advantage to preserve a close connection with the semantic building structure. Following this approach, existing three dimensional evacuation routing algorithms tend to use Dijkstra's shortest path algorithm. However, as more factors, compared to path length, influence evacuation situations, literature acknowledges a void in representing more realistic, complete and accurate emergency situations. This paper presents a first step in creating such integral algorithm by implementing capacity constraints based on user flow control on a 3D geometric network model. In the future additional topics such as zonal partitioning can be added to the algorithm, moving to an integration of both evacuation approaches

    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

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    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