Background and Aims Stent migration and subsequent adverse events are frequently observed in the use of fully covered self-expandable metal stents (FCSEMSs) for distal biliary stenosis. In this study, we identified predictors for stent migration based on biomechanical stent characteristics and associated these findings with clinical outcomes. Methods The migration resistance of FCSEMSs was quantified by measuring the pull-out force. We analyzed a single-center retrospective cohort of 178 FCSEMSs for treatment success and adverse events occurring during 180 days of follow-up. Results Biomechanical measurements revealed a 4-fold higher migration resistance of FCSEMSs with anchoring fins (AF-FCSEMSs; Fmax = 14.2 ± .1 N) compared with FCSEMSs with flared ends (FE-FCSEMSs; Fmax = 3.8 ± 1.0 N; P < .0001). Clinically, AF-FCSEMSs showed lower rates of migration compared with FE-FCSEMSs (5% vs 34%, P < .0001). Unscheduled ERCP procedures because of stent dysfunction were less frequent in the AF group compared with the FE group (15% vs 29%, P = .046). Cholangitis because of stent dysfunction was observed in 5% of the AF group compared with 19% in the FE group (P = .02). Stent patency rates at 1, 3, and 6 months were higher in the AF group (96%, 90%, and 80%, respectively) compared with the FE group (90%, 74%, and 66%; log-rank test: P = .03). Conclusions The pull-out force as a biomechanical stent property predicts the migration resistance of FCSEMSs in distal biliary stenosis and may thus be used to classify stents for this application. AF-FCSEMSs showed a significantly lower rate of migration and adverse events compared with FE-FCSEMSs.

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2014. / Background: Classical ballet is an art form that seems graceful on the surface. However, beneath the disguise of beauty and ease lies an extremely physically demanding activity that calls for dedication, strength and perseverance. Ballet requires a specific body type and precise techniques, which predispose the dancer to musculoskeletal injury. Although a few studies have been conducted to investigate biomechanical factors as risk factors for injury in ballet dancers, few have included amateur ballet dancers and a range of biomechanical factors. Objectives: This study aimed to determine characteristics of ballet-related injury in amateur ballet dancers in the greater Durban area; to measure and record lower limb biomechanical measurements of these dancers; and to identify associations between the biomechanical measurements and characteristics of injury in the population. Method: A quantitative, questionnaire-based survey with biomechanical measurements was conducted on 21 amateur ballet dancers in the greater Durban area. Statistical analysis included the description of categorical variables using frequency and percentages in tables and bar charts. Continuous variables were summarised using mean, standard deviation and range, or median and range as appropriate. Independent Sample T-tests were used to compare biomechanical measurements between two independent groups. A p value <0.05 was considered as statistically significant. Pearson’s correlations and ANOVA testing were also used. Results: The period prevalence of ballet-related injury over the last 2 years was found to be 62% and the point prevalence 38%. There were 37 total previous injuries, most of which occurred in the hamstring (24%). Most of the worst previous injuries were reported to have occurred in the low back (31%). Most of the worst previous (70%) and current (93%) injuries occurred over time. The worst previous injuries reported ranged from mild to severe in severity, while the worst current injuries reported ranged from mild to moderate. Significant associations were found between right weight-bearing ankle dorsiflexion and previous injury; right weight-bearing ankle dorsiflexion and current injury; ‘functional turnout’ and onset of injury; right non weight-bearing ankle dorsiflexion and onset of injury; and ‘compensated turnout’ and onset of injury. Conclusion: The results suggest a significant association between musculoskeletal ballet-related injury and reduced weight-bearing ankle dorsiflexion; between injuries that occur over time (overuse injuries) and decreased ‘functional turnout’; and between overuse injuries and decreased non weight-bearing ankle dorsiflexion. These findings may help identify risk factors for injury in ballet dancers and contribute towards preventing ballet-related injury. / M

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2014. / Background: Classical ballet is an art form that seems graceful on the surface. However, beneath the disguise of beauty and ease lies an extremely physically demanding activity that calls for dedication, strength and perseverance. Ballet requires a specific body type and precise techniques, which predispose the dancer to musculoskeletal injury. Although a few studies have been conducted to investigate biomechanical factors as risk factors for injury in ballet dancers, few have included amateur ballet dancers and a range of biomechanical factors. Objectives: This study aimed to determine characteristics of ballet-related injury in amateur ballet dancers in the greater Durban area; to measure and record lower limb biomechanical measurements of these dancers; and to identify associations between the biomechanical measurements and characteristics of injury in the population. Method: A quantitative, questionnaire-based survey with biomechanical measurements was conducted on 21 amateur ballet dancers in the greater Durban area. Statistical analysis included the description of categorical variables using frequency and percentages in tables and bar charts. Continuous variables were summarised using mean, standard deviation and range, or median and range as appropriate. Independent Sample T-tests were used to compare biomechanical measurements between two independent groups. A p value <0.05 was considered as statistically significant. Pearson’s correlations and ANOVA testing were also used. Results: The period prevalence of ballet-related injury over the last 2 years was found to be 62% and the point prevalence 38%. There were 37 total previous injuries, most of which occurred in the hamstring (24%). Most of the worst previous injuries were reported to have occurred in the low back (31%). Most of the worst previous (70%) and current (93%) injuries occurred over time. The worst previous injuries reported ranged from mild to severe in severity, while the worst current injuries reported ranged from mild to moderate. Significant associations were found between right weight-bearing ankle dorsiflexion and previous injury; right weight-bearing ankle dorsiflexion and current injury; ‘functional turnout’ and onset of injury; right non weight-bearing ankle dorsiflexion and onset of injury; and ‘compensated turnout’ and onset of injury. Conclusion: The results suggest a significant association between musculoskeletal ballet-related injury and reduced weight-bearing ankle dorsiflexion; between injuries that occur over time (overuse injuries) and decreased ‘functional turnout’; and between overuse injuries and decreased non weight-bearing ankle dorsiflexion. These findings may help identify risk factors for injury in ballet dancers and contribute towards preventing ballet-related injury. / M