“…Overall, 2944 procedures were performed with a mean caseload of 87 procedures per study (range 25–660). There were 13 and 20 studies in the medium-volume [ 6 – 9 , 12 , 13 , 16 , 17 , 20 , 31 , 33 ••, 35 , 36 ] and high-volume [ 4 , 5 , 10 , 11 , 14 , 15 , 18 , 19 , 21 – 24 , 25 •, 26 – 30 , 32 , 34 ] groups respectively. Given the paediatric data from the CROES database that was gathered from over 50 centres, it was excluded from this subclassification although the data was used for the overall results [ 37 ].…”