highly significantp < 0.001
Quality performance indicators could clearly show a highly significant improvement > 150 patients in SI (≤ 150: 0.38 ± 0.1 to > 151 0.44 ± 0.1; p < 0.001) and LSD (≤ 150: 0.51 ± 0.2 to > 151: 0.65 ± 0.23; p < 0.001) eventually resulting in a SL/WL-ratio of 6.1 ± 2.3 (> 151–351) coming from 5.6 ± 2.5 (1–151; p < 0.001, Fig. 3 ).