Fig. 4.

Box plots (median with 25th – 75th percentile, upper and lower percentiles [whiskers] and outliers [dots]) showing the segmental kyphosis angle (in degree; y-axis) of patients undergoing bisegmental instrumentation or primary monosegmental fusion (A) or of patients undergoing single- vs. 2-staged bisegmental instrumentation (B). Fig. 4A: Note the wider percentiles for the monosegmental fusion group for smaller group size (n=6 vs. n=55) but also less reproducible kyphosis reduction. Fig. 4B: Note the tighter percentiles in the 2-staged group, indicating a more reproducible kyphosis reduction. * = p<.05; *** = p<.001; n.s. = not significant.