Figure 8

Change in intervertebral disc space wedge angle during the simulated surgical steps for Force profile B; (A). Patient three, (B). Patient four. Note the Σ values represent the cumulative sum of the disc wedge angles at the beginning and end of the analysis and equate to the portion of the overall coronal Cobb angle due to disc wedging. The schematics show an anterior view of the spinal column for each patient, with the disc wedge angles delineated according to the legend for the bar-chart, highlighting positive, negative and zero disc wedge angles. (Note that the ordering of the disc wedge angles in the stacked bars does not reflect the anatomical ordering in the spinal column since in some cases adjacent discs have oppositely signed wedge angles.)