Fig. 6

Range of motion (ROM) in flexion, extension, lateral bending after the two-level laminectomy and posterior fixation. All the data were normalized with respect to the intact condition (dashed green line), and averaged between all the specimens. A value larger than 1.0 indicates an increase of the range of motion with respect to the intact condition. The box plot summarizes the distribution of all 12 specimens tested. The bottom of the box represents the first quartile (25th percentile) of the data; the horizontal line inside the box represents the median of the data, and the top of the box represents the third quartile (75th percentile). The “X” cross represents the mean of the data. The top and bottom whiskers include the maximum and the minimum data, excluding the outliers which are shown as dots. The asterisks * above the box indicate a statistically significant differences with respect to the intact condition (p < 0.05). The asterisks * above the squared brackets indicate a significant difference between the laminectomy and fixation conditions.