Continuous variables are expressed as mean values ±
standard deviations. Categorical data are presented by
frequencies and percentage. For the comparison of the
measured angles of the vertebral bodies at three different
time points we performed a repeated measures analysis
of variance (ANOVA) with type of surgery (cage vs. autologous
graft) as grouping factor. Differences of VAS
and VAS spine score at follow-up, ODI and SF-36 items
between subgroups (defined above) were analyzed by
means of t-tests. As all statistical tests were conducted
solely in an explorative manner, no αlpha-adjustment for
multiple testing was carried out. Thus, p-values of p ≤
0.05 could be interpreted as statistically significant test
results with respect to the investigated collective of this
study.
Statistical analyses were carried out by the SAS statistical
analysis software package (SAS for Windows, Version
9.1; SAS Institute, Cary, NC, USA).