Fig. 2

Comparison of VAS scores and ODI before and after surgery in the two groups. All patients were followed up for at least 22 months. Compared with before surgery (BS), both VAS (a) and ODI (b) scores of the two groups during the follow-up period [1 day (1D), 6 months (6 M), 1 year (1Y), 2 years (2Y), and final follow up (FF)] were shown significantly lower. However, there was no significant difference of both scores between PVP and PKP groups at each time point postoperatively. *P < 0.05 vs BS in each group