Fig. 4. Oswestry disability index (ODI) scores for operated (grey) and non-operated (black) patients at pre-epiduroscopy (0), 1 month, 6 months, and 1 year. There was a significant difference over time between the operated/non-operated and ODI (P < 0.001). Also the interaction between time and operated/non-operated was significant for ODI (P = 0.002).