Fig. 2

Proportion of patients with Numeric Rating Scale (NRS; a), Short Form-36 Health Survey (SF-36; b) and Oswestry Low Back Pain Disability Index (ODI; c) score improvements of at least 50%, and the number of patients included at each time point. Patients were subdivided into those with a pre-injection NRS ≤ 5 and those with a pre-injection NRS > 5. Values are proportions and 95% confidence intervals. Visits are defined as follows: visit 1 (2 wks), visit 2 (6–8 wks), visit 3 (12 wks), visit 4 (6 mo), visit 5 (≥ 1 yr). The number of patients (N) with follow up data is listed below visit number