Table 1.

Overview of analyses

ODI sensitivity to SI pain

Calculation of MCID of ODI for SI pain treatment

Based on the whole sample.  Patients with and without prior lumbar fusion were combined after confirming the absence of statistical difference between the two groups (Table 2)   Overall treatment results: preoperative and postoperative scores for (Table 3) (a) SI pain VAS (b) ODI (c) EQ-5D (d) SF-36 (e) Satisfaction with outcomes of surgery scale (f) Willingness to undergo surgery again scale  ODI sensitivity to SI pain. Correlation between change in SI pain and change in (Table 4) (a) ODI (b) EQ-5D (c) SF-36

Based on two subsets of patients selected according to their answers to two anchors (a) The heath transition item (HTI) of the SF-36 (b) The satisfaction with surgery scale   Correlation between change in ODI and (Table 5; Fig. 1) (a) HTI (b)  Satisfaction scale   MCID calculations. Selection (Table 6) and comparison of patients who reported no change/no satisfaction to patients who reported small change/small satisfaction. These subsets of patients are used for four MCID calculations (Table 7) (a) Minimum detectable change (b) Average change (c) Change difference (d) ROC curve