Table 2.
Treatment Results and Disposition after Facet Block
| Intraarticular Facet Block |
Medial Branch Block |
Saline Injection |
P Value* | ||
|---|---|---|---|---|---|
| Facet block | Number of participants assessed | 90 | 91 | 47 | |
| Percent reduction in preblock pain score (mean ± SD)† | 47±31 | 47±32 | 37±31 | 0.163 | |
| Facet block positive‡ (number, %) | 49 (54%) | 50 (55%) | 14 (30%) | 0.010 | |
| Complications (number, %) | 6 (7%) | 8 (9%) | 2 (4%) | 0.617 | |
| 1-Month outcomes | Number of participants assessed | 89 | 91 | 47 | |
| Reduction in average NRS pain score from baseline (mean ± SD) | 0.7±1.6 | 0.7±1.8 | 0.7±1.5 | 0.993 | |
| Reduction in worst NRS pain score from baseline (mean ± SD) | 1.0±1.9 | 0.9±1.9 | 1.1±2.1 | 0.928 | |
| Reduction in ODI score (mean ± SD) | 3±9 | 3±11 | 2±11 | 0.668 | |
| Medication reduction§ (n/N, %) | 10/75 (13%) | 9/74 (12%) | 6/35 (17%) | 0.775 | |
| Satisfaction score∥ (mean ± SD) | 3.3±1.3 | 3.1±1.3 | 3.1±1.2 | 0.378 | |
| Positive outcome# (n, %) | 11 (12%) | 10 (11%) | 3 (6%) | 0.6177 | |
| 3-Month outcomes | Number of participants assessed | 9 | 9 | 3 | |
| Average NRS pain score (mean ± SD) | 3.2±2.2 | 2.5±2.0 | 2.3±1.2 | 0.724 | |
| Worst NRS pain score (mean ± SD) | 5.0±2.8 | 4.8±2.2 | 7.2±3.7 | 0.410 | |
| ODI score (mean ± SD) | 30±13 | 17±12 | 28±12 | 0.093 | |
| Medication reduction§ (n/N, %) | 1/7 (14%) | 1/5 (33%) | 1/3 (33%) | > 0.9997 | |
| Satisfaction score∥ (mean ± SD) | 4.2±0.9 | 4.2±1.2 | 4.2±1.0 | 0.993 | |
| Positive outcome# (n, %) | 4 (4%) | 4 (4%) | 1 (2%) | > 0.9997 | |
| 6-Month outcomes | Number of participants assessed | 4 | 1 | 0 | — |
| Average NRS pain score (mean ± SD) | 2.6±1.7 | 6 | – | 0.174 | |
| Worst NRS pain score (mean ± SD) | 5.3±3.9 | 8 | – | 0.577 | |
| ODI score (mean ± SD) | 22±9 | 40 | – | 0.148 | |
| Medication reduction§ (n/N, %) | 0/2 (0%) | 0/1 (0%) | – | – | |
| Satisfaction score∥ (mean ± SD) | 4.6±0.8 | 5 | – | 0.685 | |
| Positive outcome# (n, %) | 3 (3%) | 0 (0%) | 0 (0%) | 0.400** | |
| Eligible for radiofrequency (n, %)†† | 46 (51%) | 49 (54%) | 47 (100%) | 0.713 (Groups I and II only) | |
| Proceeded to radiofrequency at any time (n, %)†† | 45 (49%) | 48 (53%) | 42 (89%) | 0.712 (Groups I and II only) | |
For continuous variables, P values for three-way ANOVA are shown. For categorical variables, P values for chi-square tests are shown, except for those in which cell count was less than 5, in which case the P value for Fisher exact test is shown and denoted as below.
Percent pain relief from diagnostic injection calculated by independent observer, based on comments and recorded pain scores from pain diary.
Positive block defined as 50% or more pain relief from baseline lasting 3h or more.
Medication reduction defined as a more than 20% reduction in opioid dose from baseline or complete cessation of a nonopioid analgesic.
Satisfaction score on 1 to 5 scale.
Positive outcome defined as 50% or more pain relief from baseline at rest combined with satisfaction score of 3 out of 5 or higher.
Based on Fisher exact test.
Facet (group I) and medial branch (group II) block patients with (+) block who fail to experience a positive categorical outcome at follow-up designated for radiofrequency denervation per protocol; all saline (group III) patients who fail to experience a positive outcome designated tor radiofrequency denervation.
NRS = numerical rating scale; ODI = Oswestry Disability Index score.