Effectiveness of Lumbar Facet Joint Blocks and Predictive Value before Radiofrequency Denervation: The Facet Treatment Study (FACTS), a Randomized, Controlled Clinical Trial

Abstract

What we already know about this topic: WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: With facet interventions under scrutiny, the authors' objectives were to determine the effectiveness of different lumbar facet blocks and their ability to predict radiofrequency ablation outcomes.

Methods: A total of 229 participants were randomized in a 2:2:1 ratio to receive intraarticular facet injections with bupivacaine and steroid, medial branch blocks, or saline. Those with a positive 1-month outcome (a 2-point or more reduction in average pain score) and score higher than 3 (positive satisfaction) on a 5-point satisfaction scale were followed up to 6 months. Participants in the intraarticular and medial branch block groups with a positive diagnostic block (50% or more relief) who experienced a negative outcome proceeded to the second phase and underwent radiofrequency ablation, while all saline group individuals underwent ablation. Coprimary outcome measures were average reduction in numerical rating scale pain score 1 month after the facet or saline blocks, and average numerical rating scale pain score 3 months after ablation.

Results: Mean reduction in average numerical rating scale pain score at 1 month was 0.7 ± 1.6 in the intraarticular group, 0.7 ± 1.8 in the medial branch block group, and 0.7 ± 1.5 in the placebo group; P = 0.993. The proportions of positive blocks were higher in the intraarticular (54%) and medial branch (55%) groups than in the placebo group (30%; P = 0.01). Radiofrequency ablation was performed on 135 patients (45, 48, and 42 patients from the intraarticular, medial branch, and saline groups, respectively). The average numerical rating scale pain score at 3 months was 3.0 ± 2.0 in the intraarticular, 3.2 ± 2.5 in the medial branch, and 3.5 ± 1.9 in the control group (P = 0.493). At 3 months, the proportions of positive responders in the intraarticular, medial branch block, and placebo groups were 51%, 56%, and 24% for the intraarticular, medial branch, and placebo groups, respectively (P = 0.005).

Conclusions: This study establishes that facet blocks are not therapeutic. The higher responder rates in the treatment groups suggest a hypothesis that facet blocks might provide prognostic value before radiofrequency ablation.

Trial registration: ClinicalTrials.gov NCT02002429.

Figures

Fig. 1.

Omnibus study flowchart.

Fig. 2.

Flowchart demonstrating progression through diagnostic and therapeutic facet injection study phase. A positive outcome is defined as 2-point or more decrease in average back pain score coupled with a satisfaction score of 3 out of 5 or higher. (1) Participants with a positive diagnostic block continued the study until a negative follow-up visit, then proceeded with radiofrequency (RF) ablation in an unblinded manner.(2) Participants with a negative diagnostic block continued in the study until a negative follow-up visit, then exited the study. (3) Participants with a positive diagnostic saline injection were treated the same as those in groups I and II (continued in the study until they had a negative follow-up outcome, then proceeded to radiofrequency denervation in an unblinded manner). (4) Participants with a negative diagnostic saline block were unblinded at the point of their negative follow-up visit, then proceeded to radiofrequency denervation. (5) Includes individuals with a negative diagnostic block but positive follow-up outcome that did not exit the study. (6) Includes individuals who were lost to follow-up, chose to exit the study before a negative follow-up visit, or withdrew to receive nonpermitted treatments (e.g., nonradiofrequency denervation treatments or opioid therapy). (7) Scheduled for radiofrequency includes participants who had a negative outcome and a positive block and those who had a positive outcome and a positive block but developed pain before the next follow-up period. (8) Individuals who declined radiofrequency ablation or withdrew from the study before radiofrequency ablation were considered dropouts for the purposes of the study. (9) Includes all those with a negative diagnostic block with initial positive outcome at 1 month, then subsequent negative outcome.

Fig. 3.

Flowchart demonstrating progression through radiofrequency (RF) ablation study phase. A positive outcome is defined as 2-point or more decrease in average back pain score coupled with a satisfaction score of 3 out of 5 or higher. (1) In individuals receiving intraarticular (Group I) and medial branch (group II) blocks, eligible patients were those obtaining a positive diagnostic block and not obtaining ongoing relief at 6 months from the block. In saline injection patients (group III), all patients not obtaining relief at 6-month follow-up during the facet phase met criteria for proceeding to radiofrequency ablation regardless of the results of their diagnostic block. (2) Individuals who declined radiofrequency ablation or withdrew from the study before radiofrequency ablation were considered dropouts.

Fig. 4.

Pain relief after different lumbar facet blocks. Data presented as means with error bars representing 1 SD. For outcomes, n = 89 for intraarticular group, 91 for medial branch group, and 47 for placebo group.

Fig. 5.

Pain relief after lumbar facet radiofrequency ablation stratified by treatment group. Data presented as means with error bars representing 1 SD. For outcomes, n = 45 for intraarticular group, 48 for medial branch group, and 42 for placebo group.

Fig. 6.

Cumulative pain relief broken down by study group. Relief after facet injection calculated based on the total number of months of pain relief from the diagnostic block, divided by the people who had a positive diagnostic block for groups I and II, or all group III participants. Relief after radiofrequency ablation (RFA) calculated based on the total number of months of pain relief from the radiofrequency ablation, divided by the number of participants undergoing RFA within each respective group. Data presented as means with SD error bars representing 1 SD. For facet injection outcomes, n = 49 for intraarticular group, 50 for medial branch group, and 47 for placebo group. For radiofrequency ablation outcomes, n = 45 for intraarticular group, 48 for medial branch group, and 42 for placebo group.