Rheumatology · Medical Literature
Ultrasound-Guided Stellate Ganglion Block in Fibromyalgia: A Randomized, Single-Center, Single-Blind, Sham-Controlled Trial.
Abstract
Fibromyalgia is a chronic pain syndrome characterized by widespread pain, fatigue, and sleep disturbance. Many patients remain symptomatic despite guideline-concordant pharmacologic therapy. Stellate ganglion block (SGB) modulates sympathetic activity and may provide an adjunctive option for fibromyalgia-related pain. In this single-center, randomized, single-blind, sham-controlled trial, adults fulfilling the 2016 American College of Rheumatology criteria and receiving stable duloxetine 60 mg/day were randomized 1:1 to ultrasound-guided SGB or a sham procedure. Two procedures were performed 1 week apart. The primary endpoint was change in the Fibromyalgia Impact Questionnaire Revised (FIQR) total score from baseline to 1 week. Secondary endpoints included FIQR change at 1 month, pain intensity on an 11-point Numerical Rating Scale (NRS), and FIQR responder rates (≥ 30% and ≥ 50% improvement). Primary analyses were per-protocol (n = 60), with modified intention-to-treat (mITT, n = 60) and last observation carried forward (LOCF, n = 68) sensitivity analyses. ANCOVA was adjusted for baseline FIQR. Of 108 screened patients, 68 were randomized (SGB n = 33; control n = 35); 60 (30 per group) completed all assessments. Baseline FIQR was 87.7 ± 7.1 in the SGB group and 82.0 ± 11.3 in controls. At 1 week, FIQR decreased to 53.4 ± 19.0 with SGB versus 77.2 ± 16.3 with control; at 1 month, FIQR was 63.1 ± 20.3 versus 80.2 ± 10.7, respectively. ANCOVA-adjusted between-group differences in FIQR change favored SGB by -29.9 points (95% CI -37.9 to -21.9; p < 0.001) at 1 week and -22.9 points (95% CI -30.1 to -15.7; p < 0.001) at 1 month. NRS pain reductions were also significantly greater with SGB at both time points (adjusted difference -3.1 points, 95% CI -4.1 to -2.0, p < 0.001 at 1 week; -2.6 points, 95% CI -3.6 to -1.6, p < 0.001 at 1 month). No serious complications occurred; adverse events were transient and mild. In treatment-resistant fibromyalgia patients receiving stable duloxetine, ultrasound-guided SGB produced clinically meaningful short-term improvements in fibromyalgia impact and pain with an acceptable safety profile. However, the large effect sizes should be interpreted cautiously given potential unblinding and placebo effects. Larger, multicenter trials with longer follow-up, objective outcome measures, and formal blinding assessment are warranted. ClinicalTrials.gov Identifier: NCT07343128.
Clinical relevance
Fibromyalgia affects a substantial proportion of the population and remains refractory to guideline-concordant pharmacotherapy in many patients; this trial directly addresses the unmet need for adjunctive interventional options in this treatment-resistant cohort maintained on stable duloxetine 60 mg/day. By employing a sham-controlled, randomized design with ANCOVA-adjusted primary analyses, it provides higher-quality evidence than prior observational reports on stellate ganglion block (SGB) in chronic pain syndromes. Rheumatologists and pain specialists should engage with these findings given the paucity of procedural therapies evaluated in rigorous fibromyalgia trials.
Key findings
1. Primary endpoint — FIQR at 1 week: Ultrasound-guided SGB produced an ANCOVA-adjusted between-group reduction in FIQR total score of −29.9 points versus sham (95% CI −37.9 to −21.9; p < 0.001), far exceeding the accepted minimal clinically important difference for the FIQR. 2. Sustained effect at 1 month: The between-group FIQR advantage was maintained at −22.9 points (95% CI −30.1 to −15.7; p < 0.001), though the magnitude attenuated from the 1-week peak, suggesting partial waning of effect. 3. NRS pain reduction at 1 week: SGB yielded an adjusted NRS pain reduction of −3.1 points versus sham (95% CI −4.1 to −2.0; p < 0.001) on an 11-point scale, representing a clinically meaningful analgesic effect. 4. NRS pain reduction at 1 month: The analgesic advantage persisted at −2.6 points (95% CI −3.6 to −1.6; p < 0.001), indicating durability of pain relief beyond the procedural window. 5. Absolute FIQR scores: SGB group FIQR fell from 87.7 ± 7.1 at baseline to 53.4 ± 19.0 at 1 week and 63.1 ± 20.3 at 1 month; control group scores changed minimally (82.0 ± 11.3 → 77.2 ± 16.3 → 80.2 ± 10.7), underscoring the magnitude of the between-group separation. 6. Safety profile: No serious procedural complications were recorded; all adverse events were transient and mild across both the per-protocol (n = 60) and LOCF sensitivity cohorts (n = 68), supporting procedural tolerability in this population.
Practice implications
Ultrasound-guided SGB, delivered as two procedures one week apart adjunctive to stable duloxetine 60 mg/day, may be considered as an investigational option for adults with ACR 2016-criteria fibromyalgia who remain significantly symptomatic despite optimized pharmacotherapy, prioritizing patients with high baseline disease burden (FIQR ≥ 80) where the absolute benefit appears greatest. Clinicians should counsel patients that effect sizes—while statistically and clinically impressive—must be interpreted with caution given a single-blind design susceptible to unblinding and placebo amplification, and that durability beyond one month is currently unknown. Adoption into routine practice should be deferred pending larger multicenter, double-blind trials with longer follow-up, formal blinding-integrity assessment, and objective outcome measures, as called for by the authors.