Botulinum Toxin Type A Combined with Fire Needling for Postherpetic Neuralgia: A Randomized Controlled Trial

Abstract

Objective: To compare the efficacy and safety of subcutaneous botulinum toxin type A (BTX-A) injection, fire needling, and their combination in patients with postherpetic neuralgia (PHN), with particular attention to whether the combined regimen sustains its benefit over six months. Methods: In this randomized controlled trial, 99 patients with PHN attending the outpatient and inpatient services of the Department of Rehabilitation Medicine, Gaoming District People’s Hospital of Foshan, between January 2024 and March 2025 were allocated 1:1:1 by a random number table to group A (subcutaneous BTX-A, n = 33), group B (fire needling, n = 33), or group C (BTX-A plus fire needling, n = 33). All patients received oral gabapentin 300 mg/d as background therapy. The primary outcome was pain intensity on the visual analogue scale (VAS) at 3 d, 15 d, 1 month, 3 months and 6 months. Secondary outcomes were the Self-Rating Scale of Sleep (SRSS), the proportion of patients achieving ≥50% reduction in VAS, the Patient Global Impression of Change (PGIC), the distribution of efficacy grades, and adverse events. Results: Ninety patients completed the study (30 per group). Mixed-effects models showed significant group × time interactions for both VAS and SRSS (both p < 0.001). VAS differed among groups at every post-treatment time point (all p < 0.001). From day 15 onward, VAS was lower in group C than in groups A and B (all p < 0.001), whereas groups A and B did not differ at any time point (all p > 0.05). At 6 months, VAS was 1.34 ± 0.64 in group C, 2.99 ± 1.13 in group A and 2.88 ± 0.98 in group B (both p < 0.001). The 6-month responder rate was 100.0% (30/30) in group C, 66.7% (20/30) in group A and 76.7% (23/30) in group B (p < 0.001). SRSS was lowest in group C at every time point, reaching 37.30 ± 4.94 at 6 months (p < 0.001). At 6 months, 30 patients (100.0%) in group C reported a PGIC of “improved” or better, compared with 21 (70.0%) in group A and 24 (80.0%) in group B (p = 0.006). Adverse events were mild in all three groups and no serious adverse event occurred. Conclusion: Subcutaneous BTX-A injection and fire needling each relieve pain and improve sleep in PHN, with comparable efficacy. The combined regimen acts faster and achieves a higher peak response, with no attenuation over six months of observation.