Abstract:
Background: Botulinum toxin type A (BoNT-A) injection is considered the first-line treatment in patients with hemifacial spasm (HFS), but therapeutic effects are temporarily, resulting in repeated injections that are associated with pain and discomfort. Although the use of microneedle is a common practice for facial aesthetic injections with evidence demonstrating minimal pain and bruises, the evidence in HFS is lacking. Objectives: The aim of this study was to compare the severity of pain and bruises between a microneedle (34-G) and standard needle (30-G) in patients with HFS with BoNT-A injections. Materials and methods: This was a cross-over, double-blind, randomised controlled trial involving 62 HFS patients to receive two, 12-week interval, BoNT-A injections with either standard needle or microneedle. All subjects were treated with BoNT-A by the same investigator using the same injection technique, BoNTA dosage and number of injection site. Primary outcomes were pain severity and characteristics, determined immediately after the injections with the Visual Analogue Scale (VAS) and Short-form McGill Pain Questionnaire (SF-MPQ-2). Secondary outcomes were bruised scores, complications, and the efficacy of BoNTA injections as rated by global rating and comprehensive scales at baseline, one week and one-month following injections. Results: Sixty-two patients with HFS were included in this study. The majority of subjects female (72.6%), with a mean age of 60.18±11.12 years and a mean disease duration of 5.64±3.98 years. Compared to standard needle injections, significant reductions of VAS (p<0.001), total SF-MPQ-2 (p<0.001), and bruise scores (p<0.001) were demonstrated with microneedle injections (Figure 1) . Complication rates and types were not significantly different between the two procedures. The efficacy between two procedures, measured at baseline, one-week, and one-month following injections demonstrated a significant time effect on global rating and comprehensive scales suggesting that both standard and microneedle injections improved patients' outcomes. Conclusion: While clinical benefits were similar between standard and microneedle injections, our study demonstrated significant reductions of pain and bruises with microneedle injections in patients with HFS.