Comparison of botulinum toxin type A administered at different dilutions in patients with clonic hemifacial spasm
Hanife Şentürk1
, İlknur Güçlü Altun2, Banu Özen Barut1
1Kartal Dr. Lütfi Kırdar Şehir Hastanesi, Nöroloji Kliniği, İstanbul, Türkiye
2Çanakkale Onsekiz Mart Üniversitesi Tıp Fakültesi, Nöroloji Anabilim Dalı, Çanakkale, Türkiye
Keywords: Botulinum toxin type A, dilution, hemifacial spasm, injection, pain.
Abstract
Background: This study aims to compare the motor, functional, and psychosocial clinical changes and post-procedural injection pain following administration of the same total dose of botulinum toxin type A (BoNT-A) diluted with 2 mL versus 1 mL of physiological saline (PS) in patients with hemifacial spasm (HFS).
Materials and Methods: This prospective study included patients with HFS, older than 18 years, who had either not previously received BoNT-A or in whom at least six months had elapsed since the last administration. Data from 21 patients who completed both application periods were analyzed. In the first application, BoNT-A was administered diluted with 2 mL of PS (0.9% NaCl), and in the subsequent period, the same total dose was diluted with 1 mL of PS. Patients were evaluated one month after each application using the Hemifacial Spasm Score; procedural pain was assessed with a 0-10 Visual Analog Scale (VAS). Changes from baseline were calculated and the dilution methods compared using the Wilcoxon signed-rank test (p < 0.05).
Results: The mean age was 51.62 ± 13.00 years. One month after both applications, a significant decrease from baseline was observed in the severity and frequency of contractions, disease-related complaints, functional difficulties, and all psychosocial parameters. When the changes produced by the two methods were compared, no significant difference was found in the main motor parameters; however, improvement in difficulty reading, depressive mood, avoidance of eye contact, and feeling of embarrassment was greater with the 1 mL application (p = 0.010, p = 0.002, p = 0.007, and p = 0.003, respectively). The post-procedural VAS score was 2.43 ± 2.20 with 2 mL and 0.29 ± 0.78 with 1 mL, with significantly lower injection pain in the 1 mL application (p < 0.001). No adverse effects were observed.
Conclusion: Administration of the same total BoNT-A dose diluted with either 1 mL or 2 mL of PS provided marked improvement in the motor symptoms of HFS, with no significant difference between the two dilutions in the main motor efficacy parameters. The 1 mL application was associated with lower injection pain and greater improvement in some functional-psychosocial parameters.