Publications

Background: Extracorporeal shockwave therapy (ESWT) can effectively relieve post-stroke spasticity; however, research comparing the impact of different ESWT frequencies is limited. In this study, we investigated the therapeutic efficacy of different ESWT frequencies for post-stroke ankle plantar flexor spasticity.

Methods: In this prospective, single-blind, randomized controlled trial, we recruited patients treated in the Rehabilitation Department of Shenzhen Second People’s Hospital for post-stroke ankle plantar flexor spasticity between January 2024 and September 2024. The participants were randomly assigned to the control (n = 15), 4 Hz ESWT (n = 15), and 10 Hz ESWT (n = 15) groups. All groups received conventional rehabilitation therapy; the 4 Hz and 10 Hz ESWT groups received additional ESWT. The ESWT intervention lasted for 3 weeks, with two interventions per week. ESWT was administered at 2 bar, 4 Hz, and 2000 pulses for the 4 Hz group and 2 bar, 10 Hz, and 2000 pulses for the 10 Hz group. Assessments were conducted before treatment, after the first treatment, and at the end of intervention using the modified Ashworth scale (MAS), passive joint range of motion (PROM), ankle clonus score, medial gastrocnemius muscle oscillation frequency (MGF), lateral gastrocnemius muscle oscillation frequency (LGF), medial gastrocnemius muscle dynamic stiffness (MGS), lateral gastrocnemius muscle dynamic stiffness (LGS), and the Fugl-Meyer assessment of the lower extremity (FMA-LE). Visual analog scale (VAS) tool was used before and after each ESWT session.

Results: The 4 Hz and 10 Hz ESWT groups showed significant difference in LGS after a single treatment (P < 0.05). Following 3 weeks of treatment, both ESWT groups exhibited significant improvements in MAS, PROM, MGF, and LGS compared with the control group (P < 0.05). The 4 Hz ESWT group also demonstrated a significant improvement in MGS compared with the control group (P < 0.05), and the 4 Hz and 10 Hz ESWT groups differed significantly in LGS (P < 0.05). We found that only five patients reported mild pain, which resolved rapidly after treatment and rest.

Conclusion: Both single and 3-week ESWT treatments safely reduced the severity of ankle plantar flexor spasticity. The results showed the possibility of superiority of 4 Hz intervention to 10 Hz intervention.

Keywords: ankle plantar flexors, extracorporeal shock wave therapy, spasticity, stroke rehabilitation

Both single and multiple ESWT treatments over 3 weeks reduced the severity of ankle plantar flexor spasticity. Furthermore, ESWT using a 4 Hz frequency may demonstrate greater efficacy in alleviating ankle plantar flexor spasticity, which is of great significance for optimizing ESWT treatment strategies. This study represents the first randomized controlled trial to evaluate the effects of different ESWT frequencies on post-stroke plantar flexor spasticity of the ankle, providing a theoretical basis for optimizing ESWT parameter settings in treating this condition. Another advantage of this study lies in its pioneering use of MyotonPRO to assess the effect of ESWT on muscle tone in post-stroke plantar flexor spasticity of the ankle, thereby enabling quantitative measurement of improvement outcomes. To further validate the robustness and clinical relevance of this study’s results, future studies should consider designing more treatment groups, conducting multi-group-controlled trials with longer-term follow-up, extending the duration of interventions, and optimizing frequency parameters more precisely.