Effects of Focal Low-Energy Extracorporeal Shock Wave Treatment (ESWT) as an Add-On to Botulinum Toxin (BoNT) Injection on Pisa Syndrome in Parkinson’s Disease

Background: Pisa syndrome (PS) is a reversible lateral trunk deviation that arises as a complication in a subset of patients with Parkinson’s disease (PD). Effective therapeutic options remain limited, and standardized protocols are lacking. Extracorporeal shock wave therapy (ESWT), an intervention with emerging antidystonic and antispastic properties, has shown promising effects on muscle spasms and dystonia. We aimed at evaluating the feasibility, safety, and preliminary therapeutic effects of ESWT combined with botulinum toxin (BoNT) for reducing paraspinal muscle tone and pain in patients with PS.

Methods: This crossover observational study analyzed data collected in routine clinical practice in patients with PS undergoing focused ESWT applied to ipsilateral paraspinal muscles immediately prior to BoNT injections.

Fifteen patients were enrolled, and eleven completed the full protocol, which included ESWT+BoNT and sham ESWT+BoNT administered according to clinical scheduling, with a washout phase lasting no less than 3 months between treatment conditions. Clinical evaluations were performed at baseline, immediately post-treatment, and at 1 and 3 months post-treatment. Outcome measures included lateral trunk flexion angle, UPDRS part III scores, pain intensity ratings, quality of life assessments, and surface electromyography (sEMG) of axial muscles.

Results: The primary finding was a significant immediate reduction in lateral trunk flexion following active ESWT compared with sham (p = 0.038). However, no sustained effects were observed at 1 or 3 month post-treatment for posture, motor severity, pain, or patient-reported outcomes. sEMG analysis did not demonstrate significant modifications in muscle activation patterns. ESWT was well tolerated, only mild, transient discomfort was reported, and no systemic adverse events occurred.

Discussion: These findings provide evidence that focused ESWT may acutely reduce lateral trunk flexion in PS when used as an adjunct to BoNT. Larger studies are warranted to better define its therapeutic potential.