Radial Shock Waves Modify Post-synaptic Neuromuscular Transmission in the Medial Spastic Gastrocnemius Muscle: Case Report, Neurophysiological Evaluation, and Review

Abstract

Spasticity is a frequent pathology, devastating in the quality of life of the patients who suffer it, and produces an important socioeconomic impact derived from both direct and indirect expenses. Therapeutic interventions on spasticity include (1) pharmacological therapy, (2) physical therapy (electrostimulation, thermotherapy), (3) occupational therapy, (4) botulinum toxin, (5) chemical neurolysis, and (6) selective neurotomy. Focal or radial extracorporeal shock waves (ESWT) have recently been added to the therapeutic armamentarium for the management of spasticity with good results, although the underlying mechanism of action is unknown. There is consensus that ESWT improve spasticity, clinically assessed by clinical tests such as the Ashworth or Tardieu modified scale; however, there is no neurophysiological confirmation of its clinical effect. We present the case of a 61year-old male patient with chronic spastic paraparesis who, after prolonged bedding due to abdominal eventration requiring hospital admission, presented worsening bilateral equine feet. Radial ESWT (3 bars, 1500 pulses, 8 Hz) were applied to the morphological most prominent part of the left medial gastrocnemius and repetitive stimulation was evaluated immediately after the intervention. With respect to the previous basal stimulation (control), a pathological decrement (> 10%) of the amplitude and area of the 4th potential was observed compared with the 1st potential, a response that is characteristic of alterations in neuromuscular to post-synaptic transmission. Radial electro shockwave therapy modifies neuromuscular transmission at the post-synaptic level. No adverse events were observed in the present clinical case.