Effects of Pulsed Ultrasound Therapy on Sensory Nerve Conduction Parameters and the Pain Threshold Perceptions in Humans
Othmar Schuhfried, Damir Vukanovic, Christian Kollmann, Karin Pieber, Tatjana Paternostro‐Sluga
PM&R 2017 · 10.1016/j.pmrj.2016.11.009
Abstract
Background Therapeutic ultrasound is an often-used clinical modality in the nonsurgical treatment of entrapment neuropathies. To date, the possible mechanism of action of pulsed ultrasound therapy on the peripheral nerve in the treatment of entrapment neuropathies is unclear. Objective To examine the effects of pulsed ultrasound therapy on peripheral nerve conduction parameters. Design A prospective, randomized, single blind, crossover study. Setting Outpatient clinic of a university department of physical medicine and rehabilitation. Participants Twelve healthy volunteers between 22 and 38 years of age (8 male, 4 female). Methods Each patient (blinded) received ultrasound therapy (1W/cm 2 , pulsed: 1:5; over the course of the superficial branch of the radial nerve of the nondominant arm) and placebo (intensity: zero). The interval between the individual interventions was 1 week. Main outcome measurement The sensory nerve conduction velocity, sensory nerve action potential, supramaximal stimulation intensity of the sensory fibers of the radial nerve, and the pressure pain threshold in the sensory area of the radial nerve before and after an ultrasound-therapy and placebo intervention. To compare the results of the intervention with placebo, a paired-samples t test was applied. Results Compared with placebo, a significant increase after pulsed ultrasound therapy was found for the supramaximal stimulation intensity (P = .02). For the other primary outcome parameters, a significant difference was not found. Conclusions The immediate effect of pulsed ultrasound therapy on a sensory nerve is minimal. Therefore, the previously reported benefit of pulsed ultrasound therapy in entrapment neuropathies might be not due to its effect on the sensory nerve. Level of evidence I.
Abstract via europepmc.
Exposures
Exposure 1: Pulsed ultrasound to the superficial branch of the radial nerve
Target: radial nerve — “superficial branch of the radial nerve of the nondominant arm”
Device: other named manufacturer · GBO Medizintechnik, Rimbach, Germany · Sonostat 133 ✓
| Waveform | pulsed | |
|---|---|---|
| Fundamental frequency (kHz) | 3,000 | ✓✓✓ |
| Pulse duration (ms) | not reported | |
| Pulse repetition frequency (Hz) | not reported | |
| Duty cycle (%) | not reported | ⚑ |
| Sonication duration (s) | 300 | ✓✓✓ |
| Free-field pressure (kPa) | not reported | |
|---|---|---|
| Free-field Isppa (W/cm²) | not reported | |
| Free-field Ispta (W/cm²) | not reported | |
| In-situ estimate | not reported | |
| In-situ pressure (kPa) | not reported | |
| In-situ Isppa (W/cm²) | not reported | |
| In-situ Ispta (W/cm²) | not reported | |
| Isppa, domain unspecified (W/cm²) | 1 | ✓✓✓ |
Therapeutic ultrasound was applied with an intensity of 1 W/cm2, pulsed 1:5, frequency 3 MHz, via a transducer with a surface area of 2.5 cm2, at the radial side of the forearm from 5 to 15 cm proximal to the metacarpophalangeal joint of the thumb, over the course of the superficial branch of the radial nerve, for 5 minutes, with the transducer moved dynamically over the treatment area. Placebo used the same device, area and duration with intensity set to zero.
Flags from extraction
exposures[0].timing.duty_cycle_pct— Paper states the pulse ratio as 'pulsed 1:5' without defining whether this is on:off or on:total; left duty_cycle_pct not_reported rather than assume a convention.exposures[0].unspecified_domain.ispta_w_cm2— Paper reports only 'intensity 1 W/cm2' without specifying ISATA/ISPTA/domain; placed in unspecified_domain.n_sessions_per_subject— Crossover design gave each subject one real-ultrasound session and one placebo session on separate days; n_sessions_per_subject counts only the real-ultrasound session.