# Optimal Low-Frequency Parameter of Percutaneous Electrical Nerve Stimulation in Patients with Lower Back Pain: A Pilot Study

## TL;DR

This pilot study found that 3 Hz stimulation during ultrasound-guided nerve treatment was more effective for lower back pain than 10 Hz.

## Contribution

The study identifies 3 Hz as a more effective low-frequency parameter for percutaneous nerve stimulation in chronic lower back pain.

## Key findings

- Both 3 Hz and 10 Hz stimulation reduced pain and improved mobility after one week.
- 3 Hz stimulation showed significantly better pain reduction and non-intervention limb strength than 10 Hz.
- The effect size for the frequency difference was small.

## Abstract

Background: The methodology of ultrasound (US)-guided percutaneous neuromodulation (PNM) remains unclear. Objective: To determine the optimal stimulation frequency (3 Hz vs. 10 Hz) during the short-term application of US-guided PNM on the sciatic nerve, we assessed the therapeutic benefits, including pain reduction, hip passive internal rotation range of motion (IR-ROM), balance, and functionality, in patients with chronic low back pain (LBP). Methods: Forty patients with LBP were randomly assigned to two groups, each receiving isolated percutaneous electrical stimulation of the sciatic nerve. One group received stimulation at 3 Hz, while the other received stimulation at 10 Hz. Pain intensity, hip passive IR-ROM, hip muscle strength, and the Oswestry Disability Index (ODI) were measured before and one week after the intervention. Results: Both interventions significantly reduced pain and improved ROM, balance, and functionality after one week (p = 0.001). However, significant between-group (treatment × time) differences were observed for pain intensity (p = 0.001) and flexion strength in the non-intervention limb (p = 0.01), though the effect size was small (η2 = 0.1). Conclusions: US-guided PNM applied to the sciatic nerve was more effective at 3 Hz than at 10 Hz in relieving pain intensity in patients with LBP.