Electrical Currents for Pain Control: TENS Overview

TENS

Transcutaneous electrical nerve stimulation, a method used to control pain.

Sensory-Level, High-Rate TENS

Controls pain by activating non-nociceptive A-beta nerves, inhibiting transmission of nociceptive signals to the spinal cord level.

Motor-Level, Low-Rate TENS

Uses low frequency pulses (2 to 10 pps) at an intensity high enough to produce a motor contraction, stimulating endogenous opioid production.

Burst Mode TENS

Stimulation delivered in bursts, thought to work similarly to low-rate TENS.

Gate Theory

A theory that explains how non-nociceptive signals inhibit nociceptive signals transmission to the spinal cord.

Endogenous Opioids

Natural pain-relieving chemicals produced by the body, which are stimulated by Motor-Level, Low-Rate TENS.

DOMS

Delayed onset muscle soreness, which may occur from low-rate TENS due to muscle contractions.

Electrode Placement for TENS

For sensory level, electrodes are placed on or around the pain location; for motor level, on the target muscle.

IFC

Interferential Current, a type of electrical stimulation using two alternating currents to produce a therapeutic effect.

Pre-Modulated Current

A type of electrical stimulation that utilizes a modulated waveform for therapeutic effects.

Electrode Placement for IFC & Pre-Mod

Electrodes should be placed on or near the painful area or on trigger points or muscle spasms.

IFC & Pre-Mod Parameters

Both utilize waveforms with a frequency between 1,000 and 10,000 Hz, known as medium frequency AC.

Pain Control Duration for Motor-Level TENS

Pain will be controlled for 4-5 hours after a 20-30-minute treatment.

Maximum Duration for Motor-Level TENS

Should not be performed for longer than 45 minutes to prevent DOMS.

Tolerance Development

Patients may develop a tolerance to low-rate TENS, requiring higher dosages by the 4th-5th day of usage.

High-Rate TENS Recommendation

Recommended when sensation, but not muscle contraction, will be tolerated, such as after an acute injury.

Low-Rate TENS Recommendation

Recommended for longer duration of pain control without continuous modality use, and when muscle contraction is tolerated.

Contraindications for E-STIM

Do not use low-rate TENS when there is compromised tissue healing, such as muscle or tendon tears.

Precautions for E-STIM

Patients should avoid potentially symptom-aggravated activities because TENS decreases pain.

Clinical Applications of Electrical Currents

Used for acute pain after surgery and chronic pain conditions like knee OA, diabetic neuropathy, and LBP.