Transcutaneous Electrical Nerve Stimulation (TENS) is a non-invasive method for managing musculoskeletal discomfort, often used for trapezius pain. This guide provides instructions on how to safely and effectively use a TENS unit.
Understanding TENS Therapy
A TENS unit is a compact, battery-operated device designed to deliver low-voltage electrical impulses through electrodes placed on the skin. These impulses interact with the body’s nervous system to help alleviate pain.
Two main theories explain how TENS therapy works. The Gate Control Theory suggests electrical impulses stimulate sensory nerves, effectively “closing the gate” in the spinal cord and blocking pain signals from reaching the brain. The Endorphin Release Theory proposes the TENS unit encourages the body to produce natural painkillers called endorphins, which reduce pain perception.
Preparing for TENS Application
Before TENS therapy, ensure the unit is ready. Consult the device’s instruction manual for specific guidance. Check that the TENS unit functions correctly and electrode pads are clean and adhesive.
Proper skin preparation is crucial for effective and safe application. The trapezius area for electrode placement should be clean and dry. Remove any lotions, oils, or sweat to ensure optimal conductivity and secure adhesion, which also helps prevent skin irritation.
Applying TENS for Trapezius Pain
Accurate electrode placement is important for effective pain relief in the trapezius muscle, which extends from the skull’s base down the spine and across the shoulders. For optimal results, place electrode pads to flank the painful area or create a square around the discomfort. Avoid placing electrodes directly over bony prominences, the spine, or irritated skin. A common approach involves placing two electrodes on either side of the painful spot within the trapezius, ensuring they are at least one inch apart.
Adjusting the TENS unit’s settings involves selecting appropriate frequency, pulse width, and intensity levels. Frequency (Hertz/Hz) determines pulses per second. For acute pain, 80-120 Hz is often recommended, supporting the Gate Control Theory. For chronic pain, lower frequencies (2-10 Hz) can stimulate endorphin release.
Pulse width (microseconds/µs) controls each pulse’s duration. A wider pulse width can deliver a stronger, potentially deeper sensation, suitable for deeper pain. Intensity (milliamperes/mA) refers to current strength. Begin with the lowest intensity, gradually increasing until you feel a strong but comfortable tingling or buzzing sensation, without muscle contraction. The goal is a noticeable sensation, not pain or muscle twitching.
Typical TENS therapy sessions for trapezius pain last 20 to 30 minutes, though some extend to 60 minutes. TENS can be used multiple times daily, often 2 to 4 sessions. Allow at least a 20-minute break between sessions to prevent skin irritation and nerve accommodation.
Important Considerations for Use
While TENS therapy is generally safe, certain precautions and contraindications apply. Individuals with implanted electronic devices (e.g., pacemakers, defibrillators) should not use TENS units. TENS is also not recommended during pregnancy, over the carotid sinus (front of the neck), open wounds, or directly over the eyes. Avoid using the device while sleeping, driving, or operating heavy machinery.
To minimize skin irritation, regularly inspect the skin under the electrodes and rotate placement sites. Expected sensations include tingling, buzzing, or tapping. If the sensation becomes uncomfortable or painful, reduce the intensity. If sensation is lost, check electrode adhesion and the unit’s battery.
TENS manages pain symptoms but does not address the underlying cause. If pain persists, worsens, or new symptoms develop, consult a healthcare professional for diagnosis and treatment.