For acute bilateral trapezius spasm, which type of transcutaneous electrical nerve stimulation is MOST appropriate for pain relief?

• A. Burst
• B. Acupuncture
• C. Conventional
• D. Low-frequency

Answer: (C)

For acute muscle spasm, the goal is fast, comfortable pain relief, and conventional high-frequency TENS is best suited for that. It delivers brief pulses at a high rate (around 50–100 Hz) that stimulate A-beta fibers. This activates the gate-control mechanism in the spinal cord, dampening the transmission of pain signals from the irritated trapezius and providing quick relief that can be felt right away.

Low-frequency TENS, which uses slower pulses (2–10 Hz), relies on triggering the body's endorphin system for analgesia and tends to produce longer-lasting relief but can be less comfortable and is often more appropriate for chronic pain or longer-standing muscle tension rather than an acute flare. Acupuncture-like TENS mimics needle acupuncture with longer pulse durations and lower frequency, and while it can help some patients, it’s not the standard first choice for rapid relief in an acute spasm. Burst TENS offers a different pattern of stimulation, but conventional high-frequency TENS remains the most reliable option for immediate relief in acute musculoskeletal pain.