Introduction
Cervical spondylosis is an age-related wear-and-tear condition affecting the spinal discs and joints in the neck. As discs dehydrate and shrink, signs of osteoarthritis develop, including bony projections along bone edges (bone spurs). This can result in neck stiffness, localized aching, and radiating pain or tingling down the shoulder and arm (cervical radiculopathy). Managing this chronic pain is essential for restoring daily function. TENS therapy for cervical pain (Transcutaneous Electrical Nerve Stimulation) is a widely used electrophysical modality that provides immediate, drug-free relief for neck spasms and stiffness.
Clinical Mechanisms of TENS for Cervical Pain
TENS units deliver low-voltage electrical currents through skin-surface electrode pads. For managing neck pain associated with cervical spondylosis, TENS works through several key physiological pathways:
- The Gate Control Theory: High-frequency stimulation (80–120 Hz) targets large sensory fibers, which block the slower pain signals from reaching the spinal cord and brain.
- Endogenous Opioid Release: Low-frequency stimulation (2–10 Hz) triggers the release of endorphins and enkephalins in the central nervous system, providing prolonged pain relief.
- Resolution of Muscle Guarding: The neck muscles (such as the upper trapezius and levator scapulae) often go into protective spasm around degenerative cervical segments. TENS relaxes these muscles, improving blood flow and reducing ischemic muscle pain.
Guidelines for TENS Electrode Placement on the Neck
Given the delicate vascular and nervous structures in the neck, correct pad placement is essential for safety and effectiveness:
* Placement: Place the adhesive pads on the muscle bellies on either side of the cervical spine. Never place pads directly over the bones of the spine (spinous processes).
* Suboccipital Placement: For spondylosis-related cervicogenic headaches, place one pair of pads at the base of the skull (suboccipital region) and the second pair across the upper shoulders.
* Safety Warning (Carotid Sinus): Never place TENS electrodes on the front or side of the neck near the throat. This can stimulate the carotid sinus, leading to a sudden drop in blood pressure or heart rate.
TENS Cervical Parameters Comparison Table
| Parameter | High-Frequency TENS | Low-Frequency TENS |
|---|---|---|
| **Frequency Range** | 80–120 Hz | 2–10 Hz |
| **Pulse Duration** | 50–100 microseconds | 150–200 microseconds |
| **Primary Sensation** | Smooth, continuous vibration | Pulsing, rhythmic tapping |
| **Best Used For** | Immediate relief during neck movement | Long-term chronic neck ache relief |
Combining TENS with Neck Stabilization Exercises
TENS is most effective when integrated into an active physiotherapy program. By reducing pain and neck muscle guarding, TENS creates a window for patients to safely perform cervical mobilization, deep neck flexor strengthening, and upper back postural re-education. These exercises build the muscular support needed to reduce load on the degenerative cervical joints.
Contraindications and Safety Precautions
Do not use TENS if you have:
* A cardiac pacemaker or implantable cardioverter-defibrillator (ICD).
* Areas of complete skin numbness or active local skin infections.
* A history of seizures (avoid head and neck placement).