This is a prospective, randomized, double-blinded, sham-controlled trial conducted to investigate the efficacy and safety of transcutaneous auricular vagus nerve stimulation (taVNS) combined with cervical epidural injection in the treatment of cervical radiculopathy. A total of 80 subjects will be enrolled and randomly assigned (1:1) to either the experimental group or the control group. The primary outcome measure is the proportion of subjects with a ≥50% reduction in the Numerical Rating Scale (NRS) pain score at discharge. Secondary outcomes include pain intensity, pain interference, psychological status, sleep quality, physical disability, and autonomic function measurements. Adverse events will be monitored throughout the study.

Cervical radiculopathy is a common condition associated with significant neck and arm pain, often resulting from cervical spondylosis. Current management strategies include epidural injections and pharmacotherapy; however, adjunctive neuromodulation therapies are being explored. This study aims to evaluate the additive effect of taVNS, a non-invasive neuromodulation technique, when combined with cervical epidural injection.

Study Design:

Eighty patients diagnosed with cervical radiculopathy scheduled for cervical epidural injection will be recruited. Participants will be randomly allocated in a 1:1 ratio to two groups:

• Experimental Group: Subjects will receive 3 consecutive days of preoperative taVNS stimulation (1-2 hours/day, 30Hz, 200μs, up to 50mA) followed by a standard cervical epidural injection of corticosteroid and local anesthetic.
• Control Group: Subjects will receive a sham taVNS stimulation (identical device with no output) for the same duration and frequency, followed by the same standard cervical epidural injection.

Outcomes:

The primary endpoint is the proportion of subjects achieving a ≥50% reduction in NRS pain score at discharge. Secondary endpoints include changes in Brief Pain Inventory (BPI) scores, Hospital Anxiety and Depression Scale (HADS) scores, Insomnia Severity Index (ISI) scores, Neck Disability Index (NDI), and heart rate variability (HRV) measurements at predefined time points (preoperatively, 24 hours postoperatively, and at discharge). Safety outcomes include the incidence of adverse events and changes in cardiac function.

This study will provide high-level evidence on the efficacy and safety of combining taVNS with cervical epidural injection for the treatment of acute cervical radiculopathy.

Inclusion Criteria:

1. Age between 18 and 85 years old.
2. Body Mass Index (BMI) between 18 and 35 kg/m².
3. American Society of Anesthesiologists (ASA) physical status I to III.
4. Diagnosed with cervical radiculopathy, scheduled for selective cervical epidural injection.
5. Estimated procedure duration ≤ 1 hour.
6. Able to understand and provide written informed consent.

Exclusion Criteria:

1. Arrhythmia requiring treatment, severe bradycardia, or postural orthostatic tachycardia syndrome.
2. Neuromuscular disorders or auricular dermatitis.
3. Cervical fracture, tumor, tuberculosis, or active infection confirmed by imaging.
4. Contraindications to vagus nerve stimulation: carotid sinus hypersensitivity, bilateral carotid artery stenosis.
5. Severe psychiatric disorder or history of substance abuse.

This study employs a double-blind design. Participants and outcome assessors are blinded to group assignment throughout the study. The intervention is administered by a dedicated research team member who is not involved in outcome assessment, ensuring blinding integrity.