Personalized Auricular Vagus Nerve Stimulation in Intractable Chronic Low Back Pain

Personalized Auricular Vagus Nerve Stimulation in Patients With Intractable Chronic Low Back Pain: A Randomized Controlled Pilot Study

One in five people in the general adult population suffer from chronic pain, a figure that is higher than heart disease, cancer, and diabetes combined. A majority of these patients is suffering from chronic back pain. Conventional treatment options offer only a partial response, with many people continuing to suffer severe chronic pain, despite receiving several treatments.

Non-pharmacological treatments by neuromodulation represent a promising treatment modality for these patients. For instance, spinal cord stimulation blocks pain signals travelling to the brain, but requires implantation near the spine with significant clinical risks. Vagus nerve stimulation (VNS) is another neuromodulation modality proposed to alleviate chronic pain. Conventional VNS devices are implanted under the skin on the chest and the electrodes are wired to the left vagus nerve in the neck. However, aside from implantation risks, VNS is often associated with side effects such as swallowing difficulties, due to unwanted stimulation of motoric vagus nerve branches in the neck.

Percutaneous auricular VNS (pVNS) is an emerging technology for stimulation of the auricular branch of the vagus nerve in the pinna of the ear. Specific electrical impulses are applied via three miniature needle electrodes located in the auricle near sensory vagus nerve fibers. Scientific data show that pVNS modulates brain circuits involved in autonomic control and pain processing. pVNS has shown positive effects in chronic low-back pain patients, in a sustainable way with a low side-effect profile. However, the optimal settings of stimulation with regards to personalization remain to be elucidated.

The present prospective, open, randomized, controlled pilot study aims at evaluating the performance of pVNS treatment, using a small wearable stimulation device (AuriMod CT01), comparing personalized and non-personalized stimulation paradigms in patients with chronic low-back pain. Patients will be randomized in one of the following treatment groups (1) Group A: Stimulation with personalized stimulation parameters and amplitude, (2) Group B: Stimulation with personalized stimulation amplitude, (3) Group C: Stimulation without personalization (comparator group).

Patients will be treated for 8 weeks. Patients will receive standardized pain medication including rescue medication in parallel. An additional follow-up period of 12 weeks allows to evaluate sustainable and late-time effects of treatment. Patients will use a therapy management system to monitor outcome.

Inclusion Criteria:

• Male or female aged 18 to 65 years at screening
• Patient has an understanding of the study and its procedures, agrees to its provisions, and gives written informed consent prior to any study-related procedures
• Chronic back pain with or without leg pain (CBLP) persisting for at least 3 months
• A minimum of 70 (out of 180) points on the Computer User Self-Efficacy Scale at the screening visit
• Patient is constant with respect to pain treatment during the screening phase
• A daily average VAS >= 4 on at least half of the days in the screening phase
• Compliance with the daily status reporting requirements as demonstrated by having valid required data entries for all days. It is acceptable if data of one day is missing in the screening phase

Exclusion Criteria:

• Patients with age under 18
• Hemophilia
• Infection, eczema, or psoriasis at application site
• Numbed and desensitized skin at the application site
• Florid malignant diseases
• Mental and physical impairments that represent a source of risk for handling the device
• The presence of a cardiac pacemaker, defibrillator, cochlear implant, or other active implantable device
• Vagal hypersensitivity
• Indication for back surgery
• High-grade spinal stenosis
• Patients with other active implants
• Patients with autonomic disorders
• Patients with diabetes type I or II
• Patients taking Beta-Blockers
• Patients taking drugs carrying the potential risk of arrhythmia (tricyclic medications, Alzheimer drugs, etc.)
• Clinically significant hip or knee arthritis
• Allergy against rescue medication used during the study
• History of Vagus Nerve Stimulation
• Pregnant or nursing female patients
• Patients with arrhythmia, bradycardia, other rhythm disorders or any other clinically significant cardiac anomalies detected during ECG at screening