The goal of this clinical trial is to investigate the effectiveness of focal microvibration on patients affected by chronic lumbosacral radicular pain. The main question[s] it aims to answer are:

• Can focal microvibration improve pain in this patient population?
• Can focal microvibration improve quality of life in these patients? Participants will attach to their skin four little devices (10x20x0,5mm) delivering focal microvibration in the painful area according to researchers indications for 6 hours/day every day except Thursday and Sunday.

Researchers will compare patients treated with focal microvibration to patients treated with a sham device and to patients treated with standard pharmacological therapy.

This is the first randomized controlled study aiming to assess the potential use of focal microvibration for the management of chronic lumbosacral radicular pain which is the pain consequent to the compression of a spinal nerve root. Focal microvibration has been so far used to treat gait disorders and instability consequent to diseases such as Parkinson's disease, stroke, ataxia, multiple sclerosis with impressive results and no reported side effects. Our trial involves three arms: one arm treated with a device able to deliver focal microvibration, one arm treated with a sham device, and one arm treated with standard pharmacological therapy according to international guidelines. Patients with the active and with sham devices will attach them on their skin for 6 hours/day except on Thursday and Sunday: this application schedule with two days of treatment suspension has intended to avoid habituation to the sub-perception microvibration stimulation. The follow up will be 12 months and periodic visits will be performed after 7, 15 30, 45, 60, 90, 180, and 360 days of treatment. All the patients enrolled in the study will have access to rescue analgesic drugs such as paracetamol 1g and tramadol 100mg in case on excessive pain. Randomization will be performed by a computer-generated sequence. During the follow up visits, patients will be asked to fill questionnaires to explore and monitor pain intensity and pain interference in daily life: brief pain inventory (BPI) and Oswestry disability index (ODI)

Inclusion Criteria:

• Pain duration≥6 months
• Magnetic resonance imaging (MRI) showing compression of lumbosacral nerve roots
• Neuropathic symptoms in the innervation territory of the compressed spinal nerve roots
• Monolateral pain
• Pain intensity: moderate-severe i.e. numeric rating scale (NRS)≥4.

Exclusion Criteria:

• Psychiatric patients
• Cancer patients
• Patients affected by disease characterized by spasticity or muscular stiffness:

Parkinson's disease, multiple sclerosis, stroke, spine injuries.

• Patients with spinal or dorsal root ganglion stimulators
• Patients undergone central of peripheral stimulation in the past 3 months
• Patients affected by fibromyalgia.
• Patients undergone central nervous system surgery
• Patients with reduced renal function eGFR≤60ml/min/1,73m2