A prospective, single-arm, mono-centre pilot study to obtain preliminary information on the ability of Dorsal Root Ganglion Stimulation (DRGS) in alleviating the painful symptoms in patients with small fiber neuropathy (SFN).

This study is a prospective, single-arm, mono-centre pilot study enrolling a maximum of 31 patients with SFN. All enrolled patients will receive a trial neurostimulation (TNS) lasting from 3 to 30 days and only patients with a positive result in terms of pain intensity reduction will be eligible for the implanted neurostimulation (INS) phase. The target number of patients eligible for INS is 10 and this population will be assessed for impact of DRGS on the neuropathic pain caused by SFN. The expected duration of patients participation will be 14 months. The rationale for this open label approach is that this is a novel technique for which pilot data with regard to applicability and efficacy have yet to be established. Data gathered in the study will provide preliminary data required to assess the feasibility of this intervention, to be used for possible future studies with a more rigorous methodological approach (i.e. controlled trial, randomized controlled trial).

Inclusion Criteria:

• 18 years or older at inclusion
• Chronic, intractable painful SFN in the peripheral limbs during at least 12 months and a biopsy positive for SFN, with a chronic pain intensity of ≥ 6 on a Numeric Rating Scale (ranging from 0 to 10), for which previous drug therapy was unsuccessful
• Stable medication dosage in the 30 days prior to inclusion
• Stable pattern of neurological symptoms

Exclusion Criteria:

• Known or suspected non-compliance
• Drug or alcohol abuse
• Pain predominantly in upper limbs
• Neuropathy or chronic pain in limbs of other origin than SFN
• Peripheral vascular disease
• Severe foraminal stenosis at the expected target level
• Coagulation disorders
• Known immune-deficiency
• Other significant concomitant diseases and any concomitant malignancies
• Presence of other indwelling devices