Electric needles could replace painkiller shots for back pain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Participants with chronic LBP lasting at least three months and clinical suspicion of facet joint pain. * A balanced sex distribution and a wide range of body mass index (BMI) will be promoted to allow subgroup analyses and to explore potential associations between obesity and procedural complications, thus strengthening the external validity of the study. This demographic selection is justified by prevalence patterns reported in the literature and by the need to capture clinically relevant effect modifiers in real clinical environments. * The suspicion of facet joint pain will be based on a compatible axial clinical pattern and the absence of objective neurological deficit, considering that neither physical examination nor imaging tests provide sufficient specificity. Therefore, diagnostic confirmation will be performed functionally through ultrasound-guided medial branch diagnostic blocks, which are the most reliable tool for attributing pain to the facet joint. The dual innervation of each lumbar facet joint will be considered; thus, two adjacent levels will be blocked per joint (the medial branch at the affected level and the one immediately above). * Eligible patients will be those with a positive functional screening in two independent medial branch diagnostic blocks performed with anesthetics of different duration, in separate sessions, to reduce false positives. * The diagnosis will be confirmed in cases reporting clinically relevant pain relief within the expected pharmacological window. Exclusion Criteria: * Exclusion criteria will include red flags or specific etiologies such as infection, neoplasm, fracture, or cauda equina syndrome, as well as patients with progressive motor radiculopathy or another demonstrated neuropathic pain source other than facet origin. * Individuals who have undergone prior procedures that could compromise response interpretation such as recent radiofrequency denervation, cryoneurolysis or intra-articular corticosteroid injections within a period that could extend analgesic effects.