This study is for people who continue to have low back pain after spinal surgery, a condition called persistent spinal pain syndrome type II. Current treatments, such as epidural injections, often provide only limited relief. Doctors are testing a procedure called pulsed radiofrequency (PRF), given through a small catheter in the epidural space, with or without the addition of corticosteroids. The goal is to see if this treatment can reduce pain and improve daily function better than standard injections. About 130 patients took part, and their pain and quality of life were followed for several months after the procedure.

Persistent spinal pain syndrome type II (PSPS II) is a frequent and disabling condition encountered in Pain Units after lumbar surgery. Conventional therapeutic options such as epidural corticosteroid injections and epidurolysis often provide only partial or temporary benefit. Pulsed radiofrequency (PRF) delivered through a catheter into the epidural space has shown promising results compared to transforaminal approaches, offering a potential alternative for managing this challenging pain condition.

The purpose of this randomized, controlled, multicenter clinical trial is to evaluate the efficacy and safety of epidural PRF with or without the addition of corticosteroids in patients with PSPS II. A total of 131 patients were enrolled and assigned to receive either epidural corticosteroids alone or PRF combined with corticosteroids. Pain intensity, functional status, neuropathic pain features, and global impression of improvement were assessed at multiple follow-up visits. The findings of this study aim to provide evidence-based guidance for interventional pain management in PSPS II.

Inclusion Criteria:

1. Men and women over 18 years old.
2. Written informed consent obtained according to ICH/GCP and Spanish legislation prior to any study procedure.
3. Pain VAS score of at least 5 points.
4. Duration of pain lasting at least 3 months after back surgery despite conservative treatment.
5. Leg-dominant radicular pain deemed neuropathic based on clinical history and examination.
6. Responsiveness to selective radicular nerve block with bupivacaine 0.125%.
7. Previous epidural steroid injection.

Exclusion Criteria:

1. Pregnancy or lactation. 2. Participation in a study involving medicines or other clinical devices 4. Inability to follow instructions or collaborate during the study. 5. Findings in physical examination, clinical analysis abnormalities, or other medical, social, or psychosocial factors that, in the researcher's opinion, could negatively influence study outcomes 6. Presence of myelopathy, systemic diseases, infection (systemic or local), cancer, indication for immediate surgery, coagulation disorders, anticoagulants use, diabetes mellitus or multiple sclerosis.

7. Life expectancy of less than one year. 8. Current diagnosis of a progressive neurological disease.

De-identified individual participant data (IPD) underlying the results reported in this article will be available upon reasonable request to the Principal Investigator (Dr. Agustín Mendiola de la Osa) after publication. Data will be shared for research purposes only, following approval of a methodologically sound proposal and under a data access agreement.

Data will be available from the publication date of the main results and for 5 years thereafter.

De-identified IPD, including baseline data, intervention details, and outcomes (VAS, ODI, DN4, PGI-I), will be available to qualified researchers upon reasonable request. Proposals require approval by the principal investigator and ethics committee. Access will be granted after signing a data use agreement and will be provided via secure electronic transfer.

Participants were blinded to treatment assignment. Care providers and investigators were aware of group allocation in order to perform the procedures. No additional parties were masked.