Chronic low back pain represents a major public health issue, with an estimated prevalence of up to 23% in the adult population and a significant impact on quality of life and functional capacity. Among these patients, a significant proportion undergo spinal surgery-including laminectomy, discectomy, or spinal fusion-when conservative treatment has failed to provide adequate relief. Current treatment strategies involve functional spinal rehabilitation (FSR). Due to the multifaceted and complex pathophysiology of this chronic pain condition, we have previously addressed the spinal syndrome in terms of its functional and muscular component: the myofascial expression. In our clinical practice, we have introduced a minimally invasive paravertebral procedure, guided by ultrasound, targeting the fascia of the erector spinae muscles in the lower lumbar region. The goal of this procedure is to provide pain relief to the patient, enabling them to better adhere to the rehabilitative treatment (functional restoration of the spine) and ultimately improve the patient's quality of life within their environment. This evaluation of professional practices highlights a clear clinical indication in favor of infiltration of the erector spinae fascia, with a significant majority of patients reporting improved pain relief and better adherence to rehabilitation.

Thus, within a coordinated, multidisciplinary care approach, this intervention appears to address patient expectations regarding comfort and leads us to consider the myofascial component of the complaint. The proposed paravertebral intervention is also appropriate in accordance with the updated recommendations, which are very restrictive in the context of a surgically treated spine (PSPS-2). This assessment of current practices justifies the implementation of a prospective controlled study. Through this study, we aim to investigate the treatment's effects and evaluate its pharmacological (via the anti-inflammatory action of corticosteroids) and mechanical (via needle-induced muscle stimulation) components.

Inclusion Criteria:

• Patient with chronic back pain, with previous surgery

Exclusion Criteria:

• Patients with specific or common low back pain
• Patients receiving posterior subcutaneous spinal cord stimulation
• Patients with a life expectancy of less than 12 months
• Patients with a contraindication to corticosteroid injections (coagulation disorder)
• Pregnant or breastfeeding patients
• Patients with cognitive and/or psychobehavioral disorders