The main objective is to evaluate the efficacy of a single posterior intra-articular injection of dexamethasone on radicular pain (RP) at 1 month in the treatment of uncomplicated chronic cervicobrachial neuralgia (CBN) in adults, resistant to well-conducted first-line medical treatment.

Cervicobrachial Neuralgia (CBN) is a common condition caused by the compression of a nerve root (C5, C6, C7, or C8) in the cervical spine. In 10% of cases, the duration of symptoms exceeds 3 months, at which point it is considered chronic. Two main etiologies are distinguished :

• Soft disc herniation,
• uncodiscarthrotic foraminal stenosis. The pathophysiology involves both mechanical compression and local inflammation. The initial management is typically medical, provided if there are no signs of severity. If medical treatment fails or if signs of severity are present, surgical intervention is required.

The role of corticosteroid injections in the therapeutic strategy in France remains controversial. Literature on the efficacy of cervical spinal injections is heterogeneous and limited, the safety of such injections is debated, and product availability is restricted.

We hypothesize that posterior intra-articular dexamethasone injection would be effective for radicular pain resistant to first-line medical treatment.

Inclusion Criteria:

• Age ≥ 18 years,
• Unilateral monoradicular cervicobrachial neuralgia (CBN),
• Predominant radicular pain, with a Radicular Visual Analog Scale (VAS) score ≥ 40/100,
• Imaging (CT or preferably MRI) performed within the last 6 months,
• Foraminal conflict at one level on imaging (CT or preferably MRI) performed within the last 6 months, confirmed by a senior investigator trained in the study,
• Failure of medical treatment that included at least one analgesic (level I to III) and one oral anti-inflammatory (NSAIDs and/or corticosteroids) for at least 7 consecutive days within the last 3 months,
• Discontinuation of oral anti-inflammatory drugs (NSAIDs and/or corticosteroids) 24 hours prior to randomization,
• Current episode duration ≥ 3 months,
• Negative pregnancy test on the day of the procedure for premenopausal female patients,
• Patients of childbearing age must have reliable contraception for the duration of the study,
• Absence of biological inflammatory syndrome, thrombocytopenia, or coagulation disorders on the day of the procedure,
• Patient capable of providing written informed consent prior to participating in the study.

Exclusion Criteria:

• Inability to speak, read, or write French fluently,
• Patient under guardianship or custody, or deprived of liberty,
• No affiliation with social security,
• Neurological signs of severity (clinical motor deficit ≤ 3/5, pyramidal irritation signs, or cervical spinal cord edema on MRI),
• Non-concordant imaging within the last 6 months (absence of conflict, contralateral conflict, or ipsilateral conflict not immediately adjacent), confirmed by a senior investigator trained in the study,
• Recent cervical spine injection (< 3 months),
• Foraminal conflict at more than 2 levels,
• History of cervical spine surgery within the last 12 months or scheduled surgery in this indication within 6 months,
• Secondary CBN (traumatic, infectious, neoplastic, or inflammatory etiology),
• Contraindication to fluoroscopy-guided injection (contrast agent allergy, allergy or contraindication to dexamethasone administration),
• Pregnant women,
• Ongoing participation in another therapeutic trial or interventional research study,
• Patient suspected of non-compliance with the study protocol.