Acute low back pain, the second leading cause of medical consultations in France, poses a major public health challenge, particularly because of its high risk of progressing to chronic low back pain-the leading cause worldwide of years lived with disability. Pharmacological treatments such as paracetamol, opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and muscle relaxants show limited benefit in terms of pain intensity or functional disability. Non-pharmacological treatments, including exercise therapy and psychological support, show promising results but remain hampered by methodological biases and small sample sizes.

A biopsychosocial approach that combines pharmacological treatments, physical therapy, psychological support and social interventions has demonstrated moderate improvements in pain and function for chronic low back pain but remains insufficiently studied for acute presentations. French guidelines advocate a combined strategy involving paracetamol, NSAIDs, physical activity and psychosocial risk assessment. However, a French multicentre retrospective study highlighted marked heterogeneity in clinical practice, along with a low adoption rate (<10 %) of these recommendations in emergency departments, underscoring the need to strengthen adherence to evidence-based management strategies. We hypothesise that a multimodal intervention targeting physicians (guideline reminders) and patients (information on disease progression and multidisciplinary care plans), to enable the systematic implementation of all aspects of a biopsychosocial approach in emergency departments, could reduce short-term pain and disability in patients with acute low back pain.

Inclusion Criteria:

• Patients aged 18 to 55 presenting to a participating emergency department, and
• Presenting with acute non-traumatic low back pain, newly developed or worsened within the past 7 days.
• Moderate to severe pain, defined as a score of ≥4 on a 0-10 numerical rating scale.
• Provision of informed consent after being given the information sheet.
• Patients covered by social security (excluding AME).

Exclusion Criteria:

• Presence of a 'red flag' according to HAS guidelines, including: motor neurological deficit or cauda equina syndrome, non-mechanical pain, trauma, active neoplastic disease or history of inflammatory rheumatism, suspected osteoarticular infection, recent spinal surgery with worsening symptoms, suspected acute vascular pathology, prolonged use of medications or corticosteroids, significant structural spinal deformity, or deterioration of general health.
• Inability to attend the 3-month follow-up.
• Poor command of French.
• Patient under guardianship/curatorship or deprived of liberty.
• Pregnant or breastfeeding women