Acute low back pain is a common reason for emergency department visits (4.39% [95% CI: 3.67-5.18]). Drug treatment options are limited and largely ineffective. Paracetamol and opioids are no better than placebo for acute low back pain. Only NSAIDs and muscle relaxants have a slightly beneficial effect on pain, but muscle relaxants have an unfavorable benefit-risk ratio.

Given this situation, it is necessary to explore new non-pharmacological treatment options to relieve the pain of these patients. Transcutaneous electrical nerve stimulation (TENS) is a non-pharmacological therapy that involves applying an electrical current through the skin. Using one or two pairs of electrodes attached to the skin, TENS delivers painless, low-intensity electrical pulses to a painful area or along the path of a nerve.

TENS works by selectively activating large-diameter, non-nociceptive afferent fibers to induce segmental analgesia. In addition, TENS increases the concentration of endorphins in the bloodstream and cerebrospinal fluid.

The use of TENS has been studied primarily in chronic low back pain. A 2007 Cochrane systematic review concluded that TENS appears to reduce pain and improve range of motion in subjects with chronic low back pain.

The use of TENS in the emergency department has been little studied. To our knowledge, there are no high-quality studies comparing TENS versus placebo for acute low back pain in patients presenting to an emergency department. This study aims to investigate the analgesic efficacy of TENS compared to placebo in the treatment of acute low back pain in the emergency department.

Inclusion Criteria:

• = or > 18 years old
• pain (EN > 3) related to acute lower back pain in the emergency department.

Exclusion Criteria:

• Refusal to participate in the study, refusal to sign the informed consent form
• Consent cannot be obtained (cognitive impairment, language barrier, etc.)
• Patients with lower back pain lasting more than 6 weeks
• Taking immediate-release pain medication within the last 6 hours
• Taking extended-release pain medication within the last 12 hours
• Taking a muscle relaxant within the last 24 hours
• Pregnant women
• Patients requiring immediate medical attention (life-threatening situation)
• Patient already treated with TENS
• Patient with a body temperature > 38°C
• Patient with a known spinal infection
• Lower back pain related to trauma
• Patient with a known systemic rheumatological or spinal disease
• Patient with a known systemic inflammatory disease
• Patient with a known chronic pain condition such as fibromyalgia
• Patient with pain radiating into the lower limb along the path of one of the following nerves (L3-L4-L5-S1)