Chronic low back pain (CLBP) is a leading cause of disability worldwide and significantly impairs functional capacity and quality of life. Non-pharmacological therapies are recommended as first-line management, and acupuncture has demonstrated potential benefits in reducing pain and disability. Thread embedding acupuncture (TEA) is a modified acupuncture technique that provides prolonged stimulation through the implantation of absorbable polydioxanone (PDO) threads at acupuncture points.

This randomized controlled trial aims to evaluate the effectiveness of TEA at the EX-B2 points compared with sham TEA in improving disability and lumbar flexibility in patients with chronic non-specific low back pain. Disability will be assessed using the Oswestry Disability Index (ODI), and lumbar flexibility will be measured using the Finger-to-Floor Distance (FFD) test over an 8-week follow-up period.

Chronic low back pain (CLBP) is a major contributor to global disability and reduced functional performance. Conventional management such as analgesics and physiotherapy often provides limited long-term functional improvement. Acupuncture has been recommended as a non-pharmacological treatment option for CLBP, and evidence suggests it can reduce pain and disability.

Thread embedding acupuncture (TEA) is a modified acupuncture technique in which absorbable medical threads are implanted into specific acupuncture points, providing continuous stimulation over several weeks. This prolonged stimulation is believed to enhance neuromodulation, improve local microcirculation, and promote tissue repair, potentially leading to sustained clinical benefits.

The EX-B2 points are located 0.5 cun lateral to the spinous processes from T1 to L5 and are anatomically close to the paraspinal muscles and posterior nerve roots. Stimulation of these points may modulate pain pathways and improve lumbar function.

This study is designed as a randomized controlled trial comparing TEA at EX-B2 points with sham TEA in patients with chronic low back pain. The primary outcome is change in disability measured by the Oswestry Disability Index (ODI) at weeks 2, 4, 6, and 8 after intervention. The secondary outcome is change in lumbar flexibility measured by Finger-to-Floor Distance (FFD) at weeks 4 and 8. Adverse events related to the procedure will also be recorded to evaluate safety.

Inclusion Criteria:

• Male or female participants aged ≥ 18 years
• Participants experiencing low back pain for at least 3 months (>12 weeks)
• Highest low back pain intensity within the past 2 weeks with a score of ≥ 3 on a 0-10 Numeric Pain Rating Scale (NPRS)
• Receiving pharmacological therapy with a stable analgesic regimen for at least 2 weeks prior to enrollment
• Presence of physical functional disability as indicated by an Oswestry Disability Index (ODI) score > 20%
• Willing and able to participate in the study until completion and to provide written informed consent

Exclusion Criteria:

• History of hypersensitivity reactions to acupuncture or thread embedding acupuncture, or known allergy to stainless steel or polydioxanone (PDO) threads
• History of keloid formation
• Presence of scars (cicatrices) or skin disorders at the thread embedding acupuncture insertion sites in the lower back area
• Specific spinal pathology including fracture, tumor, infection, or severe lumbar spinal stenosis requiring surgical intervention
• Structural spinal abnormalities (scoliosis or kyphosis) detected on physical examination
• History of spinal surgery or indication for spinal surgery due to severe neurological deficits
• Presence of cardiac disease, hematological disorders, or uncontrolled diabetes mellitus
• Regular use of systemic steroids, nonsteroidal anti-inflammatory drugs (NSAIDs), antiplatelet agents, anticoagulants, or topical analgesic medications
• Receipt of other treatments for low back pain, including dry needling, neuromuscular taping, spinal injections, or acupuncture within the past 2 weeks, or thread embedding acupuncture within the past 6 months
• Severe cognitive impairment, severe psychiatric or psychological disorders, or history of alcohol or substance abuse
• Pregnant or breastfeeding women, or women planning pregnancy within the next 6 months
• Body mass index (BMI) < 18 kg/m²

Individual participant data will not be shared publicly. Only aggregate study results will be reported in publications.

Participants will be blinded to group allocation. The sham procedure will be designed to be visually and procedurally similar to the active thread embedding acupuncture intervention. Outcome assessors will be blinded to treatment assignment.