Background <p>Lumbar radiculopathy, due to nerve root compression, leads to significant pain and functional impairment. Surgical decompression is a treatment option, but not all patients achieve good outcomes. This protocol for an ongoing randomized controlled trial aims to compare the outcomes of surgical planning with a diagnostic selective nerve root block and surgical planning without a diagnostic selective nerve root block (standard of care).</p> Methods <p>The PLAN trial is a multicenter, block-randomized, controlled, non-inferiority trial that will enroll patients diagnosed with unilateral lumbar radiculopathy. Participants who have been deemed surgical candidates will be randomly assigned to one of two groups: Group A will receive standard surgical decompression, while Group B will undergo selective nerve root block to determine what nerve root is causing the patient’s pain, followed by surgical decompression or conservative management. The primary outcome measure is the difference in the Numerical Rating Scale for Leg Pain from baseline to 3 months with a non-inferiority margin of 1.6 points. Secondary outcomes are the difference in proportions of patients reaching ≥ 1.6 points on the Numerical Rating Scale for Leg Pain, the difference in scores and time course on Numerical Rating Score for Leg Pain and Back Pain, Short-Form 36, EuroQol-5D-3&#xa0;L, and Oswestry Disability Index. Analysis will also be performed after 1 year.</p> Conclusion <p>This trial seeks to provide high-quality evidence on the effectiveness of integrating selective nerve root blocks to guide surgical decompression or avoid surgery in treating lumbar radiculopathy. The findings aim to inform clinical decision-making and optimize patient outcomes.​</p> Trial registration <p>Clinicaltrials.gov registration NCT06143813. Registration date November 9, 2023. Last update May 2, 2024, version 1.1.</p>