The Selective Intraperineural Nerve Root Block Study

The change from baseline in standing impairment

Standing impairment was documented via separate video recordings before and after each SINRB procedure, as well as on the second day of postoperative ambulation. Upon completion of data collection, Video recordings of all participants were randomly shuffled, and independent assessors evaluated the presence or absence of standing impairment for each video. Assessors were blinded to the type of nerve root injected (responsible vs. non-responsible), final surgical outcomes, clinical information, imaging results, and the number of SINRB sessions. Video content: The patient was instructed to stand upright with chest out, head raised, and lumbar spine maintained in an extended position for 20 seconds. Assessment Criteria: Standing impairment was defined as present if the patient voluntarily bent forward/backward or left/right during the test due to intolerable radicular pain and failed to maintain the initial upright posture. Otherwise, standing impairment was considered absent.

Change from baseline in walking impairment

Walking impairment was evaluated using the same recording and blinding protocols as those for standing impairment. Video content: Patients maintained an upright position and kept uninterrupted walking for 500 meters. Judgment criteria: "walking disorder" was defined as present if voluntary termination of walking occurred before completing 500 meters due to intolerable radicular pain. Otherwise, walking impairment was considered absent.

Change from baseline in straight leg raising impairment

The straight leg raising (SLR) impairment was evaluated using the same recording and blinding protocols as those for standing impairment. Video content: The straight leg raising (SLR) test was performed sequentially on the unaffected side and the affected side. Assessment criteria: The projection of the heel of the elevated leg onto the contralateral (non-elevated) leg was used as the observation index. "Presence of SLR impairment on the affected side" was defined as: the heel projection on the affected side failing to reach the patella due to intolerable radicular pain, whereas the heel projection on the unaffected side reached the patella or cephalad to it. "Absence of SLR impairment on the affected side" was defined as: the heel projection reaching the patella at maximum SLR on the affected side, with or without tolerable radicular pain.

Subjective pain relief

After each SINRB/operation, movements previously inducing severe pain (e.g., standing, walking, lying flat, stair climbing/descending) were repeated. Video questions: "Where was your worst pain during movement pre-procedure?"; "Where do you feel pain now? Point to it."; "Does residual pain affect walking speed/distance?"; "How much has pain decreased post-SINRB/surgery?" (options: no significant relief; relief with activity-limiting residual pain; essential relief \[residual pain not affecting activities\]; pain disappeared). Pain relief assessment followed the same recording and blinding protocols as for standing impairment.

Result of SINRB

This outcome measure is a derived variable automatically generated from the primary outcome measure according to a predefined scoring rule. After the independent assessors completed evaluating activity impairment and subjective pain relief in each video, all results were matched with corresponding patients and tabulated. SINRB test results were judged by the following criteria: For patients with activity impairment, results were positive if all activity impairments resolved (with or without residual pain), otherwise negative. For patients without activity impairment, results were positive if subjective pain relief was rated as "pain disappeared", otherwise negative.

Overall clinical assessment after lumbar spine surgery

This outcome measure is a derived variable automatically generated from the primary outcome measure according to a predefined scoring rule. Compared with preoperative status, if all movement impairments resolve postoperatively, or the original pain is rated as "essential relief" or "pain disappeared", the decompressed nerve root is defined as the true responsible compressed nerve root(RCNR) and the sole source of pain. If pain relief does not meet the above criteria during the initial postoperative assessment, a telephone follow-up will be conducted at 1 month after surgery for re-evaluation. If the patient reports "essential relief" or "pain disappeared" at follow-up, the decompressed nerve root is still regarded as the RCNR and the sole source of pain; otherwise, it is not considered the sole source of pain.

The occurrence of complications

The occurrence of complications during the puncture procedure, including hematoma at the puncture site, infection, allergic reactions, and other related complications, will be recorded in detail.

Changes in neurological function before and after SINRB

Changes in neurological function before and after SINRB. Baseline neurological assessment is performed before the first SINRB, including superficial sensory examination of the affected side (medial malleolus , dorsum of the foot, first and second toe web spaces , lateral aspect of the heel) and muscle strength testing of the affected side (ankle dorsiflexion, ankle plantarflexion, great toe dorsiflexion, great toe plantarflexion). At 24 hours after complete resolution of anesthetic effects following the final SINRB, patients are interviewed for new-onset numbness or discomfort, and the above neurological examinations are repeated. To supervise this key data, video recording will be conducted during inquiry and physical examination, with subsequent quality supervision by third-party senior physicians.