The Selective Intraperineural Nerve Root Block Study

Condition(s) studied

Investigational drug(s) / intervention(s)

Selective Intraperineural Nerve Root Block(SINRB): The patient was placed in a standard prone position. The cutaneous puncture point was confirmed via large C-arm oblique fluoroscopy with the projection angle strictly consistent with the preoperative protocol.All puncture manipulations were completed by an experienced spinal surgeon. Under intermittent fluoroscopic guidance, the puncture trajectory was adjusted to keep the needle parallel to the fluoroscopic beam, followed by slow needle advancement until radiating pain was evoked in the patient. The needle was further advanced approximately 1 mm, and 0.2 mL contrast medium was injected subsequently. The visualization of a linear streak shadow within the nerve root confirmed intraneural positioning. The needle was fixed in situ, and 0.5 mL lidocaine was injected.

single-level lumbar decompression surgery: All patients underwent single-level lumbar surgery with either endoscopic or conventional open single nerve root decompression, and postoperative anteroposterior and lateral lumbar radiographs were routinely obtained for imaging evaluation.

Study summary

Before lumbosacral decompression surgery for radicular pain, selective nerve root block(SNRB) is a common procedure to identify the responsible compressed nerve root(RCNR) and predict surgical outcomes. However, the diagnostic accuracy of conventional SNRB is unsatisfactory, especially in terms of specificity. The main limitation is the uncontrolled distribution of anesthetics during injection: when anesthetics spread to surrounding soft tissues instead of acting directly on the RCNR, false-negative results may occur with persistent radicular pain; when anesthetics diffuse to two or more nerve roots including the RCNR, false-positive results may occur even if a normal nerve root is punctured, leading to misdiagnosis.

This study aims to evaluate the diagnostic accuracy of a novel three-dimensional computed tomography multiplanar volume reconstruction (3D-CT MPVR) guided selective intraperineural nerve root block(SINRB) for identifying the RCNR in patients with lumbosacral radicular pain. The investigators hypothesize that this technique will achieve higher diagnostic specificity and overall accuracy than conventional SNRB, by ensuring anesthetics are delivered directly to the target nerve root. This improvement will help clinicians make more accurate surgical plans, achieve better targeted decompression, and ultimately improve postoperative pain relief and functional recovery for patients.

The main research questions to be addressed in this study are:

* What is the procedural success rate of SINRB?
* Whether SINRB may cause clinically detectable nerve injury?
* Whether sciatica is relieved after SINRB when only the responsible compressed nerve root is blocked?
* Whether sciatica is relieved after SINRB when only a normal unaffected nerve root is blocked?

Participants will:

* Undergo one or two SINRB procedures and a single-level lumbar decompression surgery
* Get assessment of pain, mobility disorder and neurological function

Eligibility

Primary outcome measure(s)

• The change from baseline in standing impairment — Baseline, 5mins after SINRB, the second day after ambulation, and 1 month postoperatively
  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 — Baseline, 5mins after SINRB, the second day after ambulation, and 1 month postoperatively
  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 — Baseline, 5mins after SINRB, the second day after ambulation, and 1 month postoperatively
  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 — 5mins after SINRB, the second day after ambulation, and 1 month postoperatively
  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.

Trial sites (1)

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