Background: Motion-preserving surgical strategies for lumbar degenerative pathology include lumbar disc replacement (LDR) and decompression without fusion (DWF). While both aim to maintain segmental mobility, their indications and reported outcomes differ substantially, particularly regarding radicular symptoms.

Objective: To map the existing evidence on LDR versus DWF for lumbar radiculopathy; in the absence of direct comparative studies, to map high-quality evidence (randomised controlled trials [RCTs]) reporting radicular outcomes in LDR and DWF individually.

Methods: A scoping review was conducted in accordance with PRISMA-ScR guidelines. An initial structured search for comparative studies evaluating radiculopathy outcomes following LDR versus DWF yielded no eligible studies, identifying a knowledge gap. A secondary search limited to RCTs was performed to identify trials reporting radicular outcomes for LDR and DWF separately. Studies were included if they evaluated surgical interventions and explicitly reported leg pain outcomes. Trials reporting only global pain without differentiation between leg and back pain were excluded. Data was charted descriptively and synthesized thematically.

Results: Of 174 LDR and 273 DWF RCTs identified, 4 (2.3%) and 44 (16.1%) respectively reported explicit radicular outcomes. In LDR studies, axial back pain due to degenerative disc disease was the primary surgical indication, with improvement in radicular symptoms a secondary product of the intervention. Radiculopathy due to lumbar disc herniation or spinal stenosis was often the primary indication in DWF (56.8% versus 0% in LDR), and leg pain was a primary endpoint with granular outcome reporting. LDR trials had larger mean sample sizes (286 versus 144 participants) and longer-term follow up (50.0% had >2-year outcomes versus 13.6% of DWF trials), while DWF trials often evaluated immediate- or short-term pain relief.

Conclusions: No direct comparative evidence exists to compare LDR versus DWF for lumbar radiculopathy. High-quality evidence for radiculopathy in DWF is substantially more robust than in LDR, highlighting a paucity of radicular-focused data in LDR. Individual group literature demonstrates differences in indications and radicular outcome reporting between LDR and DWF, emphasising a critical knowledge gap warranting future comparative studies.