Lumbar isthmic spondylolisthesis: comparative insights into patient selection, surgical techniques, and clinical outcomes

Background: Lumbar isthmic spondylolisthesis (SL), often resulting from underlying spondylolysis, is a prevalent cause of chronic lower back pain and radiculopathy. The optimal surgical strategy—particularly in relation to the severity of SL and sequence of intervention—remains a topic of clinical interest. This study aims to compare one-stage versus two-stage surgical approaches in patients with Grade 1–4 SL, with a focus on functional outcomes, complication rates, and sagittal alignment.
Methods: A retrospective observational study was conducted involving 80 patients (49 women, 31 men; aged 18–89 years) diagnosed with spondylolysis and SL. Patients were stratified into four groups (1A, 1B, 2A, 2B) based on SL grade and surgical strategy (single- or two-stage). Surgical interventions included transforaminal lumbar interbody fusion (TLIF), minimally invasive TLIF (MISS-TLIF), and posterior lumbar interbody fusion (PLIF), with decompression and interbody fusion using autograft and cages. Outcomes were assessed using the Frankel Scale, Karnofsky Index, ECOG/WHO Performance Status, and McCaffrey Pain Assessment.
Results: Sagittal alignment was restored in most cases. Group 1B (single-stage TLIF) showed complete balance restoration, while 1A (two-stage) showed sustained correction with minimal complications (3.75%). Group 2A achieved stability through staged decompression and fusion, with a 5% complication rate. Neurological improvements and reduced pain perception were noted across all groups.
Conclusion: Tailored surgical planning based on SL grade and neurological status is critical. One-stage TLIF is effective in lower-grade SL, while staged surgery is preferred in advanced cases with instability or neurological compromise. Interbody fusion significantly enhances sagittal alignment and functional outcomes.