A pilot randomized control trial comparing posterior paramedian versus midline incisions for interbody fusions of the lumbar spine

The Spine Journal 26 (2026) 85−93

This single-center pilot randomized controlled trial compares posterior midline versus posterior paramedian (Wiltse/minimally invasive) approaches for 1–2 level lumbar interbody fusions, assessing feasibility, infection rates, and reoperation. One hundred-one patients were randomized, with reported differences: higher deep infection (9.6% vs 4.1%) and greater reoperation rates (25% vs 6.1%) in the midline group, alongside improvements in PROMs for both groups.

Methods, perioperative care, and outcome measures are detailed, including CDC-defined deep infection, PROMs (ODI, SF-12, EQ-5D, VAS), and feasibility metrics for a multicenter RCT. The authors conclude the pilot supports a larger trial, recommend an interim analysis for reoperation differences, and outline limitations related to single-surgeon data, recruitment disruptions, and clustering effects.

Pilot RCT Findings: A single-center pilot randomized controlled trial compared posterior paramedian and midline incisions for lumbar interbody fusion, finding potential differences in deep infection and reoperation rates, with both groups showing improvement in patient-reported outcomes.

Infection Rates: Deep infection occurred in 9.6% of midline patients versus 4.1% in the paramedian group within 3 months post-surgery.

Reoperation Rates: 25% of midline patients required revision surgery compared to 6.1% in the paramedian group during follow-up.

Patient Outcomes: Both surgical approaches led to improvements in disability, pain, and quality of life scores at 6–18 weeks and 1 year postoperatively, with slightly greater improvements noted in the paramedian group.

Intraoperative Metrics: The paramedian group had lower average blood loss (268ml vs. 313ml) and a shorter average hospital stay (3.3 vs. 4.2 days) compared to the midline group.

Feasibility: The trial demonstrated high protocol adherence, low loss to follow-up, and good participant acceptance, supporting the feasibility of a larger multicenter RCT.

Limitations: The pilot was limited by single-center design, small sample size, protocol violations, and short follow-up; results may not be generalizable until confirmed by a larger trial.

Next Steps: The pilot data will inform sample size calculations and study design for a multicentered RCT to clarify whether paramedian approaches offer significant clinical advantages over midline incisions.