Day: September 23, 2026

Spine 2026;51:1326–1332

Choosing between minimally invasive and open transforaminal lumbar interbody fusion requires balancing adequate decompression and reconstruction against the burden of surgical exposure. In patients with single-level degenerative stenosis and low-grade spondylolisthesis, Krutko and colleagues provide randomized evidence that early functional recovery need not be compromised by a less extensive approach. Their findings favor a selective interpretation: minimally invasive surgery shortened hospitalization and reduced additional analgesic requirements, but did not establish superior clinical outcomes or lower direct costs. Patient selection, incomplete follow-up and the absence of mature fusion results remain central to applying the study.

Objective

To determine whether minimally invasive TLIF was noninferior to open TLIF for improvement in disability at three months, while comparing clinical, perioperative and direct-cost outcomes.

Methods

This single-center, open-label randomized trial enrolled 96 patients between 2022 and 2024, allocating 48 to each technique. Mean age was 55.8 years, and 74% were women. The registered protocol specified ages 40-75 years; the report describes an additional eligibility requirement of lumbar vertebral attenuation above 120 Hounsfield units. Most procedures involved L4-L5. Two surgeons, each with more than 15 years of experience, performed the operations.

The primary endpoint was change in the Oswestry Disability Index (ODI) at three months, with a prespecified noninferiority margin of 12 points. The primary analysis used available observations from the modified intention-to-treat population; a per-protocol analysis excluded major protocol deviations. Secondary measures included pain, satisfaction, complications, hospitalization and direct costs.

Main results

Three-month ODI data were available for 48 minimally invasive and 39 open-surgery patients. The reported difference was 0.4 points (90% CI -5.7 to 6.5), supporting the authors’ noninferiority conclusion; approximately 83% and 82% achieved clinically important improvement.

Hospitalization averaged 8.0 versus 9.5 days (p = 0.005), and additional analgesia was less frequent after minimally invasive surgery (p = 0.026), although direct costs were 10.5% higher. Pain, satisfaction, blood loss, operative duration and complication comparisons were not statistically significant. Six complications occurred overall, with no reoperations during three months.

Interpretation

Approach selection should follow decompression requirements, bone quality and surgical expertise. The minimally invasive technique combined unilateral paramedian exposure, over-the-top decompression and contralateral percutaneous screws; open surgery used midline exposure, laminectomy and bilateral facetectomy. Both groups received two cages and bilateral fixation.

The findings support these constructs in selected single-level disease, not reduced exposure when adequate decompression is uncertain. They do not determine whether fusion is preferable to decompression alone. Higher implant expenditure outweighed shorter hospitalization locally, so the economic result should not be generalized across healthcare systems.

Limitations

The single-center, unblinded design and highly experienced operators limit generalizability. Missing three-month observations were confined to the open group, creating an important risk of attrition bias in a noninferiority trial. The study also recorded five major protocol deviations in each arm. Secondary comparisons were not adjusted for multiplicity, and the small number of complications cannot establish equivalent safety.

The bone-density eligibility threshold restricts extrapolation to patients with poor bone quality. Three-month disability improvement does not establish fusion success, implant durability or long-term freedom from revision. Length of stay and costs reflect the national and institutional healthcare setting.

Clinical takeaway

For selected single-level degenerative stenosis with low-grade spondylolisthesis, MIS-TLIF is supported as an alternative to open TLIF for early functional recovery. Match the approach to decompression requirements, bone quality and operator experience; do not infer superior long-term fusion, fewer complications or lower costs from this trial.