Fusion versus decompression alone for single-level lumbar stenosis

Necessity of Fusion Following Decompression Surgery in Patients With Single-level Lumbar Stenosis: Study Protocol for an Open-label Multicenter Non-inferiority Randomized Controlled Clinical Trial

This trial will test whether decompression surgery without added fusion works as well as decompression plus fusion for adults aged 45–75 with single-level lumbar spinal stenosis.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 86 (estimated)
• Ages: 45 Years to 75 Years
• Sex: All
• Sponsor: Sklifosovsky Institute of Emergency Care (Government)
• Locations: 2 sites (Moscow, Moscow and 1 other locations)
• Trial ID: NCT05273879 on ClinicalTrials.gov

What this trial studies

This randomized trial will enroll 86 adults with single‑level lumbar stenosis and assign them 1:1 to decompression that preserves posterior elements or to decompression plus transforaminal interbody fusion. Surgeons will use a standardized operative protocol and postoperative rehabilitation to maximize homogeneity between groups. The primary outcome is change in the Oswestry Disability Index at 24 months, and secondary outcomes include SF‑36, EQ‑5D‑5L, psychological scales, sagittal balance, fusion status, and total cost over two years. Patients will be followed at 3, 6, 12, and 24 months to capture clinical, radiographic, and economic outcomes.

Who should consider this trial

Good fit: Adults aged 45–75 with single‑level (L2–S1) lumbar stenosis grade C or D on MRI, symptomatic neurogenic claudication or radiculopathy, failure of ≥3 months of conservative care, no prior spine surgery, and acceptable bone density and stability are ideal candidates.

Not a fit: Patients with multilevel clinically significant stenosis, prior spine surgery, spinal instability or spondylolisthesis >3 mm, significant sagittal imbalance, very low bone density (<100 HU), or ASA class 4–5 are unlikely to benefit from this comparison or be eligible.

Why it matters

Potential benefit: If decompression alone proves non‑inferior, many patients could avoid fusion, reducing surgical risk, implant-related complications, and cost.

How similar studies have performed: Only one randomized trial about 15 years ago directly addressed this question, so randomized evidence is limited and the necessity of fusion remains controversial.

Eligibility criteria

Inclusion Criteria:

* age of patients from 45 to 75 years;
* stenosis C or D according to Shizas et al. according to MRI at the level of L2-L3, L3-L4, L4-L5 or L5-S1;
* clinical manifestations of lumbar stenosis (neurogenic claudication syndrome and/or radiculopathy);
* lack of effect from conservative therapy within 3 months;
* Informed consent to take part in the study.

Exclusion Criteria:

* spondylolisthesis more than 3 mm;
* spinal instability according to functional radiography;
* sagittal imbalance (type 4 according to C. Barrey);
* bone density of the vertebrae at the level of the operation is less than 100 HU;
* clinically significant spinal stenosis at 2 or more levels;
* previously performed surgeries on the spine;
* risk of anesthesia 4 or 5 according to ASA;
* inability to take part in control examinations within 2 years after the operation;
* participation in other clinical trials related to surgical or conservative treatment of diseases of the spine.

Where this trial is running

Moscow, Moscow and 1 other locations

• Pirogov National Medical and Surgical Center — Moscow, Moscow, Russia (Recruiting)
• Sklifosovsky Research Institute for Emergency Medicine — Moscow, Moscow, Russia (Recruiting)

Study contacts

• Study coordinator: Ivan Lvov, MD, PhD

Conditions Lumbar Spinal Stenosis; Spinal Stenosis; Spinal Fusion; lumbar spine; lumbar fusion; laminotomy; decompression without fusion; lumbar stenosis