Prospective Study of ProteiOS in Lumbar Interbody Fusion (TLIF)

Transforaminal lumbar interbody fusion (TLIF) is a widely used technique for degenerative lumbar spine pathology. Prospective, randomized evidence on fusion outcomes, patient-reported outcomes, safety, and healthcare utilization for ProteiOS in TLIF is currently limited to retrospective data. This study randomizes participants 2:1 to ProteiOS versus a within-category control (standard graft material, no ProteiOS), with central, blinded, independent radiographic review of CT and X-ray fusion outcomes. The primary endpoint is CT-confirmed interbody fusion (BSF-3) at 12 months, tested for non-inferiority (margin = 5 percentage points, assumed fusion rates 95% ProteiOS vs. 89% control, 80% power, one-sided α = 0.025, Farrington-Manning likelihood score method). Secondary endpoints include fusion at 6 and 24 months, X-ray-based interbody and posterolateral fusion assessment (Lenke classification for PLF), patient-reported outcomes at 3, 6, and 24 months, adverse events, and healthcare utilization

Inclusion criteria

• Age 18-75 years, skeletally mature at time of surgery
• Degenerative disease of the lumbar spine (L2-S1) requiring 1-2 level instrumented TLIF, with or without posterolateral fusion, as determined by the treating surgeon
• For the ALIF study site only: degenerative disease of the lumbar spine (L2-S1) requiring 1-2 level instrumented ALIF
• Radiographic evidence of degenerative lumbar disease on CT, MRI, or plain radiograph (decreased disc height, herniated nucleus pulposus, ligamentum flavum/annulus hypertrophy, facet arthrosis/osteophyte, spinal canal or foraminal stenosis, or vertebral translation >3 mm)
• Symptoms of low back pain, radiculopathy, or neurogenic claudication consistent with radiographic findings
• Preoperative back pain ≥4 on a 0-10 VAS
• Preoperative leg pain ≥3 on a 0-10 VAS, consistent with radiculopathy or neurogenic claudication
• Preoperative ODI score ≥30
• Failure of ≥6 months non-operative treatment (may be waived for progressive neurological deficit, new/worsening motor weakness, bowel/bladder dysfunction, or cauda equina syndrome)
• Willing and able to comply with follow-up schedule and provide written informed consent

Exclusion criteria

• Scheduled for surgery with synthetic bone grafts containing hydroxyapatite, tricalcium phosphate, or other radio-opaque material
• BMI >40
• Prior lumbar spine fusion surgery at a level currently scheduled for surgery
• Malignancy or treatment for malignancy within the last 5 years (benign skin cancer permitted)
• Osteoporosis/osteopenia (≤2.5 SD below age-matched mean)
• Use of rhBMP-2 (Infuse) or other active biologics
• Active or systemic infection, malignancy, or severe metabolic bone disease
• Chronic steroid use (>10 days)
• Revision fusion at index levels
• Participation in another interventional clinical study within 30 days of consent
• Known pregnancy or intent to become pregnant during the study