Quantitative CT imaging as a biomarker of early bone ingrowth and recovery after lumbar interbody fusion

Abstract Chronic low back pain due to degenerative lumbar spondylosis is a major cause of disability worldwide and often requires surgical stabilization when conservative treatment fails. Additively manufactured porous titanium cages have been developed to enhance bone ingrowth and improve spinal fusion outcomes. This preliminary study evaluated clinical recovery and bone remodeling within a novel 3D-printed Ti6Al4V trabecular cage implanted during posterior lumbar interbody fusion in 21 patients. Pain and disability were assessed over one year, and computed tomography was used to quantify bone density inside the cage as a measure of osseointegration. Patients demonstrated marked and sustained improvements in back pain, leg pain, and functional disability. Intracage bone density increased substantially within the first three to four months after surgery and remained elevated at one year. Higher bone density strongly correlated with improved clinical outcomes. No implant subsidence or migration was observed. These findings indicate that quantitative computed tomography can detect early bone ingrowth within porous titanium cages and may serve as a non-invasive biomarker of fusion progression and postoperative recovery. Given the pilot nature, larger prospective randomized controlled trials are warranted to confirm these observations.