2020 Volume 11 Issue 10 Pages 1157-1162
Introduction: We examined and compared the union rate of autogenous bones implanted inside cages and in the gap between the cages (outside cages) in transforaminal lumbar interbody fusion (TLIF).
Methods: A total of 133 patients who underwent single-level TLIF for degenerative lumbar disease at our hospital from April 2014 to March 2018 were included. CT imaging was performed 3 months and 1 year after surgery, and bony union was determined. Bony union was defined on CT coronal and sagittal images with bone bridges over the vertebral endplates and without non-union sign (gas phenomenon at the vertebral endplates, loosening of pedicle screw, and cysts of the vertebral endplates).
Results: The rate of bony union was 49.6% (66 of 133 cases) vs 63.9% (85 of 133 cases) at 3 months after surgery inside cages vs outside cages, which were significant differences (p<0.05). Similarly, the rate of bony union was 72.9% (97 of 133 cases) vs 83.5% (111 of 133 cases) at 1 year after surgery inside cages vs outside cages, which were significant differences (p<0.05).
Conclusions: In this study, we identified the bony union rate of bone graft outside cages presented higher than that inside cages. We didn't compare the bony union rate between inside only and both sides of cages, so we could not approve that bone grafts outside cages promote bone fusion. However, the estimation of bony union outside cages was appropriate for spinal fusion compared to inside cages.
Above all, the bony union outside cages may be a good indicator of spinal fusion and the procedure of bone graft outside cages may have a possibility of promoting bony union in TLIF.
