Prospective, Observational Study of Anterior Bridging Cage Augmented With Bone Substitute Versus Localized Autobone in Transforaminal Lumbar Interbody Arthrodesis
Phase: NA
Conditions: Stenosis, Fusion of Spine (Disease)
Sponsor: Zenoss Co, Ltd

Anterior Bridging Cage With Bone Substitute Versus Localized Autobone in 
Transforaminal Lumbar Interbody Arthrodesis 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
NCT02485574 
 
2021-07-14 
 
 
 
 
 
 
 
 
 
 

Study protocol 
Consecutive patients aged 18-80 years with spinal stenosis or spondylolisthesis who planned to undergo single-
level lumbar transforaminal interbody fusion (TLIF) with pedicle screw fixation were included. All operations 
were performed at a single institution by a single surgeon. The enrolled patients had plain radiographs at 
postoperative 3, 6, and 12 months and fine-cut multiaxial reconstructed CT scan at postoperative 12 months to 
evaluate for bone-bridging patterns. The clinical outcomes were assessed by the Oswestry Disability Index (ODI) 
scores preoperatively and 12 months after surgery. 
 
Operation Methods 
After disc preparation following bilateral decompression with facetectomies, extra-cage bone grafting, consisting 
of half- mixed each 6 cc of local autobone and synthetic bone (OSTEON, Genoss, Korea), was performed on the 
prepared anterior disc space bilaterally; then, bilateral polyetheretherketone cages (ABB cage, Genoss, Korea) 
with different graft compositions (left cage: filled with local autobone, right cage: filled with local autobone + 
synthetic bone) were inserted. 
 
Radiographic Fusion Criterion 
We used the concept of InCBB and ExCBB to evaluate the fusion status. InCBB was defined as the bridging bone 
between the upper and lower vertebrae through the void of the cage(s) and divided into right (Rt.) and left (Lt.) 
InCBB according to the cage position. ExCBB was defined as the bridging bone between the 2 vertebrae in extra-
cage areas of the disc space and divided into 5 zones based on their relative positions to the cages in the disc space: 
anterior ExCBB: front of the cage; posterior ExCBB: back of the cage; intermediate ExCBB: between 2 cages; 
right: at the right side of the right cage; and left ExCBB: at the left side of the left cage. We graded bridging scores 
from 0 to 2 based on the degree of completion of the bridging bone in InCBBs and ExCBBs (grade 0: no bridging 
at the superior and inferior endplates; grade 1: incomplete bridging; bridging at the superior or inferior endplate, 
but with a clear radiolucent line; grade 2: complete bridging). We defined ABB as the bridging bone between the 
extra-cage grafted bone and intra-cage grafted bone through the medial, lateral, superior, and inferior holes in 
each cage. 
InCBB, ExCBB and ABB were evaluated using a software program (Extended Brilliance Workspace 4.5 
workstation, V4.5.2.4031, Philips Healthcare Nederland BV, the Nether- lands) that allows users to control the 
axis of the image planes. Three planes were set at each level as follows: the axial plane was set parallel to the 
operated disc space on coronal and sagittal views; the sagittal plane was set perpendicular to the disc space on 
coronal view and the posterior margin of the vertebrae on axial view; and the coronal plane was set per pendicular 
to the disc space on sagittal view and parallel to the posterior margin of the vertebrae on the axial view. The 
sagittal and coronal views were then serially examined for ExCBBs and InCBBs. The fusion was defined as 
meeting the following 3 criteria: no subsidence of 3 mm or more on serial postoperative 3, 6, 12 months 
radiographs until postoperative 12 months; at least having one or more grade 2 among InCBBs or ExCBBs 
(InCBB/ExCBB: 0/2, 1/2, 2/2, 2/1, 2/ 0); and the complete bridging bone, graded 2, should be con- firmed on both 
sagittal and coronal views simultaneously. After three planes (sagittal, coronal, and axial) were set at each level, 
the sagittal and coronal views were serially examined for ExCBBs, InCBBs, and ABBs. To evaluate medial and 
lateral ABBs, we adjusted the sagittal plane on the axial view in a direction parallel to the diagonal axis of the 
cage. 
Statistical Analysis 
The differences between the fused and non-fused groups based on our suggested criterion were examined using 
independent t-tests for continuous variables. A P value <0.05 was considered statistically significant. All statistical 
analyses were per- formed using SPSS version 23.0 (SPSS, Chicago, IL, USA).