Page 462 - IJB-9-5

International Journal of Bioprinting 3D-printed oblique lumbar interbody cage

Table 2. Result of 3D-printed cage dimensional accuracy
Dimension Symbol Actual dimension (mm) 3D-printed dimension
Mean (error percentage %) (mm)
Cage length L 45.00 45.37 (0.82)
Cage width W 22.00 21.77 (-1.05)
Cage height H1 H2 H3 7.86 10.26 7.93 7.71 (-1.87) 10.34 (0.75) 7.84 (-1.18)
Slot width SW1 SW2 10.00 15.00 10.19 (1.90) 15.14 (0.93)
Slot length SL1 SL2 5.00 5.00 5.17 (3.40) 4.89 (-2.27)

Figure 8. Range of motion for CA, CES, and CLS models under flexion, extension, bending, and torsion.

in the 12,000 N (50% of the maximum load) and 6000 N flat OLIF needs to be increased via lateral plate or posterior
(25% of the maximum load) groups at 470,000 and 2.73 pedicel screw fixation, but this would increase the rate
million cyclic loads, respectively. Cyclic tests could pass of clinical complications. Therefore, a better OLIF cage
5 million cycles under 3500 N, but microcracks occurred should consider the morphology of the superior/inferior
at the bottom edge of the cage. Therefore, the endurance surface to increase the contact surface to achieve good
limit was 2600 N for the compressive-shear test (Figure 7b stress transfer, optimize the structure to reduce stress
and c). shielding, and improve the bionic lattice design to enhance
the bone ingrowth effect.
4. Discussion In this study, the optimal disc region structure was
The OLIF approach can not only reduce the number obtained through feedback from the FE and WTO analysis
of wounds but also cover a larger area compared to the under different activities with load on the disc simulating
traditional posterior lumbar interbody fusion approach. daily life. An OLIF cage profile was designed according
However, the superior/inferior surfaces of the current to the optimized results based on the statistical results
commercial OLIF cages are all flat and do not consider of endplate morphology from osteoporosis patients.
the morphological changes of the endplate in patients with Then, anterior/posterior cross and transverse plane tilted
osteoporosis. In addition, the stability of the commercial embedded locking fixation screws were combined with

Volume 9 Issue 5 (2023) 454 https://doi.org/10.18063/ijb.772