Evaluation of the Stability of a Novel Lateral Plate Internal Fixation: An In Vitro Biomechanical Study

BACKGROUND: This study aims to evaluate the biomechanical stability of a novel lateral plate (NLP) that can be used in oblique lateral lumbar fusion (OLIF). METHODS: In vitro biomechanical tests were performed on 6 fresh calf lumbar vertebrae specimens. The surgical segment was set at L3-L4. Each specimen was tested in the following order intact state (INT); OLIF cage only/standalone (SA); cage supplemented with lateral screw-rod (LSR); cage supplemented with novel lateral plate (NIP); and cage supplemented with unilateral or bilateral pedicle screw-rod (UPS or BPS). A pure moment of +/- 7.5 Nm was applied to the specimen to produce 6 different motion directions, including flexion and extension, lateral bending, and axial rotation, and the range of motion (ROM) of L3-L4 in each direction was recorded. RESULTS: In addition to flexion-extension, NLP reduced the ROM of SA (P < 0.05). In flexion-extension, the ROM of NLP was similar to those of SA and LSR (P > 0.05); compared to pedicle screw-rod (PSD), the ROM of NLP was higher (P < 0.05). In lateral bending, the ROM of NLP was close to that of LSR and PSD (P> 0.05). In axial rotation, the ROM of NLP was higher than that of PSD (P < 0.05), and close to that of LSR (P > 0.05). CONCLUSIONS: NLP can enhance surgical segment stability in all directions of motion, similar to LSR, but weaker than UPS and BPS in flexion-extension and rotation.