Intradiscal Vacuum Phenomenon Contributes to Lower Cage Subsidence Through Denser Endplate Bone Quality in Patients with Lumbar Spondylolisthesis Undergoing Lateral Lumbar Interbody Fusion

Background This study was performed to investigate the clinical significance of the intradiscal vacuum phenomenon (IDVP) in lateral lumbar interbody fusion (LLIF). Methods A retrospective study analyzed 198 cases of degenerative lumbar diseases with/without spondylolisthesis (LS) who received LLIF at our hospital from January 2021 to December 2023. Radiographic evaluations, including X-ray, CT, and MRI, were used to evaluate IDVP, cage subsidence (CS), intervertebral disc degeneration (IDD) grade, endplate bone quality (EBQ), and vertebral bone quality (VBQ). The radiographic measurements were compared within the association of LS/IDVP groups using the t-test、 chi-square test and One-way ANOVA. Results The CS rate in the IDVP-positive group was 18.60%, compared to 24.52% in the IDVP-negative group( p = 0.42 ). The IDVP-positive group had higher IDD grades, segmental VBQ and EBQ than the IDVP-negative group. The CS rate between the LS group and the non-LS group, non-LS/IDVP-positive group and non-LS/IDVP-negative group were not significantly different. In the association of LS and IDVP, the LS/IDVP-positive group had the lowest CS rate at 8.70% with the lowest EBQ (Upper = 3.15 ± 0.84, Lower = 3.19 ± 1.07), VBQ (Upper = 3.26 ± 0.83, Lower = 3.47 ± 0.87), and the highest IDD grade. Conclusion IDVP is a protective factor against CS in LS, likely due to the denser endplate quality. LS/IDVP-positive exhibits the highest IDD grade, EBQ, and lowest CS rate, making it an optimal indication for LLIF.