Early Radiological Assessment of Static and Expandable Cages in Lateral Single Position for Indirect Decompression- Lateral Lumbar Interbody Fusion

Abstract

This study aimed to compare the postoperative alignment of static and expandable cages in lateral single-position (LSP) for indirect decompression in lateral lumbar interbody fusion (LLIF). We included sixty-seven patients who underwent LSP-LLIF for lumbar degenerative disease. We performed radiological assessments preoperatively and two weeks postoperatively using computed tomography and magnetic resonance imaging. We divided the patients into the expandable cage group (23 patients) and the static cage group (44 patients). We measured disc height (DH), segmental lordosis (SL), and foraminal area (FA) from computed tomography images and the area of the dural sac from magnetic resonance imaging. We recorded surgical outcomes and complications. Both static and expandable cages demonstrated improvements in DH, SL, FA, and dural sac expansion. However, we found no statistically significant differences in the average change in DH (4.4 ± 2.1 mm vs. 4.2 ± 1.8 mm, P= 0.685), the average change in SL (1.0 ± 4.4° vs. 1.9 ± 3.6°, P= 0.310), or FA change (32.5 ± 31.7 mm2 vs. 34.9 ± 29.5 mm2, P= 0.966) between the expandable and static cage groups. We also found no statistically significant difference in dural sac enlargement between the two groups. We observed no significant differences in operation time, estimated blood loss, or length of hospital stay between the two groups. No severe adverse events or additional surgeries were reported. In LSP-LLIF without facet joint resection or other posterior techniques, static and expandable cages showed comparable effectiveness in achieving increased DH, SL, FA, and indirect decompression.