Expandable Versus Static Lumbar Interbody Fusion, Would it Differ?

Background: This study aimed to compare both types of interbody fusion either expandable or static types regarding clinical and radiological changes in anterior disc height (ADH), posterior disc height (PDH), average disc height, foraminal height (FH), segmental lordosis (SL), and lumbar lordosis (LL). Aim of Study: The primary outcome was detecting which of both types of interbody fusion is superior to the other one. The secondary outcomes included comparison between both types of cages regarding the rate of complications, comparison between both techniques regarding the operative time, patient complaint improvement using the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI) scoring. Patients and Methods: This retrospective cohort study en-rolled adult patients who underwent single- or multiple-levels lumbar interbody fusion (LIF) between 2022 and 2024. Patients were categorized by the cage type used intraoperatively (stat-ic versus expandable). We enrolled 104 patients with lumbar pathology scheduled for posterior spinal fusion surgery with transpedicular screws and interbody fusion. Patients were en-rolled into two groups of 60 patients in the static arm and 44 in the expandable arm. Results: A total of 104 patients were studied (60 static non-expendable group, 44 expandable group). Groups had similar demographic characteristics. There was a significantly higher average ADH in the expandable group compared to the static group (11.3±.8 versus 10.3±.9, p<0.001). There was a signifi-cantly higher average FH in the expandable group compared to the static group. In addition, there was a significantly higher av-erage SL in the expandable group compared to the static group (22.6±5.1 versus 19±4.4, p=0.004), and there was a significant-ly higher average LL in the expandable group compared to the static group (p<0.001). Conclusions: Patients undergoing LIF using cages of either types show improvements in all the assessed parameters in our study SL, LL, ADH, PDH, and FH together with clinical im-provements in the VAS score and the ODI. However, there was evidence of superiority of expandable cages over static types regarding ADH, FH, SL, and LL. With borderline superiority of expandable cages over static cages in blood loss and operative time.