Changes in Lumbosacral Radiographic Parameters after Minimally Invasive Lumbar Interbody Fusion

Modern techniques have allowed for less aggressive surgeries and faster postoperative recovery. This study aims to evaluate changes in lumbosacral parameters after minimally invasive lumbar interbody fusion. The secondary aim was to evaluate whether interbody cage shape (crescent or rectangular shape) would influence the results.Method This is a retrospective analysis of 70 patients who underwent one or two-level lumbar interbody fusion through a minimally invasive posterolateral approach. This included midline preservation and unilateral facetectomy. Pre- and postoperative (3–6 months postoperatively) radiographs were used for measuring lumbar lordosis (LL), segmental lordosis at the level of interbody fusion (SL), and sacral slope (SS). Further analyses divided the patients into Roussouly lumbar subgroups.Results LL was significantly reduced after surgery (59:39 degrees, p = 0.001) as well as the SS (33.8:31.2 degrees, p = 0.05). SL did not change significantly (11.4:11.06, p = 0.85). There were no significant differences when comparing patients who received crescent-shaped cage ( n = 27) and rectangular-shaped cage ( n = 43). Hypolordotic patients (Roussouly types 1 and 2) had radiographic improvement in comparison to normo and hyperlordotic groups (types 3 and 4).Conclusion Minimally invasive lumbar interbody fusion caused reduction in lumbosacral parameters. Hypolordotic patients showed improvement in radiographic measurements, in comparison to normo and hyperlordotic ones.