Comparative Effectiveness of Expandable Versus Static Interbody Spacers via MIS LLIF: A 2-Year Radiographic and Clinical Outcomes Study

Abstract

Study Design: Retrospective cohort study. Objective: The purpose of this study is to compare the radiographic and clinical outcomes of expandable interbody spacers to static interbody spacers. Methods: This is a retrospective, institutional review board–exempt chart review of 62 consecutive patients diagnosed with degenerative disc disease who underwent minimally invasive spine surgery lateral lumbar interbody fusion (MIS LLIF) using static or expandable spacers. There were 27 patients treated with static spacers, and 35 with expandable spacers. Radiographic and clinical functional outcomes were collected. Statistical results were significant if P < .05. Results: Mean improvement in visual analogue scale back and leg pain scores was significantly greater in the expandable group compared to the static group at 6 and 24 months by 42.3% and 63.8%, respectively ( P < .05). Average improvement in Oswestry Disability Index scores was significantly greater in the expandable group than the static group at 3, 6, 12, and 24 months by 28%, 44%, 59%, 53%, and 89%, respectively ( P < .05). For disc height, the mean improvement from baseline to 24 months was greater in the static group compared to the expandable group ( P < .05). Implant subsidence was significantly greater in the static group (16.1%, 5/31 levels) compared with the expandable group (6.7%, 3/45 levels; P < .05). Conclusions: This study showed positive clinical and radiographic outcomes for patients who underwent MIS LLIF with expandable spacers compared to those with static spacers. Sagittal correction and pain relief was achieved and maintained through 24-month follow-up. The expandable group had a lower subsidence rate than the static group.

Instrumentation choice and early radiographic outcome following lateral lumbar interbody fusion (LLIF): Lateral instrumentation versus posterior pedicle screw fixation

“…Current literature reports LLIF fusion rates between 75–100%, which is similar to our study and those rates historically reported for ALIF, PLIF, and TLIF [23] , [24] , [25] , [26] . Ultimately, only 18 (21.95%) of our 82 patients were from the BSF analysis for not having follow-up imaging more than 6 months postoperatively, though reassuringly all of the patients who had reoperation or instrumentation complications were included in the analysis of BSF fusion scores.…”

Expandable Lateral Lumbar Cages With Integrated Fixation: A Viable Option for Rostral Adjacent Segment Disease

“…With eLLIFp, back and leg pain improved over 90% by the time of solid fusion. These results were somewhat better than the 80% improvement reported for expandable lateral cages 14 and clearly superior to the 49% to 60% improvement with static cages. 4,8,13,19 Functional status and disability improved 47% and 69% in our cohort, which were similar to improvements reported for static cages but lower than that reported for expandable lateral cages.…”

“…4 disc height with less subsidence utilizing expandable lateral cages compared with impacted static lateral cages. [12][13][14] Expandable cages with lateral fixation significantly improved segmental stability and prevented anterior cage dislodgment. 15 Early experience using these expandable lateral titanium interbody cages with integrated lateral plate fixation (eLLIFp) found the device to be robust and not require supplemental posterior pedicle screw-rod fixation.…”

Expandable vs Static Interbody Devices for Lateral Lumbar Interbody Fusion

“…In 2020, Li et al compared the radiographic outcomes in 62 patients with degenerative disc disease after insertion of a static (n = 27) or expandable (n = 35) device through an LLIF. 10 In the expandable group, the segmental lordosis improved from baseline at all timepoints (6 weeks, 3 months, 6 months, 12 months, and 24 months) and increased by a mean of 23% by 24 months. In the static group, the segmental lordosis improved significantly from baseline only at 24 months and increased by a mean of 17%.…”

“…These findings varied from those of Li et al, where they studied 62 consecutive patients treated with an expandable (n = 35) or a static (n = 25) lateral lumbar interbody device. 10 At 24 months postsurgery, the expandable group showed significantly greater improvements in VAS back and leg pain and ODI compared to the static group. These 2 studies suggest that patients who undergo LLIF with expandable interbody devices have equivalent if not better clinical outcomes compared to those who receive static devices.…”