Objective:

Interbody fusion procedures, including: transforaminal (TLIF), posterior (PLIF), anterior (ALIF), and lateral (LLIF); effectively treat lumbar degenerative pathology and provide spinopelvic balance. The objective of this study is to compare changes in spinopelvic parameters 6 months following 1-2 level TLIF, PLIF, ALIF, and LLIF.

Methods:

This retrospective study included 18 centers across the United States. Patients were included in the study if they underwent a one- or two-level primary lumbar fusion for degenerative pathology. Pre-operative and 6-month post-operative lumbar AP and lateral lumbar plain radiograph measurements included: pelvic incidence (PI), pelvic tilt, lumbar lordosis from L1-S1 (LL), and segmental lordosis (SL) of each segment between L1-S1.

Results:

474 patients met inclusion criteria, with 632 levels that underwent fusion. 181 patients underwent an ALIF/LLIF on on 381 levels, while 188 underwent a TLIF/PLIF on 252 levels. ALIF/LLIF procedures resulted in significantly more segmental lordosis (p < .001) and global lumbar lordotic alignment change (p = .01) compared to TLIF/PLIF procedures. Whether patients' alignment was preserved versus worsened was not significantly predicted by type of procedure. Similarly, whether patients' alignment was restored versus not corrected was not significantly predicted by procedure.

Conclusion:

In this large-scale multicenter study of lumbar fusion patients presenting with degenerative lumbar pathology, anteriorly-placed grafts (ALIF/LLIF) led to a greater likelihood of patients being preserved rather than worsened in their spinopelvic mismatch. Posteriorly-placed TLIF or PLF grafts tended to worsen lordosis both segmentally and globally, yet even the anterior grafts only modestly improved those two same measurements.