The Impact of Surgical Approach on Sagittal Plane Alignment in Patients Undergoing One- or Two- Level Fusions for Degenerative Pathology: A Multicenter Radiographic Evaluation 6 Months Following Surgery

Abstract

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 1- or 2-level primary lumbar fusion for degenerative pathology. Preoperative and 6-month postoperative lumbar anteroposterior and lateral lumbar plain radiograph measurements included: pelvic incidence, pelvic tilt, lumbar lordosis from L1-S1, and segmental lordosis of each segment between L1 and S1.

Results: A total of 474 patients met inclusion criteria, with 632 levels that underwent fusion. Of these, 181 patients underwent an ALIF/LLIF on 381 levels, and 188 underwent a TLIF/PLIF on 252 levels. ALIF/LLIF procedures resulted in significantly more segmental lordosis (P < 0.001) and global lumbar lordotic alignment change (P < 0.01) compared with 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.

Conclusions: 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 PLIF grafts tended to worsen lordosis both segmentally and globally, yet even the anterior grafts only modestly improved those 2 same measurements.

Keywords: Anterior lumbar interbody fusion (ALIF); Degenerative lumbar stenosis; Lateral lumbar interbody fusion (LLIF); Spondylolisthesis; Transforaminal lumbar interbody fusion (TLIF).