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Transtubular Endoscopic Posterolateral Decompression for L5-S1 Lumbar Lateral Disc Herniation
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No Difference in Lumbar Pelvic Angle Postoperative Changes Between Single-Level L5-S1 ALIF and TLIF Patients
Michelle Nakatsuka1, Remi Pelletier-Roy2, Akil Paturi2
1NYU Grossman School of Medicine.
Spine
|February 9, 2026
Summary
Anterior lumbar interbody fusion (ALIF) offers better regional and segmental lordosis restoration than transforaminal lumbar interbody fusion (TLIF) for single-level L5-S1 fusions. However, neither approach significantly impacts global spinopelvic alignment.
Area of Science:
- Spine surgery
- Orthopedics
- Radiographic analysis
Background:
- Restoring sagittal alignment is crucial in lumbar fusion surgery.
- Anterior lumbar interbody fusion (ALIF) is often considered superior for segmental lordosis compared to transforaminal lumbar interbody fusion (TLIF).
- The comparative effects of ALIF versus TLIF on global and regional lumbar alignment, as well as spinopelvic parameters, require further quantification.
Purpose of the Study:
- To compare the impact of single-level L5-S1 ALIF and TLIF on various sagittal alignment parameters.
- To quantify changes in lumbar pelvic angle (LPA), pelvic tilt (PT), and lumbar lordosis (L1-S1, L4-S1, L5-S1) after ALIF versus TLIF.
- To evaluate the differential effects of ALIF and TLIF on spinopelvic parameters and regional/segmental lordosis.
Main Methods:
- Retrospective cohort study of 174 patients undergoing single-level L5-S1 ALIF (n=73) or TLIF (n=101).
- Preoperative and one-year postoperative radiographic assessment of sagittal alignment parameters using Surgimap software.
- Statistical analysis included unpaired t-tests, Wilcoxon signed-rank tests, and ANCOVA for comparisons and sensitivity analyses.
Main Results:
- ALIF demonstrated significantly greater improvement in regional (L4-S1) and segmental (L5-S1) lumbar lordosis compared to TLIF.
- No significant differences were found between ALIF and TLIF in postoperative changes for global lumbar lordosis (L1-S1), lumbar pelvic angle (LPA), or pelvic tilt (PT).
- Permutation testing confirmed no statistically significant difference in LPA improvement between the two surgical techniques.
Conclusions:
- Single-level ALIF is more effective than TLIF in restoring regional and segmental lumbar lordosis at the L5-S1 level.
- Neither ALIF nor TLIF significantly alters global sagittal alignment (L1-S1 lordosis, LPA, PT) following single-level fusion.
- This study highlights the limited influence of single-level L5-S1 fusion on overall spinopelvic parameters, with ALIF showing advantages in segmental correction.
Keywords:
anterior lumbar interbody fusion (ALIF)fusion outcomeslumbar degenerationlumbar lordosislumbar-pelvic angle (LPA)pelvic incidence (PI)sagittal alignmentsegmental lordosisspinal fusionspinopelvic alignmenttransforaminal lumbar interbody fusion (TLIF)More Related Videos
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