Restoration of Sagittal Alignment with L5-S1 Anterior Lumbar Interbody Fusion in Patients with Prior Lumbar Fusions and Adjacent Segment Disease: A Retrospective Cohort Study
Introduction Sagittal imbalance significantly impacts outcomes in adult degenerative spine conditions. Lumbar lordosis (LL) restoration is essential for spinopelvic alignment. Posterior or posterolateral fusions using hypo-lordotic implants can exacerbate spinopelvic imbalance by increasing the alr...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Knowledge E
2025-07-01
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| Series: | Journal of Spine Practice |
| Subjects: | |
| Online Access: | https://knepublishing.com/index.php/jsp/article/view/18720 |
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| Summary: | Introduction
Sagittal imbalance significantly impacts outcomes in adult degenerative spine conditions. Lumbar lordosis (LL) restoration is essential for spinopelvic alignment. Posterior or posterolateral fusions using hypo-lordotic implants can exacerbate spinopelvic imbalance by increasing the already existing hypo-lordosis. This study examines the impact of L5-S1 anterior lumbar interbody fusion (ALIF) on sagittal alignment in patients with adjacent segment disease following prior posterior or posterolateral lumbar fusions.
Methods
This retrospective study included 17 patients with a history of lumbar fusions, treated with L5-S1 ALIF at AZ Delta Hospital between 2019 and 2024. Pre-operative and post-operative radiographs were assessed for (proximal and distal) LL and sagittal balance parameters. Changes in alignment were analyzed with paired samples t-tests after verification of normal distribution.
Results
Pre-operative LL averaged at 43.7∘ (95% CI [36.1–51.3]) and improved significantly to 50.1∘ (95% CI [43.5–56.7] p < 0.05) post-operatively, primarily due to an increase of distal LL from 25.5∘ to 35.2∘ (p < 0.001). The pelvic incidence–lumbar lordosis (PI-LL) mismatch decreased significantly from 39.0∘ to 18.9∘ (p < 0.05), while the sagittal vertical axis (SVA) reduced non-significantly from 97.3 mm to 86.7 mm.
Discussion
L5-S1 ALIF has the potential to effectively restore LL and reduce PI-LL mismatch in patients with degenerative spine conditions and a history of lumbar hypo-lordotic fusions. Study limitations include a small sample size, missing full-spine radiographic data in a subset of patients and lack of long-term follow-up. These limitations underscore the need for validation through larger, prospective studies with standardized imaging and clinical follow-up.
Conclusion
This study highlights the efficacy of L5-S1 ALIF in restoring lumbar curvature, reducing PI-LL mismatch and improving sagittal alignment in patients with a history of lumbar fusions. Despite the challenges of fixed hypo-lordosis resulting from previous hypo-lordotic lumbar fusions, our findings demonstrate that L5-S1 ALIF can significantly increase LL and reduce forward trunk inclination. Future studies involving larger patient cohorts and extended follow-up are warranted to validate these findings and evaluate their long-term clinical implications.
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| ISSN: | 2789-9454 2789-9462 |