Background:
Restoration of spinal lordosis is a critical determinant of both radiographic and clinical outcomes following lumbar interbody fusion. Minimally invasive lateral approaches including psoas-traversing procedures (PTP) and oblique lumbar interbody fusion/anterior-to-psoas techniques (OLIF/ATP) are increasingly utilised to achieve indirect decompression, disc height restoration, and sagittal alignment correction while minimising tissue disruption.
Despite growing adoption, the comparative evidence base remains fragmented. Existing studies vary in methodology, outcome definitions, and reported magnitudes of lordosis correction. In addition, real-world multicentre data evaluating pre- and post-operative lordosis restoration particularly when incorporating structured pre-operative planning and advanced neuromonitoring remain limited.
This multimodal study is designed to comprehensively evaluate spinal lordosis restoration following PTP and OLIF/ATP techniques through complementary literature, retrospective, and prospective analyses.
Methods:
Across the retrospective and prospective clinical components, 100 patients were included which the average age of 53.3 years. Adult patients undergoing lumbar interbody fusion using PTP or OLIF/ATP with available pre-operative imaging suitable for radiographic analysis were included and followed for 2 years. Patients were analysed according to surgical approach.
We evaluated the Change in disc and foraminal height, sagittal spinopelvic parameters including Lumbar Lordosis (LL), Sagittal Vertical Axis (SVA), Thoracic Kyphosis (TK), Pelvic Tilt (PT), Pelvic Incidence (PI), Sacral Slope (SS) and T1-Pelvic Angle (TPA). And the clinical outcomes including Oswestry Disability Index ODI, VAS back/leg pain, Neurological outcomes and approach-related symptoms.
Results:
At 2-year follow-up, this retrospective multicentre study demonstrated significant radiological and clinical improvements following psoas-traversing procedures (PTP) and oblique lumbar interbody fusion/anterior-to-psoas techniques. Restoration of sagittal spinopelvic alignment was observed, with lumbar lordosis increasing by 3.2° (p = 0.025). Foraminal height and disc height showed a significant increase of 3.3 mm (p < 0.001), achieved immediately postoperatively and maintained at final follow-up. Improvements in pelvic incidence (PI) and PI–lumbar lordosis mismatch were also achieved either immediately postoperatively or sustained over time, reflecting improved global alignment.
Clinically, patients demonstrated significant reductions in disability and pain scores over the 2-year period, with marked improvements in ODI and VAS scores for back, buttock, and leg pain (all p < 0.001). Functional outcomes assessed using Macnab criteria were favourable, with 89.8% of patients reporting excellent, good, or fair results. Overall, these findings support the effectiveness of both techniques in achieving durable radiological correction and meaningful patient-reported outcome improvement.
Conclusion:
Both psoas-traversing and anterior-to-psoas lumbar fusion techniques achieve significant and durable correction of spinopelvic alignment, with sustained improvements in disc and foraminal height. These radiological gains are matched by marked reductions in pain and disability, with nearly 90% of patients achieving favourable Macnab outcomes at 2 years. Overall, both approaches are effective and reliable for restoring alignment and improving clinical outcomes.