Prone transpsoas (PTP)-LLIF approach versus standard LLIF in patients undergoing surgical revision following adult spinal deformity correction surgery

Introduction: Both the prone transpsoas (PTP) single-position lateral lumbar interbody fusion (LLIF) and standard (dual-position) LLIF enable minimally invasive (MIS) indirect decompression and deformity correction. Existing studies comparing the utility of these approaches for adult spinal deformity (ASD) correction have been limited to small, single-center series. No study has investigated revision single-position PTP-LLIF versus standard LLIF in a large cohort of ASD patients. Methods: A multi-center cohort of all patients undergoing PTP-LLIF or standard LLIF revision for ASD between 2013 and 2021 were identified from 12 spine surgery centers. Standing 36″ scoliosis radiographs were retrospectively reviewed for assessment of spinopelvic parameters including pelvic incidence (PI), lumbar lordosis (LL), and PI-LL mismatch preoperatively and immediately postoperative. Multivariable analysis was performed to assess the primary outcome measure: postoperative change in regional sagittal alignment (PI-LL mismatch) between patients who had undergone revision surgery via PTP versus standard LLIF. Postoperative PI-LL mismatch correction was defined by PI-LL mismatch <10°. Results: Two-hundred and two patients were retrospectively identified and included for formal analysis. One-hundred and fifty-one (n = 151, 74.8 %) patients underwent PTP revision while 51 (25.2 %) underwent standard LLIF revision. Patients undergoing PTP had greater pre-operative PI-LL mismatch (21.4 vs. 10.45°; p < 0.001). Complication rate (p = 0.029), length of stay (<0.001) and total follow up (p = 0.005) were decreased in the PTP patients when compared to standard LLIF, while fluoroscopy time (p = 0.036) and fluoroscopy dosage (p = 0.011) was increased. Multivariate analysis demonstrated that PTP was associated with increased change of having a postoperative PI-LL value <10° (p < 0.001), in addition to being associated with increased correction of PI-LL mismatch (p = 0.002) when controlling for multiple other variables. Conclusion: Ultimately, PTP-LLIF was associated with greater net improvement in postoperative PI-LL mismatch, the primary outcome measure of this study. The present retrospective analysis expands upon previous studies demonstrating the potential superiority of PTP-LLIF versus conventional LLIF for sagittal plane correction in ASD revision surgery.