P83. Fractional curve correction using TLIF vs ALIF in adult scoliosis

Abstract

<h3>BACKGROUND CONTEXT</h3> Few studies investigate fractional curve correction after long fusion with transforaminal (TLIF) vs anterior lumbar interbody fusion (ALIF) for adult symptomatic thoracolumbar/lumbar scoliosis (ASLS). <h3>PURPOSE</h3> Our objective was to compare fractional correction, health-related quality-of-life (HRQL), and complications associated with L4-S1 TLIF vs ALIF in ASLS operative treatment. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of a prospectively collected multicenter consecutive case registry. <h3>PATIENT SAMPLE</h3> Database enrollment required age ≥18 years, scoliosis ≥20º, sagittal vertical axis (SVA) ≥5cm, pelvic tilt ≥25º, or thoracic kyphosis ≥60º. <h3>OUTCOME MEASURES</h3> Radiographic correction (including L4-S1 fractional curve), HRQL (Oswestry Disability Index [ODI], Short Form-36 [SF-36] scores, Scoliosis Research Society-22 [SRS-22r] scores), and complications. <h3>METHODS</h3> Prospective multicenter data was reviewed. Study inclusion required fractional curve ≥10°, thoracolumbar/lumbar curve ≥30°, index TLIF vs ALIF at L4-L5 and/or L5-S1, and minimum 2-year follow-up. TLIF and ALIF patients were propensity-matched using number and type of interbody fusion at L4-S1. <h3>RESULTS</h3> Of 135 potentially eligible consecutive patients, 106 (78.5%) achieved minimum 2-year follow-up (age=60.6±9.3years, women=85.8%, TLIF=44.3%, ALIF=55.7%). Index operations had 12.2±3.6 posterior levels, iliac fixation=86.8%, and TLIF/ALIF at L4-L5 (67.0%) and L5-S1 (84.0%). ALIF had greater cage height (10.9±2.1 vs 14.5±3.0mm, p=0.001) and lordosis (6.3°±1.6° vs 17.0°±9.9°, p=0.001) and longer operative duration (6.7±1.5 vs 8.9±2.5hrs, p<0.001). Final alignment improved significantly (p<0.05): fractional curve (20.2°±7.0° to 6.9°±5.2°), maximum coronal Cobb (55.0°±14.8° to 23.9°±14.3°), C7-sagittal vertical axis (5.1±6.2 to 2.3±5.4cm), pelvic tilt (24.6°±8.1° to 22.7°±9.5°), and lumbar lordosis (32.3°±18.8° to 51.4°±14.1°). Matched analysis demonstrated comparable fractional correction (TLIF=–13.6°±6.7° vs ALIF=–13.6°±8.1°, p=0.982). Final HRQL improved significantly (p<0.05): ODI (42.4±16.3 to 24.2±19.9), SF-36 Physical Component Summary (PCS, 32.6±9.3 to 41.3±11.7), SRS-22r (2.9±0.6 to 3.7±0.7). Matched analysis demonstrated worse ODI (30.9±21.1 vs 17.9±17.1, p=0.017) and PCS (38.3±12.0 vs 45.3±10.1, p=0.020) for TLIF at last follow-up (despite no difference in these parameters at baseline). Total complication rate per patient was not different (TLIF=76.6% vs ALIF=71.2%, p=0.530), but significantly more TLIF patients had rod fractures (RF) (TLIF=28.6% vs ALIF=7.1%, p=0.036). Multiple regression demonstrated 1-mm increase in L4-L5 TLIF cage height lead to 2.2° reduction in L4 coronal tilt (p=0.011), and 1° increase in L5-S1 ALIF cage lordosis lead to 0.4° increase in L5-S1 segmental lordosis (p=0.045). <h3>CONCLUSIONS</h3> Operative ASLS treatment with L4-S1 TLIF vs ALIF demonstrated comparable fractional curve correction (66.7% vs 64.8%) despite significantly larger, more lordotic ALIF cages. TLIF cage height had significant impact on leveling L4 coronal tilt, whereas ALIF cage lordosis had significant impact on lumbosacral lordosis restoration. Advantages of TLIF may include reduced operative duration; however, associated HRQL was inferior and more RFs were detected in this study. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.