105. Global coronal decompensation after adult spinal deformity surgery: comparison of upper vs lower thoracic proximal fixation

Abstract

<h3>BACKGROUND CONTEXT</h3> Deterioration of global coronal alignment (GCA) may be associated with worse outcomes after adult spinal deformity (ASD) surgery. The impact of fusion length and upper instrumented vertebra (UIV) selection for patients with this complication is unclear. <h3>PURPOSE</h3> Our objective was to compare outcomes for long sacropelvic fusions with upper-thoracic (UT) vs lower-thoracic (LT) UIV in patients with worsening GCA≥1cm. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of a prospectively collected multicenter case registry. <h3>PATIENT SAMPLE</h3> Database enrollment required age ≥18 years, scoliosis ≥20°, sagittal vertical axis (SVA) ≥5cm, pelvic tilt ≥25°, or thoracic kyphosis ≥60°. <h3>OUTCOME MEASURES</h3> Radiographic alignment, HRQL (Oswestry Disability Index [ODI], Short Form-36 [SF-36], Scoliosis Research Society-22 [SRS-22r], numerical rating scale [NRS] back/leg pain scores), and complications. <h3>Methods</h3> This is a retrospective analysis of a prospective multicenter database of consecutive ASD patients. Index operations involved instrumented fusion from sacropelvis to thoracic spine. Global coronal deterioration was defined as worsening GCA≥1cm from preoperative to 2-year follow-up. <h3>Results</h3> Of 875 potentially eligible patients, 560 (64%) had complete 2-year follow-up data, of which 144 (25.7%) demonstrated worse GCA at 2-year postop (UT 35.4%, LT 64.6%). At baseline, UT had younger age (61.6±9.9 vs 64.5±8.6years, p=0.008), more osteoporosis (35.3% vs 16.1%, p=0.009), and worse scoliosis (51.9±22.5° vs 32.5±16.3°, p<0.001). Index operations were comparable except UT had longer fusions (16.4±0.9 vs 9.7±1.2 levels, p<0.001) and operative duration (8.6±3.2 vs 7.6±3.0hrs, p=0.023). At 2-year follow-up, global coronal deterioration averaged 2.7±1.4cm (1.9 to 4.6cm, p<0.001), scoliosis improved (39.3±20.8° to 18.0±14.8°, p<0.001), and sagittal spinopelvic alignment improved significantly for all patients. UT maintained smaller positive C7-sagittal vertical axis (SVA) (2.7±5.7 vs 4.7±5.7cm, p=0.014). Postoperative 2-year health-related quality-of-life (HRQL) was significantly improved from baseline for all patients. Significant HRQL comparisons included: UT had worse SRS-22r Activity (3.2±1.0 vs 3.6±0.8, p=0.040) and SRS-22r Satisfaction (3.9±1.1 vs 4.3±0.8, p=0.021). Also, fewer UT patients improved by ≥1 minimal clinically important difference in leg pain NRS (41.3% vs 62.7%, p=0.020). Total reported complications (total=208, reoperation=53/major=77/minor=78) had comparable percentages of affected UT vs LT patients, but the percentage of re-operated patients was higher for UT (35.3% vs 18.3%, p=0.023). UT had higher reoperation rates for rod fracture (13.7% vs 2.2%, p=0.006), pseudarthrosis (7.8% vs 1.1%, p=0.006), but not proximal junctional kyphosis (9.8% vs 8.6%, p=0.810). <h3>Conclusions</h3> In ASD patients with worse 2-year GCA after long sacropelvic fusion, upper-thoracic UIV was associated with worse 2-year HRQL compared to lower-thoracic UIV. This may suggest residual global coronal malalignment is clinically less tolerated in ASD patients with longer fusions to proximal thoracic spine. These results can inform operative planning and improve patient counseling. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.