237. The effect of sagittal alignment on adult cervical deformity patient outcomes, reoperation rates and development of distal junctional kyphosis

Abstract

<h3>BACKGROUND CONTEXT</h3> Global spinal malalignment plays a vital role in cervical spinal deformity corrective surgery outcomes; however, the literature is scarce on the effects that the individual sagittal parameters have on outcomes. <h3>PURPOSE</h3> To investigate the impact of sagittal malalignment on cervical deformity patient outcomes. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study of single-center database. <h3>PATIENT SAMPLE</h3> This study included 123 CD patients. <h3>OUTCOME MEASURES</h3> Complications; radiographic parameters; HRQL metrics (NDI, EQ5D, mJOA, NRS Neck) <h3>METHODS</h3> Inclusion criteria: operative CD patients (cervical kyphosis >10°, with cSVA >4cm or CBVA >25°) and >18yrs with up to 2Y radiographic and HRQL follow-up. Significant differences in surgical, radiographic, and clinical factors and outcomes were determined. Deformity in PT, SVA, and PILL was defined using the SRS-Schwab criteria. "Unmatched" refers to patients who were under corrected or over corrected according to the Schwab age-adjusted parameters (Lafage et al.). <h3>RESULTS</h3> A total of 123 CD patients met inclusion criteria (58.3 yrs, 46% Female, 28.3 kg/m2). Overall, 27 (24%) of these patients developed DJK. At baseline, patients presented with the following radiographic profile: PT (18.3), PILL (-.65), SVA C7-S1 (-6.54), cSVA C2-C7 (23.5), and TS-CL (25.2). Patients with DJK had a higher L1-S1 (34 vs 9.2) and T12-S1 (57 vs 35, both p<0.05) and trended towards a higher cSVA (-11.7 vs -3.7), C2-T3 (57.6 vs 37.4), and C2-S1 (17 vs 5.9, p>0.05). Patients with a deformity in PT at baseline developed more DJK by 2 years (26% vs 11%), had more DJF (7% vs 2%) and a higher NDI and NSR back pain. Patients with mismatch at baseline had higher rates of DJK (30% vs 22%), and patients with SVA deformity at baseline had a lower mJOA, SWAL Food selection, SWAL Communication, and a higher EQ5D. Patients with a mismatched alignment in Roussouly preoperatively had higher rates of DJK at 3M (18% vs 12%), 6M (26% vs 16%), 1Y (24% vs 14%), and 2Y (26% vs 13%, all p<0.05). Patients who were unmatched in SVA by 2Y had higher rates of DJK development at 2Y (25% vs 6%), and those unmatched in PILL by 2Y had higher rates of 2-year DJK (31% vs 19%) and higher 2-year NDI (38 vs 31). Patients who had a mismatch in Roussouly postoperatively had higher rates of DJK by 2 years (33% vs 23%, allp<0.05). <h3>CONCLUSIONS</h3> Global spinal malalignments play an important role in the outcomes of cervical spinal deformity corrective surgery. The presence of abnormal global sagittal malignment at baseline is associated with higher rates of DJK development and worse clinical outcomes, while patients who maintained poor sagittal alignment up to 2Y were associated with significantly greater development of DJK and inferior neck disability index scores. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.