2015 Two Good to Be Screw? The Value of Two Points of Pelvic Fixation in Adult Spinal Deformity Correction

INTRODUCTION: Spinopelvic fixation significantly enhances the stability of the lumbopelvic junction, which is particularly critical in adult spinal deformity surgeries involving long fusions. METHODS: Included ASD patients with complete baseline and two-year data. Analysis compared those with =2 points of SI fixation (>TP) versus those with <2 points (<TP) using descriptive statistics, means comparison, Chi-squared, and logistic regression to assess medical and surgical predictors of outcomes. RESULTS: Among 447 ASD patients studied (mean age: 59.8 years, BMI 26.9, CCI 1.7, mASD-FI 6.3), surgical parameters included an average operative time of 415.6 minutes and EBL of 1598.4 mL, with 11.1 levels fused. Of these, 284 (59.5%) underwent sacroiliac fixation; 204 with an iliac screw, 98 with other types. The >2TP cohort, 247 patients (51.8%), was older (64.4 vs. 54.7 years, p<.001), had higher BMI (27.4 vs. 26.4, p<.001), more comorbidities (2.2 vs. 1.5, p<.001), and worse frailty scores (7.3 vs. 5.3, p<.001). This group had longer surgeries (450.5 vs. 372.0 minutes, p<.001) and higher EBL (1918 vs. 1202 mL, p<.001), with increased rates of adverse events (17.4% vs. 9.1%, p=0.008) and musculoskeletal complications (4.0% vs. 0.9%, p=0.027). However, they showed greater improvement in GAP proportionality and alignment measures (PI-LL and SVA, p<.001) at 2 years. HRQL outcomes were better, with higher rates of MCID via ODI at 1 and 2 years. Sarcopenia and osteoporosis significantly increased the need for TP SI fusion, and frail patients showed higher PJK rates at 2 years. CONCLUSIONS: Despite its invasiveness, =2 points of pelvic fixation are crucial in frail, sarcopenic, and osteoporotic patients to enhance alignment and postoperative recovery.