Predicting Outcomes Following Single-Level Lumbar Fusion

INTRODUCTION: Spinal fusions represent one of the most common neurosurgical procedures. The LACE (Length of Stay, Acuity of Admission, Charlson Comorbidity Index (CCI) Score, Emergency Department (ED) visits within the previous 6 months) index was developed to predict readmissions, but has not been tested in a large, homogenous spinal fusion population. METHODS: LACE+ scores were calculated for all patients with complete information who underwent single-level, posterior-only lumbar fusion at a single, university medical system (n = 1598). Logistic regression was performed to assess the ability of the LACE+ score as a continuous variable to predict hospital readmissions within 90 days (90D) of the index operation. Secondary outcome measures included ED visits and reoperations. Subsequently, the risk of adverse postsurgical events was compared between the lowest and the highest quartile of LACE+ scores, then between the bottom decile and top 4 deciles of LACE+ scores. Finally, patients with the bottom decile of LACE+ scores were exact matched to the top 4 deciles to control for sociodemographic and procedural variables. RESULTS: Among all patients, increased LACE+ score significantly predicted higher rates of readmissions in the 30-day (30D), 30-90-day (30-90D), and 90D postoperative windows (p < 0.001, p = 0.001, p < 0.001, respectively). LACE+ score also predicted risk of ED visits at all 3 timepoints, and reoperations at 30-90D and 90D. When comparing the lowest quartile of LACE+ scores to the highest quartile, higher LACE+ score predicted higher risk of readmissions at 30D, 30-90D, and 90D following the index surgery (p = 0.003, p = 0.016, p < 0.001, respectively). When comparing the bottom decile of LACE+ scores to the top 4 deciles, higher LACE+ score predicted higher risk of readmissions at 30D (p = 0.009) and 90D (p = 0.005). Between exact-matched cohorts, no significant difference was observed in hospital readmissions. CONCLUSION: The LACE+ index may be a powerful tool in predicting other important postsurgical outcomes.