25 - Decreased Postoperative Intensive Care Unit Utilization and Length of Stay Following Adult Spinal Deformity Surgery has No Impact on 30-day and Two-Year Outcomes

Introduction: There currently exist a paucity of data examining the need for postoperative Intensive Care Unit (ICU) admission following ASD surgery. ICU utilization results in large healthcare costs and increased risk of adverse hospital events such as nosocomial infections. With the increased demand for hospital beds at the onset of the COVID-19 pandemic, there was an institutionally driven change to decrease ICU utilization and length of stay (LOS) for surgically treated ASD patients.

Objective: This study aims to examine if decreased ICU utilization and LOS impacted 30-day, one-year, and two-year outcomes.

Methods: This study was a retrospective cohort analysis performed at a single institution. Patients undergoing ASD surgery from a single fellowship-trained orthopedic spine surgeon from January 2018 to December 2021 were included. Demographic, intraoperative, and perioperative data, including complications and readmissions within 30 days, one-year, and two-years of the index procedure, were evaluated. 262 patients were divided into groups by date of surgery: 1) Prior to the institutional change to decrease ICU utilization (n=161 patients) and 2) after the institutional change to decrease ICU usage (n=101 patients). Descriptive statistics, t-test, chi-squared analysis, and logistic regression models were used to analyze the data.

Result: Demographic factors, such as age, gender, smoking status, hypertension, Charlson Comorbidity Index scores and American Society of Anesthesiologists class did not differ between the groups. The post-institutional change group had significantly fewer people admitted to the ICU following surgery (47% (n=76/161) vs. 14% (n=14/101), P< 0.001) and a shorter LOS (5.43 vs. 4.05 days, P=.009). When controlling for differences in interbody fusion status and PSO status, the 30-day complication rate and readmission rate favored the institutional change group (OR 0.28 and 0.24, p< 0.001 and p=.003 respectively). The two-year and one-year complication rates also favored the institutional change group (OR 0.44 and 0.54, p=.01 and p=.02 respectively). The 30-day infection rate, 1-year complication rate, and 2-year infection and readmission rate did not change when sending fewer patients to the ICU. After the change, patients sent to the ICU compared to those sent to the floor had significantly longer fusions, EBL, and OR time (11.92 vs. 8.67 levels, 2111 vs. 1308 mL, 377 vs. 320 minutes, P values < 0.05).

Conclusion: With the onset of COVID-19 pandemic, there was an institutionally driven change to decrease ICU utilization following ASD surgery that has continued to the present date. When comparing the patients before and after this change, demographic details did not differ between the two cohorts of patients, while ICU usage and hospital LOS significantly decreased. When controlling for surgical differences, 30-day, one-year, and two-year outcomes either improved or did not differ. Accordingly, we recommend that spine surgeons identify patients with shorter fusions, lower blood loss, and shorter operative time for discharge to the floor postoperatively as it will help decrease postoperative complications and hospital costs without negatively impacting patient outcomes. We recommend that postoperative ICU utilization should be reserved for patients with long fusions, significant blood loss, and longer surgeries.