Prolonged Length of Stay After One- and Two-Level Transforaminal Lumbar Interbody Fusion (TLIF): Risk Factors and Consequent Outcomes

Summary of background data: While many studies have assessed factors associated with prolonged length of stay (LOS) following spine surgery, a limited number of studies have large cohorts with granular individual patient-level data, and little is known about the association between prolonged LOS and functional recovery after spine surgery. Objective: We aim to identify factors associated with prolonged length of stay (LOS) and its impact on postoperative complications and functional recovery. Methods: The present study is a retrospective longitudinal observational cohort study. Patients (N=576) who underwent one- or two-level transforaminal lumbar interbody fusion (TLIF) were identified. LOS was measured in hours, and prolonged LOS was defined as greater than the 75th percentile (>85 hours). Demographic and surgical parameters, and in-hospital and post-discharge complications were collected. Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) scores for back and leg pain, were collected preoperatively and at six weeks, three months, and one year postoperatively. Multiple logistic regression identified factors associated with prolonged LOS and post-discharge complications. Results: The mean LOS for the entire cohort was 75.0±50.1 hours, with 145 patients categorized as prolonged LOS (141.4±54.5 hours). Prolonged LOS was independently associated with older age (odds ratio (OR)=1.03, p=0.003), lower preoperative hemoglobin (OR=0.80, p=0.020), longer operative time (OR=1.01, p<0.001), and in-hospital complications (OR=11.09, p<0.001). Prolonged LOS was also associated with higher post-discharge complication rates, including 30-day readmission (14% versus 6%, p=0.004), surgical site infection (6% versus 1%, p=0.002), and deep vein thrombosis (DVT)/pulmonary embolism (PE) (3% versus 0%, p=0.001). As complications are known to prolong LOS, a sub-analysis of 205 patients with complete PROMs and no post-discharge complications was performed. In this sub-analysis, patients with prolonged LOS had significantly worse preoperative ODI (51.8 versus 48.5, p=0.025), back pain (7.1 versus 6.2, p=0.013), and leg pain (6.8 versus 5.9, p=0.035). Postoperatively, improvement in PROMs was worse in prolonged LOS patients at all time points. Conclusion: Prolonged LOS after one- or two-level TLIF was associated with older age, lower preoperative hemoglobin, longer operative time, and in-hospital complications. It was also associated with a higher risk of post-discharge complications and lower functional status.