Postoperative Ileus After Lumbar Spine Surgery: Risk Factors and Impact on Morbidity and Patient Outcomes

Level III Retrospective observational cohort study.

To identify independent risk factors for postoperative ileus (POI) after elective lumbar spine surgery and evaluate its association with postoperative outcomes including complications, length of stay, discharge disposition, and patient-reported outcomes (PROs).

Postoperative ileus is an uncommon but clinically significant complication after lumbar spine surgery. Prior studies have been limited by small sample sizes and inadequate adjustment for confounding factors such as surgical approach, open technique, and operative duration.

Data from the Michigan Spine Surgery Improvement Collaborative (MSSIC) registry (2018-2023) were analyzed for elective lumbar procedures. Multivariable generalized estimating equation (GEE) models identified independent predictors of POI and adjusted associations with outcomes. Models included demographic, clinical, and procedural factors, including surgical approach, open status, and operative time. A 2020-2023 subset further adjusted for total morphine milligram equivalents (MME) at discharge.

Among 41,164 patients, 447 (1.1%) developed POI. Independent risk factors included older age (RR 1.02 per year), male sex (RR 2.01), Black race (RR 1.79), multilevel procedures (2-level RR 1.36; 3-level RR 1.41), anterior fusion (RR 10.82), other fusion approaches (RR 3.28), and longer operative duration (RR 1.10 per hour). Preoperative independent ambulation (RR 0.81) and ambulation within 8 hours postoperatively (RR 0.69) were protective. After adjustment, POI was associated with higher complication rates (RR 1.51), increased readmissions (RR 1.40), lower discharge-to-home likelihood (RR 0.93), and longer hospital stay (+2.74 d; all P<0.05). Findings persisted in the MME-adjusted subset (n=25,273).

POI occurred in around 1% of elective lumbar spine surgeries and was associated with longer hospitalization, greater morbidity, and reduced home discharge. Surgical invasiveness and anterior exposure were key risk factors, while early ambulation was protective, underscoring its value in enhanced recovery protocols.