Incidence and Risk of Severe Ileus After Orthopedic Surgery: A Case-Control Study

Abstract

Background: Post-operative ileus (POI) is common and can be associated with significant morbidity. Questions/Purposes: We aimed to identify the incidence of and risk factors associated with severe post-operative ileus (SPOI) after elective orthopedic surgery. Methods: We conducted a retrospective case–control study of patients undergoing elective orthopedic procedures at a single musculoskeletal specialty hospital. SPOI cases matched 1:2 to non-POI controls. International Classification of Diseases, Ninth Revision (ICD-9), codes were used to identify patients who were coded as having an episode of POI. After chart review, a subset was classified as clinical SPOI cases, based on set criteria. Regression models were constructed to identify variables associated with SPOI. Results: Of 273 POI cases, 77 (28.2%) were classified as SPOI. Overall rates of SPOI were 2.74/1000 orthopedic discharges, with SPOI most common in spine surgeries (9.07/1000 spine procedure discharges). Hypothesis-generating multivariable conditional logistic regression suggested that, for hip and knee cases, not being on a full diet by post-operative day (POD) 2 posed an increased risk of SPOI. For spine cases, not being on a full diet on POD 2 and longer surgery times were associated with risk of SPOI. Conclusions: In this retrospective case–control study, patients undergoing elective orthopedic procedures who had not progressed to full diet by POD 2 and spine patients with longer operative times were most at risk for SPOI. These data can be used clinically by peri-operative physicians to stratify patients according to risk.