Incidence and risk factors for postoperative ileus following anterior, posterior, and circumferential lumbar fusion

Background context: Postoperative ileus is a known complication of surgery. The incidence and risk factors for ileus after lumbar fusion surgery is not well characterized.

Purpose: To determine rates of postoperative ileus, a population-based database was analyzed to identify incidence, mortality, and risk factors associated with anterior (ALF), posterior (PLF), and combined anterior/posterior (APLF) lumbar fusions.

Study design: This was a retrospective database analysis.

Patient sample: The sample consisted of 220,522 patients from the Nationwide Inpatient Sample (NIS) database.

Outcome measures: Outcome measures were incidence of postoperative ileus, length of stay (LOS), in-hospital costs, and mortality.

Methods: Data from the NIS were obtained from 2002 to 2009. Patients undergoing ALF, PLF, and APLF for degenerative pathologies were identified and the incidence of postoperative ileus was assessed. Patient demographics, Charlson comorbidity index (CCI), LOS, costs, and mortality were assessed. SPSS v.20 was used to detect statistical differences between groups and perform logistic regression analyses to identify independent predictors of postoperative ileus. A p value less than .001 denoted significance.

Results: A total of 220,522 lumbar fusions were identified in the United States from 2002 to 2009. There were 19,762 ALFs, 182,801 PLFs, and 17,959 APLFs. The incidence of postoperative ileus was increased in ALFs over PLFs (74.9 vs. 26.0 per 1,000; p<.001). Within PLF and APLF groups, CCI scores were increased in the presence of postoperative ileus (p<.001). Across cohorts, patients with postoperative ileus demonstrated greater LOS and costs (p<.001). PLF-treated patients with postoperative ileus demonstrated increased mortality (p<.001). Independent predictors of postoperative ileus included male gender, 3+ fusion levels, alcohol abuse, anemia, fluid/electrolyte disorders, and weight loss (p<.001).

Conclusions: The results of our study demonstrate increased incidence of postoperative ileus associated with anterior approaches for lumbar fusion. Across cohorts, postoperative ileus was associated with increased LOS and costs. To determine the mortality and resource use associated with postoperative ileus, we recommend preoperatively identifying and treating modifiable risk factors, especially when an anterior approach is used.