Incidence and Risk Factors for Pneumonia After Posterior Lumbar Fusion Procedures: An ACS-NSQIP Study

Study Design.Retrospective study of data collected prospectively by the American College of Surgeons National Surgical Quality Improvement Program.Objective.To determine the incidence and risk factors for development of pneumonia after posterior lumbar fusion (PLF).Summary of Background Data.Postoperative pneumonia has important clinical consequences for patients and the health care system. Few studies have examined pneumonia after spinal fusion procedures.Methods.Patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent PLF during 2005 to 2013 were included. The primary outcome was a diagnosis of pneumonia within the first 30 postoperative days. Independent risk factors for the development of postoperative pneumonia were identified using multivariate regression. Rates of sepsis and mortality were compared between patients who did and did not develop pneumonia using multivariate regression that adjusted for all demographic, comorbidity, and procedural characteristics.Results.A total of 12,428 patients undergoing PLF were identified. The incidence of pneumonia was 0.59%. Independent risk factors for the development of pneumonia were chronic obstructive pulmonary disease (relative risk [RR]=2.7, P=0.006), steroid use (RR=2.6, P=0.017), non-insulin-dependent diabetes mellitus (DM) (RR=2.4, P=0.003), insulin-dependent DM (RR=2.9, P=0.005), and greater number of operative levels (two level: RR=1.7, P=0.033; three level: RR=2.7, P=0.007). Patients who developed pneumonia had a higher rate of sepsis (15.1% vs. 0.8%, adjusted RR=14.5, P<0.001) and mortality (2.7% versus 0.1%, adjusted RR=27.0, P<0.001) than other patients. Of all sepsis cases and postoperative mortalities, 10.5% and 18.2% occurred in patients who had developed pneumonia, respectively.Conclusion.Pneumonia occurs in approximately 1 in 200 patients after PLF. Pneumonia plays a significant role in the development of sepsis and mortality, with 10% of sepsis and 20% of mortality cases occurring in patients who had developed pneumonia. Patients with chronic obstructive pulmonary disease, steroid use, DM, and a greater number of operative levels are at greater risk. These patients should be counseled, monitored, and targeted with preventative interventions accordingly.Level of Evidence: 3