Pulmonary Embolism in Spine Surgery A Comparison of Combined Anterior/Posterior Approach Versus Posterior Approach Surgery

Study Design. Retrospective review. Objective. To determine if Anterior/Posterior Combined approach spine surgery is associated with an increased risk of pulmonary embolism (PE) compared to Posterior Only approach surgery. Summary of Background Data. Combined anterior/posterior approach spine surgery is associated with a significantly increased risk for PE. However, it is uncertain if there is any difference in risk between combined approaches versus a posterior-only approach. Methods. A prospective cohort of patients who underwent anterior/posterior combined approach spine surgery from January 2002 to January 2006 was compared to a retrospective cohort of consecutive patients who underwent posterior only approach spine surgery from September 2007 to September 2008. Patient demographics, medical history, body-mass indexes, type of surgery, length of surgery, transfusions, and instrumented vertebral levels were collected from hospital and office records. Hospital records were used to identify patients who developed PE based on diagnosis by spiral CT scan. CT scans were only performed when a patient's clinical picture raised suspicion of PE. Fisher exact test for significance, X-2 test and odds ratios were used for analysis. Results. A total of 119 patients were included in the study: 63 patients underwent posterior approach spine surgery and 66 patients underwent combined anterior/posterior approach surgery. One patient (1.6%) developed PE after posterior approach surgery while 5 patients (7.5%) developed PE in the combined approach group. Those undergoing combined approaches were 5.08 times more likely to suffer from PE, but this increase was not signifi cant (P = 0.208). Overall, increased risk for PE was associated with the number of levels fused (P = 0.006), total blood loss (P = 0.029), and number of units transfused (P = 0.030). The combined approach was associated with older age (P = 0.001), higher BMI (P = 0.023), more instrumented vertebrae (P < 0.001), greater total blood loss (P < 0.001) and cell saver infusion (P = 0.004) compared to the posterior only approach. Conclusion. Combined anterior/posterior approach spine surgery is associated with an increased risk for pulmonary embolism compared to posterior only approaches. However, regardless of the surgical approach, risk factors for PE common in both groups were operative time, total blood loss, number of levels fused, and the number of units transfused. Patients who undergo spine surgery with prolonged operative times and greater blood loss should be recognized as higher risk patients.