BACKGROUND Previous reports suggest that earlier hospital discharges and reduced postoperative complications occur when a retroperitoneal approach is used for aortic surgery. Other publications refute this concept. In an effort to determine the most cost efficient method for aortic surgery in our institution, while maintaining high standards of care and outcome, we compared the retroperitoneal approach to the conventional transperitoneal aortic operation. METHODS Between December 1995 and April 1998, 120 patients underwent aortic surgery by either the transperitoneal (n=60) or retroperitoneal approach (n=60). All patients were enrolled prospectively in a vascular registry and retrospectively reviewed. Patients were randomly assigned to one of three vascular surgeons. A clinical pathway for elective aortic surgery was developed and applied to both groups. Patients were evaluated with respect to demographics, comorbidities, preoperative risk stratification, conduct of the operative procedure, length of stay, complications, cost, clinical outcomes and patient satisfaction. The indications for aortic surgery were similar in both groups - 64% for aneurysm disease and 36% for occlusive disease. Both symptomatic and asymptomatic aneurysms were included and size ranged from 4.4 to 14cm. All aortic reconstructions were done in the standard manner using knitted Dacron velour prostheses in either the aortic tube, bi-iliac or bi-femoral configuration. Statistical analysis of means and medians was accomplished using the Wilcoxin Rank-sum test and percentages were compared using Fisher's Exact test. P values less than 0.05 indicate statistical significance. RESULTS There were no statistically significant differences in patient demographics. The incidence of atherosclerotic coronary artery disease, obstructive pulmonary disease, diabetes, hyperlipidemia, tobacco abuse, distal lower extremity occlusive disease and the results of chemical myocardial stress evaluations were similar in both groups. Comorbidities of pre-existing renal insufficiency/failure and morbid obesity were increased in the retroperitoneal group. Five patients in the retroperitoneal group represented redo aortic surgery and there were no redo procedures in the transperitoneal group. Length of operative procedures and blood replacement requirements for both groups were similar. The transperitoneal group required 2-3l more intraoperative intravenous (IV) crystalloid than the retroperitoneal group (P<0.0001). Statistically significant reductions in ICU days, postoperative ileus and total lengths of stay were observed in the retroperitoneal group (P<0.0001). This resulted in substantial reductions in hospital costs for the retroperitoneal group (P<0.01). Postoperative complications were similar for both groups except for statistically significant increases in pulmonary edema (P<0.01) and pneumonia (P<0.001) in the transperitoneal group. Cardiac arrhythmias, primarily atrial dysrhythmias, were more frequent in the transperitoneal group but this failed to reach statistical significance (P<0.16). Combined thirty day mortality was 0.9%. Time of recovery to full activity and patient satisfaction substantially favored the retroperitoneal group. CONCLUSIONS Our clinical pathway and algorithm for aortic surgery was easily followed by those patients in the retroperitoneal approach group and resulted in decreases in ICU time, postoperative ileus, volume of intraoperative crystalloid and total length of stay. The patients in the transperitoneal group often failed to progress appropriately on the pathway. Reduced hospital costs associated with aortic surgery using the retroperitoneal approach has increased the profitability for this surgery in our institution by an average of $4000 per case and has increased the value (quality/cost) of this surgery to our patients and our institution.