In accordance with guidelines for human subjects research, approval was obtained from the institutional review board of Beth Israel Deaconess Medical Center. Data on preoperative, intraoperative, and postoperative care were prospectively collected for each case and retrospectively reviewed. Preoperative variables include patient demographics (ie, age, sex, and comorbidities), presenting symptoms (eg, jaundice, weight loss, diarrhea, and pain), cardiac or respiratory symptoms, laboratory tests, previous imaging studies, and any other diagnostic or therapeutic studies performed (ie, endoscopic ductal stenting or sphincterotomy). Baseline laboratory values were obtained within 1 to 2 weeks of the operation and include white blood cell count, hemoglobin level, hematocrit level, serum sodium and potassium concentrations, and blood urea nitrogen level. Pulse, blood pressure, and electrocardiogram readings were also obtained preoperatively. Intraoperative variables include total operative time, blood loss, fluid resuscitation, blood transfusions, gland characteristics, surgical technique, and the use of drains, stents, somatostatin analogues, or adhesive sealants. Final disease pathology was determined after each case. Postoperative events and clinical outcomes were recorded by an independent reviewer and confirmed by the operating surgeon, including results of laboratory, imaging, and diagnostic studies; therapeutic interventions; requirements for nutritional support; incidence and type of complications; intensive care unit (ICU) utilization and duration; hospitalization duration; discharge disposition; hospital readmissions; repeated operations; and the 30-day hospital mortality rate. All economic data were collected and analyzed using Casemix TSI (Department of Health Care Quality, Harvard Medical School). Total hospital costs are defined as costs from the initial operation to hospital discharge, plus any costs accrued during hospital readmissions within 30 days postoperatively.