Investigation schedule and follow-up Data will be collected pre-operatively regarding individual patient demographics, laboratory values, and the surgical procedure to be performed. Intra-operatively, data will be gathered to estimate blood loss and account for changes in fluid balance. Anesthesiologists are asked to maintain a MAP of 60 during the surgical exposure and anchor placement and a MAP of 70-90 during the surgical correction. Similarly, surgeons are asked to place only subfascial Hemovac drains at the incision site. These are both standard practice and have . Postoperatively, laboratory values, drain output, and clinical outcomes are carefully followed until the patient is discharged. Given the increased risk of renal failure with the use of Aprotinin changes in BUN to CR ratio are carefully monitored post-operatively. This data is recorded onto a de-identified data collection sheet by the researchers. These patient data sheets are then entered onto a protected electronic database, while the data sheets are stored as a back-up until the study is complete. Once the completed database is analyzed and summarized, the results will be presented to the involved participants without any identifiable patient information.