The investigators would like to further the current understanding of aspirin and its effects on perioperative bleeding by conducting a randomized controlled trial of spinal surgery patients receiving varying doses of aspirin or no aspirin perioperatively. The investigators hypothesize that there will be no significant difference in perioperative blood loss between the different groups.

Selected patients will be given either no aspirin, low-dose aspirin (81 mg), or high-dose aspirin (325 mg) in the perioperative period. These dosages are based on the Pharmacist's letter/Prescriber's letter which provides aspirin dosing recommendations for varying cardiovascular indications. Allocation of dosing will be based on computerized randomization in order to achieve approximately 100 patients in each group. Patient records will then be assessed for demographic characteristics, comorbidities, symptoms, functional outcome scores (Sf-12), operative time, intraoperative estimated blood loss, postoperative blood loss in drainage tubes (when applicable), cumulative blood loss, transfusion of blood products, hemoglobin level, preoperative International Normalized Ratio (INR), preoperative platelet count, hospital length of stay, and morbidity and mortality including development of NSTEMI, atrial fibrillation, surgical site infection, pulmonary embolism, and hospital 30-day readmission rates.

Inclusion Criteria:

• All patients over 18 years old, who are not taking aspirin at the time of operation as part of a current cardiovascular treatment plan, who will undergo spinal surgery from 2016-2019 in the practice of Dr. Eubanks.

Exclusion Criteria:

• Any patient under the age of 18 and/or is already taking anticoagulant therapy for an established cardiovascular disease at the time of surgery as part of a cardiovascular therapy.

Data will be collected on a computer database containing unique identifiers, without names, social security numbers, medical record numbers, or other information that could be used to identify individuals. University Hospitals Research Electronic Data Capture will be used as a means of secure data storage. At no time will this data spreadsheet be printed or otherwise distributed, and no Protected Health Information will be transferred to investigators at other sites of this multi-center study.