This is a single-center, prospective, observational study that will compare the blood transfusion rate between intraoperative bleeding severity characterized using the Validated Intraoperative Bleeding Scale (VIBe).

Primary Aim: Assess the association between the VIBe scale and intraoperative and postoperative blood transfusion rates for posterior thoracolumbar spine surgery.

Primary Hypothesis: Patients with higher recorded VIBe grades during the five stages of spine surgery (exposure, decompression, instrumentation, fusion, and closing) will have a higher rate of receiving blood transfusions.

Secondary Aims: Determine the association between the VIBe scale and other postoperative outcomes and complications.

Inclusion Criteria:

• Ages 18 to 88 years
• Patients receiving elective open, posterior thoracolumbar surgery

Exclusion Criteria:

• Patients receiving non-elective or trauma surgery
• Patients with pathologic spine fracture or metastatic disease to the spine
• Patients receiving thoracolumbar surgery through anterior or lateral approach
• Patients receiving spine surgery for debridement of suspected or confirmed infection

Patients undergoing elective open, posterior thoracolumbar surgery