The impact of serum albumin levels on postoperative complications in lumbar and cervical spine surgery: an analysis of the Michigan Spine Surgery Improvement Collaborative registry.

Abstract

Patients with serum albumin levels < 3.5 g/dL are considered malnourished, but there is a paucity of data regarding the outcomes of patients with albumin levels > 3.5 g/dL. The objective of this study was to evaluate the effect of albumin on postoperative outcome in patients undergoing elective cervical and lumbar spine procedures. The Michigan Spine Surgery Improvement Collaborative database was queried for lumbar and cervical fusion surgeries between January 2020 and December 2022. Patients were grouped by preoperative serum albumin levels: < 3.5 g/dL, 3.5-3.7 g/dL, 3.8-4.0 g/dL, and > 4.0 g/dL. Primary outcomes included urinary retention, ileus, dysphagia, surgical site infection (SSI), readmission within 30 and 90 days, return to the operating room, and length of stay (LOS) ≥ 4 days. Multivariate analysis was conducted to adjust for potential confounders. This study included 15,629 lumbar cases and 6889 cervical cases. Within the lumbar cohort, an albumin level of 3.5-3.7 g/dL was associated with an increased risk of readmission at 30 days (p = 0.048) and 90 days (p = 0.005) and an LOS ≥ 4 days (p < 0.001). An albumin level of 3.8-4.0 g/dL was associated with an increased risk of an LOS ≥ 4 days (p < 0.001). Within the cervical cohort, an albumin level of 3.5-3.7 g/dL was associated with an increased risk of SSI (p = 0.023), readmission at 30 days (p < 0.002) and 90 days (p < 0.001), return to the operating room (p = 0.002), and an LOS ≥ 4 days (p < 0.001). An albumin level of 3.8-4.0 g/dL was associated with an increased risk of readmission at 30 days (p = 0.012) and 90 days (p = 0.001) and an LOS ≥ 4 days (p < 0.001). This study maintains that patients with hypoalbunemia undergoing spine surgery are at risk for postoperative adverse events. However, there also exist significant associations between borderline serum albumin levels of 3.5-4.0 g/dL and increased risk of postoperative adverse events.