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

Objective: 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.

Methods: 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.

Results: 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).

Conclusions: 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.