Prevalence and Impact of Malnutrition on Postoperative Outcomes Among Adults Undergoing Multi-level Posterior Spinal Instrumentation

Introduction: Hypoalbuminemia, defined as serum albumin < 3.5 g/dL, is a widely recognized marker of malnutrition and has been associated with an increased risk of postoperative complications. Preoperative nutritional assessment practices vary widely, and limited research has explored the impact of malnutrition on complication rates in patients undergoing posterior lumbar spine surgery.

Methods: The TriNetX Research Network was queried to identify adult patients who underwent posterior spinal instrumentation surgery spanning 3-6 or 7-12 levels, with preoperative diagnoses of lumbar spinal stenosis or spondylolisthesis, and a preoperative albumin level measured within 30 days before surgery. The study cohort was divided into two groups based on serum albumin levels: those below 3.5 g/dL and those at or above 3.5 g/dL. Propensity score matching was applied to adjust for age, gender, race, and comorbidities, controlling for potential confounders. Postoperative occurrences of wound dehiscence (WD), surgical site infection (SSI), and the need for reoperation were identified using corresponding procedural and diagnostic codes within 90 days of the index surgery.

Results: A total of 10,340 patients met the initial inclusion criteria (mean age at surgery: 65.1 years [SD, 11.5]; 4,391 [42.5%] male), with 1,720 (16.6%) having a preoperative albumin level below 3.5 g/dL within 30 days of surgery. After propensity score matching, each cohort comprised 1,715 patients, with no significant differences in baseline demographics or comorbidities between the groups. Post-matching analysis revealed that malnourished patients demonstrated significantly higher odds of developing SSI or WD (OR = 1.677, 95% CI [1.285, 2.189]) and requiring reoperation (OR = 1.755, 95% CI [1.429, 2.155]) within 90 days postoperatively.

Conclusion : This large-scale retrospective study, employing propensity score matching, reveals that malnutrition, defined by hypoalbuminemia ( < 3.5 g/dL), is present in 16.6% of adults undergoing multi-level posterior lumbar spinal instrumentation. Malnourished patients demonstrated approximately 70% higher odds of experiencing postoperative complications, including SSI, WD, and the need for reoperation, compared to adequately nourished patients. These findings highlight the importance of assessing preoperative nutritional status in patients undergoing spine surgery.