Perioperative Hyperglycemia Increases Rates of Infection in Lumbar and Cervical Spine Surgery: A Case Control Study

Background/Aim: Hyperglycemic changes can occur after surgery as a response to physiological stress or medication effects. Its association with surgical site infections (SSI) has been studied in other surgical specialties but it has not been looked at in spine surgery. This study aimed to evaluate the correlation of postoperative hyperglycemia with SSI in post-operative spine surgery patients, irrespective of diabetes. Materials and Methods: We retrospectively reviewed 100 patients at our hospital who underwent spine surgery with SSI and compared them with 111 controls (2010-2020). Independent variables included average postoperative glucose (<100, 100-119, 120-139, ≥140), surgical approach, use of allograft, ASA class, and diabetes mellitus. A multivariate logistic regression analysis using the significant univariate variables was performed to calculate the odds ratio and corresponding 95% confidence intervals to identify patient demographics and surgical characteristics that were associated with development of SSI. Results: Univariate analysis revealed stand-alone ALIF and lateral transpsoas approach to interbody fusion procedures were associated with a decreased risk of SSI while average serum glucose 120-139 mg/dL and ≥140 mg/dL were at increased risk. Diabetes alone was not a significant risk factor. Multivariant analysis revealed average serum glucose levels ≥140 mg/dL within five days after surgery was found to be a risk factor for SSIs relative to an average serum glucose <100 mg/dL. Conclusions: Postoperative serum glucose levels ≥140 mg/dL were associated with an increased risk of SSI when compared to glucose levels <100 mg/dL. The role of postoperative hyperglycemia as a risk factor for SSI should be investigated further.