The Association of Preoperative hba1c and Minimally Invasive Lumbar Spine Surgery Outcomes

Introduction: Minimally invasive approaches to lumbar spine surgery are increasingly popular. Current guidelines highlight the importance of preoperative HbA1c in optimizing spine surgery outcomes. However, the role of preoperative HbA1c in minimally invasive lumbar spine surgery remains unclear. We sought to assess the association of HbA1c with readmissions, reoperations, and complications following minimally invasive lumbar spine surgery.

Methods: We retrospectively reviewed all adult patients at a single institution from 2011 to 2023 who underwent minimally invasive lumbar deformity correction using CPT and ICD9/10 codes. High HbA1c was defined as preoperative ≥ 8.0. Propensity score matching and multivariate analyses were performed to assess the effect of high HbA1c on outcomes.

Results: In total, 909 patients met the inclusion criteria. The median age at time of operation was 64 [IQR 53 -71] and 21% were African American. The median preoperative HbA1c was 5.70 (IQR 5.40 – 6.40), with 55 (6.0 %) patients having high preoperative HbA1c. Upon multivariate regression analysis adjusting for comorbidity burden and other confounders, patients with high HbA1c had increased odds of unplanned readmission within 90 days (OR 5.52, 95% CI 1.66 – 16.4, p =0.003) and within one year (OR 3.04, 95%CI 1.23-6.87, p=0.01) of the index operation. After propensity score matched analysis matching by age, race, surgical characteristics, and comorbidity burden, patients with high preoperative HbA1c were more likely to have unplanned readmission within 90 days (11% vs 2.6%, p=0.014) and one year (17% vs 7.7%, p=0.02) of index operation. Patients with high preoperative HbA1c had longer hospital lengths of stay (1.31 vs 1.22 days, p=0.007). There was no difference in infection rates between the two groups.

Conclusion : Our results suggest high preoperative HbA1C may be associated with increased rates of readmission and reoperation but not infection following minimally invasive lumbar spine surgery. Preoperative HbA1C control may be indicated for surgical optimization in minimally invasive lumbar spine surgery.