The Effect of Varying Preoperative Hemoglobin Levels on the Risk of Major Complications and Surgical Site Infections After Single Level Lumbar Fusion.

INTRODUCTION: Blood transfusions are associated with an increased risk of complications after lumbar fusion, and current anemia hemoglobin thresholds are not surgery specific. We aimed to calculate single-level lumbar fusion-specific preoperative hemoglobin strata that observe the likelihood of 90-day transfusion and evaluate whether these strata are associated with increased risk of 90-day complications and 2-year infections. METHODS: A national database identified patients undergoing primary single-level lumbar fusion with preoperative hemoglobin values (g/dL). Stratum-specific likelihood ratio analysis calculated sex-based hemoglobin strata associated with the risk of 90-day transfusion. Incidence and risk of 90-day major complications and 2-year infections were observed between strata. RESULTS: Three female (hemoglobin strata, likelihood ratio [<10.9, 2.41; 11.0 to 12.4, 1.35; 12.5 to 17.0, 0.78]) and male (<11.9, 2.95; 12.0 to 13.4, 1.46; 13.5 to 13.9, 0.71) strata were associated with varying likelihood of 90-day blood transfusion. Increased 90-day complication risk was associated with two female strata (hemoglobin strata, relative risk [11.0 to 12.4, 1.52; <10.9, 3.40]) and one male stratum (<11.9, 2.02). Increased 2-year infection risk was associated with one female (<10.9, 3.67) and male stratum (<11.9, 2.11). CONCLUSION: Stratum-specific likelihood ratio analysis established sex-based single-level lumbar fusion-specific hemoglobin strata that observe the likelihood of 90-day transfusion and the risk of 90-day major complications and 2-year infections. These thresholds are a unique addition to the literature and can assist in counseling patients on their postoperative risk profile and in preoperative patient optimization. LEVEL OF EVIDENCE: Level III.

Comparative analysis of patient demographics, perioperative outcomes, and adverse events after lumbar spinal fusion between urban and rural hospitals: an analysis of the National Inpatient Sample (NIS) database.

OBJECTIVE: Rural location of a patient's primary residence has been associated with worse clinical and surgical outcomes due to limited resource availability in these parts of the US. However, there is a paucity of literature investigating the effect that a rural hospital location may have on these outcomes specific to lumbar spine fusions. METHODS: Using the National Inpatient Sample (NIS) database, we identified all patients who underwent primary lumbar spinal fusion in the years between 2009 and 2020. Patients were separated according to whether the operative hospital was considered rural or urban. Univariable and multivariable regression models were used for data analysis. RESULTS: Of 2,863,816 patients identified, 120,298 (4.2 %) had their operation at a rural hospital, with the remaining in an urban hospital. Patients in the urban cohort were younger (P < .001), more likely to have private insurance (39.81 % vs 31.95 %, P < .001), and fewer of them were in the first (22.52 % vs 43.00 %, P < .001) and second (25.96 % vs 38.90 %, P < .001) quartiles of median household income compared to the rural cohort. The urban cohort had significantly increased rates of respiratory (4.49 % vs 3.37 %), urinary (5.25 % vs 4.15 %), infectious (0.49 % vs 0.32 %), venous thrombotic (0.57 % vs 0.24 %, P < .001), and neurological (0.79 % vs 0.36 %) (all P < .001) perioperative complications. On multivariable analysis, the urban cohort had significantly increased odds of the same perioperative complications: respiratory (odds ratio[OR] = 1.48; 95 % confidence interval [CI], 1.26-1.74), urinary (OR = 1.34; 95 %CI, 1.20-1.50), infection (OR = 1.63; 95 %CI, 1.23-2.17), venous thrombotic (OR = 1.79; 95 %CI, 1.32-2.41), neurological injury (OR = 1.92; 95 %CI, 1.46-2.53), and localized infection (OR = 1.65; 95 %CI, 1.25-2.17) (all P < .001). CONCLUSIONS: Patients undergoing lumbar fusions experience significantly different outcomes based on the rural or urban location of the operative hospital.