Novel Graft Materials for Lumbar Spinal Fusion Procedures:12 Months Outcomes

OBJECTIVES: Novel graft materials to enhance bone growth in spinal surgery are continuously developed. Evaluating the effectiveness of these grafts is challenging due to potential confounding by indication with novel and more expensive grafts used in more challenging patients. Our study evaluated twelve-month outcomes in patients undergoing lumbar spinal fusion, based on graft material.

METHODS: Patients undergoing lumbar fusion surgery in the Premier Healthcare Database from October 2015 to December 2022 were identified. Use of bioactive glass (“bioglass”) and/or bone morphogenetic protein-2 based graft materials (BMP) were identified from chargemaster entries. Outcomes included pseudarthrosis and infection twelve months post-index. Variables included patient, provider and surgery characteristics. Descriptive statistics were performed on all variables and outcomes. Adjusted rates of infection and pseudarthrosis were estimated using Poisson regression. Hospital costs were adjusted to 2022 inflation and index and twelve-month costs were estimated using generalized linear models.

RESULTS: 1,196 patients with bioglass graft and 72,204 with BMP were included in the analysis, with average age 62 in both groups, 17% of bioglass and 15% of BMP patients ≥ 75. In both groups, ~ 90% were elective and 94% were treated in the inpatient setting. Patients with three or more comorbidities represented 40% of the bioglass and 34% of the BMP cohorts. Obesity and complicated diabetes were observed in 24% and 9% patients in both groups, respectively. At twelve months post-index, the pseudarthrosis rate was 1.6% (95% confidence interval (CI): 0.9%-2.3%)) in the bioglass group and 1.5% (95%CI: 1.4%-1.6%) in the BMP group. Index procedural costs averaged $44,815 (SD: 30,980) for bioglass and $47,227 (SD: 31,547) for BMP, and post-index twelve-month costs averaged $13,557 (SD: $28,919) for bioglass and $15,078 (SD: $37,396) for BMP groups.

CONCLUSIONS: When used for lumbar spinal fusion procedures, the bioglass graft material resulted in twelve-month pseudarthrosis rates below 2%.