SAT-781 Exploring the Impact of Osteoporosis Treatments on Posterior Fusion Outcomes in Adult Patients

Abstract Disclosure: A.V. Nguyen: None. R.J. Weber: None. J. Park: None. N. Alan: None. M. Praveen: Depuy Synthes, Globus, NREF, ISSG, AO Spine, NIH, PCORI (CSM), SLIP II, Pacira, DoD, Discgenics, Springer Publisher, Thieme Publisher, BK Medical, Brain Lab, SI Bone, Medtronic. A. Jamieson: None. E.C. Hsiao: None. K.L. Wentworth: None. Background: Osteoporosis significantly increases the risk of fusion and hardware failures after spine fusion operations. Exploration of perioperative therapies to enhance fusion outcomes is of great interest. Previous small cohort studies indicated favorable outcomes associated with anabolic therapy before or shortly after spinal fusion surgeries, however, the role of perioperative bone therapies remains uncertain and controversial. Methods: We performed a retrospective cohort study of patients age 50+ with osteoporosis who underwent posterior thoracolumbar fusion surgery from 2013-2023 at an established research and teaching hospital and evaluated the effect of anabolic versus antiresorptive treatments on surgical outcomes. Patients with prior malignancy or surgeries due to osteomyelitis or trauma were excluded. Patients were stratified by osteoporosis, osteopenia, normal bone density, or uncategorized status using ICD-10 codes, DXA scans, and chart review. The osteoporosis group was further divided into those receiving anabolic, antiresorptive, both therapies, or neither within the time frame of one year before to two years after surgery. Results: We identified 732 patients with osteoporosis who underwent spinal fusion surgery. We confirmed 160 patients were taking only anabolic and 165 were taking only antiresorptive therapy. There were no significant demographic differences between groups. The anabolic group had a 19.4% revision surgery rate and 3.1% hardware removal rate. The antiresorptive group showed 26.0% and 6.7% rates, respectively. The differences between therapies were not statistically significant, with p=0.186 for revision surgery rate and p=0.199 for hardware removal rate. Early failure rates were similar in both groups. The median time to revision surgery was shorter in the anabolic group (310.5 days) compared to the antiresorptive group (661.5 days). 80.6% of the anabolic group vs. 73.9% of the antiresorptive group did not need revision surgery. The non-inferiority margin for revision surgery was set at 15% and was met in this analysis. Conclusions: Our analysis suggests that anabolic therapy may marginally decrease the likelihood of revision procedures or hardware removal compared to antiresorptive therapy. Importantly, patients on antiresorptive therapy experienced longer intervals before revision surgery, though these differences were not statistically significant. Our results indicate that peri-operative antiresorptive therapy is not inferior to anabolic therapy. Given surgical delays while awaiting insurance approval for anabolic therapy as well as the increased out-of-pocket cost for off-label anabolic use, antiresorptive therapy may provide an important strategy for reducing post-spinal fusion complications. These data highlight the need for randomized controlled trials to definitively compare the two therapies. Presentation: Saturday, July 12, 2025