Perioperative teriparatide use in osteopenic and osteoporotic patients undergoing multi- and long-segment posterior spinal fusion

Osteoporosis and osteopenia are common in spine surgical patients and are associated with adverse outcomes. Perioperative Teriparatide use improves bone quality and decreases the risk of adverse events. We hypothesized that teriparatide use before and after long-segment posterior spinal fusion (PSF) would decrease the rate of adverse surgical events, including pseudoarthrosis, secondary fracture, and revision surgery, in osteoporotic and osteopenic patients compared to patients in a non-osteoporotic, non-teriparatide group. Between 2016 and 2020, 58 adult patients who underwent long-segment PSF were included. The cases ( n = 17) were patients with osteoporosis or osteopenia who received a minimum of six weeks of pre- and at least six months of post-operative teriparatide treatment. The control group ( n = 41) included patients without osteoporosis who did not require teriparatide treatment. Cases and controls were matched based on surgery type, surgical levels, and follow-up length. The minimum follow-up time was 12 months. The mean age was 69.0 in the cases vs. 65.4 years in the control group. There were no significant differences based on age, body mass index, gender, race, history of diabetes, history of steroid use, or tobacco usage between the 2 groups. The number of fused vertebral levels and interbody cages placed did not significantly differ either, with 7.8 vs. 6.4 fused levels ( p -value = 0.06) and 0.7 interbodies vs. 0.3 interbodies ( p -value = 0.15) for the cases and controls, respectively. The case group experienced a higher rate of extension into the pelvis (47.1% vs. 17.1%, p -value = 0.03). The rates of pseudarthrosis (29.4% vs. 17.1%, p -value = 0.31) and reoperation rate (23.5% vs. 17.1%, p -value = 0.72) were not statistically different for the case or control groups, respectively. No postoperative fractures were observed. Teriparatide use resulted in similar postoperative outcomes in the case group compared to the control group in patients undergoing long-segment PSF despite a less favorable baseline in the case group, including the presence of osteoporosis and fusion that required extension into the pelvis. Given the retrospective observational design and absence of an untreated osteopenic/osteoporotic comparison group, these findings should be interpreted as exploratory and hypothesis-generating. Further prospective studies are needed to determine whether teriparatide independently influences outcomes after long-segment spinal fusion.