Impact of Hormone Replacement Therapy on Clinical and Radiographic Outcomes in Postmenopausal Women Undergoing Posterior Spinal Fusion: A Retrospective Cohort Study

Introduction: Postmenopausal women undergoing spinal fusion face unique challenges related to estrogen deficiency. This study investigates the effects of hormone replacement therapy (HRT) on outcomes in postmenopausal women undergoing posterior spinal fusion. The Purpose of this study is to compare the effectiveness and use of HRT in post-menopausal women undergoing posterior spinal fusion.

Methods: We conducted a retrospective cohort study of 104 postmenopausal women who underwent posterior spinal fusion between 2016 and 2023. Primary outcomes were NDI, ODI, PROMIS, and VAS scores. Secondary outcomes where screw loosening, adjacent segment disease, and hardware failure. Patients were divided into HRT (n=51) and non-HRT (n=53) groups. Clinical outcomes (ODI, NDI, VAS Back, PROMIS Pain) and radiographic outcomes were assessed at baseline, 3, 6, 9, and 12 months postoperatively.

Results: The HRT group demonstrated significantly greater improvements in all clinical outcome measures compared to the non-HRT group (p < 0.05). Radiographically, the HRT group showed a trend towards better fusion status at 12 months (94.1% vs. 86.8%, p=0.208) and lower rates of hardware complications, though not statistically significant. Multivariate analysis revealed that lower modified Frailty Index-5 scores, younger age, lower BMI, and ERAS protocol implementation were associated with higher odds of successful fusion.

Conclusion : HRT use in postmenopausal women undergoing posterior spinal fusion is associated with improved clinical outcomes and trends towards better radiographic results. These findings suggest that HRT may play a role in optimizing surgical outcomes in this population.