Objective:

To evaluate the efficacy of teriparatide versus zoledronate on spinal fusion in osteoporotic patients following posterior lumbar interbody fusion (PLIF).

Methods:

Postmenopausal women with osteoporosis undergoing PLIF for degenerative spondylolisthesis were randomly assigned to receive either zoledronate or teriparatide administration. During the 2-year follow-up, serial radiographies were applied to determine fusion status and instrumentation-related sequelae (a composite of adjacent vertebral compressive fracture, instrumentation failure, and fusion failure). Bone mineral density (BMD) and the Oswestry disability index (ODI) scores were also serially measured.

Results:

Finally, 36 cases in the teriparatide group and 41 in the zoledronate group completed the 2-year follow-up assignments. Bony union achieved more frequently in the teriparatide group versus the zoledronate group at 6 months post-operation (P < .05), whereas the overall rate of bone union was comparable between groups. The incidence of instrumentation-related sequelae was comparable between the teriparatide group and zoledronate group (13.9% vs. 22.0%, respectively). Regarding anti-osteoporosis, BMD values were significantly improved in both groups at the last follow-up. Notably, the teriparatide group versus the zoledronate group attained more BMD increments at postoperative 12 months from baseline. Furthermore, ODI scores consistently decreased both in the two groups with lower ODI score observed in the teriparatide group versus the zoledronate group at 12 months after surgery.

Conclusion:

Among postmenopausal women with osteoporosis, teriparatide versus zoledronate administration showed superior bone union at 6 months and greater BMD improvement at 12 months after PLIF, although both brought similar overall effect on spinal fusion.