Zoledronic acid infusion for lumbar interbody fusion in osteoporosis

Clinical outcomes of intravenous (IV) infusion of zoledronic acid (ZOL) for lumbar interbody fusion surgery (LIFS) remain unknown. We investigated the efficacy of IV ZOL on clinical outcome and bone fusion after LIFS.

We retrospectively analyzed 64 patients with both degenerative lumbar spondylolisthesis and osteoporosis who underwent LIFS from January 2007 to April 2010. All patients were followed up for 2 y. Thirty-two were treated with an IV infusion of ZOL 3 d after surgery and a second injection 1 y later, and the other 32 patients did not receive ZOL. Preoperatively and every 3 mo postoperatively, oswestry disability index questionnaire and visual analog scale (VAS) scores for back and leg were compared. Preoperative and final postoperative follow-up to evaluate for subsequent compression fractures were also performed. Pedicle screw loosening, cage subsidence, and fusion rate were documented 2 y after surgery.

At 2-y follow-up, a solid fusion was achieved in 75% of the ZOL group and only 56% of the control group. At final follow up, the incidence of final subsequent vertebral compression fractures (19% of the ZOL group and 51% of the control group, P = 0.006), pedicle screw loosening (18% of the ZOL group and 45% of the control group, P = 0.03), and cage subsidence >2 mm (28% of the ZOL group and only 54% of the control group, P = 0.04) were significantly lower in the ZOL group than in the control group. The ZOL group demonstrated improvement in VAS (for leg pain VAS, 2/10 for the ZOL group and 5/10 for the control group; for back pain VAS, 2/10 for the ZOL group and 6/10 for the control group) and oswestry disability index scores (7/25 for the ZOL group and 16/25 for the control group).

ZOL treatment has beneficial effects on instrumented LIFS both radiographic and clinically. Thus, ZOL treatment can be recommended for osteoporosis patients undergoing LIFS.