Delayed Height Loss After Kyphoplasty in Osteoporotic Vertebral Fracture with Severe Collapse: Comparison with Vertebroplasty.

Objective: To compare clinical and radiographic outcomes and complications after vertebroplasty (VP) and kyphoplasty (KP) for osteoporotic vertebral fractures with severe collapse.

Methods: Patients >65 years old with single osteoporotic vertebral fracture (T10-L2) with severe collapse (>40%) were prospectively enrolled and allocated to either KP or VP. Visual analog scale and Oswestry Disability Index were used for clinical assessment. Vertebral height loss (HL) and segmental kyphotic angle were measured radiographically at preoperative; postoperative; and 1-, 3-, 6-, and 12-month postoperative time points. Procedure-related and postoperative complications were recorded.

Results: Forty-six patients (27 with VP, 19 with KP) were enrolled. Visual analog scale and Oswestry Disability Index scores were similar at all time points in the 2 groups. Complication rates were also similar. HL and kyphotic angle were restored significantly in both groups. KP showed a better result in HL (KP group HL 20.5% ± 5.6% vs. VP group HL 29.8% ± 4.6%, P < 0.001). Progressive vertebral HL was observed, and patients with KP showed a greater collapse in height. At 1-year follow-up, there was no significant difference in vertebral height (KP group HL 29.8% ± 6.3% vs. VP group HL 33.0% ± 5.2%, P = 0.075).

Conclusions: KP and VP showed similar improvements in pain and disability during treatment for osteoporotic vertebral fractures. Although vertebral height and segmental kyphotic angle were restored significantly in both groups, progressive vertebral HL was inevitable, especially after KP. This likely resulted from the difference of bone-cement interface as a consequence of balloon tamping in KP. Surgeons must consider the respective features of vertebral augmentations.