Is Kiva implant advantageous to balloon kyphoplasty in treating osteolytic metastasis to the spine? Comparison of 2 percutaneous minimal invasive spine techniques: a prospective randomized controlled short-term study.

STUDY DESIGN

Prospective, parallel-group, controlled, comparative randomized study.

OBJECTIVE

To compare cement leakage rate and efficacy for vertebral body restoration of balloon kyphoplasty (BK) versus Kiva novel implant with polymethylmethacrylate (PMMA) for treating osteolytic vertebral body metastasis.

SUMMARY OF BACKGROUND DATA

Minimally invasively vertebral augmentation techniques with PMMA are mostly performed for treating osteoporotic compression fractures. The Kiva implant with PMMA offers better vertebral body restoration and less PMMA leakage than BK in osteoporotic fractures. No previous study compared leakage rate and efficacy for vertebral body restoration in traditional BK and Kiva with PMMA in osteolytic vertebral body metastases.

METHODS

This study examined 23 patients (71 ± 13 yr) with 41 osteolytic vertebral bodies, who received Kiva with low viscosity PMMA and 24 patients (70 ± 11 yr) with 43 vertebral body osteolyses, who were reinforced with BK and high viscosity PMMA. All osteolyses were graded as Tomita 1 to 3. Anterior vertebral body height ratio (AVBHr), posterior vertebral body height ratio (PVBHr), and middle vertebral body height ratio (MVBHr), Gardner kyphotic deformity, PMMA leakage and were measured and compared between the groups. Visual analogue scale and Oswestry Disability Index were used for functional outcome evaluation.

RESULTS

No patient survived after 3 months. Asymptomatic PMMA leakage occurred in 4 (9.3%) vertebrae in the BK group solely (2 to the spinal canal, in Tomita grade 3 osteolysis) Anterior, posterior and middle vertebral body height ratio, Gardner angle improved insignificantly in both groups. Visual anlogue scale and Oswestry Disability Index improved postoperatively similarly in both groups (P < 0.001).

CONCLUSION

BK and Kiva provided equally significant spinal pain relief in patients with cancer with osteolytic metastasis. The absence of cement leakage in the Kiva group and absence of neurological complication in the BK group leakages reflects the safety of both augmentation techniques even in significant osteolysis. The lack of cement leakage in the Kiva cases, although low viscosity PMMA was used, increases this implant safety in augmenting severely destructed thoracolumbar vertebrae and sacrum from osteolytic metastasis.

LEVEL OF EVIDENCE