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Treatment of Vertebral Compression Fractures with Cortoss in Vertebroplasty and Kyphoplasty; One Year Follow-up 2006

Interventional Spine

Philip M Maurer, MD, Non ASSR Member
Choll W Kim, MD, PhD, Non ASSR Member
Isador Lieberman, MD, Non ASSR Member
Erik L Westerland, MD, Non ASSR Member
William J Buetler, MD, Non ASSR Member
Hyun W Bae, MD, Non ASSR Member

Scientific Paper

Purpose

Cortoss is a high-strength, bioactive, self-setting composite engineered to mimic the characteristics of human structural bone. Because it is inherently radiopaque, Cortoss is easily visualized during its placement under fluoroscopy, or in post-operative imaging. Animal studies demonstrated that the Cortoss-bone interface continues to be strengthened over time, with new bone being formed and integrated onto and into the material(1).
The purpose of this study was to assess the feasibility and clinical outcome of the use of Cortoss in treating osteoporotic vertebral compression fractures (VCF).

Methods & Materials

40 patients were enrolled in 2 FDA approved pilot IDE studies conducted using Cortoss for the treatment of VCFs using vertebroplasty technique at 3 centers (20 patients) and kyphoplasty technique at 5 centers (20 patients). Treatment was limited to one or 2 levels from T6 to L5. The objective was to compare the patients' condition prior to and after treatment. 20 patients were treated using the Vertebroplasty technique. There were 8 males and 12 females with a mean age of 72. 15 lumbar and 11 thoracic vertebrae were treated, with an average of 1.9cc injected per vertebra. 20 patients were treated using the Kyphoplasty technique. There were 6 males and 14 females with a mean age of 79. 25 vertebrae were treated with an average of 4.1cc per vertebra. Primary endpoints included pain (Visual Analogue Scale, VAS) and function (Oswestry Disability Index, ODI), SF-12, radiographic evaluation and safety. Patients meeting the inclusion/exclusion criteria were admitted into the study. There was no randomization between groups.

Results

Vertebroplasty patients VAS improved from 74.1 pre-op to 32 at 1 month, 24.1 at 3 months and 32 at 12 months. Similarly, ODI decreased from 52% pre-op to 36% at 1 month, 30% at 3 months and 23% at 12 months.

Kyphoplasty patients VAS improved from 78 pre-op to 27 at 1 month, 22 at 3 months and 20 at 6 months. Similarly, ODI decreased from 60% pre-op to 38% at 1 month, 33% at 3 months and 38% at 6 months.

SF-12 was maintained or improved at each time point for both groups

Leakages were calculated from post-op CT scans and found to be similar in both groups. All extravasations were asymptomatic with no cardiac irregularities or pulmonary emboli.

Conclusion

The results obtained in these 2 pilot IDE studies indicate that Cortoss is safe and effective in the treatment of osteoporotic VCF. These results are consistent with the results obtained in the prospective vertebroplasty study using Cortoss conducted in Europe(2). These studies suggest that a smaller volume of Cortoss appears to successfully reinforce the vertebrae and achieve symptomatic relief, as compared to the volumes reported in the literature for PMMA(3). This may be due to the interdigitated fill pattern observed with Cortoss which results in trabecular reinforcement. A larger, prospective randomized controlled IDE study to confirm these findings is under way.

References

1. Erbe, E., Clineff, T., Gualtieri, G., 'Comparison of a new bisphenol-a-glycidyl dimethacrylate-based cortical bone void filler with polymethyl methacrylate' Eur Spine J (2001) 10:S147-S152.
2. Palussiere J, Berge J, Gangi A, Cotton A, Pasco A, Bertagnoli R, Jackshe H, Carpeggiani P, Deramond H, Clinical Results of an Open Prospective Study of a bis-GMA Composite in Percutaneous Vertebral Augmentation, European Spine Journal, 2005.
3. Liebschner et al. Effects of Bone Cement Volume and Distribution on Vertebral Stiffness After Vertebroplasty, Spine, Vol.26, No.14, 2001.

Hyun Bae, MD - unrestricted grant from Orthovita

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