Addressing vertebral height restoration and sustainability

Clinical outcomes

Challenging prior competitive data, a 2022 study1 compares the height restoration and sustainability for three percutaneous vertebral augmentation procedures.

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Achieving sustainable height restoration in vertebral fracture procedures

A recent  cadaveric study1 evaluated three different bi-lateral procedures with respect to height restoration and sustainability post-operatively:

  • BKP
  • BKP using Kyphon Assist™ with directional cannula (BKP w/KA)
  • Titanium implantable vertebral augmentation device (TIVAD)
Healthcare providers gather around X-ray films to analyze and discuss them.

Anterior height loss was lower for BKP with Kyphon assist compared to TIVAD (p=0.02)1,2

BKP using Kyphon Assist™ sustained vertebral height after highest loading1,2

The study found that while all three treatments restored height nearly equally, BKP with Kyphon Assist™ best sustained height after highest loading.1,2

Less anterior height loss (~10%) following high-level 1250N cyclic loading was observed in the BKP w/KA group compared to TIVAD after highest level of loading.1,2

Anterior height decreased after 1250 N loading to 93.8 ± 6.8% of the post-surgery height for BKP, 95.9 ± 6.4% for BKP w/KA, and 86.0 ± 6.6% for TIVAD (p = 0.02).1

The mean anterior height loss between post-surgery and post-1250 N loading was lower for BKP w/KA compared to TIVAD (p = 0.02), but not when comparing BKP to TIVAD (p = 0.07).1 No difference in height sustainability at lower load levels (600 N (p = 0.76) and 850 N (p = 0.20)) was observed among treatment groups.1

BKP, BKP with Kyphon Assist, and TIVAD procedure post-operative vertebral height after loading

At least
height restoration was attained with all treatments.1

BKP, BKP with KA, and TIVAD procedure post-operative vertebral height

Evidence challenges a recent clinical trial

The SAKOS study3 (2019) aimed to support a non-inferiority finding for the use of titanium implantable vertebral augmentation device (TIVAD) compared to BKP. In this study, the analysis of primary endpoint on the ITT (intention to treat) population demonstrated non-inferiority of the TIVAD to BKP. The analysis of the additional composite endpoint demonstrated the superiority of TIVAD over BKP (p<0.0001) at 6 months (88.1% vs. 60.9%) and at 12 months (79.7% vs. 59.3%) in height restoration.

There were several limitations4 to this study:

  1. It leveraged first-generation Medtronic technology for the BKP arm with Gen 1 Xpander™ balloons (400psi). Gen 2 balloons (700psi) were commercially available at the time of the study but were not used.
  2. The authors state, “Radiographic reviews were performed independently by experienced radiologists blinded to treatment.” It is impossible to blind an experienced radiologist from the presence of a metallic device.
  3. There was no significant difference between groups in pain intensity at the final time point. The authors point to improved pain intensity scores at different secondary time points. The presence of new fractures should be considered in these pain differences.
  4. The SAKOS study found statistically significant difference in height restoration only at midline. There was no statistically significant difference in anterior or posterior height restoration.
  5. The study did not report the individuals’ DEXA scores. Without this information, we do not know if there was a higher degree of osteoporosis in one group or another.

By measuring the performance of procedures using Medtronic’s most advanced balloons and directional instruments, the Height Restoration study further confirms the role of bilateral BKP in fracture reduction and height restoration for the management of vertebral compression fractures.

Kyphon Assist™ directional cannula for balloon kyphoplasty

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Cadaveric and bench testing may not be indicative of clinical results.


Holyoak DT, Andreshak TG, Hopkins TJ, et al. Height restoration and sustainability using bilateral vertebral augmentation systems for vertebral compression fractures: a cadaveric study. Spine J. 2022 Jun 23;S1529-9430(22)00274-1. doi: 10.1016/j.spinee.2022.06.011. Online ahead of print.


Medtronic data on file. Exponent Study 1602000.002.


Noriega D, Marcia S, Theumann N, et al. A prospective, international, randomized, noninferiority study comparing an implantable titanium vertebral augmentation device versus balloon kyphoplasty in the reduction of vertebral compression fractures (SAKOS study). Spine J. 2019;19(11):1782-1795. doi: 10.1016/j.spinee.2019.07.009. Epub 2019 Jul 17. PMID: 31325625.


Levy JR. Letter to the editor regarding: "a prospective, international, randomized, noninferiority study comparing an implantable titanium vertebral augmentation device versus balloon kyphoplasty in the reduction of vertebral compression fractures (SAKOS study)." Spine J. 2020;20(12):2037-2038. doi: 10.1016/j.spinee.2020.08.016. Epub 2020 Sep 2.