Re-expansion of Osteoporotic Compression Fractures Using Bilateral SpineJack Implants: Early Clinical Experience and Biomechanical Considerations.

Robert E Jacobson,Hoang Doang,Anastas Nenov

doi:10.7759/cureus.4572

Robert E Jacobson, Hoang Doang + Show 1 more

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https://doi.org/10.7759/cureus.4572

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Abstract

Thoraco-lumbar osteoporotic compression fractures have a higher incidence of continued collapse with development of deformity and progression to vertebra plana when untreated and even after vertebral augmentation (VA) or balloon kyphoplasty (BKP). Even when there is the restoration of height and improvement in angulation, multiple long-term follow-up series have repeatedly documented that over time, many patients lose the initial height correction and in a smaller group the vertebral body re-collapses leading to the development of progressive deformity with an increased risk for adjacent level fractures. At first, larger balloons and more cement were used to try and avoid these problems, but it did not reduce the risk of adjacent fractures. Several procedures were developed to place various types of intervertebral implants combined with bone cement to maintain the initial height correction. Initial studies with these implants showed a reduction in adjacent level fractures but the systems did not proceed to market. The SpineJackR (SJ) system (Stryker Corp, Kalamazoo, MI), consisting of bilateral expandable titanium implants supplemented with bone cement, was first used approximately 10 years ago in Europe and recently gained FDA approval in the United States. This system provides more symmetric and balanced lateral and anterior support and is effective with lesser amounts of bone cement compared to BKP. Follow-up studies have documented that there is equal or better pain control, with better long-term results based both on maintaining vertebral height restoration and deformity correction. Most importantly, statistically it clearly reduces the risk of adjacent level fractures by at least 60%. The biomechanical effects of intravertebral implants for osteoporotic fractures in regard to the risk of adjacent level fractures and preliminary experience with the use of the SJ is reviewed.

Highlights

Evolution of vertebral augmentation and kyphoplasty proceduresVertebroplasty (VP), known as vertebral augmentation (VA) and balloon kyphoplasty (BKP), have been used for over 30 years for the treatment of osteoporotic vertebralHow to cite this article Jacobson R E, Nenov A, Duong H D (April 30, 2019) Re-expansion of Osteoporotic Compression Fractures Using Bilateral SpineJack Implants: Early Clinical Experience and Biomechanical Considerations
Anatomic studies show that osteoporotic vertebral compression fractures are essentially comminuted 'eggshell' like fractures of the vertebrae initially affecting the cortical endplates with progression to various degrees of compression and collapse of the vertebral body [2]
Many fractures have vertebral clefts that can be identified on magnetic resonance imaging (MRI) or computerized tomography (CT) that are regarded as a clear sign of micro-instability and if the cleft is not filled with cement the fracture can continue to progressively collapse [3,4]

Summary

Introduction

Evolution of vertebral augmentation and kyphoplasty proceduresVertebroplasty (VP), known as vertebral augmentation (VA) and balloon kyphoplasty (BKP), have been used for over 30 years for the treatment of osteoporotic vertebralHow to cite this article Jacobson R E, Nenov A, Duong H D (April 30, 2019) Re-expansion of Osteoporotic Compression Fractures Using Bilateral SpineJack Implants: Early Clinical Experience and Biomechanical Considerations. Clinical and radiologic observations found that vertebral fractures, especially with concurrent vertebral fluid filled clefts found on CT and MRI scans, often re-expanded when the spine was placed in extension, indicating micro-instability and indicating the fracture height could be restored by re-expansion with a balloon [3,4] Fractures with these vertebral clefts are more prone to progressive deformity and collapse [4]. Follow-up studies show that as early as onemonth post-procedure, loss of height restoration, and recurrent collapse, leading to further sagittal kyphosis with angulation of the fractured vertebra is found in 5% to 12% of treated one level fractures [8,9] These fractures are almost always found in their early stages in the anterior and inferior part of the superior vertebra indicating a reproducible biomechanical stress point [4,5,6,7]. The shifting of the center of gravity more anteriorly has been considered a major biomechanical reason for these fractures but studies comparing VA to BKP have consistently shown a higher incidence of adjacent level fractures with BKP, which is thought to be related to the larger volume, solid cement filled defects created after balloon expansion which puts upward stress on the adjacent osteoporotic vertebra [6,7,10,12]

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