Intravertebral Expandable Implants in Thoracolumbar Vertebral Compression Fractures

Abstract

Current scientific evidence enhances the importance of the anatomic restauration of vertebral bodies with compression fractures aiming, as with other human body joints, to obtain a biomechanic and functional spine as close as the one prior to the fracture as possible. We consider that anatomic reduction of these fractures is only completely possible using intravertebral expandable implants, restoring vertebral endplate morphology, and enabling a more adequate intervertebral disc healing. This enables avoiding disc and osteodegenerative changes to that vertebral segment and its adjacent levels, as well as the anterior overload of adjacent vertebral bodies in older adults - a consequence of post-traumatic vertebral flattening - thus minimizing the risk of adjacent vertebral fractures. The ability of vertebral body fracture reduction and height maintenance over time and its percutaneous transpedicular application make the intra-vertebral expandable implants a very attractive option for treating these fractures. The authors show the direct and indirect reduction concepts of vertebral fractures, review the biomechanics, characteristics and indications of intravertebral expandable implants and present a suggestion for updating the algorithm for the surgical treatment of vertebral compression fractures which includes the use of intravertebral expandable implants. Level of Evidence V, Expert Opinion.

Stent-armed kyphoplasty in osteoporotic thoracolumbar fractures—clinical and functional results and a center experience over 10 years

“…As patients with this condition are usually elderly, we highlight the practically immediate capacity of cementoplasty techniques (vertebroplasty and kyphoplasty) to provide pain relief and consequent standing up and walking after a few hours’ time, no pain, and no restriction of activity usually within 24 hours ( 17 - 20 ). The advantage of armed kyphoplasty with expansive intravertebral implants over classic vertebroplasty and kyphoplasty is mainly the superior preservation of restored vertebral height, as it is mechanically supported by the expanded devices (they work as a supporting endoskeleton or interior sustentaculum), which has been shown in diverse studies regarding medium and long-term follow-up ( 11 , 12 , 13 , 17 - 19 , 25 - 28 , 31 - 36 ). The authors of the present study defend, in the case of acute burst osteoporotic vertebral fractures [OF3 and OF4 of the classification of the German Orthopedic Society ( 8 )], in which the patient is unable to verticalize the trunk or with an unfavorable evolution after an attempt of a conservative treatment, the surgical intervention of armed kyphoplasty, that is, fracture reduction and stabilization with expansive intravertebral implants which are filled with bone cement.…”

“…Particularly in compression fractures of vertebral bodies, we defend the importance of anatomical restoration or the most similar to this (at the angle of vertebral kyphosis, vertebral height and vertebral endplates morphology), as in other joints of the human body, so as to ensure a spine which is functionally and biomechanically closer to the one existent before the fracture. While in young individuals, an anatomical reduction of the vertebral body is sought to prevent progression to osteodegenerative and disc changes in that vertebral segment as well as adjoining levels, in the elderly, often with osteoporosis, the objective of anatomical reduction is mainly to prevent anterior overload of adjacent bodies, this way reducing the peril of adjacent vertebral fractures ( 11 , 12 , 17 , 18 , 25 , 41 , 42 ). It is now recognized that in osteoporotic vertebral fractures, restoring the height of the vertebral body at the time of the first fracture is pivotal to avoid the disease’s domino effect, that is, the consecutive occurrence of osteoporotic fractures in adjacent vertebrae due to overload of the anterior column after the first uncorrected vertebral wedge fracture.…”

“…It is now recognized that in osteoporotic vertebral fractures, restoring the height of the vertebral body at the time of the first fracture is pivotal to avoid the disease’s domino effect, that is, the consecutive occurrence of osteoporotic fractures in adjacent vertebrae due to overload of the anterior column after the first uncorrected vertebral wedge fracture. The wedge of the vertebrae progressively shifts the load axis to a more anterior position, exposing the fragile osteoporotic vertebral bodies to excessive anterior loads, favoring a cascade of consecutive pathological fractures and the kyphotization of the spine ( 11 , 20 , 25 , 43 ).…”

“…Armed kyphoplasty refers to the application of intravertebral expansive implants, also permitting prompt analgesia and stabilization advantages of kyphoplasty and vertebroplasty. Moreover, it allows for the preservation of the restored vertebral height over the medium to long term, which has been demonstrated in several studies ( 11 , 12 , 13 , 17 - 19 , 25 - 27 , 31 - 33 ). Expanded devices mechanically support vertebral platforms, functioning as an interior sustentaculum or a supporting endoskeleton, preventing flattening of the vertebrae, reducing the hazard of post-traumatic local and segmental kyphosis, and also assuring consistent anterior support at the vertebral body’s level ( 15 , 17 , 18 , 34 - 36 ).…”

“…Therefore, intravertebral expansive implants have become popular regarding the treatment of vertebral body compression fractures, as they ensure a consistent anterior support at the vertebral body’s level provided by a posterior percutaneous transpedicular approach ( 15 , 16 , 34 ). The first intravertebral expansive implant developed was the VBS ® (Vertebral Body Stenting) implant, which emerged as an adaptation of vascular stents to spinal surgery, now being applied and expanded inside the vertebral body ( Figure 1 ) ( 7 , 11 , 12 - 14 , 16 - 19 , 25 , 27 , 31 , 32 , 36 , 37 ).…”