Fixation and Augmentation of Incomplete Burst Fractures
Fixation and Augmentation of Incomplete Burst Fractures
Incomplete burst fractures in osteoporotic patients are one of the most upcoming and challenging issues in spinal traumatology and optimal treatment remains an unresolved question. So far there is a paucity of randomized control trials as well as biomechanical studies which address the question of appropriate treatment and the understanding of the mechanical stability of these common injuries. In patients with good bone quality, recommended treatment options vary from conservative treatment to combined posterior-anterior fusion. In osteopenic or even osteoporotic patients with traumatic incomplete burst fractures, treatment options are even more manifold, but again without sufficient supporting evidence for positive outcomes.
In case of neurologically and posterior ligament intact fractures with low-grade destruction of the vertebral body, a panel of leading spine surgeons (The Spine Trauma Study Group) recommended a posterior approach.
In elderly patients, fractures are frequently accompanied by comorbidities, so that the anterior thoracic, retroperitoneal or abdominal approach is not preferable. Nevertheless, particularly in this patient population, prolonged immobilization needs to be averted and immediate primary stability is aspired.
Several factors, including the physiological stress to the patient, morbidity and complication rates need to be taken into account in the choice of surgical approach. Even if an anterior reconstruction could have been considered, a single posterior approach is recommended in the elderly with poor bone quality.
However, it is known that conventional pedicle screws or other posterior stabilization strategies may fail more often in osteoporotic patients because of the poor bone-implant interface. This effect may even be worse if there is a lack of support for the anterior column. Aside from the already discussed mortality in older patients from anterior surgery, conventional anterior constructions with cages may also fail. Relatively hard cages from titanium, polyether-ether ketone (PEEK) or other materials may easily breach into the endplate. This may lead to loss of correction, increase of bearing load to the posterior implants or even in complete implant failure.
Conscious of these mechanical problems in osteoporotic bone and the lack of evidence supporting any treatment, the most recent publications describe a stand-alone cement augmentation in different techniques such as vertebroplasty or kyphoplasty and augmentation support of conventional instrumentation with a dorsal approach only.
Kyphoplasty is considered to be a relatively safe and effective treatment of osteoporotic thoracolumbar burst fractures. It is reported to be able to treat pain, restore vertebral body height, and reduce kyphosis without deterioration of fragment retropulsion. Also, vertebroplasty (VP) as a stand-alone procedure is reported to be safe in burst fractures. Like kyphoplasty, VP reportedly is able to restore vertebral body height and to reasonably correct kyphotic deformity. In addition, there are also biomechanical indications that cement injection might restore mechanical properties of the fractured vertebra. Therefore, some authors appraise VP as being adequate in eliminating the need for major operations. However, to our knowledge, further biomechanical investigation on kinematic effects of cement augmentation in incomplete burst fractures in osteoporosis is lacking. Also, the clinical value of the available reports is questionable in terms of evidence-based treatment.
Several published clinical reports describe a form of hybrid technique (hybrid augmentation, HA) by combining a dorsal short segment pedicle screw construction with an augmentation of the fractured vertebra. By augmenting the fractured vertebra, a stabilization of the anterior column is anticipated.
The HA technique seems to combine the advantages of 2 relatively less invasive procedures to treat this kind of fractures even in older and potentially osteoporotic patients where isolated dorsal instrumentation would possibly fail. The technique is expected to reduce kyphotic loss and instrumentation failure in comparison to stand-alone dorsal instrumentation. It is also expected to decrease the inherent morbidity, blood loss, operative time, length of the hospital stay, and costs associated with an anterior thoracic or abdominal approach. Complete percutaneous treatment using HA has also been reported in literature but there is little knowledge on the biomechanical effects of this technique.
Having been premised on the lack of conceptual clarity of treatment in incomplete burst fractures in osteoporosis and based on the little biomechanical knowledge we have so far, this study was designed to gain kinematic awareness in this challenging question using a validated method that experimentally inflicts incomplete burst fractures.
The objective of this study is to investigate the kinematic effects of different dorsal augmentation-related treatment options of incomplete burst fractures in osteoporosis.
Background
Incomplete burst fractures in osteoporotic patients are one of the most upcoming and challenging issues in spinal traumatology and optimal treatment remains an unresolved question. So far there is a paucity of randomized control trials as well as biomechanical studies which address the question of appropriate treatment and the understanding of the mechanical stability of these common injuries. In patients with good bone quality, recommended treatment options vary from conservative treatment to combined posterior-anterior fusion. In osteopenic or even osteoporotic patients with traumatic incomplete burst fractures, treatment options are even more manifold, but again without sufficient supporting evidence for positive outcomes.
In case of neurologically and posterior ligament intact fractures with low-grade destruction of the vertebral body, a panel of leading spine surgeons (The Spine Trauma Study Group) recommended a posterior approach.
In elderly patients, fractures are frequently accompanied by comorbidities, so that the anterior thoracic, retroperitoneal or abdominal approach is not preferable. Nevertheless, particularly in this patient population, prolonged immobilization needs to be averted and immediate primary stability is aspired.
Several factors, including the physiological stress to the patient, morbidity and complication rates need to be taken into account in the choice of surgical approach. Even if an anterior reconstruction could have been considered, a single posterior approach is recommended in the elderly with poor bone quality.
However, it is known that conventional pedicle screws or other posterior stabilization strategies may fail more often in osteoporotic patients because of the poor bone-implant interface. This effect may even be worse if there is a lack of support for the anterior column. Aside from the already discussed mortality in older patients from anterior surgery, conventional anterior constructions with cages may also fail. Relatively hard cages from titanium, polyether-ether ketone (PEEK) or other materials may easily breach into the endplate. This may lead to loss of correction, increase of bearing load to the posterior implants or even in complete implant failure.
Conscious of these mechanical problems in osteoporotic bone and the lack of evidence supporting any treatment, the most recent publications describe a stand-alone cement augmentation in different techniques such as vertebroplasty or kyphoplasty and augmentation support of conventional instrumentation with a dorsal approach only.
Kyphoplasty is considered to be a relatively safe and effective treatment of osteoporotic thoracolumbar burst fractures. It is reported to be able to treat pain, restore vertebral body height, and reduce kyphosis without deterioration of fragment retropulsion. Also, vertebroplasty (VP) as a stand-alone procedure is reported to be safe in burst fractures. Like kyphoplasty, VP reportedly is able to restore vertebral body height and to reasonably correct kyphotic deformity. In addition, there are also biomechanical indications that cement injection might restore mechanical properties of the fractured vertebra. Therefore, some authors appraise VP as being adequate in eliminating the need for major operations. However, to our knowledge, further biomechanical investigation on kinematic effects of cement augmentation in incomplete burst fractures in osteoporosis is lacking. Also, the clinical value of the available reports is questionable in terms of evidence-based treatment.
Several published clinical reports describe a form of hybrid technique (hybrid augmentation, HA) by combining a dorsal short segment pedicle screw construction with an augmentation of the fractured vertebra. By augmenting the fractured vertebra, a stabilization of the anterior column is anticipated.
The HA technique seems to combine the advantages of 2 relatively less invasive procedures to treat this kind of fractures even in older and potentially osteoporotic patients where isolated dorsal instrumentation would possibly fail. The technique is expected to reduce kyphotic loss and instrumentation failure in comparison to stand-alone dorsal instrumentation. It is also expected to decrease the inherent morbidity, blood loss, operative time, length of the hospital stay, and costs associated with an anterior thoracic or abdominal approach. Complete percutaneous treatment using HA has also been reported in literature but there is little knowledge on the biomechanical effects of this technique.
Having been premised on the lack of conceptual clarity of treatment in incomplete burst fractures in osteoporosis and based on the little biomechanical knowledge we have so far, this study was designed to gain kinematic awareness in this challenging question using a validated method that experimentally inflicts incomplete burst fractures.
The objective of this study is to investigate the kinematic effects of different dorsal augmentation-related treatment options of incomplete burst fractures in osteoporosis.
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