Which anatomic structures are responsible for the reduction loss after hybrid stabilization of osteoporotic fractures of the thoracolumbar spine?

Abstract

Introduction: Hybrid stabilization is an accepted therapy strategy for unstable osteoporotic thoracolumbar fractures. However, a moderate reduction loss has been reported and it remains unclear which anatomic structure is responsible for the reduction loss. Methods: This retrospective study was performed at a level I trauma center. Patients aged 61 and older were stabilized using hybrid stabilization after suffering acute and unstable osteoporotic vertebral body fractures at the thoracolumbar spine. Posterior stabilization was done short-segmental and minimal invasive with cement-augmentation of all pedicle screws. The minimum follow-up has been 2 years. The outcome parameters were the reduction loss and the relative loss of height of both intervertebral discs adjacent to the fractured vertebral body, the fractured vertebral body and a reference disc (intervertebral disc superior of the stabilization) between the postoperative and latest lateral radiographs. Additionally, implant positioning and loosening was analyzed. Results: 29 mainly female (72%) patients (73.3 ± 6.0 years) were included. Fractures consisted of 26 incomplete burst fractures and 3 complete burst fractures of the thoracolumbar junction (Th11-L2: 86%) and the midlumbar spine. The mean follow-up time was 36 months (range: 24-58 months). The mean reduction loss was 7.7°(range: 1-25). The relative loss of heights of both intervertebral discs adjacent to the fractured vertebral body, the reference disc, and the central vertebral body were significant. Thereby, the relative loss of the superior disc height was significant higher compared to the reference disc. Additionally, only the relative loss of central vertebral body height and reduction loss correlated significantly. There were no signs of implant loosening in any patient. Conclusions: The mean reduction loss was moderate 3 years after hybrid stabilization of unstable osteoporotic vertebral fractures of the thoracolumbar spine. A significant loss of both adjacent disc heights and the central vertebral body was seen, with the highest loss in the superior adjacent disc significantly outranging the reference disc. The superior adjacent intervertebral disc and the central part of the fractured vertebral body seem to be responsible for the majority of reduction loss.

Posterior short segment fixation including the fractured vertebra combined with kyphoplasty for unstable thoracolumbar osteoporotic burst fracture

“…Different strategies of hybrid stabilization about the combination of cement augmentation accompanied with posterior instrumentation for the treatment for unstable osteoporotic burst fractures have been reported, most of the studies demonstrated satisfactory clinical and radiological results, however, loss of reduction was unavoidable, the rang can be high to 4.6° to 23°, the causes of reduction appear to be the structural and mechanical deficiency of the anterior-middle columns [ 20 , 21 ]. Recent study reported that the superior disc adjacent to the fractured vertebral body and the central part of the fractured vertebral body seem to be responsible for the majority of reduction loss, and this might be reduced by optimal cement technique and cement positioning between the upper and middle third of center and the anterior third of the fractured vertebral body [ 22 ].…”

Midterm outcome after posterior stabilization of unstable Midthoracic spine fractures in the elderly

“…Additionally, the authors found a significantly better vertebral body height restoration, significantly lower Cobb angles, and a reduced number of adjacent fractures after additional posterior stabilization compared to kyphoplasty of the fractured vertebral body alone. Spiegl et al [ 28 ] analyzed the structures which are responsible for the reduction loss after hybrid stabilization at the thoracolumbar junction and found the highest loss at the intervertebral disc adjacent to the fracture. Thus, the beneficial effect of a persistent restoration of the vertebral height on the sagittal alignment might be even more pronounced in the midthoracic spine based on the smaller intervertebral discs.…”

A Finite Element Study on the Treatment of Thoracolumbar Fracture with a New Spinal Fixation System

“…The traditional SSPF system replaces the fractured vertebral body by indirect traction. The fractured vertebral body can be effectively reduced by the traction of the fibrous annulus of the intervertebral disc, but the central bone mass of the anterior and middle column cannot be pulled, resulting in a central collapse defect, resulting in insufficient reduction [26,27]. Although the height and shape of the fractured vertebral BioMed Research International body are restored after indirect reduction, it is difficult to restore the trabecular structure in the vertebral body.…”