This study evaluates minimally invasive vertebral augmentation combined with percutaneous fixation for the treatment of severe thoracolumbar burst fractures. Traditionally, fractures with a Load Sharing Classification (LSC) score ≥7 require corpectomy, which is associated with significant morbidity. Newer techniques, such as vertebral expansion devices, may restore vertebral height and alignment while reducing the need for invasive anterior procedures. This study aims to assess their effectiveness in this population.

Burst fractures account for approximately 17% of thoracolumbar fractures occurring after high-energy trauma. They are characterized by collapse of the anterior column, leading to loss of vertebral height and a local kyphotic deformity. Involvement of the middle column is a key factor in mechanical instability and largely explains the neurological risk, thus giving burst fractures a particular status among thoracolumbar injuries

In the 1990s, McCormack developed the Load Sharing Classification (LSC) to guide treatment strategy. A score below 7 supported isolated posterior fixation, whereas a score of 7 or higher led to the recommendation of a more invasive approach, including upfront corpectomy combined with supplementary anterior grafting to prevent early construct failure . Grobost demonstrated that corpectomies performed upfront yielded better functional outcomes than those performed secondarily in the context of pseudarthrosis . Although corpectomies provide reliable restoration of the anterior column, they are associated with significant morbidity, prompting the search for less invasive alternatives capable of restoring vertebral height and kyphosis while limiting complications.

Today, newer minimally invasive techniques allow reduction of vertebral height loss and local kyphosis while decreasing the mechanical load on posterior instrumentation . The systematic need for a major anterior procedure (grafting or corpectomy) may therefore be reconsidered. Among these techniques, vertebral expansion devices such as SpineJack have demonstrated the ability to effectively restore vertebral body height and maintain correction over time, particularly when combined with short posterior fixation.

Since 2005, publications on burst fractures have been predominantly limited to meta-analyses, with few new clinical series. Furthermore, available studies mainly focus on fractures of moderate severity, resulting in a lack of data on more severe fractures with an LSC score ≥ 7.

The aim of this study is to evaluate the clinical and radiological outcomes of patients treated at Grenoble Alpes University Hospital for thoracic and lumbar spine burst fractures with a Load Sharing Classification (LSC) score ≥7, managed with vertebral augmentation and percutaneous fixation.

Our hypothesis is that the combined use of percutaneous posterior fixation and anterior vertebral augmentation provides satisfactory clinical and radiological outcomes, thereby avoiding the need for corpectomy in thoracolumbar burst fractures (LSC ≥7).

DESIGN OF THE STUDY :Descriptive, single-center, observational cohort study, both retrospective and prospective, without a control group.

Inclusion Criteria:

• Adult patient at the time of the fracture.
• Patient who underwent posterior fixation (+1/-1 levels) combined with anterior vertebral augmentation:

Fracture with a Load Sharing Classification (LSC) score ≥ 7 Single vertebral level involved Percutaneous surgery

• Preoperative CT scans (thoracic and lumbar spine)
• Postoperative CT scans (thoracic and lumbar spine)

Exclusion Criteria:

• Persons deprived of liberty by judicial or administrative decision, or persons under legal protection measures.
• Non-inclusion criteria include:

Performance of a laminectomy Pathological fractures Fractures classified as type C or B2 according to the AO Spine classification Presence of severe scoliosis Neurological deficit More than one vertebral fracture

In this study, all adult patients treated for thoracic and lumbar spine fractures with a Load Sharing Classification (LSC) score ≥ 7, who underwent posterior fixation (+1/-1 levels) combined with anterior vertebral augmentation, will be eligible for inclusion.

Epidemiological data, preoperative management, AO Spine classification [1], operative data, and radiological findings are collected and analyzed.

Data collection is performed using patients' medical records and during a follow-up telephone visit.