This observational study will evaluate how degenerative changes in the facet joints and intervertebral discs develop over time after treatment of AOSpine type A2, A3, and A4 fractures of the thoracolumbar junction. Patients treated conservatively and patients treated surgically will be compared with each other and with a control group of patients who underwent repeated computed tomography examinations for reasons unrelated to traumatic or degenerative spinal disease.

The study will assess computed tomography findings at the injured spinal motion segment and adjacent segments, including facet joint degeneration, intervertebral disc degeneration, signs of ankylosis, facet joint space parameters, and facet joint angle. Clinical outcomes in the fracture cohort will be evaluated using pain scores and validated questionnaires. The purpose of the study is to identify factors associated with progression of degenerative changes after thoracolumbar junction fractures and to clarify whether treatment method is associated with long-term degeneration of the injured and adjacent spinal motion segments.

This is an ambispective longitudinal comparative cohort study designed to evaluate the development and progression of degenerative changes in the facet joints and intervertebral discs after treatment of traumatic fractures of the thoracolumbar junction.

The fracture cohort will include adult patients with AOSpine type A2, A3, or A4 fractures of the thoracolumbar junction who were treated at the N.V. Sklifosovsky Research Institute for Emergency Medicine. Patients will be analyzed according to treatment strategy, including conservative treatment and surgical treatment without disruption of the posterior supporting column. Surgical treatment may include anterior fusion, transpedicular fixation, or combined procedures without direct posterior decompression. Retrospective medical records and imaging data will be reviewed, and available patients will be invited for follow-up clinical and radiological assessment.

A control cohort will include adult patients who underwent at least two computed tomography examinations covering the thoracolumbar junction for conditions unrelated to traumatic or degenerative spinal disease. The interval between computed tomography examinations must be at least 1 year.

Radiological assessment will be performed using computed tomography. The analysis will include the injured spinal motion segment and adjacent segments. Imaging parameters will include facet joint degeneration according to Pathria criteria, intervertebral disc degeneration with assessment of ankylosis, facet joint space width, facet joint angle, facet tropism, fracture type according to the AOSpine classification, bisegmental Cobb angle, anterior vertebral body height, vertebral body index, relative spinal canal stenosis, pedicle screw position, facet joint violation by pedicle screws, radiological evidence of fracture healing or pseudarthrosis, implant-associated complications, and sagittal balance, as applicable.

Clinical outcomes in the fracture cohort will be assessed using the Visual Analog Scale for pain, the Oswestry Disability Index, and the SF-36 quality-of-life questionnaire.

The primary purpose of the study is to compare the longitudinal dynamics of degenerative changes in the facet joints and intervertebral discs between patients treated conservatively, patients treated surgically, and patients without traumatic or degenerative thoracolumbar junction disease. The study will also explore clinical and radiological factors associated with progression of degeneration at the injured and adjacent spinal motion segments.

Inclusion Criteria:

Conservative Treatment Cohort:

• Age 18 to 50 years.
• Acute or subacute traumatic fracture of the thoracolumbar junction at the start of treatment.
• AOSpine type A2, A3, or A4 fracture.
• No clinical evidence of nerve root or spinal cord compression at the injured level.
• Conservative treatment of the thoracolumbar junction fracture.
• Minimum follow-up period of 1 year.
• Written informed consent for prospective follow-up or additional study procedures, when applicable.

Surgical Treatment Cohort:

• Age 18 to 50 years.
• Acute or subacute traumatic fracture of the thoracolumbar junction at the start of treatment.
• AOSpine type A2, A3, or A4 fracture.
• No clinical evidence of nerve root or spinal cord compression at the injured level.
• Surgical treatment performed without disruption of the posterior supporting column.
• Surgical treatment may include anterior fusion, transpedicular fixation, or combined surgery without direct posterior decompression.
• Minimum follow-up period of 1 year.
• Written informed consent for prospective follow-up or additional study procedures, when applicable.

Control Cohort:

• Age 18 to 50 years.
• At least two computed tomography examinations covering the Th9-L4 vertebral levels.
• Interval of at least 1 year between computed tomography examinations.
• Computed tomography performed for reasons unrelated to traumatic or degenerative thoracolumbar junction disease.
• No imaging artifacts at the spinal levels included in the study assessment.

Exclusion Criteria:

Conservative Treatment Cohort:

• Severe combined trauma.
• Severe concomitant disease.
• Systemic bone or joint disease associated with changes in facet joints or intervertebral discs, including diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, rheumatoid arthritis, or similar disorders.
• Verified osteoporosis.
• Bone density of thoracolumbar vertebrae less than 100 Hounsfield units.
• Previous spine surgery.
• American Society of Anesthesiologists physical status class 4 or 5.
• Participation in another clinical study related to treatment of spinal disease or spinal trauma.
• Withdrawal of informed consent, when applicable.

Surgical Treatment Cohort:

• Severe combined trauma.
• Severe concomitant disease.
• Systemic bone or joint disease associated with changes in facet joints or intervertebral discs, including diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, rheumatoid arthritis, or similar disorders.
• Verified osteoporosis.
• Bone density of thoracolumbar vertebrae less than 100 Hounsfield units.
• Previous spine surgery.
• Direct posterior decompression or other surgery disrupting the posterior supporting column.
• American Society of Anesthesiologists physical status class 4 or 5.
• Participation in another clinical study related to treatment of spinal disease or spinal trauma.
• Withdrawal of informed consent, when applicable.

Control Cohort:

• Complicated fracture of any spinal region.
• Combined trauma or severe concomitant disease limiting patient mobility.
• Systemic bone or joint disease associated with changes in facet joints or intervertebral discs, including diffuse idiopathic skeletal hyperostosis, ankylosing spondylitis, rheumatoid arthritis, or similar disorders.
• Grade 4 facet joint degeneration according to the Pathria classification at the studied levels.
• Bone density of thoracolumbar vertebrae less than 100 Hounsfield units.
• Previous spine surgery, including surgery without implants.
• Spinal fracture with injury to the posterior supporting column.
• Participation in another clinical study related to treatment of spinal disease or spinal trauma.

The study population will include adults aged 18 to 50 years enrolled in three cohorts. The conservative treatment cohort will include patients with acute or subacute AOSpine type A2, A3, or A4 thoracolumbar junction fractures treated nonoperatively. The surgical treatment cohort will include patients with the same fracture types treated surgically without disruption of the posterior supporting column. The control cohort will include adults without traumatic or degenerative thoracolumbar junction disease who underwent at least two computed tomography examinations covering Th9-L4 for unrelated clinical indications, with an interval of at least 1 year between examinations.

Individual participant data will not be shared. The study will use clinical records, imaging data, and questionnaire results, which may contain sensitive health information. Data obtained during the study will be stored at the N.V. Sklifosovsky Research Institute for Emergency Medicine. Study results will be reported in aggregate form in peer-reviewed publications and scientific presentations.