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Chapter Summary
• Context: Traumatic injuries of the thoracic and lumbar spine represent the most frequent fractures of the entire vertebral axis, predominantly concentrating across the biomechanically vulnerable thoracolumbar junction (T10–L2). High-energy trauma (motor vehicle collisions, falls from height) affects younger populations with substantial risk of conus medullaris and cauda equina injury, whereas low-energy fragility fractures affect osteoporotic elderly individuals. The functional spinal unit comprises the anterior column (vertebral bodies, intervertebral discs, anterior and posterior longitudinal ligaments) and the posterior tension band (pedicles, lamina, facet joints, and the Posterior Ligamentous Complex [PLC: supraspinous, interspinous ligaments, ligamentum flavum, and facet capsules]). Classifications have evolved from mechanistic models (Denis three-column model, McCormack Load Sharing Classification) to the globally standardized AO Spine Thoracolumbar Classification and Thoracolumbar Injury Classification and Severity Score (TLICS). Multi-detector CT defines fracture morphology, comminution, and canal compromise, while MRI evaluates PLC disruption, cord contusion, and epidural hematoma. The central therapeutic challenge is distinguishing mechanically stable compression injuries amenable to functional bracing from unstable burst, distraction (Chance), or rotational translation fractures requiring open or percutaneous posterior pedicle screw instrumentation, anterior column cage reconstruction, or spinal decompression.
• Chapter Objective: To present the clinical evaluation, classification, biomechanical stability assessment, and non-operative/surgical management of thoracic and lumbar spine trauma. The reader should be able to apply the AO Spine Thoracolumbar Classification (Types A, B, C) and the TLICS scoring system; recognize the clinical and radiological hallmarks of posterior ligamentous complex (PLC) disruption; understand the indications for percutaneous versus open pedicle screw fixation, direct vs. indirect decompression, and anterior column reconstruction; and prevent post-traumatic kyphosis and neurological deterioration.
• Biomechanics and the Thoracolumbar Transition ZoneThe thoracolumbar junction (T10–L2) transitions from the rigid thoracic cage (coronal facets, kyphosis) to the mobile lumbar spine (sagittal facets, lordosis). Denis established the 3-column model (anterior, middle, posterior). Mechanical stability relies fundamentally on the integrity of the middle column (posterior vertebral body cortex and PLL) and the posterior tension band (PLC). Loss of middle column integrity (burst fracture) combined with PLC disruption results in progressive mechanical collapse and post-traumatic kyphotic deformity.
• AO Spine Thoracolumbar Classification SystemThe AO Spine system organizes injuries hierarchically into three primary morphological types: 1) Type A: Compression fractures (A0 minor non-structural, A1 wedge compression, A2 coronal split/pincer, A3 incomplete burst involving one endplate, A4 complete burst involving both endplates and posterior wall retropulsion); 2) Type B: Distraction injuries / Tension band failure (B1 transosseous Chance fracture through posterior elements and vertebral body, B2 osseoligamentous posterior tension band disruption, B3 hyperextension injury through anterior tension band/ALL); 3) Type C: Translation/Displacement in any plane (subluxation, dislocation, fracture-dislocation). Neurological status is classified from N0 (intact) to N4 (complete cord/conus deficit), and clinical modifiers include M1 (indeterminate PLC) and M2 (comorbidities/ankylosing spine).
• TLICS Score and Decision-Making AlgorithmsThe Thoracolumbar Injury Classification and Severity Score (TLICS) assigns points across three core categories: 1) Morphology (compression = 1, burst = 2, distraction = 3, translation/rotation = 4); 2) Neurological status (intact = 0, nerve root injury = 2, complete cord = 2, incomplete cord/conus = 3, cauda equina syndrome = 3); 3) PLC integrity (intact = 0, suspected/indeterminate = 2, disrupted = 3). A total TLICS score <=3 indicates non-operative management (early mobilization with or without a rigid TLSO brace); TLICS = 4 is indeterminate (surgeon discretion); and TLICS >=5 mandates surgical reduction and stabilization.
• Diagnostic Imaging and Clinical AssessmentMulti-detector CT with multiplanar reconstructions is the primary investigation to assess vertebral body height loss, sagittal kyphosis (Cobb angle), pedicle splay, and canal stenosis. MRI (STIR and T2-weighted sequences) is mandatory when physical examination reveals focal interspinous widening or palpation tenderness, demonstrating PLC hyperintensity (black line disruption of ligamentum flavum/supraspinous ligament). MRI also evaluates conus medullaris contusion and traumatic disc disruption.
• Management Principles: Conservative, Percutaneous, and Open ReconstructionNon-operative treatment (early ambulation, Jewett or molded TLSO brace, serial standing radiographs at 1, 2, and 6 weeks) is indicated for stable A1, A2, and neurologically intact A3 fractures with intact PLC and local kyphosis <15°–20°. Surgical treatment is indicated for unstable burst fractures (A4 with significant comminution), distraction injuries (B1, B2, B3), fracture-dislocations (Type C), or any fracture with progressive neurological deficit. Surgical options include minimally invasive percutaneous pedicle screw fixation (sparing paraspinal muscles in intact neurology), open posterior decompression and instrumentation with intermediate screws, and anterior or posterolateral corpectomy with expandable cage reconstruction for severe anterior load-bearing deficiency (McCormack Load Sharing score >=7).
• Clinical Application: In clinical practice, evaluate three interconnected factors: neurological deficit, PLC integrity, and anterior column comminution. In a patient with an L1 burst fracture, intact neurology, and intact PLC on MRI (TLICS 2), non-operative treatment with a molded TLSO brace and immediate protected ambulation yields functional outcomes equivalent to open surgery without operative morbidity. In contrast, if MRI reveals hyperintensity of the supraspinous ligament and ligamentum flavum (PLC disruption, AO Type B2 / TLICS 5), surgery is mandatory even in a neurologically intact patient, as non-operative bracing fails, leading to progressive kyphosis and chronic back pain. In patients with an A4 burst fracture and progressive neurological deficit from retropulsed bone fragments, urgent posterior decompression, postural ligamentotaxis reduction, and pedicle screw fixation within 24 hours provide excellent canal clearance and neurological recovery. In patients with high McCormack Load Sharing scores (>=7) undergoing short-segment posterior instrumentation, anterior column support (interbody cage) is necessary to prevent posterior hardware fatigue failure.
