Classification of Thoracolumbar spine injuries Abdulaziz Alomar MD

Classification of Thoracolumbar spine injuries Abdulaziz Alomar, MD, MSc FRCSC Assistant Professor and consultant Orthopaedic surgeon. KKUH, KSU

Historical Classification Systems System Summary Comments Nicoll Differentiates stable from unstable fractures Serves as a foundation for subsequent classification systems Holdsworth Modifies previous classification systems to include the mechanisms of injury and twocolumn theory Fails to appreciate some burst fracture instabilities Kelly & Whitesides Denis Refines the two-column model Classification guides treatment of neurologic deficit Development of the threecolumn model The middle column is the primary determinant of mechanical stability. Gertzbein et al. Suggests a posterior component, anterior component and body component Involves the vertebral body as it relates to kyphosis.

Denis • Goal: – To emphasize pathologic anatomy of different types of spinal injuries, each of which was based on a different mechanism of injury. – did not consider methods of treatment or the results.

Denis: Three-column model Anterior column- formed by the ALL, the anterior annulus, and the anterior portion of the vertebral body Middle osteoligamentous- the critical feature. Very important to spinal stability; consists of PLL, the posterior portion of the annulus, and the posterior aspect of the vertebral body Posterior column- includes the neural arch, facet joints and capsules, ligamentum flavum, and remaining ligamentious complex Denis F. Clin Orthop Relat Res. 1984

Denis: Middle-column concept • Developed to define burst fracture n middle column is the primary determinant of mechanical stability of the thoracolumbar region of the spine.

Denis- Minor injuries Isolated fractures of – Transverse process. – Articular process. – pars interarticularis, or – Spinous process.

Denis- Major injuries Compression type

Denis- Major injuries Burst Type E

Denis- Major injuries Seat belt type

Denis- Major injuries Fracture dislocation type Flexion rotation Flexion distraction Shear type

Load Sharing Classification • Created system in response to poor patient outcomes when the vertebral body sustained a disproportionately severe injury § Classification system grades: § § § Amount of damaged vertebral body Spread of the fragments in the fracture sight Amount of corrected kyphosis Mc. Cormack et al. Spine, 1994

Load Sharing Classification • Load-Sharing Classification: a straight-forward way to describe the amount of bony comminution in a spinal fracture • Can help the surgeon select short-segment pedicle-screwbased fixation using the posterior approach for less comminuted injuries and the anterior approach for those more comminuted injuries.

Load sharing classification

AO Classification • Based on the review of 1445 consecutive thoracolumbar injuries • Primarily based on pathomorphological criteria • Categories based on: – Main mechanism of injury – Pathomorphological uniformity – Prognostic aspects regarding healing potential Magerl et al. Eur Spine J. 1994.

AO Classification • Classification reflects progressive scale of morphological damage by which the degree of instability is determined • Consists of a 3 -3 -3 grid for sub-grouping injuries into three types: – A, B and C – Every type has three groups, each of which contains three subgroups with specifications Magerl et al. Eur Spine J. 1994.

AO Classification • Types have a fundamental injury pattern which is determined by the three most important mechanisms acting on the spine – Compression – Distraction – Axial torque Magerl et al. Eur Spine J. 1994.

AO Classification Type A(compression)

AO Classification Type B (Distraction)

AO Classification Type C (Torsion)

Examples of AO Classification

AO Classification-

AO Classification

AO Classification

Summary Currently no classification system that has achieved global clinical utility and acceptance.