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 two-column theory

Fails to appreciate some burst fracture instabilities

Kelly & Whitesides Refines the two-column model Classification guides treatment of neurologic deficit

Denis Development of the three-column 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

middle column is the primary determinant of mechanical stability of the thoracolumbar region of the spine.

Isolated fractures of– Transverse process. – Articular process. – pars interarticularis, or– Spinous process.

Denis- Minor injuries

Denis- Major injuries

Compression type

Denis- Major injuries

Burst Type

E

Seat belt type

Denis- Major injuries

Fracture dislocation typeDenis- Major injuries

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

McCormack 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-screw-based 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 ClassificationType A(compression)

AO ClassificationType B (Distraction)

AO ClassificationType 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.