Spinal instability (overview)

Spinal instability is a broad term with no generally agreed-upon definition but can be thought of the potential for or actual abnormal segmental spinal motion. 

Terminology

Spinal microinstability refers to abnormal segmental movement without bony changes ¹. 

Pathology

Spinal instability is best thought of due to its etiology due to different clinical presentations, pathogenesis and management. Broadly, the three most important types are ²:

• degenerative spinal instability
• traumatic spinal instability
• oncological spinal instability

There are other causes of spinal instability including infectious, inflammatory and iatrogenic ¹.