Schizas Classification

Grade

Characteristics

Degree of stenosis

A1

The nerve roots are located dorsally and occupy less than half of the dural sac area.

There is no or mild stenosis.

A2

The nerve roots are located dorsally and contact the Dura in a horseshoe-shaped configuration.

There is no or mild stenosis.

A3

The nerve roots are located dorsally and occupy more than half of the dural sac area.

There is no or mild stenosis.

A4

The nerve roots are located centrally and occupy a large portion of the dural sac area.

There is no or mild stenosis.

B

The nerve roots occupy the entire area of the dural sac. Cerebrospinal fluid can still be delineated between the nerve roots.

There is moderate stenosis.

C

The individual nerve roots can no longer be delineated. The dural sac shows a homogeneous gray signal without discernible Cerebrospinal fluid.

There is severe stenosis.

D

In addition to the lack of delineation of the nerve roots and the absent cerebrospinal fluid signal, no discernible epidural fat is seen posteriorly.

There is extreme stenosis.