Authors of section

Authors (on behalf of the AOSpine Knowledge Forum Tumor)

Ilya Laufer, JJ Verlaan

General Editor

Luiz Vialle

Open all credits

Evaluation of stability

1. Definition of stability

Spine instability due to cancer is defined as “Loss of spinal integrity as a result of a neoplastic process that is associated with movement-related pain, symptomatic or progressive deformity, and/or neural compromise under physiologic loads”.

2. Spinal neoplastic instability score (SINS)

Patients with tumor related mechanical instability who experience pain with movement may benefit from stabilization.

Evaluation of spinal stability in the setting of cancer is facilitated with the use of the Spinal Neoplastic Instability Score (SINS).

evaluation of stability

SINS scores range from 0-18.

0-6 : No mechanical instability.

7-12 : Indeterminate stability based on the SINS. Patients with who experience mechanical pain generally benefit from stabilization.

13-18 : Mechanically unstable fractures. Stabilization is normally required in consenting patients who are fit for surgery.

The SINS score is determined with the use of CT (preferred) and MRI scans.

Examples of findings are given below:

3. Bone lesions

Lytic bone lesion.

evaluation of stability

Mixed lytic and blastic bone lesion.

evaluation of stability

Blastic bone lesion.

evaluation of stability

4. Radiographic spinal alignment

Normal alignment

evaluation of stability

Subluxation/translation

evaluation of stability

De novo deformity

evaluation of stability

5. Vertebral body collapse

More than 50% vertebral body collapse.

evaluation of stability

Less than 50% vertebral body collapse.

evaluation of stability

No vertebral body collapse, but more than 50% vertebral body tumor involvement.

evaluation of stability

No vertebral body collapse, and less than 50% vertebral body tumor involvement (none of the above).

evaluation of stability

6. Posterolateral involvement of the spinal elements

Bilateral

evaluation of stability

Unilateral

evaluation of stability