Clinical calculator
SINS Calculator
Spinal Instability Neoplastic Score
The Spinal Instability Neoplastic Score grades the mechanical stability of a spine affected by tumour by adding six components — location, mechanical pain, lesion quality, alignment, vertebral body collapse and posterolateral involvement — to a total from 0 to 18, where 0 to 6 is stable, 7 to 12 is indeterminate and 13 to 18 is unstable, and any total of 7 or more warrants surgical consultation.
What the SINS score means
SINS scores run from 0 to 18, where a lower score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Stable0–6
No surgical consultation required on stability grounds alone. Oncological management proceeds as planned.
- Indeterminate — possibly impending instability7–12
Surgical consultation is recommended. Indeterminate does not mean borderline-stable: it means the imaging and the symptoms together do not settle the question, which is a reason to ask, not to wait.
- Unstable13–18
Surgical consultation is recommended.
Published criteria and reliability
The published cut-offs that define this instrument, and the measured agreement between observers using it. Each is reported with the population it was derived in.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| Criterion | Total 0 to 6 — stable | — | Adults with neoplastic involvement of the spine | — | Fisher CG 2010 |
| Criterion | Total 7 to 12 — indeterminate or potentially unstable; surgical consultation recommended | — | Adults with neoplastic involvement of the spine | — | Fisher CG 2010 |
| Criterion | Total 13 to 18 — unstable; surgical consultation recommended | — | Adults with neoplastic involvement of the spine | — | Fisher CG 2010 |
| Criterion | Reliability of the three-category classification is high among both spine surgeons and radiation oncologists, and the score identifies patients warranting surgical consultation with high sensitivity | — | Spine surgeons, radiologists and radiation oncologists applying SINS to spinal tumour cases | — | Fourney DR 2011 |
Criterion is a published cut-off, definition or performance figure belonging to a classification or decision rule — it is not a change score and should not be read as one.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Six components are scored and added. Location scores 3 for a junctional level (occiput to C2, C7 to T2, T11 to L1, L5 to S1), 2 for the mobile spine (C3 to C6, L2 to L4), 1 for the semi-rigid thoracic spine (T3 to T10) and 0 for the rigid sacrum (S2 to S5). Mechanical pain — pain relieved by lying down, or provoked by movement and axial loading — scores 3; occasional pain that is not mechanical scores 1; a pain-free lesion scores 0. Bone lesion quality scores 2 for lytic, 1 for mixed and 0 for blastic. Radiographic alignment scores 4 for subluxation or translation, 2 for a de novo kyphotic or scoliotic deformity and 0 for normal alignment. Vertebral body collapse scores 3 for more than 50% collapse, 2 for less than 50% collapse, 1 for no collapse where more than 50% of the body is involved by tumour, and 0 otherwise. Posterolateral involvement — fracture or tumour replacement of the facet, pedicle or costovertebral joint — scores 3 if bilateral, 1 if unilateral and 0 if absent. The total runs from 0 to 18: 0 to 6 is stable, 7 to 12 is indeterminate or potentially unstable, and 13 to 18 is unstable. A total of 7 or more is the trigger for surgical consultation. Several components have gaps in their point values — pain has no 2, alignment has no 1 or 3 — because the weights came from expert consensus rather than from a regression, and they should not be interpolated.
Missing data
All six components must be assessed. There is no imputation rule, and because unanswered components contribute nothing, an incomplete total can only be too low — which is the dangerous direction for a score whose purpose is to trigger a referral. Do not act on a partial total that falls below 7.
Instrument profile
- Developer
- Charles G. Fisher and the Spine Oncology Study Group
- Institution
- University of British Columbia, Vancouver, Canada
- First published
- 2010
- Custodian
- Spine Oncology Study Group
- Items
- 6
- Response format
- Six clinician-assessed components, added
- Score range
- 0 to 18
- Direction
- Lower score = better
- Completion time
- About 3 minutes
- Age range
- Adults
- Regions
- Spine
- Conditions
- Spinal metastasis, Vertebral metastatic disease, Pathological vertebral fracture, Primary spinal tumour, Multiple myeloma of the spine
- Procedures
- Spinal instrumentation and fusion, Vertebroplasty, Kyphoplasty, Separation surgery, Stereotactic body radiotherapy to the spine
- Observer agreement
- Intraobserver agreement for the three-category classification is high across specialties
- Validity
- Built for a specific decision — whether to involve a spine surgeon — and validated against that decision rather than against a biomechanical measurement. Its adoption by radiation oncology is the practical point: it gives a non-surgeon a defensible reason to refer before treating a lesion with radiotherapy alone.
- Reliability
- Agreement is highest for the three-category output and lower for the exact numeric total, so the category rather than the number is what should be recorded and communicated.
When to use the SINS
Well suited to
- Assessing a patient with a spinal metastasis before radiotherapy, systemic therapy or a procedure, to decide whether a spine surgeon should see them first.
- Documenting a referral decision in a form that a multidisciplinary tumour board will read consistently.
- Screening in a radiation oncology or medical oncology clinic, which is the setting the score was designed to serve.
Limitations and poor fits
- Deciding what operation to perform, or whether to operate at all — the score triggers a conversation, it does not plan one.
- Grading epidural spinal cord compression, which is what the Bilsky scale is for, or estimating prognosis, which is what the Tokuhashi and Tomita systems attempt.
- Non-neoplastic instability — degenerative, traumatic and infective instability are different problems with different frameworks.
- Acting on a total assembled from incomplete data: missing components only ever lower the score, which is the direction that wrongly reassures.
SINS compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| Mirels | 4 | 4–12 | Mirels' score estimates the risk of pathological fracture through a long bone metastasis by scoring four variables — site, pain, radiographic appearance and lesion size — from 1 to 3 each, giving a total from 4 to 12, where 9 or more is the conventional threshold for prophylactic fixation. |
| Meyerding | — | 0–100 | The Meyerding classification grades spondylolisthesis by the percentage of anterior translation of one vertebral body over the one below, measured on a standing lateral radiograph, from grade I at 25% or less through to grade V, spondyloptosis, beyond 100%. |
| TLICS | 3 | 1–10 | TLICS grades a thoracolumbar injury by adding three components — injury morphology scored 1 to 4, integrity of the posterior ligamentous complex scored 0 to 3, and neurological status scored 0 to 3 — giving a total from 1 to 10 in which 3 or less favours non-operative treatment, 4 is left to the surgeon’s discretion and 5 or more favours surgery. |
| Kellgren-Lawrence | 1 | 0–4 | The Kellgren-Lawrence classification grades radiographic osteoarthritis from 0 to 4 based on osteophyte formation, joint space narrowing, subchondral sclerosis and bone contour deformity, with grade 2 conventionally taken as the threshold for definite radiographic osteoarthritis. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
A published consensus scoring system, described in full in the peer-reviewed literature and reproduced throughout the spine oncology literature with no licensing programme attached. No licence is required.
References
- Fisher CG, DiPaola CP, Ryken TC, et al.. A novel classification system for spinal instability in neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology Study Group. Spine. 2010.
- Fourney DR, Frangou EM, Ryken TC, et al.. Spinal instability neoplastic score: an analysis of reliability and validity from the Spine Oncology Study Group. Journal of Clinical Oncology. 2011.
Editorial status
This page has not yet been signed off by a named clinical reviewer. The scoring logic is stated in full above so it can be independently verified, and every threshold is traceable to its source. See our editorial methodology.