1. Modeling Survival After Surgery On
The Metastatic Spine
Ahmer Ghori MD, Dana Leonard BA, Andrew Schoenfeld MD, Ehsan Saadat MD, Mitch B Harris MD
Ahmer K Ghori MD
Harvard University Orthopaedic Surgery Program

2. My GoalToday
 Review the past and present state of
managing metastatic spine.
 Discuss how our model may improve the
present state.

3. Historical: No advantage with surgery
Present: Surgery helps
Limitation: Can’t predict post op survival
Who to operate on?
Our Model
Future: Patient specific management
Evolution of
spinal
instrumentation
Patient
Specific
Variables
Predict survival
reliably

4. Historic Management:Why no surgery ?
 Laminectomy was the only surgical option.
 No difference in laminectomy + radiation versus
radiation alone with regard to:
 pain relief
 ambulation
 sphincter function.
Young et al 1980

5. Paradigm Shift
 Evolution of modern spinal instrumentation.
Wider decompressions
&
Robust stabilization

6. Modern Literature
Surgery helps in managing metastatic spine
Pain.
Ambulation.
Maintain independence at end of life.
Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial. The Lancet.
2005;366(9486):643–648. doi:10.1016/S0140-6736(05)66954-1.

7. Present Limitations
 Choosing surgical candidates
 Not a reliable process.
 Existing models:
 Do not predict survival reliably !
 Correlation with survival 20-50 %
Ragel, B. T. et al. Life Expectancy and Metastatic Spine Scoring Systems: An Academic Institutional Experience. J Spinal Disord Tech
(2014).
Wang M, Bünger CE, Li H, Wu C, Høy K, Niedermann B, et al. Predictive value of Tokuhashi scoring systems in spinal metastases,
focusing on various primary tumor groups: Evaluation of 448 patients in the Aarhus spinal metastases database. Spine 2012;37: 573-
582.

8. Harrington Score

9. Tokuhashi Score

10. Tomita Score
Tomita et al. Surgical strategy for spinal metastases. Spine (2001) vol. 26 (3) pp. 298-306

11. Modified Bauer Score

12. Existing scoring systems do not
capture patient’s overall health state.
Ghori et al 2015
Why can’t we predict survival ?

13. Let’s consider a hypothetical scenario
Bauer Score: 4
Can we predict post op
survival from a score of 4
alone?
Consider 2 patients
Female
• Breast cancer
• No visceral metastases
• Solitary spine metastasis

14. Modified Bauer Score 4
Case 1
 First patient is :

15. • Young
• Can Ambulate
• Normal
nutrition
status.
Modified Bauer Score 4
Case 1

16. Modified Bauer Score 4: Case 2
 Second patient is:

17. • Old.
• Cannot ambulate.
• Poor nutritional status.
Modified Bauer Score 4
Case 2

18.  Both patients have a Bauer score of 4 !
 Differences will affect survival
 Need a model that is more specific.
Existing Models: Shortcoming
VS.

19. Hypothesis
Model
Quantifies patient
health status
Predict post op
survival reliably
Ghori et al 2015

20. Methods
 Retrospective review at four participating
institutions (BIDMC, BWH, MGH, Dartmouth).
 Identify patients who had undergone spine surgery
for metastatic disease between 2007 and 2013.
 Over 300 patients across 5 years included.
Ghori et al 2015

21. Variables we studied
 Main predictors of survival we studied
 Pre-operative modified Bauer score
 Pre- operative ambulatory status
 Pre-operative serum albumin level.
 Pre-operative serum creatinine level.
 Primary tumor type.
 Demographics: age, sex, race.
 Number of comorbidities.
 We coined these “healthiness states”
Ghori et al 2015

22. Ghori et al 2015: Our Model
 Analyzed all permutations of these three variables.
 Chose combination which has best correlation with survival.
 High Bauer score (3,4): 2 points
 Intact ambulatory status: 1 point
 Normal serum albumin level : 1 point
 Ceiling score of 3.
Ghori et al 2015

23. Ghori et al 2015: Model
3
2
1
0

24. Ghori et al 2015
 Our Model was able to explain 74% of the variation
in 1-year survival.
 What does that mean?
 In contrast existing scoring systems : 20- 50 %
correlation with survival
Ragel, B. T. et al. Life Expectancy and Metastatic Spine Scoring Systems: An Academic Institutional Experience. J Spinal Disord Tech (2014).
Wang M, Bünger CE, Li H, Wu C, Høy K, Niedermann B, et al. Predictive value of Tokuhashi scoring systems in spinal metastases, focusing on various
primary tumor groups: Evaluation of 448 patients in the Aarhus spinal metastases database. Spine 2012;37: 573-582.

25. Our Model
 Practical advantage ?
 Let us apply it to our two cases.

26. High modified Bauer
score and
1. Intact ambulation
2. Normal albumin
78% survival
Modified
Bauer Score
(4):
59% survival
Case 1:Bauer 4

27. High modified Bauer
score BUT
1. CANNOT ambulate
2. Low albumin
32% survival
Modified
Bauer Score
(4):
59% survival
Case 2:Bauer 4

28. Ghori et al 2015
Modified Bauer Score (4): 59%
No additional heath states: 30 %
Modified Bauer Score (4): 59%
Intact Ambulation/Normal albumin: 78 %

29. Ghori et al 2015
30% Vs. 78% survival: big difference !
Capture patient health state Tell apart patients predict survival reliably

30. Our Model: Advantages
 Simple to apply.
 Superior to existing models in predicting survival.
 300 patients in our analysis:
 one of the largest cohorts in literature.

31. Our Model: Limitations
 Retrospective nature of our data.
 Model developed from surgical patients so may not
be extrapolated to non-surgical patients.

32. Future Direction
 Studies to validate our model by applying it to:
 Different databases.
 Prospectively studying it.

33. Managing Spine Metastases
Where did we come from?
Where are we going?

34. Historical: No benefit with Surgery
Present : Surgery – too much ?
 Who to operate on?
Our Model
Future approach: Improve patient selection
Operate on the RIGHT PATIENT
Evolution of
spinal
instrumentation
Include Patient
“Health State”
Predict survival
reliably