Devin et al reported a model and nomogram for predicting return to work for a patient who has had cervical spine surgery. The authors are from multiple institutions in the United States.
Patient selection: status post cervical spine surgery
Outcome: return to month at 3 months after surgery
Parameters:
(1) age at surgery in years
(2) job arrangement
(3) education level
(4) employment
(5) occupational intensity
(6) worker's compensation
(7) baseline neck disability index (NDI) score, from 0 to 50
(8) symptom duration in months
(9) predominant symptom
(10) number of levels fused
points for baseline NDI score =
= (-0.01825 * ((score)^2)) - (1.145 * (score)) + 100.9
|
Parameter |
Finding |
Points |
|
age in years |
< 55 years |
18.7 |
|
|
55 to 65 years |
4.8 |
|
|
> 65 years |
0 |
|
job arrangement |
part-time |
0 |
|
|
full-time |
23.2 |
|
education level |
less than high school |
0 |
|
|
high school |
14 |
|
|
2-year college |
26.7 |
|
|
4-year college |
29.2 |
|
|
post college |
49.6 |
|
employment |
currently not working |
0 |
|
|
currently working |
57.4 |
|
occupational intensity |
heavy |
0 |
|
|
medium |
12.7 |
|
|
light |
27.1 |
|
|
sedentary |
31.9 |
|
workers compensation |
yes |
0 |
|
|
no |
37.4 |
|
symptom duration |
> 12 months |
0 |
|
|
3 to 12 months |
3.2 |
|
|
less than 3 months |
25.9 |
|
predominant symptom |
myelopathy |
0 |
|
|
mechanical |
14.7 |
|
|
radiculopathy |
27.7 |
|
levels fused |
3 to 5 levels |
0 |
|
|
2 levels |
22.3 |
|
|
1 level |
30.4 |
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 402.3
value of X =
= (0.02556 * (score)) - 5.329
probability of return to work =
= 1 / (1 + EXP((-1) * X))
Performance:
• The area under the ROC curve is 0.81.
