Background
Methods
Derivation study 1
LSS (n = 137) | LDH (n = 97) | |
---|---|---|
Male (%) | 46 | 58 |
Female (%) | 54 | 42 |
Mean age (yr) | 68 | 41 |
Mean duration of symptoms (mo) | 21 | 5 |
Cauda equina type intermittent claudication | 50 | - |
Radicular type intermittent claudication | 87 | - |
Findings on MRI | ||
One level stenosis | 102 | 14 |
Two level stenosis | 23 | 0 |
Three level stenosis | 12 | 0 |
Derivation study 2
Radicular type (n = 55) | Cauda equina type (n = 60) | |
---|---|---|
Male (%) | 52 | 42 |
Female (%) | 48 | 58 |
Mean age (yr) | 68 | 71 |
Mean duration of symptoms (mo) | 19 | 32 |
Findings on MRI | ||
One level stenosis | 43 | 47 |
Two level stenosis | 12 | 10 |
Three level stenosis | 0 | 3 |
Validation study
LSS (n = 165) | The others (n = 85) | |
---|---|---|
Male (%) | 47 | 51 |
Female (%) | 53 | 49 |
Mean age (yr) | 71 | 48 |
Mean duration of symptoms (mo) | 28 | 24 |
Clinical impressions of patient condition | Cauda equina type 78 | LDH* 61 |
Radicular type 87 | DN* 13 | |
PAD* 11 | ||
Findings on MRI | ||
One level stenosis | 127 | 12 |
Two level stenosis | 31 | 2 |
Three level stenosis | 7 | 0 |
Statistical analysis
Results
Univariate analysis for predictors of LSS
LSS (-) (n = 97) | LSS (+) (n = 137) | Odds Ratio | 95% CI | p-value | |
---|---|---|---|---|---|
Age (years) > 50 | 20.6% | 94.9% | 71.50 | 28.9 – 176.9 | < 0.001 |
Gender (Female) | 42.0% | 54.0% | 1.60 | 0.95 – 2.71 | 07 |
Symptoms | |||||
Leg pain or numbness (+) | 87.6% | 94.9% | 2.62 | 0.99 – 6.93 | 0.045 |
Low back pain (+) | 72.2% | 65.0% | 0.72 | 0.41 – 1.26 | 0.245 |
Worse when walking but relieved by taking a rest | 18.6% | 94.2% | 70.77 | 29.39 – 170.4 | < 0.001 |
Numbness in both legs (+) | 15.5% | 24.8% | 1.80 | 0.92 – 3.54 | 0.083 |
Numbness in the soles of both feet (+) | 13.4% | 20.4% | 1.66 | 0.81 – 3.40 | 0.163 |
Numbness around the buttocks (+) | 9.3% | 15.3% | 77 | 77 – 4.05 | 173 |
Numbness without pain | 8.2% | 11.7% | 1.53 | 0.63 – 3.75 | 0.344 |
A burning sensation around the buttocks | 6.2% | 8.2% | 0.94 | 0.32 – 2.80 | 0.912 |
Walking nearly causes urination | 3.1% | 5.1% | 1.69 | 0.43 – 6.70 | 0.452 |
Worse when standing for a while | 24.7% | 84.7% | 11.38 | 6.20 – 20.91 | < 0.001 |
Symptoms improve on bending forward | 8.1% | 72.3% | 25.47 | 11.66 – 55.64 | < 0.001 |
Physical Examination | |||||
Straight Leg Raising test positive | 33.0% | 21.9% | 0.57 | 0.32 – 1.02 | 0.058 |
Symptoms induced by having patients bend forward (+) | 30.9% | 20.4% | 0.57 | 0.32 – 1.04 | 0.067 |
Symptoms induced by having patients bend backward (+) | 53.6% | 62.0% | 1.38 | 0.81 – 2.35 | 0.229 |
Abnormal manual muscle strength test 1) | 8.2% | 10.2% | 1.27 | 0.51 – 3.15 | 0.611 |
Sensory disturbance | |||||
(-) | 57.7% | 49.6% | reference | ||
(+) 2) | 37.1% | 45.3% | 1.40 | 0.82 – 2.38 | 0.214 |
Missing data | 5.2% | 5.1% | 0.99 | 0.30 – 3.22 | 0.988 |
Achilles tendon reflex | |||||
Normal | 51.5% | 48.2% | reference | ||
Abnormal 3) | 43.3% | 46.7% | 1.15 | 0.68 – 1.94 | 0.605 |
Missing data | 5.2% | 5.1% | 0.99 | 0.30 – 3.22 | 0.988 |
Patellar tendon reflex | |||||
Normal | 70.1% | 62.8% | reference | ||
Abnormal 3) | 24.7% | 32.1% | 1.44 | 0.80 – 2.58 | 0.221 |
Missing data | 5.2% | 5.1% | 0.99 | 0.30 – 3.22 | 0.988 |
Radicular type (n = 87) | Cauda Equina type (n = 50) | Odds Ratio | 95% CI | p-value | |
---|---|---|---|---|---|
Age (years) > 50 | 94.3% | 96.0% | 1.46 | 0.27 – 7.84 | 0.655 |
Gender (Female) | 51.7% | 56.0% | 1.20 | 0.60 – 2.38 | 0.608 |
Symptoms | |||||
Leg pain or numbness (+) | 97.7% | 96.0% | 0.56 | 0.08 – 4.14 | 0.569 |
Low back pain (+) | 65.5% | 62.0% | 0.86 | 0.42 – 1.77 | 0.679 |
Worse when walking but relieved by taking a rest | 96.6% | 96.0% | 0.86 | 0.14 – 5.31 | 0.868 |
Numbness in both legs (+) | 11.5% | 82.0% | 35.08 | 13.20 – 93.19 | < 0.001 |
Numbness in the soles of both feet (+) | 6.9% | 78.0% | 47.86 | 16.49 – 138.9 | < 0.001 |
Numbness around the buttocks (+) | 11.5% | 68.0% | 6.36 | 6.74 – 39.73 | < 0.001 |
Numbness without pain | 10.3% | 37.0% | 5.31 | 2.17 – 13.01 | < 0.001 |
A burning sensation around the buttocks | 6.9% | 34.0% | 6.95 | 2.52 – 19.19 | < 0.001 |
Walking nearly causes urination | 4.6% | 26.0% | 7.29 | 2.23 – 23.86 | < 0.001 |
Worse when standing for a while | 92.0% | 82.0% | 0.40 | 0.14 – 1.15 | 0.08 |
Symptoms improve on bending forward | 86.2% | 74.0% | 0.46 | 0.19 – 1.10 | 0.07 |
Physical Examination | |||||
Straight Leg Raising test positive | 21.8% | 22.0% | 1.01 | 0.44 – 2.34 | 0.983 |
Symptoms induced by having patients bend forward (+) | 19.5% | 22.0% | 1.16 | 0.49 – 2.73 | 0.731 |
Symptoms induced by having patients bend backward (+) | 63.2% | 58.0% | 0.80 | 0.39 – 1.64 | 0.546 |
Abnormal manual muscle strength test 1) | 9.2% | 12.0% | 1.35 | 0.44 – 4.13 | 0.602 |
Sensory disturbance | |||||
(-) | 49.4% | 50.0% | reference | ||
(+) 2) | 43.7% | 46.0% | 1.40 | 0.82 – 2.38 | 0.214 |
Missing data | 6.9% | 4.0% | 0.56 | 0.11 – 2.90 | 0.486 |
Achilles tendon reflex | |||||
Normal | 65.5% | 30.0% | reference | ||
Abnormal 3) | 27.6% | 66.0% | 5.10 | 2.41 – 10.79 | < 0.001 |
Missing data | 6.9% | 4.0% | 0.56 | 0.11 – 2.90 | 0.486 |
Patellar tendon reflex | |||||
Normal | 63.2% | 62.0% | reference | ||
Abnormal 3) | 29.9% | 34.0% | 1.21 | 0.57 – 2.54 | 0.617 |
Missing data | 6.9% | 4.0% | 0.56 | 0.11 – 2.90 | 0.486 |
A self-administered, self-reported history questionnaire (SSHQ)
Clinical prediction rule
Validity
Estimate | ||
---|---|---|
Index | Derivation Data Set (n = 234) | Validation Data Set (n = 250) |
Sensitivity | 0.855 | 0.843 |
Specificity | 0.791 | 0.781 |
Likelihood Ratio | ||
Positive Test Result | 1.951 | 1.886 |
Negative Test Result | 0.201 | 0.214 |
Area under the ROC curve | 0.797 | 0.782 |