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The Egyptian Journal of Neurology, Psychiatry and Neurosurgery

Table 6 Comparison of NASS classification and the degree of nerve root compression

From: Correlation between lumbar spinal canal magnetic resonance imaging grading systems and parameters in lumbar spinal canal compromise

  

Normal

Asymmetric bulge

Diffuse bulge

Focal protrusion

Extrusion

p-value

L3–4

       

 Number

 

42

10

46

2

0

 

  Central spinal canal grading

Median [IQR]

0 [0–0]b,c

2 [2]a

2 [1–3]a

0 [0–0]

–

 < 0.001*

 

Min–Max

(0–1)

(1–3)

(0–3)

(0–0)

–

 

  Grade of Rt. LSC

Median [IQR]

0 [0–0]b,c

2 [1, 2]a

2 [1–3]a

1 [1]

–

 < 0.001*

 

Min–Max

(0–1)

(0–3)

(0–3)

(1–1)

–

 

  Grade of Lt. LSC

Median [IQR]

0 [0–0]b,c

1 [1, 2]a

2 [1, 2]a

0 [0–0]

–

 < 0.001*

 

Min–Max

(0–1)

(0–3)

(0–3)

(0–0)

–

 

  Grade of Rt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]b

1 [0–2]a

0 [0–1]

0 [0–0]

–

0.013*

 

Min–Max

(0–1)

(0–2)

(0–3)

(0–0)

–

 

  Grade of Lt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]b

1 [0–1]a

0 [0–0]

0 [0–0]

–

0.005*

 

Min–Max

(0–0)

(0–2)

(0–3)

(0–0)

–

 

L4–5

       

 Number

 

12

24

56

4

4

 

  Central spinal canal grading

Median [IQR]

0 [0–0]c

2 [0–3]

3 [1–3]a

1 [0–2]

2 [1–3]

0.003*

 

Min–Max

(0–1)

(0–3)

(0–3)

(0–2)

(1–3)

 

  Grade of Rt. LSC

Median [IQR]

0 [0–0]b,c

2 [1–3]a

3 [2, 3]a

1 [1]

2 [1, 2]

 < 0.001*

 

Min–Max

(0–0)

(0–3)

(1–3)

(1–1)

(1–2)

 

  Grade of Lt. LSC

Median [IQR]

0 [0–0]b,c

2 [2, 3]a

3 [2, 3]a

3 [2, 3]

2 [1, 2]

 < 0.001*

 

Min–Max

(0–0)

(0–3)

(0–3)

(2–3)

(1–2)

 

  Grade of Rt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]c

0 [0–1]

1 [0–2]a

0 [0–0]

0 [0–0]

0.027*

 

Min–Max

(0–0)

(0–2)

(0–3)

(0–0)

(0–0)

 

  Grade of Lt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]c

0 [0–1]

1 [0–2] a

1 [0–2]

1 [0–1]

0.046*

 

Min–Max

(0–0)

(0–2)

(0–3)

(0–2)

(0–1)

 

L5–S1

       

 Number

 

20

22

32

26

0

 

  Central spinal canal grading

Median [IQR]

0 [0–1]c

1 [1, 2]

1 [1, 2]a

2 [0–3]

–

0.028*

 

Min–Max

(0–1)

(0–3)

(0–3)

(0–3)

–

 

  Grade of Rt. LSC

Median [IQR]

0 [0–0]c

1 [0–3]

2 [2, 3]a

0 [0–2]

–

0.001*

 

Min–Max

(0–1)

(0–3)

(0–3)

(0–3)

–

 

  Grade of Lt. LSC

Median [IQR]

0 [0–0]b,c

2 [1–3]a

2 [2, 3]a,d

0 [0–2] c

–

 < 0.001*

 

Min–Max

(0–1)

(0–3)

(1–3)

(0–3)

–

 

  Grade of Rt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]c

1 [0–2]

1 [0–2] a

0 [0–1]

–

0.029*

 

Min–Max

(0–0)

(0–2)

(0–3)

(0–2)

–

 

  Grade of Lt. lumbar foraminal stenosis

Median [IQR]

0 [0–0]b,c

1 [0–2] a

1 [0–2]a

0 [0–1]

–

0.025*

 

Min–Max

(0–0)

(0–3)

(0–3)

(0–3)

–

 
  1. IQR interquartile range; Max maximum; Min minimum
  2. *Significant at p < 0.05
  3. aSignificant difference from the normal disc
  4. bSignificant difference from asymmetric bulge
  5. cSignificant difference from diffuse bulge
  6. dSignificant difference from focal protrusion; categories with less than 5 patients were not included in the statistical test
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