Table 1

Sites of measurement, measurement points and radiologic definitions for central lumbar spinal stenosis

Imaging method

Author

Site of measurement

Level, where measured (measurement points)

Definition of stenosis (cut-off values)


MRI


Antero-posterior diameter of spinal canal


Fukusaki [22]

Not reported

< 15 mm


Koc [23]

Not reported

< 12 mm


Mid-sagittal diameter of thecal sac


Herzog [15]

Midbody of each vertebra

Compression of thecal sac area in % of normal mid-sagittal diameter:

Grade 1: anterior < 15%

posterior < 10%

Grade 2: anterior 15 - 30%

posterior 10 - 20%

Grade 3: anterior > 30%

posterior > 20%


Cross-sectional area of dural tube or sac


Hamanishi [24]

Intervertebral levels: L2/3, L3/4, L4/5

< 100 mm2, at more than two of three intervertebral levels


Mariconda [25]

Not reported

< 130 mm2


Laurencin [26]

Motion segment: Intervertebral disc level coincident with flexible joint;

Stable segment:

Level coincident with the mid-pedicle unaffected by stenosis

Stenosis ratio:

Cross-sectional area of dural sac of motion segment divided by stable segment cross-sectional dural sac area:

Level: L3-L4 < 0.66

L4-L5 < 0.62

L5-S1 < 0.73


Ligamentous interfacet distance


Herzog [15]

Distance between the innner surface of flaval ligaments on a line connecting the joint space of facet joints at the level of the intervertebral disc

< 10 mm (L2 - L3)

< 10 mm (L3 - L4)

< 12 mm (L4 - L5)

< 13 mm (L5 - S1)


Transverse diameter of spinal canal


Koc [23]

Not reported

< 15 mm


Ullrich [27]

4 zones of measurement:

upper, middle, lower zone of vertebral body and disk space

< 16 mm



CT


Antero -posterior diameter of spinal canal


Bolender [28]

5 mm intervals from L2 to L5

< 13 mm


Haig [4]

Not reported

≤ 11.95 mm


Lee [29]

Not reported

< 15 mm (suggesting narrowing)

< 10 mm (usually diagnostic)


Ullrich [27]

Four zones of measurement:

Upper, middle, lower zone of vertebral body and disk space

< 11.5 mm


Verbiest [30]

Not reported

< 12 mm (relative)

< 10 mm (absolute)


Antero-posterior diameter of dural sac


Kalichman [3]

Midvertebral body level

10 - 12 mm (relative)

< 10 mm (absolute)


Herzog [15]

Midbody of each vertebra

Compression of thecal sac area in % of normal mid-saggital diameter:

Grade 1: anterior < 15%

posterior < 10%

Grade 2: anterior 15 - 30%

posterior 10 - 20%

Grade 3: anterior > 30%

posterior > 20%


Jönsson [31]

Disc level

≤ 10 mm


Cross-sectional area of dural sac


Bolender [28]

5 mm intervals from L2 to L5

100 - 130 mm2 (early stenosis)

< 100 mm2 (present stenosis)


Laurencin [26]

Motion segment: Intervertebral disc level coincident with flexible joint

stable segment:

Level coincident with the mid-pedicle unaffected by stenosis

Stenosis ratio:

Area of motion segment divided by stable segment area

Level: L3-L4 < 0.66

L4-L5 < 0.62

L5-S1 < 0.73


Schönström [32]

On each CT scan slice

< 100 mm2


Schönström [33]

Not reported

75 - 100 mm2 (moderate)

< 75 mm2 (severe)


Ullrich [27]

4 zones of measurement:

Upper, middle, lower zone of vertebral body and disk space

< 145 mm2



Ligamentous interfacet distance


Herzog [15]

Intervertebral disc level

< 10 mm (L2-L3)

< 10 mm (L3-L4)

< 12 mm (L4-L5)

< 13 mm (L5-S1)


Wilmink [34]

Pedicular, infrapedicular and/or disc level

< 11 mm (L4-L5)



Myelography


conventional

Antero-posterior diameter of contrast column


Airaksinen [35]

Narrowest point

> 12 mm

10 - 12 mm

< 10 mm

Subtotal block

Total block


Bolender [28]

Intervertebral level

< 13 mm


Herno [36]

Not reported

< 12 mm


Jönsson [31]

Disc level

≤ 10 mm




Sortland [37]

Disc level

< 10.5 mm (lower limit)

< 5.5 - 7 mm (considerable)


Verbiest [38]

Superior and inferior boarders of the laminae

10 - 12 mm (relative)

< 10 mm (absolute)


Myelo-CT

Mariconda [25]

Not reported

< 130 mm2


Steurer et al. BMC Musculoskeletal Disorders 2011 12:175   doi:10.1186/1471-2474-12-175

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