Magnetic resonance imaging findings of redundant nerve roots of the cauda equina

Table 1 Number of patients and reasons for their exclusion from the study

The reason for exclusion	n
Spinal or cranial surgery history	29
Poor image quality	3
Spondylodiscitis	2
Spinal metastasis	1
Stenosis due to synovial cyst	1
Total	36

Table 2 Cross-sectional areas of the dural sac at lumbar intervertebral disc levels in patients with spinal stenosis without redundant nerve roots and with redundant nerve roots of the cauda equina on lumbar magnetic resonance imaging

Intervertebral discal space levels	Cross-sectional area without redundant nerve roots of the cauda equina, mean ± SD dev (range) mm2	Cross-sectional area with redundant nerve roots of the cauda equina, mean ± SD dev (range) mm2
L2-L3	130.85 ± 38.56 (48.68-240.56)	93.84 ± 34.63 (39.40-194.50)
L3-L4	100.90 ± 31.50 (38.86-176.00)	68.87 ± 31.23 (25.42-164.59)
L4-L5	78.92 ± 22.69 (21.03-126.02)	61.05 ± 35.76 (14.94-163.92)
L5-S1	102.56 ± 43.27 (17.57-251.53)	97.11 ± 41.90 (15.05-211.13)

SD: Standard deviation.

Table 3 Association of localization level of redundant nerve roots with relative length of redundant nerve roots and cross-sectional area

	Localization level of redundant nerve roots			P value
	Inferior (n = 7), mean ± SD	Superior (n = 30), mean ± SD	Inferior + Superior (n = 18), mean ± SD
Relative length of redundant nerve roots	2.07 ± 0.67 (a)1	2.95 ± 1.09 (a)	4.66 ± 0.73 (b)	< 0.001
Cross sectional area (mm2)	49.27 ± 8.06 (a)	35.61 ± 9.78 (b)	46.77 ± 14.73 (a)	0.001

¹One-way ANOVA test was used for statistical comparisons. The means with the same letters (a or b) in the same line are not significantly different. SD: Standard deviation.

Table 4 The relationships between the disc herniation type at the stenosis levels causing redundant nerve roots, the relative length of redundant nerve roots, and the cross-sectional area of the dural sac of redundant nerve roots of the cauda equina

	Type of disc herniation		P value
	Soft margin (n = 29), mean ± SD	Sharp margin (n = 26), mean ± SD
Relative length of RNRs	3.3 ± 1.42	3.5 ± 1.2	0.562
CSA of RNRs of the cauda equina (mm2)	39.62 ± 12.02	42.54 ± 13.62	0.401

RNRs: Redundant nerve roots; CSA: Cross-sectional area of dural sac; SD: Standard deviation.