TABLE II.

Comparison of IA Between Single and Multiple HV

	Single HV (n = 806)	Multiple HV (n = 242)	p
Age	11.95 ± 9.04	10.43 ± 6.94	p < 0.001
Gender (male: female)	442:364	139:103	0.456
Intraspinal abnormalities
With abnormalities	114 (14.1%)	59 (24.4%)	p < 0.001
Without abnormalities	692 (85.9%)	183 (75.6%)
Type of intraspinal abnormalities
Syringomyelia (%)	63 (7.8)	33 (13.6)	0.003
Diastematomyelia (%)	17 (2.1)	8 (3.3)	0.285
Tethered spinal cord (%)	18 (2.2)	12(5.0)	0.026
Chiari malformation (%)	12 (1.5)	8 (3.3)	0.075
Lipoma filum terminale (%)	38 (4.7)	25 (10.3)	0.001
Low-lying conus medullaris (%)	21 (2.6)	11 (4.5)	0.124
Presence of rib deformities
Yes	26	30	p < 0.001
No	780	212
The location of the HV
C	2	-
T	349	113
L	455	38
C+T	0	5
T+L	0	85
C+T+L	0	1