Table 2.

Discrepancies of treatment effect between the two groups

	Sequestered disk	Non-sequestered disk	P
	Baseline(V1)
Mean JOA(SD)	12.90 ± 2.04	12.93 ± 1.95	0.936
Mean NDI(SD)	17.76 ± 7.62	17.87 ± 6.44	0.930
Mean VAS(SD)	4.20 ± 1.70	4.38 ± 1.92	0.611
	V2
Mean JOA(SD)	15.04 ± 1.26	14.45 ± 1.43	0.026
Mean NDI(SD)	10.12 ± 5.51	10.50 ± 5.79	0.729
Mean VAS(SD)	2.62 ± 1.44	2.67 ± 1.58	0.858
	V3
Mean JOA(SD)	15.38 ± 1.29	15.24 ± 1.25	0.572
Mean NDI(SD)	7.24 ± 4.48	8.22 ± 6.17	0.352
Mean VAS(SD)	1.80 ± 1.16	2.09 ± 1.54	0.283
	V4
Mean JOA(SD)	16.00 ± 0.95	16.03 ± 0.86	0.843
Mean NDI(SD)	4.50 ± 2.94	4.83 ± 3.74	0.618
Mean VAS(SD)	1.22 ± 0.68	1.33 ± 1.07	0.540

JOA Japanese Orthopedics Association, NDI the Neck disability index, VAS the Visual analog scale, SD standard deviation

Visits: baseline (V1); 2nd month after surgery (V2); 4th month after surgery (V3); 6th month after surgery (V4)