Table 4. Dysphagia, prothesis migration, subsidence and adjacent segment degeneration of patients between the 2 groups.

	Discover Group	Zero-P Group	P
Dysphagia	6/60(10.0%)	7/68 (10.3%)	0.956
Migration	10/60 (16.7%)	0/68 (0%)	0.000
Subsidence	2/60 (3.3%)	1/68 (1.5%)	0.600
Adjacent segment degeneration	2/60 (3.3%)	2/68 (2.9%)	1.000
Disc height loss	0/60 (0%)	0/68	1.000
New osteophyte formation or enlargement of existing osteophytes	2/60 (3.3%)	1/68 (1.5%)	1.000
New or increasing anterior longitudinal ligament calcification	0/60 (0%)	1/68 (1.5%)	1.000