Evaluation of the Effect of Fixation Angle between Polyaxial Pedicle Screw Head and Rod on the Failure of Screw-Rod Connection

Table 1

Axial pullout test results.

	6.5 45		7.0 45		7.5 45
	V	A	V	A	V	A
Maximum load (N)	8216	7485	10360	9320	9838	9102
Std.	300	289	210	491	457	780
Displacement at maximum load (mm)	3.02	4.18	3.67	4.96	3.84	4.98
Std.	0.23	0.39	0.49	0.56	0.17	0.96
Stiffness (N/mm)	2732.68	1800.87	2854.4	1899.48	2562.69	1863.99
Std.	141.26	137.86	344.67	241.24	64.05	271.30