Table 1

Summary of In Vitro Studies Involving Pedicle Screw-Based PDS Devices Currently Available for Use Clinically

References	n	Protocol	Parameter(s)	Device
Strauss et al., 1994¹²	13	Axial compressive load of 500 N, and pure moments of 10 Nm in F/E, LB, and AR; Intact/Injured/Instrumented	Balance point, compressive compliance, and ROM in F/E, LB, and AR	Graf ligament
Freudiger et al., 1999¹⁴	4	18.3 Nm flexion moments and 12.5 Nm extension moments; Intact/Instrumented	ROM in F/E and translations (horizontal, and vertical)	Dynesys
Schmoelz et al., 2003¹⁵	6	Pure moments of 10 Nm in F/E, LB, and AR; Intact/Injured/Instrumented/Rigid	ROM in F/E, LB, and AR	Dynesys
Schmoelz et al., 2006¹⁶	6	Pure moments of 10 Nm in F/E, LB, and AR; Intact/Injured/Instrumented/Rigid	Intradiscal pressure	Dynesys
Niosi et al., 2006¹⁷	10	Pure moments of 7.5 Nm in F/E, LB, and AR; Intact/Injured/Instrumented/long spacer/short spacer	NZ, location of the HAM, and ROM in F/E, LB, and AR	Dynesys
Xu et al., 2006²¹	6	pure moments of 10 Nm in F/E, LB, and AR; Intact/Injured/Instrumented/Rigid	ROM in F/E, LB, and AR	Osteotech
Cheng et al., 2007¹⁸	12	Pure moments of 6 Nm in F/E, LB, and AR; Intact/Injured/Instrumented	ROM in F/E, LB, and AR	Dynesys
Meyers et al., 2008²⁰	5	Testing in F/E, LB, and axial compression of 210 N, and 630 N; Instrumented	Moments within the pedicle screws	Dynesys
Niosi et al., 2008¹⁹	10	Pure moments of 7.5 Nm in F/E, LB, and AR; Intact/Instrumented	Facets loads	Dynesys