Table 1.

Average intradiscal pressure (IDP) in flexion-extension for the adjacent level (T9–T10) and first instrumented level (T10–T11) for all constructs. All data are normalized to intact (100%). *P ≤ .05 versus intact.

Construct	Adjacent Level (T9–T10) (Mean ± SD)	1st Instrumented Level (T10–T11) (Mean ± SD)
Rigid	258 ± 121*	159 ± 71
SPT 1	210 ± 87	234 ± 96*
SPT Helix HT 1	182 ± 76	302 ± 170*
SPT Helix 1	181 ± 67	227 ± 95
SPT Trans-Helix 1	203 ± 74	221 ± 103
SPT 2	226 ± 100	230 ± 152*
SPT Helix 2	183 ± 88	211 ± 152
SPT Trans-Helix 2	191 ± 86	207 ± 150