Table 1.
Mean (SD) vertical and horizontal stress values (kPa) in 3 disc regions for 5 test conditions
| 300 N Compression | 500 N Compression | 90 N Distraction | 90 N Distraction, 5 Nm extension | 90 N Distraction, 5 Nm flexion | |
|---|---|---|---|---|---|
| Anterior-horizontal | |||||
| All | 231.4 (139.9) | 305.0 (188.8) | -0.7 (9.1) | 61.9 (59.0) | 104.6 (44.9) |
| Low | 302.4 (134.3) | 383.2 (202.3) | 2.1 (10.7) | 94.2 (53.0) | 111.8 (49.2) |
| High | 150.3 (101.0) | 215.6 (134.1) | -3.8 (6.1) | 25.0 (43.1) | 96.3 (41.6) |
| Anterior-vertical | |||||
| All | 269.9 (141.0) | 331.3 (185.6) | 3.1 (11.8) | 76.4 (56.5) | 124.6 (46.2) |
| Low | 345.7 (121.5) | 411.5 (190.0) | 5.5 (8.9) | 107.8 (48.5) | 135.6 (56.5) |
| High | 183.2 (112.8) | 239.7 (141.0) | 0.4 (14.8) | 40.6 (43.6) | 112.0 (30.3) |
| Nucleus-horizontal | |||||
| All | 337.9 (160.4) | 447.6 (228.8) | 0.9 (17.2) | 89.7 (74.1) | 120.7 (73.5) |
| Low | 434.1 (115.4) | 563.5 (222.8) | 7.3 (15.9) | 132.9 (66.1) | 146.6 (72.8) |
| High | 227.9 (134.2) | 315.2 (160.8) | -6.4 (16.7) | 40.3 (48.8) | 91.1 (67.2) |
| Nucleus-vertical | |||||
| All | 341.7 (158.1) | 439.9 (228.6) | 2.9 (10.3) | 92.5 (68.1) | 119.3 (76.6) |
| Low | 430.4 (123.1) | 552.9 (223.5) | 6.5 (9.1) | 130.2 (64.2) | 149.2 (76.3) |
| High | 240.3 (134.7) | 310.8 (164.9) | -1.3 (10.7) | 49.4 (44.1) | 85.1 (65.9) |
| Posterior-horizontal | |||||
| All | 287.6 (125.0) | 391.9 (207.5) | -0.7 (14.7) | 84.7 (59.9) | 91.1 (78.2) |
| Low | 355.3 (97.3) | 478.1 (211.9) | 2.0 (18.0) | 120.0 (51.6) | 123.3 (70.2) |
| High | 210.1 (110.9) | 293.5 (163.9) | -3.9 (10.3) | 44.4 (41.2) | 54.3 (74.5) |
| Posterior-vertical | |||||
| All | 275.5 (144.9) | 369.0 (210.3) | 1.3 (8.9) | 82.1 (62.5) | 87.3 (75.7) |
| Low | 345.4 (120.2) | 449.8 (217.6) | 2.3 (11.7) | 112.6 (66.2) | 113.8 (77.6) |
| High | 195.6 (134.7) | 276.8 (171.2) | 0.2 (4.8) | 47.3 (36.9) | 57.1 (66.1) |
All = all specimens combined (n = 15), Low = low degeneration (grades 1 & 2, n = 8), High = high degeneration (grades 3 & 4, n = 7), Posterior = posterior annulus, Nucleus = nucleus pulposus, Anterior = anterior annulus