1. Biomechanical evaluation
The range of motion (ROM) angles for each group in each direction was presented in Table 1. Compared with Group A, the ROM of Group B and Group C increased significantly in the movement of inflexion, extension, left/right lateral bending and left/right rotation (P < 0.05, vs group B, P < 0.05 vs. Group C). The ROM of Group C in any movements significantly increased comparing with that of Group B (P < 0.05).
The ROM of Group D, E, F with the implantation of ISDF was significant less than that of Group A, B, C in any motion models, respectively (P < 0.05).
1.1 Extension and Flexion
As can be seen from Table 1, the ROM of flexion in group B increased by 60.95% and that in group C increased by 97.16%. After applying the ISFD, the ROM of group D decreased significantly compared with group A (P < 0.05), a decrease of about 21.43%. Group E and F showed a decrease in ROM compared with group B and C (P < 0.05), about 39.98% and 34.53%, respectively.
The extension ROM in group B increased by 42.61% compared with that in group A, and that in group C increased by 76.52%. After the implantation of ISFD, the ROM of group D significantly decreased compared with group A (P < 0.05), a decrease of about 26.70%. Group E and F showed a decrease in ROM compared with group B and C (P < 0.05), by 22.07% and 21.76%, respectively.
1.2 Lateral bending
The ROM of left lateral bending in group B increased by 34.20% and that in group C increased by 78.67%. After applying the ISFD, the ROM of group D decreased significantly compared with group A (P < 0.05), a decrease of about 19.32%. Group E and F had significantly decreased in motion compared with group B and C (P < 0.05), about 28.05% and 27.30%, respectively.
The ROM of right lateral bending in group B increased by 26.56% and that in group C increased by 66.30%. After applying the ISFD, the ROM of group D decreased significantly compared with group A (P < 0.05), a decrease of about 21.45%. Group E and F had significantly decreased in motion compared with group B and C (P < 0.05), about 21.49% and 25.44%, respectively.
1.3 Axial rotation
The ROM of left rotation in group B increased by 88.20% and that in group C increased by 175.85%. After the implantation of ISDF, the ROM of group D decreased significantly compared with group A (P < 0.05), a decrease of about 49.25%. Group E and F had significantly decreased in motion compared with group B and C (P < 0.05), about 24.97% and 18.67%, respectively.
The ROM of right lateral bending in group B increased by 108.60% and that in group C increased by 212.21%. After the implantation of ISFD, the ROM of group D decreased significantly compared with group A (P < 0.05), a decrease of about 33.77%. Group E and F had significantly decreased in motion compared with group B and C (P < 0.05), about 17.21% and 21.59%, respectively.
Table 1
ROM of specimens in different directions (X ± SD)
| A | B | C | D | E | F |
Fl | 2.707(0.0376) | 4.357(0.1204) | 5.337(0.3320) | 2.127(0.0687) | 2.615(0.0594) | 3.494(0.3173) |
Ex | 1.929(0.0240) | 2.751(0.0484) | 3.405(0.1741) | 1.414(0.2695) | 2.144(0.1258) | 2.664(0.2560) |
L-LB | 4.482(0.7696) | 6.015(0.3980) | 8.008(0.4543) | 3.616(0.3199) | 4.328(0.4294) | 5.822(0.3309) |
R-LB | 4.695(0.3964) | 5.942(0.5724) | 7.808(0.5761) | 3.688(0.1894) | 4.665(0.8230) | 5.822(0.3820) |
L-Ar | 1.466(0.0641) | 2.759(0.3103) | 4.044(0.2883) | 0.744(0.218) | 2.070(0.2017) | 3.289(0.0904) |
R-Ar | 1.359(0.2704) | 2.835(0.1095) | 4.243(0.3170) | 0.900(0.173) | 2.347(0.3655) | 3.327(0.1884) |
FL: Flexion; EX :Extension; LB: Lateral bending; AR: Axial rotation. A, Intact; B. Unilateral laminotomy (UL); C. Bilateral laminotomy (BL); D, ISFD + intact; E. ISFD + UL; F. ISFD + BL. |
2. Histological evaluation
2.1 Toluidine blue staining
The toluidine blue staining results were shown in Fig.4. The blue part representedthe new formation bone and the black was the precursor condition of new bone formation. Mostoftheareawasfilledwith precursor condition of bone tissue. The new formation bone area took account of 8.71% through OsteoMeasure 64 software analysis.
Figure 4. The results of hematoxylin-eosin staining. The blue part represented the new formation bone and the black was the precursor condition of new bone formation.
2.2 HE staining
As described in Fig. 5, the cavity of ISFD was occupied with osteoblast cells and bone tissues. The surround black part was metal frame. The red staining part indicated new bone formation which was constituted with osteoblast cells and bone tissues. The brown part was the precursor condition of new bone formation. The blank part was caused of tissue exfoliation.