Typical hysteresis curves of C2-C4 level of the four groups after fatigue test in the directions of flexion-extension (A), lateral bending (B), and rotation (C).

<p>Typical hysteresis curves of C2-C4 level of the four groups after fatigue test in the directions of flexion-extension (A), lateral bending (B), and rotation (C).</p

CT images of goats in control group, ACVC group, ACCF group 24 weeks after the surgery (ACVC and ACVC-HA appears similar).

<p>A, B, C, Lateral views of C2 to C4 for the three groups; D, G, transverse views of C3 and C4 vertebral bodies in control group; E, H, transverse views of C3 and C4 vertebral bodies in ACVC group; F, I, transverse views of C3 and C4 vertebral bodies in ACCF group.</p

Comparison histological images of ACVC and ACVC-HA.

<p>A and B, 25X- and 100X- magnified images at the level of ACVC vertebral body component; C and D, 25X- and 100X- magnified images at the level of ACVC-HA vertebral body component; E and F, 25X- and 100X- magnified images at the level of fixation screws of ACVC; G and H, 25X- and 100X- magnified images at the level of fixation screws of ACVC-HA; I, Bone implant contact (BIC) of ACVC and ACVC-HA at vertebral body and screw level.</p

Average changes in the stability index ROMs and stability index NZs from ACVC group, ACVC-HA group and ACCF group.

<p>Average changes in the stability index ROMs and stability index NZs from ACVC group, ACVC-HA group and ACCF group.</p

Average unidirectional ROM (A), NZ (B), and stiffness (C) of the four different groups at 24 weeks after surgery in all directions before the fatigue test.

<p>Average unidirectional ROM (A), NZ (B), and stiffness (C) of the four different groups at 24 weeks after surgery in all directions before the fatigue test.</p

Stability index of the flexibility test before the fatigue test.

<p>Stability index of the flexibility test before the fatigue test.</p

Ranges of motion, neutral zones, and stiffness profiles of the C2-4 segments of the four groups before the fatigue test in all directions.

<p>Ranges of motion, neutral zones, and stiffness profiles of the C2-4 segments of the four groups before the fatigue test in all directions.</p

Scheme diagram and photos of the three different artificial implants.

<p>A, Scheme diagram of the ACVC; B, actual photo of the ACVC; C, actual photo of the ACVC-HA; D, actual photo of the titanium cage, anterior plate, and fixing screws.</p

Typical hysteresis curves of C2-C4 level of the four groups before fatigue test in the directions of flexion-extension (A), lateral bending (B), and rotation (C).

<p>Typical hysteresis curves of C2-C4 level of the four groups before fatigue test in the directions of flexion-extension (A), lateral bending (B), and rotation (C).</p

Ranges of motion profiles of the cervical segments of the four groups before the fatigue test in all directions.

<p>Ranges of motion profiles of the cervical segments of the four groups before the fatigue test in all directions.</p