Bone resorption of vertebral bodies at the operative segment after prevail cervical interbody fusion: A case report

Abstract

Background: We report an interesting case of bone resorption of vertebral bodies at the operative segment after Peek Prevail cervical interbody fusion. Instability of cervical vertebrae is likely to occur due to increased stress in Peek Prevail implant body for bone resorption. The finite element analysis was used to clarify the biomechanical effects of bone resorption and stress distribution in Peek Prevail implant body.

Methods: We reported the case of a 48-year-old male patient who underwent Peek Prevail cervical interbody fusion and exhibited bone resorption 1 month after the surgery in X-ray of cervical vertebra. The degree of bone resorption was aggravated 2 months after surgery. Bone resorption in 3 months was similar to that in 2 months. We established a 3D reconstruction of the surgical segment in this case using Mimics software (vision 20.0) to generate basic boss resorption model. We simulated models of bone resorption using Ansys 17.0. The stress distribution of the contact surface between the screw and bone was analyzed under 6 conditions: flexion, extension, left and right flexion, and left and right rotation.

Results: The loading conditions affected the stress distribution in the implant body. When bone resorption occurred, the stress distribution of the contact surface between screw and bone focus in the tip of the screw increased sharply.

Conclusion: Bone resorption of vertebral bodies in the operative segment may be a potential complication after Peek Prevail cervical interbody fusion. Great attention must be paid when bone resorption was occurred in order to avoid screw loosening before vertebral fusion.

Figure 1.

The radiology of patients was followed up before and after operation. (A–B) Preoperative magnetic resonance imaging. (C) CT imaging three days after operation. (D–E) The X-ray films of 1 month and 2 months after operation, bone resorption was indicated by red arrow. (F–G) CT three months after operation showed obvious signs of bone resorption. CT = computed tomography.

Figure 2.

Prevail cervical interbody fusion model after meshing.

Figure 3.

Validation of the model and ROM showed the degree of intervertebral motion. ROM = range of motion.

Figure 4.

Comparison of ROM on the model between no bone resorption and bone resorption in two months. ROM = range of motion.

Figure 5.

Comparable nephogram of equivalent stress in the prevail screws between no bone resorption (the pictures above) and bone resorption two months after operation (the pictures below). (A) Forward flexion, (B) back extension, (C) lateral flexion of plasty, (D) lateral flexion opposite plasty, (E) lateral rotation of plasty, and (F) lateral rotation opposite plasty.