Biomechanical effects of the prone stretching and adjusting cervical manipulation : a three-dimensional finite...

The "prone stretching and adjusting cervical manipulation", known for its therapeutic benefits in treating cervical spondylotic radiculopathy (CSR), has demonstrated notable clinical success. However, understanding its mechanism of action remains an underexplored area. This study aimed to elucidate the biomechanical impact of this technique on the cervical spine using three-dimensional finite element analysis.

Leveraging detailed CT scan data from a healthy adult female, we constructed a comprehensive three-dimensional finite element model encompassing the seven cervical vertebrae and five intervertebral discs. The model was validated by comparing its predicted segmental range of motion with experimental data from the literature under flexion, extension, lateral bending, and axial rotation. We simulated the manipulation process on this model, applying relevant mechanical parameters, and measured the stresses and foraminal areas across the cervical vertebrae and discs before and after the simulated manipulation.

Post-simulation analysis revealed a marked reduction in overall stress within the cervical spine's vertebral bodies, with the maximum stress dropping from 123.31 MPa to 29.637 MPa. Similarly, the intervertebral discs exhibited a substantial decrease in overall stress, plummeting from 36.859 MPa to 8.4136 MPa. Additionally, the intervertebral foramen area on the contralateral side to the manipulation expanded, with the most substantial increase reaching 0.75 mm².

These findings suggest that the"prone stretching and adjusting cervical manipulation"may biomechanically reduce stress on the vertebral bodies and intervertebral discs while expanding the intervertebral foraminal area, providing a biomechanical basis for the symptomatic relief in CSR.

The study was approved by the Ethics Committee of Gannan Medical University, China (no.2019806). (Clinical trial number: not applicable).