Simulation of the surgical steps necessary to correct the scoliotic spine of a patient.
For patients with significant scoliotic deformities of the spine, surgery is necessary. Screws are inserted in the vertebrae and a rod is positioned in these screws in order to correct the scoliotic spine in the coronal, sagittal and transverse planes. The surgical procedure is quite complex and generates huge forces at the screw-vertebrae interface, sometimes causing a screw to pull out during or after the surgery, leading to serious complications for the patient. Companies manufacturing the spinal instrumentation (screws, rods and surgical tools) are therefore trying to develop new devices to reduce the forces at the screw–vertebrae interface and hence the risks for patients.
Spinologics used the ANSYS Mechanical APDL language to create a patient-specific finite element model of the spine and pelvis, including all anatomical components (vertebrae, intervertebral discs, ligaments, articular facets, etc.). A new spinal instrumentation system was modeled, and the surgical steps were simulated to evaluate and compare the corrective potential, the screw–vertebrae interface forces, and the rod stresses between the new system and current generic spinal instrumentation. The new system reduced the screw–vertebrae interface forces by 40 percent when compared to a generic system, while correcting the scoliosis to the same degree.
ANSYS simulations provide meaningful data that cannot be monitored during an actual spinal surgery. The simulations led to three peer-reviewed scientific articles for Spinologics and helped to prove the advantages of the new spinal instrumentation system. It produced a better understanding of the biomechanics at work in a scoliotic spine surgery, which could reduce the risks of such surgeries in the near future.
- ANSYS Mechanical