Look at this MRI.  Those screws are supposed to go into the bone.  The one on the left is going into the muscle, tendons, ligaments and surrounding fascia.

Surgical fusion and Failed Back Surgery Syndrome due to horribly wrong pedicle screw insertion. The patient is permanently and profoundly disabled.

This is why surgery should always be the last option.  In the vast majority of cases, chiropractic care is superior to the results from surgery.

Chiropractic first.