Objectives: To evaluate the incidence and pattern of spinous process fractures (SPFs) in patients with osteoporotic compression fractures (OCFs) of the thoracolumbar spine.
Methods: Spinal MRI or CT of 398 female patients (age range 50-89 years, mean age 70 years) who had OCFs in the thoracolumbar spine were retrospectively reviewed. The incidence, location and imaging results for the SPFs were evaluated.
Results: Of the 398 patients who had thoracolumbar OCFs, 14 (3.5%) had SPF. In six patients with single compression fractures, the SPF occurred at the level just above the vertebral compression fracture. In six out of seven patients with multiple continuous compression fractures, the SPF occurred just one level above the uppermost level of the compression fracture. The remaining one patient who had thoracolumbar spinal fixation at T12-L2 with continuous compression fractures in T12-L5 had a SPF in L2. In one patient who had multiple compression fractures in discontinuous levels (fractures at T10 and L1, respectively), the SPF occurred at T12. The directions of the fractures were vertical or oblique vertical (perpendicular to the long axis of the spinous process) in all cases.
Conclusion: In the presence of an OCF in the thoracolumbar spine, a SPF was found in 3.5% of cases, and most of the fractures were located just one level above the compression fracture. Therefore, in patients who have OCF, the possibility of a SPF in the level just above the compression fracture should be considered.