Are L5 fractures an indicator of metastasis?

Abstract 

Objective. To determine whether L5 vertebral body fractures are an indicator of malignancy.

Design and patients. A retrospective study of L5 vertebral body fractures was carried out using plain radiographs, CT, and/or MRI. Over a 5-year period, 51 patients with L5 vertebral body fractures were seen at our institution. Since L1 vertebral body fractures are common, 51 age- and gender-matched (20 men, 31 women; mean age 60 years) patients with L1 fractures were utilized as the control group. The frequency of neoplastic infiltration of the vertebrae was compared between these two populations to determine whether pathologic fracture was more frequent at L5.

Results. Twelve (24%) of the L5 fractures were pathologic compared with four (8%) of the L1 fractures (chi-square test, P<0.05). Neoplasm types included multiple myeloma (n=4), prostate (n=3), breast (n=2), lung (n=2), melanoma (n=2), bladder, colon, and leukemia (each n=1).

Conclusion. Although most L5 fractures are not pathologic, there is an increased incidence of pathologic fractures in this location compared with L1. Therefore, a fracture of L5 should raise the suspicion of metastasis.