Biopsy of osteoporotic vertebral compression fractures during kyphoplasty: unsuspected histologic findings of chronic osteitis without clinical evidence of osteomyelitis.

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To evaluate biopsy results obtained during vertebral augmentation (kyphoplasty) for presumed/confirmed osteoporotic vertebral compression fractures (VCFs).

SUMMARY OF BACKGROUND DATA

Kyphoplasty to augment vertebrae in osteoporotic VCFs is well established. When VCF etiology is in question, bone biopsy can be performed at that time. Biopsy results, however, can be misleading without careful clinical correlation.

METHODS

From July 2003 to July 2006, 94 vertebral biopsies were obtained from 66 patients during kyphoplasty for VCFs. Average patient age was 73 (range, 22-99), including 47 females and 19 males. There were 48 one-level, 17 two-level, and 4 three-level biopsies. Biopsy levels included: T6 (3), T7 (7), T8 (7), T9 (3), T10 (3), T11 (8), T12 (21), L1 (18), L2 (13), L3 (8), L4 (2), L5 (1). Histologic/immunohistochemical evaluations were performed.

RESULTS

All specimens showed features of fracture in various stages of bony healing. Initially, 13 of 66 (19.7%) cases were read by a surgical pathologist as chronic inflammation, with 6 having features suggestive of chronic osteomyelitis, including polyclonal plasma cells, necrosis, and lymphoplasmacytic infiltrate. For this study, these biopsies were evaluated by an independent surgical pathologist (N.W.). Re-review showed 7 of the 13 cases were consistent with osteoporotic VCF healing in various stages with adjacent trilineage hematopoiesis. Six of 13 (46%), were read as containing fragmented bony spicules, fibrotic and fatty marrow, lymphoplasmacytic inflammation, and aggregates of mature, polyclonal plasma cells, suggesting the possibility of chronic osteomyelitis. However, at average follow-up of 37 months (range, 21-57 months), no patient demonstrated clinical and/or laboratory evidence of infection. Additionally, biopsies from 4 patients confirmed suspected or unsuspected malignancy, or confirmed no recurrence of malignant disease.

CONCLUSION

Patients undergoing first-time vertebral augmentation should be considered for vertebral biopsy. Tissue examination is useful and may reveal pathologic fracture or possible infection. However, if infection is reported, clinical and laboratory correlation are important to make a diagnosis of osteomyelitis.