A new Mayo Clinic study finds that vertebroplasty - a procedure used to treat painful compression fractures in the spinal vertebrae due to osteoporosis - appears to increase the risk for new fractures in adjacent vertebrae.
The study also found vertebrae adjacent to fractures treated with vertebroplasty fracture significantly sooner than more distant vertebrae.
Findings are in the current issue of American Journal of Neuroradiology (www.ajnr.org ).
The researchers discovered that following vertebroplasty, which involves injecting bone cement into the vertebrae to stabilize fractures, patients' risk for new fractures in vertebrae adjacent to those treated was 4.62 times the risk for nonadjacent vertebral fractures. In addition, they found that new fractures occurred in adjacent vertebrae sooner than in nonadjacent vertebrae: a median of 55 days following vertebroplasty for adjacent fractures and 127 days for nonadjacent vertebral fractures.
This is the largest study yet to address the risk of new fractures postvertebroplasty, and the first study to examine whether there is a difference in time between the development of new fractures adjacent and nonadjacent to the original fracture after treatment with vertebroplasty.
"Previous studies of vertebroplasty in cadavers and using computer simulation suggested that inserting cement in one bone weakens adjacent bones," explains David Kallmes, M.D., Mayo Clinic neuroradiologist and senior study investigator.
The weakening effect is possible due to the overall cushioning effect of the spine, where stiffening one part puts greater stress on another, he says.
Adds Kallmes: "Of course, we do not want to cause new fractures by treating existing fractures, so we are studying treated patients to see if their bones are fracturing sooner or more frequently than would otherwise be expected."
Kallmes explains that though this study points to a significant association between vertebroplasty and new fractures occurring in adjacent vertebrae, it is not absolute proof of cause and effect.
Indeed, at this point in the research, Kallmes still practices vertebroplasty and believes the potential advantages outweigh the risks.