BMD, kyphotic angle predict post-surgical adjacent vertebral fractures
MedWire News: Low bone mineral density (BMD) and high kyphotic angle are both associated with an increased risk for adjacent vertebral compression fractures (VCFs) following balloon kyphoplasty (BK) or vertebroplasty (VP), study findings indicate.
These findings suggest that the adjacent vertebrae would fracture eventually, even without the procedure, as both the degree of osteoporosis and kyphosis are independent risk factors for VCFs, remark Igor Movrin (University Medical Center Maribor, Slovenia) and colleagues.
It is currently uncertain whether adjacent VCFs after percutaneous augmentation procedures are a consequence of the procedure itself or are simply the result of the natural progression of osteoporosis, says the team.
To investigate, they evaluated the adjacent vertebral fracture risk among 73 consecutive patients with painful VCFs who underwent BK (n=46) or VP (n=27).
At 1 year after the surgery, three (6.5%) patients treated with BK and two (7.4%) patients treated with VP had sustained an adjacent vertebral fracture.
All adjacent fractures were asymptomatic and occurred in patients with a BMD T-score at or below -2.9 standard deviation (SD) of the mean, calculated in a reference population of the same gender. The mean postoperative local kyphosis in these five patients was 11.2°.
Movrin and team revealed that patients with a BMD T-score of -3.0 SD or lower were 13 times more likely to experience a new fracture than those with a BMD above -3.0 SD.
In addition, patients with a postoperative kyphotic angle at or above 9° were 12 times more likely to have an adjacent fracture than those with a postoperative kyphotic angle below 9°.
Age, gender, the augmentation method, cement volume, and amount of cement leakage did not predict adjacent fractures.
Therefore, "the most important factors for new VCFs after a percutaneous augmentation procedure are the degree of osteoporosis and altered biomechanics in the treated area of the spine due to resistant kyphosis," write Movrin and co-authors in the Archives of Orthopedic and Trauma Surgery.
"It seems that without these augmentation procedures, adjacent fractures would be more frequent, because vertebral fractures change the biomechanics of the spine, which might increase the risk of additional vertebral fractures," they add.
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By Laura Dean