MedWire News: The so-called halo phenomenon around bone cement in patients who have undergone vertebral augmentation heralds a poor prognosis, a study by South Korean researchers indicates.
Their analysis, which appears in Osteoporosis International, found that the development of a peri-cement radiolucent area was associated with an increased risk for subsequent vertebral recollapse.
Dong Kyu Chin (Yonsei University, Seoul) and team prospectively studied 175 patients who underwent vertebral augmentation (either vertebroplasty or kyphoplasty) because of symptomatic osteoporotic vertebral compression fractures.
A total of 202 vertebrae were treated, which the researchers divided into two groups: those that developed a peri-cement halo (n=32) and those that did not (n=170).
A comparison of the two groups revealed a number of interesting differences. First, preoperative osteonecrosis was much more common in the halo group as compared with the no-halo group (62.5 vs 31.2%).
Second, kyphoplasty was the predominant procedure in the halo group (43.8 vs 17.6%) whereas vertebroplasty predominated in the no-halo group (82.4 vs 56.2%). Third, regarding the injected cement, the "lump" pattern of distribution was much more common in patients with halo than in those with no halo (93.8 vs 30.6%).
Finally, in terms of outcome, vertebral recollapse was markedly more likely in patients with halo as compared with no halo (78.1 vs 24.7%).
In logistic regression analysis, each of these factors remained significantly and independently associated with peri-cement halo, Chin et al remark.
The team concludes: "The peri-cement halo phenomenon should be viewed as a significant radiological warning sign for poor outcome after vertebral [bone cement] injection, as 78% of patients demonstrating this sign experienced recollapse of the treated vertebrae."
They add: "We propose that pre-existing osteonecrosis of the index vertebrae should be considered a relative contraindication for any vertebral cement augmentation procedure."
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