Vertebroplasty is known to have a low complication rate, however, severe complications can occur. The majority of these are related to cement extrusion. While this does not cause pain, a study presented at the RSNA meeting in Chicago from November 26 - December 1, 2006 revealed that cement leakage in vertebroplasty can be predicted with MR imaging (MRI).
Presenting data from a study entitled, 'Cement leakage with vertebroplasty can be predicted on preoperative MR imaging', Dr Akio Hiwatashi, now from Kyushu University Japan, explained how researchers at the University of Rochester School of Medicine and Dentistry, NY, examined images from 46 patients (107 vertebrae) who underwent preoperative MRI. The primary endpoint of the study was to determine if preoperative MRI could predict the risk of cement leakage into adjacent disc spaces.
According to Hiwatashi, the preoperative MR imaging were evaluated for vertebral body height, wedge angle, presence of cleft and cortical defect and T2 hyperintensity in the adjacent disc space. Using CT and logistic regression analysis to observe cement leakage postoperatively, the team also examined the association between leakage and the patient's preoperative MRI appearance.
Hiwatashi explained that the team discovered cement leakage in 51 of 214 (24%) disc spaces adjacent to the vertebral bodies. "Such a side effect does not result in pain for most patients. It can relate to a subsequent fracture in adjacent vertebrae," he commented.
Hiwatashi also reported that cortical defect in treated vertebral bodies, abnormal T2 hyperintensity in adjacent intervertebral discs and absence of intervertebral cleft were associated with the cement leakage.
Benefits of predicting cement leakage
According to Per-Lennart Westesson, a professor in the Department of Radiology at the University of Rochester School of Medicine and Dentistry, the ability to predict cement leakage benefits both the patient and physician.
"If we know there is a risk of cement leakage we would probably do kyphoplasty instead," he said.
As well as helping physicians and patients make more informed decisions between vertebroplasty and kyphoplasty, Hiwatashi believes that the study also illuminates potential changes in techniques when vertebroplasty is the chosen method of intervention.
"When we see T2 hyperintensity, for example, we change the placement of the tip of the needles," said Hiwatashi. "Throughout the procedure, physicians can consult the MR images and move the needles accordingly, aiming at areas located further away from potential leakage sites."
Additionally, the study could potentially promote the use of alternative cement products. Hiwatashi explained "We can also use cement that has stickier properties or is harder, in the effort to prevent leakage."
Cost benefits
Westesson commented that an additional advantage of carrying out MR studies to predict leakage leads to cost benefits. Already MRI is necessary to identify which vertebral body has the acute fracture, as quite often there are several fractures and the acute one needing treatment has to be identified. Therefore, because MRI is already required, additional costs for observing cement leakages are not essential.
"Even if the cost is slightly more, precise evaluation of the patient is much more important," said Hiwatashi.
However, both physicians commented that with MRI it is difficult to predict how much cement leakage has occurred and therefore difficult to evaluate how cement leakage could be reduced using MRI. Further research in this area will help overcome this problem.
Date: Feb/2007
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