VERTEBROPLASTY:

Radiation Exposure During Intervention
(Author: Thammo Weise)

In comparison with potential complications connected with cement-based vertebral body augmentations, the operator and the patient are likely to disregard even more the issue of potential radiation exposure during such minimally invasive interventions. That is why there are only a few publications in general dealing with the above topic in connection with vertebroplasty/kyphoplasty. In order to determine the radiation burden of a person, the radiation dose data is supplemented by radiation quality, mostly given in Grays [Gy], which includes weighting factors for various tissue types while reflecting the radiation type. The equivalent dose is proportional to the radiation exposure time and indirectly proportional to the square of distance between the source of the radiation and the exposed organ. In Germany, the Radiation Protection Regulation (RPReg) stipulated a dose limit of maximum 20 mSv per year for persons who are exposed to ionizing radiation in the course of their activities at work.

Although the methods used in the studies under review, in terms of the materials examined and the imaging techniques, vary greatly, every now and then we may hear statements that, in contrast to other interventions, the doctor and the patient are exposed to relatively high radiation levels during vertebroplasty and kyphoplasty. In order to identify any potential leakage early, highresolution angiography devices are used, for example, which naturally deliver high-quality images but, on the other hand, they also use significantly higher radiation doses. Depending on the vertebral bodies treated (number and location), the radiation burden of the patient corresponds roughly to that of a computer tomography screening of the entire body and, in view of the utility/risk relation, it can be thoughtlessly tolerated. Skin damage is also not to be expected since the distance from the radiation source is great enough and, usually, the intervention is not performed more than once a year.

The operating doctor may, however, under certain circumstances find himself, at least with one hand while applying local anesthesia, penetrating the vertebral body and injecting the cement in a radiation beam and can receive a radiation dose of 100 to 300 μSv, depending on the intervention duration. This increases the risk of cancer developing in the doctor’s body by 0.025% per intervention. The studies also show that by adopting additional protective measures, such as wearing thyroid gland protection and lead gloves, the effective radiation exposure can be reduced by 43 to 86%. By using a suitable injection system, which keeps the operator’s hands farther from the source of radiation, the radiation exposure can be decreased by an additional 22 to 64%. The use of a cement applicator exposes the patient to additional radiation since the bone cement can be administered slowly, which leads to X-ray times up to three times longer in comparison with simple injections.

It is commonplace for radiologists to follow all radiation hygiene rules strictly, yet for surgeons and orthopedists this issue sometimes plays a minor role. In view of the general acceptance of vertebroplasty, it becomes evident that injection systems (ensuring a sufficient distance from the radiation source) are equally effective in limiting radiation exposure as well as in preventing potential leakage. With its Cement-Injection-System (CIS®) and the VTP needle holder, SOMATEX offers right away two instruments that effectively reduce radiation exposure, representing yet another major step toward maximum safety.

Sincerely yours,
Thammo Weise