The Effect of C-Arm Position on Radiation Exposure During Fixation of Pediatric Supracondylar Fractures of the Humerus.

Abstract

Closed reduction and percutaneous pinning of a pediatric supracondylar fracture of the humerus requires operating directly next to the C-arm to hold reduction and perform fixation under direct imaging. This study was designed to compare radiation exposure from two C-arm configurations: with the image intensifier serving as the operating surface, and with a radiolucent hand table serving as the operating surface and the image intensifier positioned above the table. We used a cadaveric specimen in this study to determine radiation exposure to the operative elbow and to the surgeon at the waist and neck levels during simulated closed reduction and percutaneous pinning of a pediatric supracondylar fracture of the humerus. Radiation exposure measurements were made (1) with the C-arm image intensifier serving as the operating surface, with the emitter positioned above the operative elbow; and (2) with the image intensifier positioned above a hand table, with the emitter below the table. When the image intensifier was used as the operating surface, we noted 16% less scatter radiation at the waist level of the surgeon but 53% more neck-level scatter radiation compared with when the hand table was used as the operating surface and the image intensifier was positioned above the table. In terms of direct radiation exposure to the operative elbow, use of the image intensifier as the operating surface resulted in 21% more radiation exposure than from use of the other configuration. The direct radiation exposure was also more than two orders of magnitude greater than the neck and waist-level scatter radiation exposure. Traditionally, there has been concern over increased radiation exposure when the C-arm image intensifier is used as an operating surface, with the emitter above, compared with when the image intensifier is positioned above the operating surface, with the emitter below. We determined that, although there was a statistically significant difference in radiation exposure between the two configurations, neither was safer than the other at all tested levels. In contrast to traditional teaching regarding radiation exposure, neither C-arm configuration-with the image intensifier serving as the operating surface or with the image intensifier positioned above a radiolucent hand table-was shown to be clearly safer for pediatric supracondylar humeral fracture fixation.