Polytrauma Patients Face Cancer Risk from Imaging Radiation
Orthopaedic surgeons work with radiation in some capacity almost every day. We would struggle to provide quality patient care if it were not for the many benefits that radiographic images provide us. But the more we are exposed to something, the less we tend to think about it. For example, how often do we discuss the risks of radiation exposure with our patients—especially those who are exposed to a large amount of it after an acute traumatic injury?
The article by Howard et al. in the August 7, 2019 issue of JBJS strongly suggests that polytrauma patients need to better understand the risks associated with radiation exposure as they progress through treatment of their injuries. The authors evaluated the cumulative 12-month postinjury radiation exposure received by almost 2,400 trauma patients who had an Injury Severity Score of 16+ upon admission. Those patients received a median radiation dose (not counting fluoroscopy) of 18.46 mSv, and their mean radiation exposure was 30.45 mSv. These median-versus-mean data indicate that a small subset of patients received substantially more radiation than others, and in fact, 4.8% of the cohort was exposed to ≥100 mSv of radiation. To put these amounts in context, the average human in the UK (where this study was performed) is exposed to about 2 mSv of background radiation per year, and there is good evidence suggesting that carcinogenesis risk increases with acute radiation doses exceeding 50 mSv.
Based on mathematical models (actual occurrences of cancer were not tracked), the authors conclude that for these patients, the median risk of fatal carcinogenesis as a result of medical radiation following injury was 3.4%. In other terms, 85 of these patients would be expected to develop cancer as a result of medical imaging—which struck me as a startling estimate.
So what are we to do? In a Commentary accompanying this study, David A. Rubin, MD, FACR offers some practical suggestions for reducing unnecessary radiation exposure. I personally feel that because the radiation associated with CT scans and radiographs can be, quite literally, life-saving for patients who have sustained traumatic injuries, increasing the chance that patients develop cancer later in life in order to save their life now is a good risk-benefit proposition. But the findings from this study should make us think twice about which imaging tests we order, and they should encourage us to help patients better understand the risks involved.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
JBJS Editor’s Choice: Research into Female Surgeon Safety
The evolution of more rational educational programs and other societal changes point to a future where an increasing number of orthopaedic surgeons will be female. Thankfully, we have made gains in adjusting the medical community’s perspective on careers in orthopaedic surgery. No longer are we perceived to be “stronger than a mule and twice as smart” or merely “buckles and braces men.” Evolving interventional techniques that rarely require brute force have also helped change this view.
At the same time, with the rapidly increasing need for musculoskeletal care as the population ages, we need every orthopaedic practitioner—male and female—to remain as healthy and active as possible. Epidemiologic studies of surgeon health have revealed real concerns for neck and back degenerative changes and cancer risk.
In the November 2, 2016 edition of The Journal, Valone et al. tackle the issue of exposure of the female breast to intraoperative radiation. In a nifty study incorporating C-arm fluoroscopy and an anthropomorphic torso phantom equipped with breast attachments and dosimeters, the authors found that:
- The median dose-equivalent rate of scatter radiation to the breast’s upper outer quadrant (UOQ) was higher than that to the lower inner quadrant.
- C-arm cross-table lateral projection was associated with higher breast radiation exposure than anteroposterior projection.
- Size, fit, and breast coverage of lead protection matter.
The findings should prompt redesign of protective aprons and vests to more effectively cover the breast and axilla. We could also use more well-designed longitudinal studies to identify the risk factors for neck, back, and shoulder injury as well as gain a better understanding of the real risk of surgeon exposure to intraoperative radiation.
Annual occupational radiation dose limits to the breast have not yet been established. But in the meantime, Valone et al. recommend distancing the axilla from the C-arm and placing the X-ray source beneath the operating table or on the contralateral side to reduce radiation exposure to the UOQ of the breast.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
Protecting Surgeons’ Hands from Radiation during Fluoroscopy
The In
ternational Commission on Radiological Protection (ICRP) currently recommends a maximum of 50 rem (500 millisieverts, or mSv) of occupational hand-radiation exposure annually. A fascinating study using a surgeon manikin, mini and standard fluoroscopic c-arms, and a Sawbones model of distal radial fracture fixation showed that hand-radiation exposure averaged 31 µSv per minute. That finding suggests that hand surgeons would not approach the ICRP-recommended hand-exposure limit unless they performed close to 2,000 hand procedures involving fluoroscopy each year. However, authors Hoffler et al. are quick to add that “the effect of consistent exposure that does not exceed the annual limit, but continues for a multiple-decade career, is unknown.”
It comes as little surprise that treating a distal radial fracture can be a high-exposure event. To quantify the situation more precisely, Hoffler et al. fit a surgeon manikin with radiation-attenuating glasses, thyroid shield/apron, and gloves, and measured radiation exposure with dosimeters placed on the manikin in both exposed and shielded positions. They exposed the Sawbones model and the manikin, which was in a standard seated position for hand surgery, to radiation from three mini and three standard fluoroscopes for fifteen minutes continuously. The authors explained their rationale for fifteen minutes of continuous exposure as follows: “The mean fluoroscopy time for volar radial plating at our institution is sixty seconds…It is common for hand surgeons to use a fluoroscope fifteen times a month…If exposures average sixty seconds each, the hand surgeon could be routinely exposed to fifteen minutes of fluoroscopy monthly.”
The authors found that hand exposure was 13 times higher than exposures at the thyroid, groin, or chest. The eyes, the second-most exposed site, received an average of 4 µSv per minute. Radiation-attenuating gloves reduced hand exposure by a mean of 69%, and radiation-attenuating glasses decreased eye exposure by a mean of 65%. There were no significant differences in hand exposure between the mini and standard fluoroscopes.
OrthoBuzz encourages orthopaedic surgeons to consider these findings in light of the current proliferation of fluoroscopes outside the OR, especially in office settings. For their part, the authors encourage surgeons to minimize their own and their patients’ radiation exposure “by understanding the basic physics of x-ray radiation and maximizing all of the safety technologies that their specific fluoroscopy units offer,” including the use of personal protective equipment.
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