C-arm Positioning is a Significant Source of Unnecessary Radiation Exposure

Presented at SMISS Annual Forum 2014
By Robert Isaacs MD
With Frank Phillips MD, Cary Idler MD, Kris Radcliff MD, Elizabeth Reiser , Sarah Byrd MSN, ANP-BC,

Disclosures: Robert Isaacs MD A; NuVasive. B; NuVasive, Providence Medical Technology. C; Association for Collaborative Spine Research. D; SafeRay Spine, LLC, SafeWire, LLC, VilaSpine LTD, Vertera Spine, Providence Medical Technol Frank Phillips MD D; Nuvasive, SI-Bone, Providence, Theracell, Vital 5, Spinal Motion, Spinal Kinetics, Axiomed, Cross Trees, F; Nuvasive, DePuy, Medtronic, Stryker, Cary Idler MD B; Nuvasive, Inc., Corelink, Kris Radcliff MD A; Depuy, Medtronic, Paradigm. B; Globus Medical, Inc., Depuy. F; Globus Medical, Inc., Elizabeth Reiser None, Sarah Byrd MSN, ANP-BC None,

Introduction:
It is well-known that radiation exposure during minimally invasive spine procedures can be substantial, but less interest has focused on the radiation exposure occurring in the OR before the procedure begins. Often, many images are taken even before the procedure commences, as the fluoroscope is used to determine proper entry points and angles needed for an operation.

Aims/Objectives:
Herein, we evaluate the amount of radiation exposure that occurs during the setup and positioning of the C-arm relative to the procedure as a whole.

Methods:
From an IRB-approved database of over 1100 orthopedic procedures, the minimally invasive spine cases for which set-up radiation was recorded were extracted. The amount of total radiation, set-up radiation, and type of procedure were evaluated. Statistics were generated using a chi squared analysis.

Results:
Setup and total radiation data were collected for 270 spine surgeries performed by four different surgeons at two locations. 30 surgeries were thoracic and 240 were thoracolumbar or lumbar. There were 78 anterior cases and 192 posterior cases. In total, the average radiation recorded during the entire procedure (set-up, positioning, and surgery) was 8.04 rad, of which the average amount used during set-up was 1.90 rad (28%, std 2.97 rad). For cases that only involved the thoracic spine, this percentage was 52% with averages of 3.07 rad for setup and 7.08 rad total. The lumbar and thoracolumbar cases averaged 25% for setup/total, 1.76 rad average setup for 8.16 total rad. Not only do thoracic cases get more than twice the setup/total percentage of what is obtained for a thoracolumbar or lumbar only case, but statistically they also get more overall radiation during this portion of the case (p=0.02). Having said that, the amount of positioning radiation during all procedures was over a quarter of the total for that procedure and not insignificant for any cases except simple decompressions.

Conclusions:
The radiation exposure induced during C-arm positioning can be substantial. This is especially true in thoracic cases because 90% of spine physicians in the United States use fluoroscopy to localize pathology in that region. Everyone in the OR including ancillary personnel should recognize the high percentage of radiation that occurs during positioning of a C-arm, and merit should be given to technologies that can help limit unnecessary radiation exposure during this portion of the procedure and not simply during the intervention itself.