SLR - April 2022 - Kyle D. Miller
References: Guyonnet C, Mulliez A, Fessy MH, Besse JL. Prospective Analysis of Intraoperative Radiation Dose in Foot and Ankle Surgery Using Mini-c-arm Fluoroscopy. Continuous Series of 1064 Procedures. Orthop Truamatol Surg Res. 2021 Oct;107(6)Level of Evidence: Level IV
Scientific Literature Review
Reviewed By: Kyle D. Miller, DPM
Residency Program: INOVA Fairfax – Falls Church, Virginia
Podiatric Relevance: Over recent years there has been a resurgence and development of minimally invasive and percutaneous type procedures in foot and ankle surgery. With this comes increasing use of mini-C-arm fluoroscopy and subsequent exposure. Within the literature quantification of radiation exposure has been determined in other areas of orthopaedics revealing increase rates of breast cancer in females. This has not been looked at specifically for foot and ankle surgery procedures in recent years with development of improved mini fluoroscopy machines.
Methods: This was a single surgeon prospective study with patients undergoing foot and/or ankle surgery over a 3-year period (February 2014-December 2017.) The fluoroscopy machine utilized was the Fluoroscan InSight. The procedures performed were divided into three categories including forefoot, hindfoot/ankle and minimally invasive type procedures. For each procedure emitted dose DAP (cGy/cm2), radiation time and number of images were recorded from the mini-C-arm. Also, for all procedures three passive dosimeters were recorded in mSv located on: the thorax, eyes, and a ring for the hands. An active dosimeter was utilized to evaluate daily active or operational doses. All dosimeters were worn over leaded personal protective devices.
Results: Overall there were on average 266 procedures performed per year, totaling 1,064 procedures. The distribution of procedures was predominantly forefoot making up 64.4 percent, hindfoot/ankle 35.3 percent and minimally invasive only making up 0.3 percent. Because of the small number of MIS cases, they were grouped into the forefoot category. The hands were most exposed region (avg 1.28 mSv/year), followed by the eyes (avg 0.6 mSv/year). The overall average whole-body exposure was 0.31 mSv/year. It was found that isolated forefoot surgery was the least radiating with mean DAP of 1.1 cGy/cm2, mean radiation time of 7.8 seconds and mean number of images was 4.1. While TAR revision was the most irradiating with mean DAP of 20.1 cGy/cm2, mean radiation time of 78.9 seconds and mean number of images was 39.7.
Conclusions: In the present study the radiation dose to a single foot and ankle surgeon followed over a four-year period was found to be below the International Commission on Radiological Protection (ICRP) thresholds. The area of highest exposure was the hand at 1.28mSv/year with the thresholds established by the ICRP as 20 mSv/year for the whole body, 150 mSv/year for the thyroid and 500 mSv/year for the hands. This is something that has been scantly reviewed in foot and ankle surgery. There has been no true evaluation of radiation exposure with minimally invasive techniques and the present series had too few cases for any real conclusions to be drawn. It should be noted that surgeon experience and comfort level with certain procedures can drastically change the radiation level for any given case. The authors concluded that mini-C-arm should be used for foot and ankle surgery, when at all possible, in order to minimize radiation exposure to the surgical team and patient. The authors also concluded that traditional use of lead apron may be unnecessary depending on the type of surgery being performed.