Study design: A series of anterior-posterior and lateral fluoroscopic exposures at 5 spinal levels were performed on anthropomorphic phantoms simulating the 3 trimesters of gestation.
Objectives: To provide normalized data for the determination of conceptus dose specific to gestational stage and treated spinal level. To estimate the conceptus radiation dose and risk associated with typical fluoroscopically guided spinal treatments performed on the pregnant patient.
Summary of background data: To our knowledge, there are no available data on conceptus doses and radiogenic risks resulting from fluoroscopically guided spinal surgery of the expectant mother.
Methods: Direct measurement of conceptus doses from simulated fluoroscopic projections involved in orthopedic surgery at different spinal levels for the 3 trimesters of gestation with use of anthropomorphic phantoms and thermoluminescent dosimetry. Estimation of conceptus radiation risks from a typical pedicle screw fixation and kyphoplasty procedure using the experimentally derived data.
Results: Conceptus doses from fluoroscopically guided spinal treatments are smaller than 4 mGy during all gestational stages, provided that the conceptus lies outside the primarily irradiated region. The associated risks of fatal cancer during childhood and congenital malformation on its progeny are at least 2 and 1500 times, respectively, lower than the spontaneous incidence rates. When the embryo is primarily irradiated, mean conceptus dose can be as high as 105 mGy from a nonoptimized exposure. At least 35 minutes of fluoroscopy are required for the induction of deterministic effects.
Conclusions: Individual dose assessment is paramount in every pregnancy. Variations in fluoroscopy practices and gestational stage significantly affect fetal doses.