Adolescent idiopathic scoliosis (AIS) patients treated before the 1990s have a 1-2% increase in the lifetime risk of developing breast and thyroid cancer as a result of ionizing radiation from plain radiographs. While current radiographic techniques have been able to reduce the risks from plain films, modern treatment algorithms for scoliosis often include computed tomography and intra-operative fluoroscopy. The exact magnitude of the exposure to ionizing radiation by adolescents during modern scoliosis treatment therefore remains unclear.
A retrospective chart and film review was performed of AIS patients treated between 2007-2012, aged 9-18 yrs and followed for at least 2 yrs. The number of plain films for each patient was recorded along with radiation exposures from fluoroscopy and CT scan. Published data was used to estimate the radiation exposure from digital plain radiographs. Total radiation exposure per year was then calculated for each patient. Patients were divided into 3 treatment groups (operative, brace, observation) and a single-factor ANOVA (α=0.01) with a Tukey HSD post-hoc analysis was used to test differences.
267 patients were evaluated: 86 operative, 80 brace, 101 observation. All groups had similar demographics and curve types. There was a significant difference between groups in the mean number of plain radiographs received per year: operative (12.2), brace (5.7) and observation (3.5) [p<0.001]. The mean radiation exposure per year (mRad/yr) inclusive of all studies was significantly different between groups: operative (78,900), brace (446) and observation (274) [p<0.001]. Importantly, almost 99% of the radiation in the operative group was attributable to the operative fluoroscopy exposure.
Significant differences exist in the radiation exposure per year for scoliosis patients with different treatment regimens. Almost 99% of the annual radiation exposure for operative patients occurs during surgery. Since children are notably more sensitive to the carcinogenic effects of ionizing radiation, a search for imaging methods with limited radiation in the treatment of scoliosis is necessary.