Background context: Adolescent idiopathic scoliosis (AIS) patients treated before the 1990s have a 1% to 2% increased lifetime risk of developing breast and thyroid cancer as a result of ionizing radiation from plain radiographs. Although present plain radiographic techniques have been able to reduce some of the radiation exposure, modern treatment algorithms for scoliosis often include computed tomography (CT) and intraoperative fluoroscopy. The exact magnitude of exposure to ionizing radiation in adolescents during modern scoliosis treatment is therefore unclear.
Purpose: To determine the difference in radiation exposures in patients undergoing various forms of treatment for AIS.
Study design: Retrospective cohort.
Patient sample: Patients aged 9 to 18 years with a diagnosis of AIS, followed and/or treated with nonoperative or operative management for a minimum of 2 years.
Outcome measures: Number of radiographs and total radiation exposure calculated.
Methods: The charts and radiographs of patients managed for AIS at a single institution between September 2007 and January 2012 were reviewed. Patients were divided into three groups: operative group, braced group, and observation group. Patient demographics, Cobb angles, and curve types were recorded. The number of radiographs per year that each patient received and the total radiation dose were recorded. The plain radiographic radiation exposure was then combined with the direct exposure recording from ancillary tests, such as fluoroscopy and CT, and a radiation exposure rate was calculated (mrad/y). A single-factor analysis of variance (α=0.01) with a Tukey honest significant difference post hoc analysis was used to test significance between groups.
Results: Two hundred sixty-seven patients were evaluated: 86 operative, 80 brace, and 101 observation. All groups had similar demographics and curve type distribution. The mean initial Cobb angle at presentation was significantly different between the groups: operative (57°±11°), brace (24°±7.9°), and observation (18°±9.4°) (p<.01). There was a significant difference among the groups in terms of the mean number of radiographs received per year; operative group, 12.2 (95% confidence interval [CI]: 10.8-13.5; p<.001); braced group, 5.7 (95% CI: 5.2-6.2; p<.001), and observed group, 3.5 (95% CI: 3.160-3.864; p<.001). The operative group received 1,400 mrad per year (95% CI: 1,350-1,844; p<.001), braced group received 700 mrad per year (95% CI: 598-716; p<.001), and observed group received 400 mrad per year (95% CI: 363-444; p<.001). Importantly, 78% of radiation in the operative group was attributable to the operative fluoroscopy exposure.
Conclusions: Significant differences exist in the total radiation exposure in scoliosis patients with different treatment regimens, with operative patients receiving approximately 8 to 14 times more radiation than braced patients or those undergoing observation alone, respectively. Operative patients also receive more than twice the radiation per year than braced or observed patients. Almost 78% of the annual radiation exposure for operative patients occurs intraoperatively. Because children are notably more sensitive to the carcinogenic effects of ionizing radiation, judicious use of present imaging methods and a search for newer imaging methods with limited ionizing radiation should be undertaken.
Keywords: Absorbed radiation dose; Adolescent idiopathic scoliosis; Brace treatment; Fluoroscopy; Radiation exposure; Treatment algorithm.
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