Elsevier

The Spine Journal

Volume 14, Issue 9, 1 September 2014, Pages 1984-1990
The Spine Journal

Clinical Study
Management decisions for adolescent idiopathic scoliosis significantly affect patient radiation exposure

https://doi.org/10.1016/j.spinee.2013.11.055Get rights and content

Abstract

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.

Introduction

Evidence & Methods

The negative health effects of long-term exposure to ionizing radiation are well known. Patients with adolescent idiopathic scoliosis (AIS) have been shown to be at elevated risk of breast and thyroid cancer in the past. The impact of modern treatment algorithms, in terms of radiation exposure, remains unclear at present.

The authors retrospectively evaluated 267 patients treated nonoperatively, as well as surgically for AIS. They determined that patients treated surgically for AIS received as much as 14 times the radiation dose of individuals managed through nonoperative methods. Seventy-eight percent of radiation exposure in the operative group was due to fluoroscopy used at the time of surgery. The authors anticipate that the extent of radiation exposure in patients with AIS may elevate the lifetime risk of solid cancers to between 1.4% and 2.4%.

Although this was a retrospective cohort study, the findings are important from both a surgical, as well as a health policy perspective. In light of the topic, as well as the population under consideration, findings such as these may represent best available evidence. The authors correctly advocate that surgeons treating AIS patients need to be cognizant of cumulative radiation does at a minimum and carefully evaluate the strategic necessity of radiographs and computed tomography. The authors’ calls for broader approaches at the societal level and changes to postoperative surveillance algorithms are also laudable.

—The Editors

Adolescent idiopathic scoliosis (AIS) has a reported incidence of 25 adolescents per 1,000 in a population aged 10 to 18 years [1]. Full spinal radiographs in both posteroanterior (PA) and lateral projections remain central to the diagnosis and management of patients with scoliosis. Depending on the age, the initial curve magnitude, and any associated bracing or surgical interventions, patients may require repeated studies in intervals of 3 to 12 months. It has been estimated that the typical patient with scoliosis will have approximately 22 plain radiographic examinations over a 3-year treatment period [2]. As many as 618 plain films in a single patient have been reported [3], [4].

Multiple major scientific committee reports have shown that children are more sensitive to radiation than adults because they have more time to express a cancer and have more dividing cells on which the radiation acts [5], [6]. There is particular concern about the risk of breast cancer because progressive scoliosis is seen most commonly in the female population and the breast tissue of teenage girls is particularly sensitive to radiation [3], [6]. Nash et al. [7] reported a 110% increase in breast cancer risk after routine radiographic follow-up for AIS. Bone et al. repeated the study by Nash et al. almost 20 years later and found a 4.2% increased lifetime risk of developing breast cancer with a 3% increased risk of birth defects [8].

The magnitude of radiation exposure in the modern treatment of scoliosis is unclear. Although modern plain radiographic techniques have been able to reduce a patient's exposure, new diagnostic imaging technologies and surgical techniques such as intraoperative fluoroscopy, computed tomography (CT), and pedicle screw instrumentation necessarily increase a patient's exposure. The purpose of this study is to determine the average radiation exposure for a child undergoing management of AIS over a minimum duration of 2 years in the modern era.

Section snippets

Methods

In this institutional review board approved study, a comprehensive review of a single institution's medical records between September 2007 and January 2012 was performed. Patients were included if the patient was diagnosed and treated for AIS, were 9 to 18 years of age at the time of first evaluation, were managed with either nonoperative or operative means for their AIS, and were followed for a minimum of 2 years. Patients were excluded if they were diagnosed with neuromuscular scoliosis,

Results

Statistical significance was noted between groups with regard to the mean age at initial presentation (p<.001), the mean age at treatment completion (p<.001), the gender distribution among groups (p<.001), and the total number of months that each group was followed (p<.001) (Table 1). In the operative group, the average length of time that a patient was followed before surgery was 13.1±11.6 months, with an average of 3.9±2.8 office visits. Postoperatively, patients averaged 21.6±12.0 months

Discussion

The present study demonstrates that in the modern era of AIS treatment, pediatric patients continue to be subjected to a potentially hazardous amount of radiation. Most alarming are the differences in annual radiation exposure between treatment groups, with the operative group receiving upwards of 14 times the radiation dose of patients treated with nonoperative modalities. To put things into perspective, the standard background radiation exposure in North America is thought to be about 100

Conclusion

Surgically treated patients received significantly greater average annual radiation doses than braced or observed AIS patients. Braced patients received significantly more annual radiation exposure than patients who were simply observed. The vast majority (78%) of the average annual radiation exposure to the operative patient is derived from intraoperative sources. Surgeons should, therefore, be aware of the impact of intraoperative imaging for treatment of spinal deformity on the long-term

Acknowledgments

Special thanks to Matt Solomito for all of his hard work and dedication to orthopedic research.

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Cited by (0)

FDA device/drug status: Not applicable.

Author disclosures: SMP: Nothing to disclose. TK: Nothing to disclose. ML: Nothing to disclose.

The author (SMP) verifies that he had full access to all the data in the study and takes responsibility for the integrity of the data, the accuracy of data analysis, and the decision to submit for publication.

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