Background: The evaluation and treatment of patients with early-onset scoliosis requires multiple imaging studies and involves potential exposure to high cumulative lifetime doses of ionizing radiation. The Vertical Expandable Prosthetic Titanium Rib (VEPTR) used in the treatment of early-onset scoliosis requires numerous lengthening procedures and frequent radiographic follow-up. The purpose of this study was to quantify the ionizing radiation exposure in pediatric patients undergoing VEPTR treatment and to identify factors that place patients with early-onset scoliosis at greater risk of radiation exposure.
Methods: Data were collected by retrospective review of the records of all patients with early-onset scoliosis who were treated with a VEPTR over a 4-year period (2007 to 2010). Diagnostic radiographs, computed tomography, intraoperative fluoroscopy, and nuclear medicine studies were identified and analyzed for ionizing radiation exposure. Total radiation exposure was determined and compared for risk factors such as etiology (eg, neuromuscular or congenital) and surgeon experience. In addition, radiographic studies directly related and unrelated to scoliosis treatment were compared.
Results: Twenty-four patients had 121 surgical procedures (mean 5.0/patients) and 962 imaging studies (mean 40/patients). The mean estimated cumulative radiation dose per patient during follow-up was 86.7 mSv (range, 42.6 to 174.9 mSv) with a mean dose per year of 34 mSv (range, 22.9 to 47.1 mSv). Patients with congenital scoliosis received greater mean amounts of radiation (35.2 mSv) than patients with neuromuscular scoliosis (31.9 mSv). Patients treated within the first 2 years of the study period had higher radiation exposure (42.4 mSv) compared with patients treated in the last 2 years (24.9 mSv) (P<0.001).
Conclusions: Ionizing radiation is an inevitable side effect of the VEPTR treatment for early-onset scoliosis. There are differences in the amount and sources of radiation exposure between patients with early-onset scoliosis secondary to congenital and neuromuscular causes. Surgeon experience is correlated with decreased levels of radiation exposure. Awareness of the potential for high levels of radiation exposure, as well as patient and surgeon-related factors involved, may lead to more effective radiation-reduction strategies.
Level of evidence: Level IV--retrospective case study.